NBSIR 77-1314

Solar Energy Systems - Survey

of Materials Performance

L. F. Skoda

L. W. Masters

Materials and Composites Section

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

October 1977

Final Report

Prepared for Energy Research and Development Administration

Division of Solar Energy

20 Massachusetts Avenue

Washington, D.C. 20545

NBSIR 77-1314

SOLAR ENERGY SYSTEMS - SURVEY

OF MATERIALS PERFORMANCE

L. F. Skoda

L. W. Masters

Materials and Composites Section

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

October 1977

Final Report

Prepared for Energy Research and Development Administration

Division of Solar Energy

20 Massachusetts Avenue

Washington, D.C. 20545

U S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Acting Director
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TABLE OF CONTENTS

Page

ACKNOWT .EDOVIENT iv

ABSTRACT . 1

1. INTRODUCTION 1

. 1.1 Background 1

1.2

Objectives 2

2. MATERIALS PERFORMANCE IN WORKING SOLAR SYSTEMS 3 2.1 Flat Plate Collectors 3 2.2 Concentrating and Evacuated Tube Collectors 8 2.3 Transport Subsystems 9 2.4 Storage Subsystems 10

2.5 Conclusions frcm Field Inspections 11

3. RESULTS OF LETTER SURVEY AND QUESTIONNAIRE 11

4. TEST METHOD STANDARDS FOR MATERIALS 19

4.1 Identification of Standards 19

4.2 Assessment of Standards 20

4.3 Conclusions Regarding Existing Test Method Standards 24

5. CONCLUSIONS AND RECOMIYIENDATICNS 33

5.1 Recatmended Priorities for the Development of Material Test

Method Standards 35

5.2 Recotmendations for Laboratory-Based Studies 36

6. GUIDELINES TO AID THE SELECTION OF MATERIALS FOR USE IN SOLAR ENERGY

SYSTEMS 52

7. REFERENCES 58

FIGURES 59

APPENDIX A 78

APPENDIX B 89
ACKNOWLEDGVIENT

The authors are indebted to many persons for contributions and guidance that made this

report possible. Special thanks are given to NBS staff members Paul Brown, Elizabeth

Clark, Robert Dikkers, McClure Godette, Arthur Hockman, Robert Stiehler , Elmer Streed, and

David Waksman, who helped in compiling information for the report, to the Energy Research

and Development Administration, which supported the study, and to Stanley Moore of Los

Alamos Scientific Laboratory, who provided valuable review carments.

Sheldon Butt, President, and John Blake, Executive Director, of the Solar Energy

Industries Association (SEIA) and the membership of SEIA are to be commended for their

support and cooperation.

The contributions of project managers and support personnel, who gave of their time

and knowledge in the field inspection effort and permitted the use of the photographs

included in this report are gratefully acknowledged.

Finally, a very special thanks is given to all of the manufacturers and installation

contractors of solar equipment and systems who completed the questionnaire.

iv
Solar Energy Systems - Survey of Materials Performance

L. F. Skoda

L. W. Masters

ABSTRACT

A study was performed to obtain data on the performance of materials in

operational solar energy systems, to identify and assess available standards

for evaluating materials, to provide reconTtiendations for the development of

test method standards for materials and bo provide guidelines to aid the

selection of materials for use in solar energy systems. During the study,

field inspections of twenty-five operational solar energy systems were

performed and a questionnaire was sent to 459 manufacturers and installation

contractors to obtain materials performance data. This report contains the

findings of the study. A primary conclusion is that the process of selecting materials for specific applications within solar energy systems is

hindered by the lack of an adequate data base of materials performance under

the conditions experienced in solar systems and subsystems. Recommendations

are made that would help in establishing an improved data base.

1. INTRODUCTION

1.1 Background

Standards for materials used in solar heating and cooling systems are urgently needed

to fulfill the goal of the Energy Research and Development Administration's (ERDA) National

Plan for Solar Heating and Cooling (ERDA-76-6) [1]—^ The goal as stated in the Plan is to

"stimulate the creation of a viable industrial and commercial capability to produce and

distribute solar heating and cooling systems and thereby reduce the demand on present fuel

supplies through widespread applications." The systems which are produced and installed

must be capable of meeting the expected heating/cooling requirements for the buildings in

which they are used and they must perform their functions for an acceptable period of time.

Widespread acceptance of solar heating and cooling systems is unlikely to be achieved until

adequate performance standards are established and compliance with these standards is

demonstrated. The achievement of the goal therefore hinges upon the development of standards

that ensure minimum acceptable levels of performance for solar heating and cooling systems.

Numbers in parentheses refer to references at the end of this report.

1
The performance standards must establish both measurements of initial properties and

measurements of long-term properties (e.g. materials properties after in-service or simulated

exposure)

.

Published information on solar systems generally describes the design and performance

of the systems with very little information on the materials problems encountered. Exceptions

are a number of National Science Foundation reports that did describe operational and

materials problems as well as the methods used to correct sane of the problems. Unfortunately,

most of the systems discussed had not been in operation for long so that an evaluation of

the durability/reliability aspects of material performance for any extended period of time was not possible. For those systems that have performed successfully for an extended

period, no recent evaluations of their material performance of system efficiency have been

made. Although feedback on materials performance in demonstration systems, sponsored by

the Department of Housing and Urban Development (HUD) and EFDA, will aid in developing a

data base of materials performance, standards are also needed to ensure adequate performance

and help in improving the data base.

There is an urgent need to identify needed standards and to develop priorities for

their development. This requires assessment of materials performance in operational systems

and assessment of available standards that may be useful for evaluating materials used in

solar energy systems.

In addition to standards, there is a need for guidelines to aid the selection of

materials for use in solar energy systems. These guidelines should provide for identification

of information regarding the ability of materials to perform the intended functions and

their durability/reliability, safety, maintainability, cost and compliance with local

building codes.

1.2 Objectives

The objectives of this study are 1) to obtain data on the performance of materials in

operational solar energy systems, 2) to identify existing standards for evaluating materials

and to assess the standards in terms of applicability to materials for use in solar systems,

3) to provide recommendations for the development of test method standards for materials

and 4) to provide guidelines to aid the selection of materials for use in solar energy

systems.

The project plan included a survey of published literature, field inspections of

twenty-five working solar energy systems and the sending of questionnaires to manufacturers

and installers of solar energy systems requesting information on materials usage and

materials problems encountered. It also included studies to identify and assess currently

available materials standards that might apply to solar energy systems, identify areas of

2
need for new standards, recommend priorities for the development of new standards and

future laboratory studies, and propose guidelines to aid the selection of materials for use

in solar energy systems.

2. MATERIALS PERFORMANCE IN WORKING SOLAR SYSTEMS

The field inspection phase of the project included visits to twenty-five active solar

system installations. The period of operation for the systems visited was from a few

months to over three years. The inspections revealed that many materials problems had been

encountered and that field expedient fixes had had to be made. In some cases, no adequate

fixes were possible because of basic design deficiencies. In retrospect, it was obvious

that design and materials performance can rarely be separated. In most cases, field

expedient fixes for failures were accomplished with readily available materials which were

not always the optimum solution to a problem. Unfortunately, seme of the projects visited,

which were sponsored by the National Science Foundation, were built this way originally,

i.e. readily available materials were used which did not always perform satisfactorily.

Field inspections of working solar systems revealed materials problems in all major

components of the various subsystems comprising solar systems. The emphasis in this

chapter is on the materials problems observed rather than those materials that are performing

adequately. The four subsystems into which solar systems can be divided are the collector,

transport, storage and control subsystems . Control subsystems will not be discussed in the

following evaluation of materials problems but the field study revealed that control

problems are numerous and could be the subject for a considerable investigation in itself.

The following discussions of observations made during the field investigation cannot

in every case be interpreted as evidence of materials "problems" at this time. Although

all problems identified are reported, the extent to which seme of them will indeed adversely

affect the long-term performance of the systems is not known.

2.1 Flat Plate Collectors

Collectors used in active (as opposed to passive) solar systems can be divided into

three basic types, i.e. flat plate, concentrating and evacuated tube. The majority of

collectors inspected were of the flat plate type (both liquid and air) . A small number of

concentrating and evacuated tube-type collectors were inspected and these problems will be

discussed separately. The following is a list of observed problems for each component of

collectors.

3
Cover Plates (General)

1. Condensation was observed on cover plates of 24 out of 25 systems inspected. The

amount and degree of condensation appeared to depend on the time of day and the design

of the collector (see fig. 2-1.) Condensation, such as that in figure 2-1, may affect

the transmittance of the cover.

2. Deposits were observed on the underside of cover plates that resulted either frcm

condensation (contaminant inclusion) or outgassing products from an internal source

(see figs. 2-2 and 2-3.) Such deposits may affect the cover plate transmittance.

3. There was a high incidence of dirt retention of the exterior surfaces of cover

plates. Dirt retention appears to be dependent on location of collector array and

local geographical conditions (see fig. 2-4.)

4. In one system, there was substantial dirt retention on the underside of the cover plate due to inproper sealing. The collectors were purposely not sealed to prevent

formation of condensation and allow the collectors to breathe (see fig. 2-5.)

Cover Plates (Inorganic)

1. Glass cover plate breakage, ranging from none to approximately 90% in one system, was observed. The breakage that occurred in the system with 90% failure was a double

cover system with both covers broken (see fig. 2-6.)

2. There appeared to be a higher incidence of glass cover breakage on a system that

used reflectors on a portion of the collector array as compared to those collectors

not subjected to added reflector radiation [2].

3. There was a complete adhesion loss in a system utilizing a heat trap adhered

between two cover plates (see fig. 2-7.)

4. A polymeric heat trap, under a glass cover plate, exhibited distortion and decomposition manifested in cover plate discoloration on a system exposed to several months

of no-flow conditions prior to activation (see figs. 2-1 and 2-3.)

5. Undersize glass, which was inproperly bedded and supported, allowed rain leakage

into absorber panels (see fig. 2-9) . This resulted in degradation of the absorber and

the collector enclosure.

4
Cover Plates (Polymeric)

1. Excessive warpage was observed in several systems using polycarbonate cover

plates (see fig. 2-10.) In one system where standoffs were used to prevent contact of covers and absorber plates, incompatibility between the polycarbonate cover and the

ethylene propylene diene monomer (EPDM) standoff was noted (see fig. 2-11) . In another system, contact between the absorber and cover resulted in cover plate damage

(see fig. 2-12)

.

2. Stress cracking of polycarbonate cover plates that had been designed with indented

sections to provide structural rigidity was observed. Approximately 60 to 70% of the

indentations exhibited stress cracking to a greater or lesser extent (see fig. 2-13)

.

3. Embrittlement resulting in complete failure of all covers in a system using a double layer of thin film poly (vinyl fluoride) was observed. Collectors had been

subjected to no-flow conditions for several months due to system failure (see fig. 2-

14).

Absorber Coatings (Selective)

In a majority of systems where selective coatings had been in service for a year or more color changes were apparent. The range of color change was from minor discoloration

to complete changes that gave the appearance of light tan colors (see fig. 2-15) . One

system that had been subjected to rain leakage as well as transfer fluid leakage exhibited

changes frcm black to light tan (see fig. 2-16) . It is not known, at this time, what

affect the color change has on the optical properties. Another system had extensive white

deposits on the selective coating that was not possible to identify. These deposits may

have been coating failures, effects of outgassing or transfer fluid leakage as a result of

corrosion (see fig. 2-17)

.

Absorber Coatings (Nonselective)

Peeling and cracking of nonselective coatings were observed in several cases. The

peeling and cracking seemed to be confined to absorber plate edges (within 2 or 3 inches of

the edge) and to the lower portions of the absorber plate (see fig. 2-18)

.

Absorber Plates

1. Leakage resulting from corrosion has been observed in several systems utilizing

aluminum absorber plates with integral fluid flow passages. These observed leakages

may not be the fault of the absorber plate itself and the cause of the corrosive

action may well originate in seme other component of the system (see fig. 2-19)

.

5
2. The insulation behind the absorber plates was visible through the cover plates in

two of the systems inspected. This condition could result in deterioration of the

insulation, excessive outgassing, and certainly reduces the absorber plate effective

area. The cause may be attributed to either dimensional tolerances of the absorber

plate, inadequate support or fastening of the plate to its supporting frame, thermal

changes or creep occurring after installation, or poor workmanship during assembly

(see fig. 2-20)

.

3. Separations of as much as 1/4" occurred between the tubing and absorber plates in

two systems that depended on intimate contact of tubing to absorber for transfer of

heat to the fluid (see fig. 2-21)

.

4. Extensive weld failures were observed in one system. The system was of aluminum

construction with the inlet and outlet tubing being welded to the absorber plate.

Threaded connections were then used to connect the inlet to the transport piping.

Overstressing of the weldments during the tightening of the threaded tubing to the

transport system was a possible cause for the failures (see fig. 2-22)

.

5. Instances of warped absorber plates were observed in several systems. Warpage was so extensive in several cases that the absorber plates came into physical contact

with polymeric cover plates resulting in cover plate fogging (see fig. 2-12)

.

Insulation

It was not possible to inspect the insulation used on all systems because most systems

are designed to provide protective covers or containment for insulation, but, several

problems were recorded with systems that had exposed insulation.

1. Exposed polyurethane foam was used in three of the systems inspected. In each

case, deterioration of the urethane, probably due to ultraviolet radiation, was

observed (see fig. 2-23)

.

2. In one case the system utilized fiberglass insulation on the back of the collector

with minimal restraint and no cover system. The insulation had separated and sagged

away from the back of the absorber plate so that the back of the absorber was easily

visible. This same system did not have any edge insulation (see fig. 2-24)

.

6
3. A problem of polyurethane insulation swelling had been reported [3] as having

occurred at one of the sites visited. Considerable damage had occurred as a result of

elevated temperatures that caused the foam to swell affecting other components of the

collectors. At the time of the inspection, the collectors had been rebuilt and no

further problems were apparent.

Seals

1. At one installation visited, the sealant used between the glass covers and the

wood and aluminum collector enclosure was a major problem. The gray-colored (probably

butyl) sealants used originally did not permanently seal the joints. The sealant

between the inner cover and the wood enclosure was very brittle and lacked adhesion to

the substrate. The sealant between the outer cover and either the wood enclosure or

the aluminum cross tee was very brittle and had cracked and shrunk due to weather

exposure. A number of the glass covers were undersized which meant that a joint of

3/4" to 1 1/2" had to be sealed. Thus not only was an inadequate sealant used but the

joints were often impossible to seal with any sealant. The unsealed joints permitted

water to penetrate into the collector interior (see figs. 2-9 and 2-25)

2. In another case, a butyl tape was used between the cover plate and enclosure.

This design was not meant to seal the enclosure with the thought that "breathing" of

the enclosure would eliminate or substantially reduce condensation formation. This

lack of sealing however resulted in the deposition of dust and dirt on the interior of

the glass covers and on the surface of the absorber plates (see fig. 2-5)

3. One site visited used a silicone sealant between the outer cover plate and the

aluminum retaining frame. Workmanship was excellent but potential problems may occur due to a discoloration of the sealant adjacent to the attachment bolts. The discoloration observed may be an indication of material degradation. Apparently a "hot spot" was created by the attachment bolts which is subjecting the sealant to deteriorating

elevated temperatures (see fig. 2-26)

4. Outgassing of improperly cured silicone sealant was observed. The outgassing

caused fogging of the cover plates (see fig. 2-3)

Enclosure

1. Of those enclosures constructed of galvanized steel or aluminum no materials

problems per se were obvious. Design changes with respect to connections and/or

joints in metallic enclosures in seme cases however could have improved the collectors

ability to perform satisfactorily for a longer period of time.

7
2. In one case, the collectors were made of wooden restraining frames with plywood

backing. The painted wood collector frames had deteriorated because the paint coatings

had peeled and cracked exposing the wood to the elements. The surface condition of

the painted wood in the interior of the collector was worse than that of the exterior

membranes. The plywood backing had not been painted and was deteriorating and delaminating due to moisture penetration even though these collector backs were not subjected

to direct weathering. The condition of the wood indicated that it will probably

require major repair or replacement within 2-3 years (see fig. 2-27)

.

Structural Support

Those structural support members made of metallic materials seemed to be performing

satisfactorily. Of those structural support members utilizing wood construction it was

obvious that more maintenance (frequent repainting) would be required to attain the same expected life as their metallic counterparts. On several systems it seemed as though wood

was used for low first cost with no regard to long-time durability/reliability.

Reflective Surfaces

Two flat plate collector systems were inspected which used reflective surfaces.

Figure 2-28 shows problems observed on one of the reflective systems. The surface irregularity

resulted from difficulties in applying self-adhering aluminized film. Subsequent loss of

adhesion required the addition of batten strips.

2.2 Concentrating and Evacuated Tube Collectors

Concentrating and evacuated tube collector systems have unique materials design

problems when compared to flat plate collector systems because of the much higher temperatures

generated in such systems, particularly during stagnation conditions. Component and

materials surface temperatures developed in concentrating and evacuated tube systems are difficult to accurately measure; therefore designs must rely on calculated expected limits

of temperature.

Of the two concentrating systems inspected, one contained a bank of small follow-thesun collectors with the other being an experimental system where the entire roof of the

building was designed to focus radiation to a moveable tube that was elevated above the

roof. Neither system had been in service long enough to have had durability/reliability

problems with materials. In both cases, the primary problems were in the controls and the

mechanical system used to track the sun (see figs. 2-29 and 2-30)

.

8
Two systems utilizing evacuated tube collectors were visited. Of the problems encountered and those described by the owners, the primary cause of failures can most generally

be attributed to over temperature of materials or components during operation or during

times of stagnation conditions. Problems encountered include leakage, gasket hardening,

dimensional tolerances, tube breakage, tube coating discoloration, dirt accumulation in

filter tubes, air entrapment, pump cavitation, manifold insulation discoloration, and

system operational control problems (see fig. 2-31)

2 . 3 Transport Subsystems

The greatest single problem encountered in regards to transport piping was the flexible

hoses at inlet and outlet couplings of flat plate liquid collectors. At every site visited

where flexible coupling hoses were used, leakage problems have occurred to a greater or

lesser degree. Causes for leakage have been attributed to age hardening and loss of

elasticity, plastic flow of hose materials through slotted holes of gear-type clamps resulting in reduced clanping forces, cumulative slippage of hoses due to thermal movements of

collectors and ozone or ultraviolet attack of hoses exposed to weathering. Also, it was

reported that it is sometimes difficult to replace collectors that are attached with rubber

hoses because of the tightness of the hose/hetal bond. Attempts to solve these problems

ranged frcm application of sealants and adhesives to the exterior of leaking hoses to the

complete replacement of organic hoses with metallic couplers (see figs. 2-32 and 2-33)

Figure 2-34 illustrates a design problem. The hose to collector connection was placed

inside the collector enclosure making it difficult to tighten the hose connection or replace the hose.

Several other problems were apparent as regards flexible hose couplings. In many

cases the hoses were not insulated resulting in heat losses and weathering deterioration

(see fig. 2-35) . In one case, where coiled copper connections were used to replace flexible

hoses, the insulation at the transport piping was not sealed allowing water to enter the

insulation resulting in additional heat losses (see fig. 2-33) . At another side, different

paint coating systems were used to protect the cellular insulation surrounding the hose

connections. In one case, the insulation became enbrittled and cracked while the same insulation coated with a different material remained flexible with no damage to the insulation

(see figs. 2-36 and 2-37)

On another system (not inspected but described by an installation contractor) , a

solder joint failure occurred in the transport piping due to poor workmanship. Inclement

weather necessitated the system to be drained and secured for several months before repairs

could be made. The resulting stagnation conditions caused the cover plate material to fail

completely which damaged the absorber plates to the point where the entire collector system

had to be replaced.

9
Another potential problem in piping is the use of dissimilar metals within the system.

The use of aluminum, copper and steel pipes in conjunction with galvanized connections,

brass and steel valves, and steel or aluminum storage tanks was not unusual. Such conditions can lead to corrosion problems, especially in closed loop systems where metal ions are

recirculated. Systems using dissimilar metals must be designed as carefully as possible

taking into account the area ratio of one metal to another so that the proper inhibitor

materials can be added and periodically adjusted to reduce corrosion to a minimum.

Pump problems were encountered at two of the sites visited. In one case, a substitution was made for the particular pump specified, due to time constraints of the project and lack

of availability of the proper pump. The substitute pump used a controlled leakage stuffing

box system on the main shaft. Leakage occurred during periods when the pump was not running

so that ingested air was present on start up. The air tended to damage the packing and

increase the leakage rate resulting in an unusual amount of required maintenance. Replacement of the pump with a sealed shaft system solved the problem.

The other pump problem occurred on a sealed shaft unit. Leakage occurred that was

traceable to deterioration of the impeller shaft packing material by the high concentration

of chromate inhibitor used in the system. The solution to this problem was to fabricate a system that allowed the material to be washed with untreated water.

2 . 4 Storage Subsystems

Of the systems inspected, only three storage subsystem problems were encountered. The

most serious problem occurred at a site that used two concrete transformer vaults for

storage of liquid. In this particular case, project time and financial constraint resulted

in the selection of transformer vaults to expedite completion of the project on schedule.

Leakage frcm the two 4,000 gal capacity vaults occurred at varying rates of from 40 to 50

gals a day and appeared to be related to the temperature of the stored liquid. Repairs to

the tanks were initiated and the leakage rate was greatly reduced but not eliminated.

The other two storage problems had to do with the tank insulation. In one case a liquid leak frcm a tank connection resulted in the deterioration of vermiculite plaster

insulation used on the ends of the cylindrical roof mounted tank (see fig. 2-38) . In the

other case, an insufficient amount of insulation was used on three buried tanks resulting

in excessive heat losses. This was evidenced by the fact that the earth cover did not

support the growth of vegetation. This heat loss was also substantiated by the rapid

drying of the area above the buried tanks after a rain storm when compared to adjacent

areas.

10
2.5 Conclusions from Field Inspections

The observations made during the field inspections illustrate that numerous material

related problems have occurred in operational solar energy systems. Field problems were

identified in each of the major subsystems, collector, transport and storage, of one or more of the solar energy systems surveyed. Also materials problems were identified for

most components within the subsystems. For example, problems were identified in one or

more collector subsystems with materials used for cover plates, absorptive coatings,

absorber plates, insulation, seals, enclosures and structural supports

Although some of the observed problems result from improper design considerations,

most result from inadequate resistance of materials to the exposure conditions experienced

in the solar systems. Recommendations to reduce the extensive field problems reported in

this chapter are provided in Chapter 5 of this report.

3. RESULTS OF LETTER SURVEY AND QUESTIONNAIRE

A questionnaire accompanied by appropriate instructions and an explanatory letter

describing the scope of the project was sent to the 459 manufacturers and installers of

solar equipment. The primary purpose of the questionnaire was to obtain data on materials

performance in operational systems. A questionnaire, instructions and sample letter are included in Appendix A. The mailing list is included in Appendix B. The questionnaire,

titled "Data Sheet for Operational Solar Energy Systems" is divided into five parts. Part

I identifies the respondent, Part II identifies the location, age and function of the solar

systems, Parts III, IV and V deal with the materials used in the collector, thermal storage

and energy transport subsystems, respectively.

Of the 459 questionnaires sent out, 136 responses were received. Sixty-five responses

did not contain usable information on materials performance. Twenty-one questionnaires were returned as not deliverable due to either change in address or the fact that the

company was out of business. Fifty responses contained usable materials performance information and of those fifty, twenty-one were from installation contractors, eighteen were

from manufacturers, and eight responses were from companies that both manufactured and

installed solar equipment. Three respondents failed to indicate whether they were manufacturers or installers.

Part II of the questionnaire was to identify the location, age and function of the

solar systems reported. Table 3-1 is a resume of the responses to Part II by the fifty

respondents that presented usable information. The questionnaire did not specify solar

swimming pool heaters but information on such heaters was included in a number of questionnaires

One manufacturer indicated that his company had installed over 200 swimming pool heaters

but did not indicate the age of any of them. Another manufacturer indicated that approximately 30 swimming pool heaters were installed that had been in service for one to two

11
Table 3-1. Summary of Responses to Questionnaire —

System Function and Time in Operation

Operation

Time (Years)

Function Domestic

Hot

Water Heating Cooling

Swiirming

Pool

Heat Total

0-1 86 33 7 8 134

1-2 17 10 1 30 58

2-3 12 7 2 0 21

3-4 1 1 0 0 2

Undated 6 6 1 201 214

Total 122 57 11 239 429

12
years. Except for pool heaters, the greatest number of solar devices reported on were

domestic hot water heaters that are less than one year old. The next most ccmmon solar

device reported were home heating systems with the least information beingreceived on heme

cooling systems.

Table 3-2 lists the types of collectors reported on and the materials that were used

in the collectors as reported in Part III of the questionnaire. The dominant collector

system was the flat plate, liquid type, which comprised 134 systems. Seventeen flat plate

air systems were reported on with only three concentrating collector systems reported.

The listings in table 3-2 include the liquid transfer medium used, cover plate materials, cover plate reflective coatings, absorber coatings and substrate, fluid passages that

differed from the absorber substrate, gaskets and sealants, insulation, enclosure materials,

reflector materials and the dessicants used.

Table 3-3 lists the types of thermal storage units reported on and the materials used

in the thermal storage units as reported in Part IV of the questionnaire. Table 3-3 also

includes the use conditions, storage medium, insulation, gaskets and sealants and those

storage units that were designed with integral heat exchangers. The predominant system was

steel tanks for the storage of liquid, insulated with glass fibers and located in a shelter

above ground. Since 75% of the storage systems reported were steel tanks, table 3-4 is a resume of the location, interior lining and insulation used in these systems.

Table 3-5 lists the materials used in the transport subsystems reported on in Part V

of the questionnaire. Copper piping was used in 68 of the 113 systems reported. The

connections were predominantly rigid and the insulation material used most often was foam

rubber. Of all the systems reported on, 14 included filters or getter columns.

The data presented in tables 3-1 through 3-5 do not reflect all questions asked in the

questionnaire. The last three questions in Parts III, IV and V are directed toward any

problems that may have been encountered during the operation of the solar systems. Of the

fifty questionnaires used in the compilation of data, positive responses to these questions were received in thirteen cases. Six manufacturers, five installation contractors and two

respondents that are both manufacturers and installation contractors indicated some problems.

Ten problems that required repair or replacement of collectors were reported, corrosion was

reported in four cases, transport system repairs were required in four cases and only one

storage problem was reported.

13
Table 3-2. Summary of Responses to Questionnaire — Collector Information

Type

Flat plate

Liquid, open

Liquid, closed

Air

Concentrating

Liquid Transfer Medium

Type

Water

Ethylene glycol/water

Propylene glycol/water

Other

Cover Plates

Glass

Tempered glass

Poly (vinyl fluoride)

Vinyl tube

Fiber reinforced polyester

Polycarbonate

Acrylic

Fluorinated ethylene propylene

Poly (ethylene terephthalate)

Poly (ethylene) heat trap

Cellulose acetate butyrate

Reflective Coatings

Aluminum

Acid etch

Absorber Coating/Substrate

Aluminum

Copper

Steel

Plastic

Unknown

134

28

94

12

3

Total

70

26

10

6

Primary

45

30

4

422

115

0

0

0

1

3

4

Selective

8

7

9

0

0

With Additives

714

0

4

Secondary

14

9

4

0

1

0

0

3

4

5

0

Nonselective

46

32

61

5

Dye in Fluid

0

00

0

4

14
Table 3-2 . (continued)

Fluid Passages Different Than Absorber Substrate

Copper/aluminum

Copper/steel

Gaskets/Sealants

Silicone

Neoprene

Butyl

Polysulfide

EPDM

RTV

Cork

Insulation

Glass fiber

Urethane

Cellulosic

Mineral wool

Isocyanurate

Polystyrene

Enclosure

Metal

Aluminum

Galv. steel

Steel

Stainless steel

Copper

Plastic

Vfood

Reflectors

Muminum

Dessicants

23

2

60

13

8

4

6

21

72

23

87

7

5

52

21

9

2

3

2 26

Silica gel

( Passage/Substrate

)

15
Tank or Container

Table 3-3. Summary of Responses to Questionnaire

Thermal Storage Information

Composition

Steel 82

Concrete 23

Wood 2 Fiber reinforced polyester 3 Use

Buried 17

Above ground sheltered 55

Above ground unsheltered 9 In basement 22

Storage Medium

Liquid 98

Aggregates 12

Insulation

Glass fiber 63

Urethane 17

Polystyrene 11

Cellulosic 1

Mineral wool 1 Foamed glass 1 Foamed rubber 1 Isocyanurate 1

Gaskets/Sealants

Silicone 1 Rubber 1

Storage Units with Heat Exchangers 43

16
17
Table 3-5. Sunrtary of Responses to Questionnaire

Transport Subsystem Information

Piping/Ducting

Copper 68

CFVC 19

Sheet metal (air) 8 Poly (ethylene) 4 Steel 4 Aluminum 4 Poly (vinyl chloride) 4 Neoprene 1

Aluminum faced fiber glass (air) 1

Connections

Rigid

Soldered 57

Bonded 27

Threaded 15

Bolted 5 Flexible

Metal 15

Rubber 9

Insulation

Foam rubber 68

Glass fiber 16

Urethane 6 Neoprene 2 Isocyanurate 4

Gasket/Sealants

Neoprene 4 Silicone 4 Teflon tape 2 Epoxy adhesive 1

Transport with filters or getters 14

18
The number of reported problems seems to be small when compared to those observed in

the field inspection phase of this study. There are several possible explanations for this

inconsistency: 1) neglecting swimming pool heaters and undated responses, over 85% of the

systems reported on were less than two years old and problems may not occur in such short

times on many systems, 2) problems may have been considered insignificant and not worthy of

reporting unless a considerable reduction in efficiency was reported by the user, 3) the

materials used in systems reported on in the questionnaire may have been much better

performers than those in systems actually inspected, 4) problems may have occurred but went

undetected by those responding to the questionnaire and 5) respondents to the questionnaire

may not have reported all known problems. In sunmary, the questionnaire results did not

yield the materials performance data which had been anticipated. The data obtained,

however, are useful in identifying the types of materials that are currently being used in

operational systems.

4. TEST METHOD STANDARDS FOR MATERIALS

Numerous standard methods of test for materials have been developed by standards

setting organizations such as ASTM (American Society for Testing and Materials) , ANSI

(American National Standards Institute) and ISO (International Organization for Standardization)

Also test methods are available in trade association specifications and guidelines and in

Federal and military specifications and standards.

The purposes of this chapter are to identify available standards for materials cotmonly

used in solar energy systems and to assess the standards in terms of their applicability to

materials used in solar energy systems.

4.1 Identification of Standards

Tables 4.1 through 4.7 include test methods for materials comronly used in solar

energy systems: coatings, fluids, glass, insulation, metals, plastics and rubbers. The

tables divide test methods according to the type of test. Reference [4] also identifies numerous standard test methods for building materials.

Each of the types of materials nay be used in many ways within solar energy systems.

For example, coatings may be used as absorbers of solar energy, as reflective or antireflective surfaces and as protective coatings for system components. Fluids may be used

for transporting and storing energy. Typical applications of glass include cover plates,

absorber substrates and fluid conduits and containers. Insulation materials are used in

collectors as well as with transport and storage subsystems. Metals may be used in collectors

as absorber plates, enclosures and structural supports, in transport subsystems as piping

19
and connections and in storage subsystems as heat exchangers, connections and tank materials.

Metallic solders may also be used to join metallic components. Plastics may be used in

collectors as cover plates, absorbers and enclosures, in transport subsystems as piping and

connections and in storage subsystems as heat exchangers, connections and tank materials

and liners. Rubbers may be used as seals, adhesives and flexible couplings throughout

solar energy systems.

4.2 Assessment of Standards

Test methods for evaluating materials used in solar energy systems must be based upon

the properties that are important and the exposures expected in service. In order to assess the applicability of existing standards to materials used in solar energy systems,

the use of the material must be considered. For example, test conditions for evaluating

the thermal stability of absorber coatings will be different from test conditions for

evaluating exterior protective coatings.

The remainder of this chapter will consider the applicability of existing materials

standards to specific applications of materials in solar energy systems. Test methods

relative to the primary performance requirements will be included. The test methods will

be classified either as property measurement tests or aging tests. Property measurement

tests provide a means of measuring specific properties of materials, such as adhesion,

impact resistance, strength, color, etc. Aging tests are tests which provide for exposure

of materials to environments which may change their initial properties. By measuring a

property or group of properties before and after aging, the effect of the aging test can be

determined.

4.2.1 Coatings

The key properties of absorber coatings are absorptance, emittance and adhesion. Test

methods for measuring optical properties are listed in table 4.1 and are judged to be

applicable to solar absorber coatings. However, the standard method for measuring reflectance (ASTM E424) , which is used to calculate absorptance, involves costly instrumentation

and the lack of a suitable standard coating has led to questions regarding the comparison

of values obtained using different instruments. For absorber coatings which are protected

from the exterior atmosphere by cover plates, the primary factors that should be included

in aging tests are elevated temperature, temperature cycles, weathering (particularly

ultraviolet radiation) and humidity. Existing accelerated methods for these factors, as

listed in table 4.1 under moisture, thermal aging and weathering, have been developed for

coatings other than absorber coatings. Methods for determining the effects of moisture,

such as ASTM D1735 and D2247 and Mil. Std. 8 IOC are probably useful in evaluating absorber

coatings. However, the effects of moisture in combination with elevated temperature should

20
be considered. Energy methods for thermal aging and ultraviolet stability are not directly

applicable to absorber coatings. Thermal aging tests do not include temperatures as high

or as low as those observed in service. One problem which can result from thermal instability

is called outgassing in which degradation products affect the performance of other components.

Accelerated methods for radiation exposure using carbon or xenon arc exposure do not include a simulated cover plate and do not include temperatures to simulate those obtained on

absorber coatings. For coatings designed to be in direct contact with heat transfer liquids,

a test is needed for compatibility of the coating and liquid. Also outdoor exposure tests

do not simulate in-service exposure of absorber coatings. One additional consideration is

that many of the existing test methods are designed for either specific coatings or specific

substrates. It is not known if these methods are applicable to other coatings or substrates.

The key properties of reflective or anti-reflective coatings are optical properties

and adhesion. Optical properties may be measured by the methods listed in table 4.1.

Adhesion test methods are seldom completely satisfactory but can be used for comparing the

relative adhesion of various coatings. The primary factors which could affect the properties

of reflective or anti-reflective properties are the same as those for absorber coatings.

As with absorber coatings, the existing test methods do not include temperatures which

simulate in-service exposure. This leads to questions regarding the applicability of the

methods in evaluating the effect of temperature and ultraviolet radiation. The resistance

to humidity can probably be determined using the same methods mentioned for absorber

coatings

Protective coatings for collector components can be evaluated as exterior coatings for

buildings would be. The aging tests for resistance to atmospheric pollutants, impact,

moisture, thermal aging and exterior weathering may be useful. Protective coatings for use

in direct contact with transfer or storage liquids must be tested for compatibility. A

standard test method for this is not available.

4.2.2 Fluids

A number of properties of liquid transport or storage fluids may be evaluated using

the methods in table 4.2. Aging tests for fluids should include the effect of elevated

temperature and temperature cycles and compatibility with adjoining materials. Standard

test methods for thermal stability of fluids are not available. Compatibility of fluids

with metals is discussed in 4.2.5 and with rubbers in 4.2.7.

21
4.2.3

Glasses

Table 4.3 lists test methods for glass. As indicated in Chapter 2, the differential

coefficients of expansion between glass covers on flat plate collectors and the collector

enclosure can lead to glass breakage. Assuming this problem has been overcome through

design considerations, a primary concern with glass covers is inpact resistance, particularly

hail impact. The inpact tests listed in table 4.3 may be useful for comparing the relative

impact resistance of various types of glass. These methods, however, have not been shewn

to relate to hail impact. Another concern, particularly with evacuated tube collectors, is

burst strength or shattering initiated near defects.

4.2.4 Insulation

Table 4.4 lists test methods for insulation. The key thermal property of insulation

is thermal conductivity, which indicates the ability of the insulation to prevent heat

losses. It can be measured by the methods shown in table 4.4.

In addition to thermal properties, insulation for use in solar collectors must be

highly resistant to changes in chemical composition and physical dimensions. Chemical

stability ensures functional performance and compatibility with surrounding components over an extended service life. Physical (dimensional) stability is essential to ensure that a physical barrier of constant volume is maintained between two substrates which are thermally

different, and also, to ensure that the enclosure is not subjected to excessive pressures.

For insulation not exposed to the exterior atmosphere, moisture and elevated temperature

are the primary factors that should be included in aging tests. The procedures outlined in

Mil. Std. 810C should be useful if the test temperature is altered to reflect that obtained

in solar applications. A test method is needed to determine the effect of degradation

products at elevated temperature on other components

.

For insulation exposed to the exterior environment, aging tests should include ultraviolet radiation and possibly atmospheric pollutants in addition to those factors mentioned

above. The test methods listed under resistance to weathering may be useful for exterior

exposures.

Insulation buried in soil must be compatible with constituents of the soil. A test to

determine this compatibility is needed.

4.2.5 Metals

Table 4.5 lists test methods for metals. The primary concern regarding the use of

metals is corrosion. This is particularly true for collector, transport and storage

22

1
subsystems in which metals are in direct contact with heat transport or storage liquids.

Although numerous test methods for corrosion are included in table 4.5, none are completely

adequate for ensuring long-term corrosion-free performance. The corrosion tests listed in

table 4.5 may be useful for ccttparing the relative corrosion resistance of various metals.

To obtain accurate predictions of long-term performance, however, tests should include

temperature, flow rates and additives to more closely simulate service conditions.

The extent of corrosion is often evaluated by visually examining the metals before and

after aging tests. In a laboratory test or in an actual solar energy system, visual

inspections are often difficult or impossible to perform. Often corrosion is not obvious

until leaks occur. A nondestructive test method other than visual inspection is needed for

determining if corrosion is occurring on the interior of enclosed metallic components.

4.2.6 Plastics

Table 4.6 lists test methods for plastics. The key property of plastics for use as cover plates is transmittance. However, other properties such as abrasion resistance,

embrittlement, impact strength and warping may be important for seme materials. Property

measurement tests in table 4.6 should be useful with the possible exception of abrasion

resistance. Most plastics would be expected to perform poorly with existing abrasion tests

and the results may not adequately reflect performance in service. The primary factors

that should be included in aging tests of plastic covers are elevated temperature , temperature cycles and weathering resistance (particularly ultraviolet radiation exposure)

.

Existing tests for thermal aging of plastics do not include temperatures that simulate inservice solar exposure. Thus, they are not directly applicable to plastic covers. Accelerated radiation exposures using carbon or xenon-arcs likewise, do not include temperatures

experienced in service. Outdoor exposure tests provide for exposure of plastics but not in

the configuration used in solar collectors. This results in lower exposure temperatures

than would be experienced in service.

Plastics are used as absorbers or absorber substrates in some commercial collectors.

The key to the long-term performance of plastics in these applications is thermal stability.

Existing tests for thermal stability are not directly applicable unless the maximum inservice temperature is less than that specified in the tests. In addition to thermal

stability, weathering resistance (particularly ultraviolet radiation exposure) may be

important. Applicability of tests for weathering resistance is also dependent upon the

relationship between the maximum service temperature and the test temperature.

Plastics for use in exterior applications, such as collector enclosures may be evaluated

by existing tests. As with most materials, however, there is seldom a satisfactory relationship between accelerated tests and in-service exposure. These tests may be useful for

comparing the relative performance of plastics under identical exposure conditions.

23
For plastics used in direct contact with transport or storage liquids, the key aging

test involves determining the compatibility between the plastic and the liquid under service

conditions. Tests are needed in this regard.

4.2.7 Rubbers

Table 4.7 lists test methods for rubbers. Rubber materials are typically used as

seals, flexible coupling hoses and adhesives. For sealing, properties such as adhesion,

compression set, hardness, tensile strength and ultimate elongation are particularly

important. These properties may be measured by existing tests. Primary factors which

should be included in aging tests include atmospheric pollutants (particularly ozone)

,

moisture or liquid immersion (particularly for hydraulic seals) , elevated and depressed

temperature, temperature cycles and weathering resistance (particularly ultraviolet radiation)

.

Existing tests as outlined in table 4.7 may be useful providing the test temperature is

modified to reflect the temperatures experienced in service. A test method is needed to

determine the effect of degradation products at elevated temperature on other components

.

Important properties of flexible coupling hoses include compression set, creep, extensionrecovery, strength, hardness, tear resistance and ultimate elongation. These properties

may be measured by existing tests. Primary factors which should be included in aging tests

include atmospheric pollutants (particularly ozone), liquid immersion with transfer fluids,

elevated and depressed temperature, temperature cycles and weathering resistance (particularly ultraviolet radiation) . The types of aging tests listed in table 4 . 7 may be useful

provided the test temperature is modified to simulate in-service exposure. In addition to

the factors listed above, the clamping mechanism used on rubber hoses can affect their

long-term performance. The use of clamps needs to be addressed in standards in such a way

that field problems can be avoided.

Properties of adhesive bonds which are particularly important are flexural, shear and

tensile strengths. These may be measured with existing tests. The key factors which

should be included in aging tests are moisture resistance, elevated temperature, temperature

cycles and possibly creep, if sustained loads are applied. Existing aging tests may be

useful if test temperatures are modified to reflect service conditions.

4.3 Conclusions Regarding Existing Test Method Standards

It is obvious from the lists in tables 4.1 through 4.7 that many test method

standards for materials are available. Although many of the property measurement tests are apparently applicable to materials used in solar energy systems, most aging tests are not

directly applicable. In some cases, modification of the exposure conditions may result in

acceptable aging tests but laboratory verification is needed of the modified tests. A

number of new tests are also needed as outlined in 4.1 through 4.7.

24
Table 4.1. Existing Test Methods for Coatings

Type of Test

Abrasion, resistance to

Adhesion

Atmospheric pollutants, resistance to

Cleanability

Color change

Corrosion resistance

Flairmability

Flexural strength

Fungus resistance

Gloss

Impact resistance

Moisture, resistance to

Optical properties

Permeability

Physical integrity

checking

cracking

Scratch resistance

Surface uniformity

Tensile strength

Thermal aging, resistance to

Thickness

Weathering, resistance to

Test Designation

ASTM D658, D968, Fed. Std. 141a

ASTM B571, C633, D2197, D3359, ISO 2819

ASHVl B117, B287, D1543, D1654, D3129, Gl,

G33, Fed. Std. 141a, Fed. Specs. TT-P-31D,

TT-P-103B, TT-C-530A, TT-C-00498A, TT-E-516A,

TT-E-522A, TT-P-102D

ASTM C756 , D2486

ASTM D1535, D1543, D1729, D2244, D2616,

G45

ASTM B117, D1014, D1654, D2933, Gl, ISO 1462

ASTM D1360, E162, E286

ASTM B571, D522, D1737, Fed. Std. 141a

ASTM D3129, D3272, D3273, G21, Mil. Std.

810C, Fed. Std. 141a, Fed. Specs. TT-P-31D,

TT-P-51D, TT-P-61E, TT-P-71E, TT-P-81E,

TT-P-19C , TT-P-55B

ASTM D523 , D1471

ASTM D1474, D2794 , D3170, SAE J400

ASTM D1010, D1187, D1735, D2246, D2247,

D2366, D2932, Mil. Std. 810C, Fed. Specs.

TT-P-641F, TT-C-1079A

ASTM E97, E424, E434

ASTM C355, D1653, E96

ASTM D660

ASTM D661

ASTM D2197

ASTM E136

ASTM D522, D1737, D2370

ASTM D2246, Mil. Std. 810C

ASTM B567, D1005, D1186, D1400, E376, ISO

2178, 2360, 2361

ASTM D822, D1006, D1014, D2620, G7, G23,

G24, G25, G26, G27, Mil. Std. 810C, Fed.

Std. 141a, Fed. Specs. TT-P-31D, TT-P-61E,

TT-P-71E, TT-P-81E, TT-C-530A, TT-P-19C,

TT-P-55B, TT-P-95B, TT-P-1181A, TT-C-00498A,

TT-E-516A, TT-E-522A, TT-P-37C, TT-P-102D

25
Table 4.2. Existing Test Methods for Fluids

Type of Test

Analyzing stress

Annealing point, strain point

Atmospheric pollutants, resistance to

Coefficient of expansion

Creep

Density

Fatigue

Flatness

Flexural strength

Inpact strength

Indentation hardness

Optical properties

Softening point

Thermal aging, resistance to

Thermal conductivity

Thermal shock

Young's modulus, shear modulus, Poisson's

ratio

Test Designation

ASTM F218

ASTM C336, C598

ASTM C724 , 0. 111 , ISO 1776

ASTM C824 , E228, E289

Fed. Spec. DD-G-1403

ASTM C693, C729

ASTM C314

ASTM C158

ANSI Z97.1, Fed. Std. 406

ASTM Cl 30

ASTM E424

ASTM C338

ANSI Z97.1

ASTM C177, C408

ASTM C149

ASTM C623

26
Table 4.3. Existing Test Methods for Glasses

Type of Test Test Designation

Ash content ASTM D482, D1119

Autoignition temperature ASTM D2155

Boiling point ASTM D1120

Color

Corrosivity ASTM D807, D2688, D2776, D3263

Expansion coefficient ASTM D1903

Fire point ASTM D92

Flash point ASTM D56

Foaming ASTM D1881

Freezing point ASTM D1015, D1177

pH ASTM D1287

Reserve alkalinity ASTM D1121

Specific gravity, density ASTM D941, D1122

Specific heat ASTM D2766

Thermal conductivity ASTM D2717

Ultraviolet absorbance ASTM D2008

Vapor pressure ASTM D323

Viscosity ASTM D445

Water content ASTM D1123, D1744

27
Table 4.4. Existing Test Methods for Insulation

Type of Test

Atmospheric pollutants, resistance to

Biodeterioration

Breaking strength

Compressive strength

Deflection

Density

Dimensional stability

Expansion

Flame spread

Flexural strength

Impact resistance (by dropping)

Indentation hardness

Mechanical stability

Moisture absorption

Moisture, resistance to

Parting strength

Properties at abnormal temperature

Racking load

Specific heat

Tensile strength

Thermal aging, resistance to

Thermal conductivity

Thermal resistance

Thermal transference

Thickness

Transverse strength

Vapor permeability

Weathering, resistance to

Test Designation

ASTM D3273 , G21, G22

ASTM C446

ASTM C165

ASTM C209

ASTM C167

,

C209, C302

ASTM C548, D1042

ASTM D1037

ASTM E84

ASTM C203

ASTM C487

ASTM C569

ASTM C421

ASTM C209

Mil. Std. 810C

ASTM C686

ASTM D759

ASTM E72

ASTM C351

ASTM C209

ASTM C356

,

C411, C447

ASTM C177, C236, C335

ASTM C653, C687

ASTM C691

ASTM C167

,

C209

ASTM C209

ASTM C355, E96

ASTM G7

C303, C519, C520

D794, Mil. Std. 8 IOC

C518, C745, D2326

28

1
Table 4.5. Existing Test Methods for Metals

Type of Test Test Designation

Acetic acid, resistance to ASTM B287 , B368

Atmospheric pollutants, resistance to ASIM B537, G33

Compression ASTM E9, E209

Density and open porosity ISO 2738

Corrosion, resistance to ASTM C464 , D130, D538, D849, D930, D1280,

D1374, D1384, D1616, D1654, D2247, D2251,

D2570 , D2649, D2809, D2933, D2966, G3, G4,

G31, G32 , G46 , G48, AWPA M-14-72, NACE

TM~01-71, TM-02-70, TM-02-74, TO-01-69

Creep ASTM E139

Creep at elevated temperature ASTM E150

Ductility ASTM B489

EMF ASM E189

Fatigue ASTM E466

Fracture toughness ASTM E399

Grain size ASTM E112

Hardness ASTM E10, E18, E103, E110, E384, E448

Impact, resistance to ASTM E23

Oil content ISO 2737

Salt spray, resistance to ASTM B117, G44 , Fed. Std. 151b

Stress corrosion ASTM G30, G35, G37, G38

Tensile strength ASTM E8

Thermal expansion B95, E80

29
Table 4.6. Existing Test Methods for Plastics

Type of Test Test Designation

Abrasion, mar, resistance to ASTM D673, D1044, D1242

Atmospheric pollutants, resistance to ASTM B117, B287, D543, D1149, D1712, Gl,

G33, Fed. Std. 406

Blister-delamination ASTM C363

Burst strength ASTM D774

Cleanability AIMA-7

Coefficient of expansion ASTM D696, D864, D1204

Color change ASTM D1729, D1925, D2244, D2616, D3134, G45,

Fed. Std. 141

Creep ASTM D674, D2552, D2648, D2990, D2991,

Fed. Std. 406

Deflection ASTM D621, D648

Density ASTM D792, D1505

Qnbrittlement ASTM D1790

Fatigue ASTM C394, D671, SAE J783

Flammability ASTM D635, D658, D876, D1692, D1929, D3014,

E84 , E136

Flatness ASTM D1604 , Fed. Spec. DD-G-1403, Mil.

Spec. 3787

Flexural strength ASTM C393, D747, D790

Fungus resistance ASTM G21, G22, G29, Fed. Std. 406,

Fed. Spec. L-P-380C

Impact strength ASTM D256, D1790, D1822, D3029, D3099,

D3420, ANSI Z97.1, Fed. Std. 406

Indentation-hardness ASTM D785, D2240, D2583, Fed. Std. 406

Modulus of elasticity ASTM D638, D695, D882

Moisture, resistance to ASTM D756, D2126, D2383, Mil. Std. 810C,

Fed. Spec. L-P-380C

Optical properties ASTM E424, E434, Fed. Spec. DD-G-451

Permeability ASTM C355 , D1434, E96, F372, Fed. Std. 406,

TAPPI T-482

Refractive index ASTM D542

Scratches, defects Fed. Spec. DD-G-1403

Tensile strength ASTM C297, D638, D882

Thermal aging, resistance to ASTM D648, D793, D1299, D2115, D2126,

D2288, D2445, D2951, D3045, Mil. Std. 810C

Thermal conductivity ASTM C177, C518, D2326

Thickness ASTM D374 , D1777

Ultimate elongation ASTM D638, D882

Warping, bowing ASTM D709, D1181

30
Table 4.6. (continued)

Type of Test Test Designation

Weathering, resistance to ASTM D1435, D1499, D1501, D2565, G7, G23,

G24 , G25, G26, G27, Fed. Spec. L-P-508f,

Fed. Std. 406, ANSI Z97.1

Wind, resistance to ASTM E330

31
Table 4.7. Existing Test Methods for Rubber Materials

Type of Test

Adhesion/cohesion

Adhesion, peel

Atmospheric pollutants, resistance to

Brittleness point

Compression-recovery

Compression set

Creep resistance

Extrusion rate

Flexural strength

Flow properties

Fungus resistance

Impact strength

Hardness

Low temperature flexibility

Moisture or liquid immersion,

resistance to

Sealability

Shear strength

Staining

Tear resistance

Tensile strength

Thermal aging, resistance to

Ultimate elongation

Weathering, resistance to

Young's modulus

Test Designation

ASTM C719 , C766

ASTM C794 , D413, D429, D903, D1781, D1876

D2630

ASTM D518, D1149 (ozone)

ASTM D2137

ASTM F36

ASTM D395, D1229

ASTM D1390, D1456, D1780, D2293, D2294, F38

ASTM C603

ASTM D1184

ASTM C639

ASTM D1286, D1877

ASTM D950

ASTM C661, D1415, D2240

ASTM C711, C734, C765, D797, D1053, D1329

D2137

ASTM D471, D1101, D1151, D1460, D3137,

F82

ASTM D1081, F37, F112

ASTM D905, D1002, D2919, D3165

ASTM D925, D2203

ASTM D624

ASTM D412, D897, D906, D2095, D2295, F152

ASTM C771, C792, D573, D865, D1870

ASTM D412

ASTM C718, C732, C793, D904, D1171, D1183,

D1828, D2559, ANSI A116.1, AAMA 802.2,

804.1, 805.2, 806.1, 807.1, 808.1,

Fed. Specs. TT-G-410E, TT-S-00227E,

TT-S-00230C, TT-S-001543A, TT-S-001657

ASTM D797

32
5. CONCLUSIONS AND RECOMMENDATIONS

The observations made during inspections of operational solar energy systems, described

in Chapter 2, illustrate that numerous material related problems have occurred in operational systems and the results of the questionnaire, described in Chapter 3, illustrate

that many types of materials have been used in components and subsystems. Field problems were identified in each of the major subsystems, collector, transport and storage, of one

or more of the solar energy systems surveyed. Also materials problems were identified for

most components within the subsystems. For example, problems were identified in one or more collector subsystems with materials used for cover plates, absorptive coatings,

absorber plates, insulation, seals, enclosures and structural supports.

It is imperative that premature failure of materials be rninimiized and that systems and

subsystems be made as maintenance free as possible to ensure widespread consumer acceptance

of solar as a viable energy alternative. The primary concern, then, is to identify a path

of action to ensure improved materials performance in solar systems and subsystems.

There are at least two factors which contribute to the premature failure of materials

in the field and must be addressed by the planned path of action: 1) improper design

considerations and 2) inadequate resistance of materials to the conditions experienced in

solar energy systems. Many of the field problems result from improper selection of materials

for the particular design. At present, the process of selecting materials for specific

applications is hindered by the lack of an adequate data base of materials performance

under the conditions experienced in solar systems and subsystems. In particular, data are not available to characterize the longterm performance of various materials under expected

in-service conditions. It is often impossible to compare adequately the expected long-term

performance of various candidate materials and identify the best candidate. Clearly, the

development of a data base of materials performance which identifies the attributes and

limitations of materials under specific use conditions would significantly aid the process

of selecting materials and hence reduce the extent of field problems.

The needed data base of materials performance can be obtained from experience based on actual installations and from laboratory studies (including tests performed in a laboratory

and tests performed on materials and subsystems outdoors) . The field experience with solar

energy systems in recent years has provided a start toward obtaining an adequate data base.

For example, changes incorporated in recently marketed systems and subsystems by collector

manufacturers and system designers to help alleviate problems observed with earlier designs

reflect a growing data base of materials performance. One problem, however, is that information on the experience gained is often not widely disseminated within the solar industry.

Another problan is that, even if data obtained frcm field experience were widely disseminated,

the time required to obtain an adequate data base would be prohibitively long if trial and

error in the field were the only source of data.

33
Laboratory studies of materials is another source of materials performance data.

Initial properties of materials can often be determined using existing standard test methods, as shown in Chapter 4. Such property measurements are available for many materials used in

components and subsystems, e.g. strength properties of glass, plastics and metals, hardness

of rubber materials, thermal properties of insulation etc. Aging tests, which provide for

exposure of materials to environments that may change their properties, can be useful in

obtaining long-term performance data. The effect of the environment on materials properties

during an aging test can be determined by measuring one or a group of properties before and

after aging. Accelerated aging tests, which have been designed in an attempt to induce

changes in materials properties in a short period of time, have been developed for many

materials as mentioned in Chapter 4. One problem with testing by accelerated aging procedures is that it is difficult to relate the results of accelerated tests quantitatively

with in-service performance [5, 6]. A systematic approach to predicting service life has

been developed [7] which may aid in obtaining improved correlations between accelerated

test results and in-service performance. The systematic approach is also being prepared as an ASTM standard practice by Contrattee E6 on Performance of Building Constructions.

Another problem with existing accelerated tests for materials, as shown in Chapter 4, is

that the exposure environments are seldom adequate to simulate the exposure conditions of

materials experienced in solar energy components and subsystems. Thus, in developing a data base of materials performance for solar energy applications, it will be necessary to

first establish standard test procedures for obtaining the data. The test procedures

needed are primarily accelerated aging tests in which the exposure environments simulate

the service conditions experienced in solar. However, Chapter 4 points out that improved

property measurement tests are also needed for some materials.

In order to expedite the development of the urgently needed data base of materials

performance for solar applications, the following is proposed:

1. Compile materials performance data from solar energy systems that are installed

in the field.

Commentary: It was mentioned earlier in this chapter that experience gained from

field installations is often not widely disseminated within the solar industry. One reason for this is that the materials used in many systems are proprietary. During

the course of this study, it has been difficult to obtain from the private sector, the

type of data needed. It is unlikely that a comprehensive compilation of materials

performance on operational systems can be obtained. It is suggested, therefore, that

the data compilation be limited to Federally sponsored or owned installations. The

data which could be obtained would serve two purposes: 1) it would provide an interim

data base and 2) it would aid the interpretation of data frcm accelerated tests of

materials and subsystems

34
2. Perform laboratory studies of materials and subsystems to develop test method

standards

.

Commentary : Standard test methods are needed at the materials level, particularly for

estimating the long-term performance of materials in solar applications. In order to

develop test method standards, laboratory tests of available and currently used

materials must be performed and the data obtained from the tests compared to actual

field data fran operational systems. Also accelerated tests of subsystems, particularly stagnation tests of collectors, must be performed to develop standard procedures

and to obtain data for comparison with materials tests.

3. Develop a data base of materials performance for solar applications.

Commentary : The data base should be developed as rapidly as possible, utilizing input

from the areas 1 and 2 above. The data base should be a compilation of materials test

results, based on field and laboratory tests, which could be used by manufacturers and

designers in selecting the best candidate material for each specific application. It

is unlikely the data base could ever be complete. In particular, new materials will

undoubtedly be utilized in solar applications in an attempt to lower the initial cost

or improve the performance of systems. However, if there are standards by which the new materials can be evaluated quickly and reliably, and if data are available in the

data base to minimize the selection of materials of poor or questionable performance,

the benefits to the solar industry and to the consumer would be invaluable.

The remainder of this chapter will outline the recommended priorities for the development of test method standards for evaluating materials and the types of laboratory-based

studies that are needed in regard to the proposal mentioned above to perform laboratory

studies of materials.

5.1 Recommended Priorities for the Development of Material Test Method Standards

The National Bureau of Standards has prepared a plan for the development and implementation of standards for solar heating and cooling applications [8] . Based upon that plan,

upon the types of material-related problems which have occurred in operational systems

(Chapters 2 and 3 of this report) and upon the availability of existing standards (Chapter

4 of this report) , the following components (listed in alphabetical order) are recommended

for the development of material test method standards: absorptive coatings, coatings/liners

for transport or storage subsystems, collector insulation, cover plates, dessicants,

dielectric insulators, filters and getter columns, flexible couplings, heat transport

liquids, metallic containment materials, nonmetallic containment materials, transport and

storage subsystem insulation, reflective surfaces, seals and thermal storage media. In addition, standards are needed in two related areas: stagnation testing of collector

subsystems and measurement of surface temperature of materials.

35
Table 5-1 lists the areas for standard development according to recommended priority

for actions. Priority ratings of high, medium and low are used in the table. The priority

ratings reflect the need for standards to determine the functional and durability/reliability

attributes of materials for use in solar systems. Criteria used in establishing the

priorities are:

1. The importance of the material to the total system performance.

2. The extent of field problems observed within the material.

3. The availability of existing standards to measure functional and durability/

reliability attributes.

4. The potential for developing useful consensus standards.

5.2 Reccmmendations for Laboratory-Based Studies

In order to develop definitive test method standards for the material-related areas

listed in table 5-1, laboratory-based studies of available and currently used materials

must be performed to obtain data needed to prepare the standards. The purpose of this

discussion is to outline the types of studies that are needed for each area identified in

table 5-1 in terms of key needs, key properties to be measured and key aging tests needed

and subsystems to which the standards could be applied. A general need for each of the

materials areas in which aging tests are studied is to relate the results of the aging

tests to results obtained from stagnation testing of collector subsystems (5.2.8) and to

field results obtained from operational systems. Another general need for each of the

materials areas is to obtain data for use in the data base discussed earlier.

ASTM Committee E21.10 on Solar Heating and Cooling Applications is currently performing

research in a number of the areas to be discussed. Task groups on absorptive coatings,

collector insulation, cover plates, heat transport liquids, metallic containment materials,

seals and stagnation testing are currently working to develop standards. In conjunction

with ASTM, the National Bureau of Standards (NBS) is performing research to develop draft

standards for absorptive coatings, collector insulation, cover plates and seals. These

drafts will be submitted for consideration by ASTM as consensus standards.

36
Table 5-1. Recommended Priorities for the

Development of Material-Related Standards

Material Standards Area Priority

Absorptive coatings High

Collector insulation High

Cover plates High

Heat transport liquids High

Metallic containment High

Nonmetallic containment and absorber

substrates High

Seals High

Stagnation testing of collector

subsystem High

Surface temperature measurement High

Flexible couplings Medium

Reflective surfaces Medium

Thermal storage media Medium

Transport and storage insulation Medium

Coatings/liners for transport or storage

subsystems Low

Dessicants Low

Dielectric insulators Low

Filters/getters Low

37
5.2.1 Absorptive Coatings

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance.

2. Develop lower cost property measurement tests for measuring reflectance and

emittance.

3. Develop standard coatings which can be used to compare results obtained in

different laboratories and on different instruments.

Key Properties to be Studied

1. Reflectance (absorptance)

.

2 . Emittance.

3. Adhesion.

Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated temperature and temperature cycles (including test to measure the effect of outgassing products on other components)

.

b. Effects of moisture.

c. Effects of solar radiation.

d. Compatibility with heat transport fluids (for trickle systems and systems in

which the absorber is dispersed in the transport fluid)

.

e. Compatibility with substrate.

2 . Natural Exposure

a. Exposure of coatings in several climates using an exposure apparatus to

simulate service conditions in actual collectors.

38
Applicable Subsystems

1. Collector.

5.2.2 Collector Insulation

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance.

Key Properties to be Studied

1. Thermal conductivity.

2. Chemical stability.

3 . Water absorption.

4. Form retention.

5. Dimensional stability.

Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated temperature and temperature cycles (including test to measure the effect of outgassing products on other components)

.

b. Effects of moisture.

c. Effects of solar radiation and atmospheric pollutants (for exterior applications)

.

Applicable Subsystems

1. Collector.

39
5.2.3 Cover Plates

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance

2. Assess existing property measurement tests and develop new tests where needed.

Key Properties to be Studied

1. Transmittance.

2. Abrasion resistance.

3.

Impact strength.

4 . Bnbrittlement

.

Key Aging Tests Needed

1. Accelerated tests

a. Effects of elevated and depressed temperature and temperature cycles (particularly for plastics)

.

b. Effects of moisture (particularly for plastics)

.

c. Effects of solar radiation (particularly for plastics)

.

d. Compatibility with reflective/anti-reflective coatings.

e. Effects of atmospheric pollutants.

2 . Natural Exposure

a. Exposure of coatings in several climates using an exposure apparatus to

simulate service conditions in actual collectors.

Applicable Subsystems

Collector.

40
5.2.4 Heat Transport Liquids

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance.

2. Assess property measurement tests and tests to characterize flammability of

organic fluids and develop new tests as needed.

Key Properties to be Studied

1. Specific heat.

2 . pH and reserve alkalinity.

3. Thermal conductivity.

4. Viscosity.

5. Safety related properties (autoignition temperature, fire point, flash point)

Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated and depressed temperature and temperature cycles.

b. Compatibility with materials with which fluids ccme in contact (particularly

corrosion)

c. Effects of additives.

d. Effects of decomposition products.

Applicable Subsystems

1. Collector.

2. Transport.

3. Storage (if transport and storage contain the same liquids)

41
5.2.5 Metallic Containment Materials

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance.

2. Develop nondestructive property measurement tests for characterizing properties,

particularly during and after aging tests.

Key Properties to be Studied

1. EMF.

2. Nondestructive evaluation (including visual inspection).

3 . Mechanical properties

.

4. Weight.

5. pH of liquids.

Key Aging Tests Needed

1 . Accelerated tests

a. Compatibility with heat transfer fluids under various conditions of flew,

oxygen content, tanperature and additives.

Applicable Subsystems

1. Collector.

2. Transport.

3. Storage.

42
5.2.6 Nonmetallic Containment Materials and Absorber Substrates

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance.

2. Assess existing property measurement tests, particularly for plastics, and develop new tests as needed.

Key Properties to be Studied

1. Transmittance (e.g. solar ponds)

.

2. Impact strength (e.g. solar ponds, piping, absorbers).

3. Burst strength (e.g. piping)

.

4. Embrittlement (e.g. solar ponds, piping, absorbers)

.

5. Flexural strength (e.g. absorbers).

6. Abrasion resistance (e.g. solar ponds, piping).

Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated and depressed temperature and temperature cycles.

b. Effects of solar radiation.

c. Compatibility with heat transfer or storage liquids.

d. Effects of atmospheric pollutants.

e. Compatibility with absorber coatings (particularly for absorber substrates)

.

43
2 . Natural Exposure

a. Exposure of materials in several climates to simulate in-service conditions

in field applications.

Applicable Subsystems

1. Collector.

2. Transport.

3. Storage.

5.2.7 Seals

Key Needs

1. Modify existing aging tests to include temperatures which more closely simulate

those observed in solar systems.

2. Develop a test to determine the effect of outgassing products on other ocrponents.

Key Properties to be Studied

1. Adhesion.

2. Compression set.

3. Hardness.

4. Tensile strength.

5. Ultimate elongation.

Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated and depressed terrperature.

b. Effects of atmospheric pollutants (particularly ozone)

.

44
c. Effects of moisture.

d. Effects of solar radiation.

e. Compatibility with heat transfer liquids (for hydraulic seals)

Applicable Subsystems

1. Collector.

2. Transport.

3. Storage.

5.2.8 Stagnation Testing of Collector Subsystems

Key Needs

1. Develop a standard stagnation aging test which can be used to estimate stability

of materials to stagnation conditions.

2. Obtain materials data under stagnation conditions in order to relate the results

of stagnation tests, materials tests and in-service performance.

Key Properties to be Studied

1. Thermal performance of collector before and after stagnation exposure.

2. Selected properties of materials.

3. Visual observation.

Key Aging Tests Needed

1 . Natural Exposure

a. Exposure under stagnation conditions in several climates.

Applicable Subsystems

1. Collector.

45
5.2.9 Surface Temperature Measurement

Key Needs

1. Development of standard procedure for measuring the surface temperature of

materials in subsystems.

2. Obtain measurements of materials temperatures under various operational and stagnation conditions and feed the data into projects aimed at developing aging tests for

materials. Temperature data are needed to establish maximum and minimum test temperatures for aging tests of materials.

5.2.10 Flexible Couplings

Key Needs

1. For rubber based couplings, modify existing aging tests to include temperatures

which more closely simulate those observed in serivce.

2. Identify other materials used for couplings and assess existing aging tests and

develop new tests as needed.

3. Develop recommendations for joining flexible couplings to other components.

Key Properties to be Studied

1. Compression set (rubbers)

.

2 . Hardness (rubbers)

.

3 . Tensile strength (rubbers)

.

4. Ultimate elongation (rubbers).

5. Dimensional stability (rubbers) .

6. Other properties dependent upon materials used.

46
Key Aging Tests Needed

1

.

Accelerated tests

a. Effects of solar radiation.

b. Effects of elevated and depressed temperatures

.

c. Effects of atmospheric pollutants (for rubbers)

.

d. Compatibility with heat transfer liquids.

Applicable Subsystems

1 . Collector

.

2. Transport.

3. Storage.

5.2.11 Reflective Surfaces

Key Needs

1. Develop aging tests based upon laboratory studies which can be used to estimate

long-term in-service performance

.

2. Develop lower cost property measurement tests for measuring reflectance and

emittance

.

Key Properties to be Studied

1. Reflectance.

2. Emittance.

Key Aging Tests Needed

1. Accelerated tests

a. Effect of solar radiation.

b. Effect of moisture.

47
Applicable Subsystems

1. Collector.

d. Effect of atmospheric pollutants.

c. Compatibility with substrate

.

5.2.12 Thermal Storage Media

Key Needs

1. Develop aging tests which can be used to estimate the long-term in-service performance

of thermal storage media other than rock and water.

Key Properties to be Studied

1 . Accelerated tests

Applicable Subsystems

1. Storage.

5.2.13 Transport and Storage Insulation

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service perfontance.

Key Properties to be Studied

1. Thermal conductivity.

a. Effects of elevated temperature and temperature cycles.

b. Effects of moisture.

c. Compatibility with adjoining materials.

2 . Thermal resistance.
Key Aging Tests Needed

1

.

Accelerated tests

a. Effects of elevated temperature and temperature cycles.

b. Effects of solar radiation and atmospheric pollutants (for exterior applications) .

c. Effects of moisture.

d. Effects of soil constituents (for buried insulation)

.

e. Dimensional stability.

f . Compatibility with protective coatings.

Applicable Subsystems

1. Transport.

2 . Storage

.

5.2.14 Coatings/Liners for Transport or Storage Subsystems

Key Needs

1. Develop aging tests based upon laboratory studies which can be used to estimate

long-term in-service performance.

Key Properties to be Studied

1. Adhesion (coatings)

.

2. Permeability (coatings, plastics)

.

3. Color (coatings, plastics).

4. Thickness (coatings, plastics).

5. Strength properties (plastics).

49
Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated temperature and temperature cycles.

b. Compatibility with transport or storage liquids.

c. Compatibility with substrate.

Applicable Subsystems

1. Transport.

2. Storage.

5.2.15 Dessicants

Key Needs

1. Develop aging tests which can be used to estimate long-term in-service performance.

Key Properties to be Studied

1. Moisture absorption.

2. Dimensional stability.

Key Aging Tests Needed

1 . Accelerated tests

a. Effects of elevated temperature

.

b. Effects of heating/drying cycles.

c. Compatibility with adjoining materials.

d. Effects of moisture.

50
Applicable Subsystems

1. Collector.

5.2.16 Dielectric Insulators

Key Needs

1.

Develop aging tests which can be used to estimate long-term in-service performance.

Key Properties to be Studied

1 . Hardness

2. Electrical conductivity.

3. Compression set (rubber-based materials)

Key Aging Tests Needed

1. Accelerated tests

a. Effects of elevated and depressed temperatures and temperature cycles.

b. Compatibility with heat transfer or storage liquids and other adjoining

- materials

Applicable Subsystems

1. Collector.

2. Transport.

3. Storage.

5.2.17 FiIters/Getters

Key Needs

1. Develop aging tests which can be used to estimate useful lifetime under various

conditions of use.

51
Key Properties to be Studied

1.

Dependent upon the material used.

Key Aging Tests Needed

1 . Accelerated tests

a. Compatibility with transport or storage liquids.

Applicable Subsystems

1. Transport.

2. Storage.

6. GUIDELINES TO AID THE SELECTION OF MATERIALS FOR USE IN SOLAR ENERGY SYSTEMS

Factors which must be included in criteria for selecting materials to be used in solar

energy systems include 1) ability of the material to perform the intended function, 2)

durability/reliability, 3) safety, 4) maintainability, 5) cost and 6) compliance with local

building codes. As pointed out in Chapter 5, the process of selecting materials for specific

applications is hindered by the lack of an adequate data base of materials perforrtance under

the conditions experienced in solar systems and subsystems. Because of the lack of an

adequate data base, it is not possible to provide definitive reconmendations for the use of

materials. The purpose of this chapter is to present guidelines to aid the selection of

materials for specific applications. The guidelines outline a general procedure for obtaining the data needed to make the selection. The guidelines should be useful in identifying

the types of data that should be considered in selecting materials for use in solar energy

systems.

The process of selecting a material for a specific application can be outlined into ten

steps:

1. Define in-service performance requirements.

2. Identify key functional attributes (or properties).

3. Identify environmental conditions to which the material will be exposed in service.

4. Identify key durability/reliability attributes.

52
5. Identify key safety attributes.

6. Identify the types of test or field data needed to demonstrate compliance with

requirements for function, durability/reliability and safety attributes.

7. Obtain test data.

8. Rank candidate materials in order of predicted short-term and long-term performance.

9. Consider factors related to maintainability, cost, and code compliance.

10. Select the "best" material.

Tables 6-1 and 6-2 are is included to aid in identifying primary attributes of materials

typically used in collector, transport and storage subsystems. Table 6-1 lists functional

attributes while table 6-2 lists durability/reliability and safety attributes. Attributes

of each material which are generally considered to be important are marked with an "X". However, the importance of attributes may vary depending on design and geographic location

in service. These tables will be referenced in the following discussion regarding the ten

steps outlined above.

Step 1 . Define In-Service Performance Requirements

Performance requirements identified in Step 1 of the above outline should provide

answers to two important questions: 1) what is the material expected to do in the system or

subsystem and 2) how long should it perform its function before replacement?

Step 2 . Identify Key Functional Attributes (or Properties)

The key functional attributes (or properties) should be identified. The attributes

should be based upon the requirements identified in Step 1. Functional attributes of

materials typically used in solar energy systems are identified in table 6-1 and are divided

into two categories: optical and physical. Optical attributes include absorptance, reflectance, emittance and transmittance. Physical attributes include abrasion resistance,

adhesion, boiling point, burst strength, compression set, density, dimensional stability,

electrical conductivity, embrittlement, expansion coefficient, flexural strength, freezing

point, hardness, impact strength, melting point, permeability, specific heat, stress cracking,

swelling/shrinking, tensile strength, thermal conductivity, ultimate elongation, viscosity

and water absorption.

53
Table 6-1. Primary Functional Attributes of Materials Performance for Consideration

in Selecting fteterials for Use in Solar Energy Systems

FUNCTIONAL attributes Materials OPTICAL PHYSICAL

a, *>

A. COLLECTOR

SUBSYSTEM

Absorptance Reflectance Quittance

!

-1

i

l

l

Abrasion

resistance

Adhesion

Boiling

point

Burst

strength

Conpression

set

Density bimens

ional

stability

Electrical

conductivity

4J

•

1 P

4J-Hy

Expansion

coefficient!

Flexural

strength

j

Freezing

point

1

Hardness Impact

strength

Permeability

Specific

heat

Stress

cracking

Svoelling/shr

inking

Tensile

strength

\

Thermal

conductivity

Ultimate

elongation

Viscosity

Water

absorption

j

1. Absorptive Coatings

Solid X X X X X X

Liquid or dispersed in transport fluid X X X X X X X

2. Absorber Substrate

Metallic X X

Nonmetallie X X X X

3. Cover Plates

Glass X X X X X X

Plastics X X X X X X X X X X X

4. Insulation X X X X X

5. Transport Liquids X X X X X X

6. Containment

Metallic X X X

Nonmetallie X X X X X X X X

7. Seals-/ X X X X X X X X

8. Reflective Surfaces X X X X X

9. Dessicants X X

10. Dielectric. . Insulators-7 X X X X

11. Enclosure X X X X X X X X

12. Structural Supports X X X X

13. Connections (adhesives, solders, etc.)!/ X X X X X X

B. TRANSPORT

SUBSYSTEM

i. Piping

Metallic X X X X X

Nonmetallic X X X X X X X X

2. Pipe Lining—

Organic X X X X X x V X Inorganic X X X X X X

3. Flexible Couplings

Metallic X X X

Nonmetallic X X X X X X X X

4. Insulation X X X X X

5. Filters/Getters X X

c. STORAGE SUBSYSTEM

1 . Tank Material

Metallic X X X X X

Normstallie X X X X X X X X

2. Storage Media X X X X X X X X X

3. Insulation X X X X

4. Heat Exchanger X X X X X X

1/ Also applicable to transport and storage subsystems.

2/ Also applicable to storage liners.

54
Table 6-2. Primary Durability/Reliability and Safety Attributes of Materials Performance for Consideration in Selecting Materials

for Use in Solar Energy Systems

DURABILITY/RELIABILITY COMPATIBILITY

Materials RESISTANCE TO WITH SAFETY

A. COLLECTOR SUBSYSTEM

r

Elevated

temperature

Depressed

temperature

Thermal

cycling

Solar

radiation

Moisture

Pollutants

Ozone

Imposed

stresses

Outgassing Adjoining

materials

Heat

transport

liquids

Soil

constituents

Flanmability

Toxicity

Structural

adequacy

1 . Absorptive Coatings

Solid X X X X X X X X

Liquid or dispersed in transport fluid X X X X X X X

2 . Absorber Substrate

Metallic XXX X X X X

Nonmetallie XXX X XX X X X

3 . Cover Plates

Glass XXX X X Plastics xxxxxxxx X X

4 . Insulation XXX XX X

5 . Transport Liquids XXX X X X

6 . Containment

Metallic XXX X X X

Nonmetal lie XXX X X X X

7. Sealsi/ XXXXXXX X X

8. Reflective Surfaces X X X X X X

9 . Dessicants X X X

10 . Dielectric, . Insulators—' X X X

11. Enclosure X X X X X X X X X

12. Structural Supports X X X X X X X X X

13. Connections (adhesives, solders, etc.) 1/ XXX X X X X X

B. TRANSPORT SUBSYSTEM

1. Piping

Metallic XXX X XX X

Nonmetallic XXX XX XX X X

2/

2 . Pipe Lining—

Organic XXX X X

Inorganic XXX X X

3 . Flexible Couplings

Metallic XXX X X X X

Nonmetallic XXX X X X X

4 . Insulation X X X X X X X

5 . Filters/Getters X X X X

C. STORAGE SUBSYSTEM

1. Tank Material

Metallic XXX X X X

Nonmetallic XXX X X X X X

2 . Storage Media X X X X X

3 . Insulation XXX X X

4 . Heat Exchanger X X X X

1/ Also applicable to transport and storage subsystems.

2/ Also applicable to storage liners.

55
Step 3. Identify Environmental Conditions to Which the Material Will be Exposed In-Service

The environmental conditions to which the material will be exposed in service should be

identified. In particular, the temperature ranges, level of solar radiation and level and

type of pollutants should be identified. The maximum temperature reached in service will

probably be under stagnation conditions for collector materials and the solar radiation and

pollutant levels will depend upon geographic location.

Step 4. Identify Key Durability/Reliability Attributes

The key durability/reliability attributes should be identified. The attributes should

be based upon the performance requirements identified in Step 1 and the environmental

conditions identified in Step 3. Table 6-2 contains a list of durability/reliability

attributes. The list includes resistance to elevated temperature, depressed temperature,

thermal cycling, solar radiation, moisture, pollutants, ozone, imposed stress and outgassing

as well as compatibility with adjoining materials, heat transport liquids and soil constituents. Compatibility with adjoining materials includes chemical and physical compatibility

and is important for each material. An example of the lack of chemical compatibility is

corrosion caused by contact between two dissimilar materials while an example of the lack of

physical compatibility is unacceptable levels of stress caused by the different thermal

expansion coefficients of rigidly connected dissimilar materials. In Chapter 2, it was

mentioned that one instance of extensive glass cover plate breakage in an operational system was observed. This breakage may have been the result of a lack of physical compatibility

between the cover plates and the aluminum frame.

C Step 5 . Identify Key Safety Attributes

The key safety attributes should be identified. Safety attributes listed in table 6-2

include f larnmability, toxicity and structural adequacy.

Step 6 . Identify the Types of Test or Field Data Needed

Based on the key attributes identified in steps 2, 4 and 5, the types of test of field

data needed to demonstrate compliance with the level of required performance should be

identified. This is a difficult task because of the lack of an adequate data base of

materials performance and the lack of adequate standards for evaluating many materials.

However, if the key attributes have been adequately defined in previous steps, the types of

tests that should be performed can be identified and new tests can be designed or existing

tests altered to give comparative data for the various materials being considered. The

available standards identified in Chapter 4 should be helpful in this regard.

56
Step 7. Obtain Test Data

Once the types of materials performance data needed and tests to obtain the data are

identified, the data should be obtained. Data are often available from manufacturers or in

the technical literature for materials vfriich have been used in the building industry.

However, the adequacy of existing data must be assessed in view of the conditions of use in

solar systems.

Step 8 . Rank Candidate Materials

The materials should be ranked in order of predicted short-term and long-term performance

based on the data obtained in Step 7. In particular, the adequacy of the material to perform

its intended function both initially and for its design life should be addressed.

Step 9 . Consider Factors Related to Maintainability, Cost and Code Compliance

Other factors affecting the selection of a material, such as maintainability, cost and

code compliance, should be addressed.

Step 10 . Select the Best Method

Based on materials performance data and other factors considered in Step 9, the "best"

material should be selected.

57
7. REFERENCES

1. National Program for Solar Heating and Cooling of Buildings, Report 76-6, Energy

Research and Development Administration , Washington, DC 20545, November 1976.

2. Hobbs, Norman P. , "Investigation of Glass Breakage," Report prepared by Kaman Avidyne, a Division of Kaman Sciences Corporation, Burlington, Mass 01803, October 15, 1976.

3. Annual Report of the Solar Heating Experiment on the Grover Cleveland School, Boston,

Massachusetts, General Electric Company, Space Division, July 15, 1975.

4. Masters, Larry W. , Clark, Elizabeth, J., Sleater , Gerald A., Hockman, Arthur, "Durability

and Related Tests for Selected Elements and Materials Used in the Exterior Envelope of

Buildings," NBSIR 75-955, November 1975.

5. Masters, Larry W. , Wolfe, Winthrop C., Rossiter, Walter J. Jr., Shaver, James R.

,

"State of the Art on Durability Testing of Building Components and Materials," NBSIR 73-

132, March 1973.

6. Masters, Larry W. , Wolfe, Winthrop C., "The Use of Weather and Climatological Data in

Evaluating the Durability of Building Components and Materials," NBS Technical Note 838,

August 1974.

7. Masters, Larry W., "An Approach to the Development of Predictive Service Life Tests for

Building Components and Materials," to be published in the Proceedings of the RILEM/

ASTM/CIB Symposium on Evaluation of the Performance of External Vertical Surfaces of

Buildings, September 1977.

8. Waksman, D., Pielert, J. H., Dikkers, R. D., Streed, E. R. , "Plan for the Development

and Implementation of Standards for Solar Heating and Cooling Applications," NBSIR 76-1143,

August 1976.

58
Figure 2-1. Condensation on Cover Plate

Interior Surface

Figure 2-2. Deposits on Cover Plate

Interior Surface

59
Figure 2-3. Fogging of Cover Plate Interior

Surfaces Caused by Outgassing

Figure 2-4 . Dirt on Cover Plate Exterior

Surface

60
Figure 2-5. Dirt on Cover Plate Interior

Surface

Figure 2-6. Extensive Breakage of Plate

Glass Cover Plates

61
Figure 2-7. Adhesive Deterioration Which

Resulted in Bond Failure Between

Plate Glass Cover Plates and

Aluminum Honeycomb Heat Trap

Figure 2-8. Plastic Heat Trap Distortion and

Decomposition as a Result of

Stagnation Exposure

62
Figure 2-9. Undersized and Improperly

Bedded Tempered Glass Cover

Plates

Figure 2-10. Warpage of Polycarbonate

Cover Plates
Figure 2-11. Incompatibility Between Polycarbonate Cover Plates

and EPDM Standoffs

Figure 2-12. Absorber Plate and Cover Plate Warpage Resulting in

Contact Between Absorber and Cover
Figure 2-13. Cracking of Polycarbonate

Cover Plates at Edge of

Indented Stiffening Ribs

Bnbrittlerment of Polyvinyl

Fluoride Cover Plates after

Exposure to Stagnation

Conditions

65

Figure 2-14
Figure 2-15. Color Variations of

Anodized Aluminum Absorber

Figure 2-16. Effect of Transfer Fluid Flows, Due to Hose Failure,

on the Color of Anodized Aluminum Absorber

66

Figure 2-19. Leaking Aluminum Absorber

Plate

Figure 2-20. Gaps in Absorber Plate

Resulting in Exposure of

Insulation

68
Figure 2-21. Failure of Joint Between

Fluid Conduits and Absorber

Plate
Figure 2-23 Exposed Urethane Collector

Insulation

Figure 2-24. Fiberglass Insulation

Sagging Away from Back of

Absorber Plate

70
j

Figure 2-25. Failure of Sealant Between

Tempered Glass Covers and

Aluminum Extrusion

Figure 2-26. Discoloration of Silicone

Seals

71
Figure 2-21 . Deterioration of Wooden

Restraining Frames

Figure 2-28. Reflective Surfaces

72
Figure 2-29. Tracking Collectors

Figure 2-30. Concentrating Collector

with Roof Mounted Reflective

Surfaces

73

. - ~
Figure 2-32. Field Expedient Repair of

Flexible Coupling Hose

Figure 2-31. Evacuated Tube Breakage

. >|8|

74
Figure 2-33. Copper Coil Replacement of

Flexible Hoses

Figure 2-34. Inaccessible Hose Connection

75
Figure 2-35. Uninsulated Flexible

Coupling

Figure 2-36. Surface Cracking on Cellular

Insulation

76
Figure 2-37. Effective Coating Protection

on Cellular Insulation

Figure 2-38. Deterioration of Vermiculite

Plaster Storage Tank

Insulation

77

APPENDIX A

-v.:, „* •, ;v

j

78

SAMPLE LETTER

Mr. John Doe

600 Main Street

Anywhere, U. S. A.

Dear Mr. Doe:

[

The National Bureau of Standards (NBS) has initiated a project, sponsored

by the Energy Research and Development Administration (ERDA) , to identify

the needs for performance standards for materials used in solar energy

systems. The results of the project will include recommended priorities

for the development of materials standards and recommended laboratory

studies needed to develop the standards. The recommended priorities and

recommended laboratory studies for the development of materials standards

will aid ERDA in its effort to support the development of consensus

standards through standards setting organizations such as ASTM and ANSI.

The purposes of this letter are to briefly describe the project and to

ask your cooperation and assistance in obtaining data regarding the

types of materials used and the performance of materials in currently

operative solar energy systems.

One part of the project will include tasks to (1) identify solar energy

systems that are currently being used in the field and their locations,

(2) identify the types of materials used and obtain information regarding materials performance in those systems by communicating with manufacturers, installation contractors, and other knowledgeable sources.

Your company has been identified by the Solar Energy Industries Association

as an installation contractor of solar energy systems. In order to

complete the project, your assistance in providing the following information is needed: (1) the types of materials used, and (2) the performance of the materials in operational systems that have been installed

by your company. A form is enclosed for presenting the information

along with a brief instruction sheet. Your cooperation in completing

the form will be greatly appreciated. The reports prepared during the

79
-2-

project will not refer to specific systems by manufacturer’s name or to sources of data. The data will be compiled and presented solely for the

purpose of illustrating the types of materials that have performed well

and those that have experienced problems in the field.

The project is being performed in a compressed time frame so that the

results can be used in standards development activities. Your response

within thirty days will help keep the project on schedule.

Thank you for any assistance you can provide in this activity. If you

have any questions, please contact me or Larry Masters at any time. The

phone number is 301-921-3371.

Sincerely,

Leo F. Skoda

National Bureau of Standards

Materials and Composites Section

Building 226, Room B-348

Washington, DC 20234

Enclosures

80
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—

i'
Part

III

-

Collector

Information
BUILDING

DESIGNATION

NUMBER

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83
Part

IVThermal

Storage

Information

(continued)

84
Part VEnergy

Transport

Information

(continued)

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Yes

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Yes V)0) >

D.

Connections

(continued)

2.

Flexible

a.

Material

and

manufacturer 1

b.

Attachment

method

(e.g.,

clamped,

threaded) j

c.

Location (1)

Indoors

(2)

Outdoors

E.

Insulation 1

Material

and

thickness

2.

Protective

coating

(if

applicable)

F.

Gaskets

and

Sealants 1

Material

and

manufacturer 2

Locations

of

use

G.

Filters

and/or

Getters 1

Type 2

Location j H

Have

changes

been

observed

in

any

of

the

transport

materials

that

affected

the

performance

of

the

system? 1

Has

it

been

necessary

to

repair

or

replace

materials

due

to

inadequate

performance?

J

Have

signs

of

corrosion

been

observed

in

the

transport

subsystem?

85

O9

</) CDZ5Oo

COD

Larry

W.

Masters

Building

Research,

Room

B348

National

Bureau

of

Standards

Washington,

D.

C.

20234
Instructions for Completion of "Data Sheet for Operational

Solar Energy Systems"

Part I. MANUFACTURER OR INSTALLER OF SYSTEM

Name of person to contact: The individual sited here should be

one that is familar with the operation of the solar systems

reported as to materials durability and required maintenance.

A follow-up phone call to this individual will be made after

return of the data sheet to NBS to discuss materials performance.

Part II. BUILDING AND SYSTEM INFORMATION

Building Designation Number: Please assign a number (Building

Designation Number) to each building that contains an operational

solar energy system manufactured or installed by your company.

Use these same numbers in completing Parts III, IV and V of the

questionnaire. Space is provided on the forms for up to four

buildings. If more than four buildings are available, please

include the building that has been equipped with a solar system

for the longest time, the building most recently equipped with

a solar system and two other buildings which, in your opinion,

illustrate typical materials performance data observed by you

in regard to solar energy systems.

Part III. COLLECTOR INFORMATION

A. 3. "Open" collector refers to a trickle system. "Closed"

refers to a collector in which the transfer fluid cannot

absorb oxygen in addition to that which is in the fluid

initially.

B. l. "Primary" cover plate is the outermost plate, i.e. the one that forms the exterior envelope of the collector.

B.2. The "reflective coating" is the material (if any) applied

to the underside of each cover plate.

D.2. Refers to mechanism for attaching tubing to absorber

plate, i.e. solder, adhesive, mechanical clamp, etc.

F.l. Include all insulating materials and thicknesses used if

more than one.

F.2.a. "Back" refers to insulation used behind absorber plate.

F,2.b. "Edge" refers to peripheral insulation.

86
- 2 -

1.1.2. Report generic name or trade name if generic name is

not used. ’’Location" would refer to loose dessicant

within collector body or dessicant filled vent plugs,

etc.

J-K-L. If the answer to any of these questions is "yes" it

is not necessary to explain in detail as the details

will be discussed in follow-up telephone conversations.

Part IV. THERMAL STORAGE INFORMATION

A. 5. Exterior finish refers to material applied directly to

container surface not including insulation. Insulation

and coatings for insulation to be reported in IV-C.

B. l. Water, potable water, or other transfer liquid.

D.l & Materials used (gaskets or sealants) at inlets or outlets

D.2. of storage tank or container.

F-G-H. If the answer to any of these questions is "yes" it

is not necessary to explain in detail as the details

will be discussed in the follow-up telephone conversations.

Part V. ENERGY TRANSPORT INFORMATION

A-B. If more than one size or type of material is used, please

report all sizes and types.

C. "Manifolding" refers to any special method of interconnecting collectors other than those listed in D-l and

D-2

.

D.l. If more than one connection system is used indicate type

and where used, i.e. soldered at collector, threaded at

tank, bonded to pumps, etc.

D.2. Refers to any flexible connectors used, for example,

connecting collectors with rubber hose, etc.

D.2.b. If clamps are used on flexible rubber or plastic connectors,

indicate whether spring type, worm drive open web, worm

drive solid band, etc.

D.2.c. If flexible hose connectors are used outdoors indicate

if any protective coating or covering is used.

87
-3-

E.l & Pipe or duct insulation only.

E. 2.

F. l & Include gaskets or sealants used at inlet and outlet

F. 2. of pumps or blowers and at connections to collectors

(if any).

G. Filters or getter columns refer to liquid systems only.

H-I-J. If the answer to any of these questions is "yes" it is

not necessary to explain in detail as the details will

be discussed in the follow-up telephone conversations.

88
. -

.

:

APPENDIX B

V

'

•

' '

t

' «

.

89
AAI Corporation

Box 6767

Baltimore, MD 21204

Irwin R. Barr

A—1 Hydro Mechanics Corporation

94-150 Leokane Street

Waipahu, Oahu, Hawaii 96797

The A. Bentley & Sons Company

P. O. Box 956

Toledo, OH 43695

John D. Hilton

Acorn Glas - Tint International

1123 W. Century Blvd.

Los Angeles, CA 90044

Chris T. Dunkle

A. Goodman & Company, Inc. 7621 Greenwood Avenue, S. Chicago, IL 60619

Robert L. Goodman, V.P.

Aaron Plumbing & Mechanical Systems, Inc. 15 Poland Place

Staten Island, NY 10314

Paul Gardner, Pres.

Albuquerque Western Industry, Inc. Albuquerque, NM 87107

Alcan Aluminum Corp.

1108 Hereford Rd.

Cleveland Heights, OH 44112

Allied Fabricators, Inc. 1254 Thomas Avenue

San Francisco, CA 94124

Alpha Designs

Suite 2230 Kroeger Bldg.

Cincinnati, OH 45202

M. Uroshevich

Alternative Systems

Tasker Hill Road

Conway, NH 03818

Russ Lanoie

Aluminum Company of America

1501 Alcoa Building

Pittsburgh, PA 15219

William M. Foster

Amelco Window Corp.

77 Route 17, Box 333

Hasbruck Heights, NJ 07604

American Energy Alternatives, Inc. P.O. Box 905

Boulder, CA 80302

J. P. Sayler

American Heliothermal Corporation

3515 S. Tamarac, Suite 360

Denver, GO 80237

Bill L. Phillips, Pres.

American Pool Service Corporation

210 N. Aberdeen Avenue

Wayne, PA 19087

Samuel C. Miller, Pres.

American Solar Companies, Inc. 92 Broadway

Denville, NJ 07834

Edward Smith, President

American Solar Corporation

7425 S.W. 159th Terrace

Miami, FL 33157

Albert H. Ziegler

American Solar Energy, Inc. 8652 Magnolia Avenue, #7

Santee, CA 92071

James Bartell, Pres.

American Solar King Corporation

6801 New McGregor Highway

Waco, TX 76710

Brian Pardo, Pres.

Ametek , Inc

.

One Spring Avenue

Hatfield, PA 19440

John Bowen

Arizona Solar Enterprises

6719 E. Holly St.

Scottsdale, AZ 85257

Arkla Industries Inc. Special Products Division

400 East Capitol

Little Rock, AR 72203

Thomas M. Helms

Artech Corp.

2816 Fallfax Dr. Falls Church, VA 22042

Mr. Robert A. Hermann

Atlas Corp.

2060 Walsh Ave.

Santa Clara, CA 95050

90
Atlantic Solar Products, Inc. Reston Int. Center-Suite 227

11800 Sunrise Valley Drive

Reston, VA 22091

D. L. Ringwalt, Jr., Pres.

Automatic Energy Corp.

P. 0. Box 21

Rehoboth, MA 02769

John M. McNamara

B & B Plastic Corporation

107 Menchaca

San Antonio, TX 78102

Earl Brown

Barber-Nicols Engineering Co.

6325 West 55th Ave.

Arvada, CO 80002

Kenneth E. Nichols

Barwood

Boca Raton, FL 33432

George H. Sparling

B. Gilbert Contracting Company

41 Mechanic Street

Bristol, CT 06010

Bruno J. Gilbert

Barrett Heating & Air

Conditioning Company, Inc. 2260 Union Blvd.

Bayshore, NY 11706

Gary Shoemaker

Basic Designs, Inc. 3000 Bridgeway

Sausalito, CA 94965

Bateman & Son, Inc. 2004 Rhode Island Avenue, N.E.

Washington, D.C. 20018

Joseph L. Bateman, Pres.

Berry Solar Products

Woodbridge at Main

P. 0. Box 327

Edison, NJ 08817

Calvin C. Beatty

Boeing Aerospace Company

Field Operations and Support Division

P. 0. Box 3999

Mail stop 85-57

Seattle, WA 98124

John H. McGowan

Mr. Stanley R. Borgman

709 N. Federal Hy.

Stuart, FL 33494

Bonhag Company, Inc. 116 Washington Avenue

Hawthorne, NJ 07506

Wayne T. Bonhag, V.P.

Brewer Sheet Metal Company

125 Garfield Avenue

West Chester, PA 19380

Vernon S. Brewer

Bright Horizons

1200 Jackson Road

Carollton, TX 75006

Mike Goetz

Brown Manufacturing Co.

P. 0. Box 14546

Oklahoma City, OK 73114

Russell Brown

D.W. Browning Contracting Co.

475 Carswell Ave.

Holly Hill, FL 32017

Don Willis

Burke Rubber Co.

2250 S. Tenth St.

San Jose, CA 95112

Business & Technology, Inc. 2800 Upton Street, N.W.

Washington, D.C. 20008

S. Molivadas, Pres.

Robert J. Buswick

259 Holstein Road

Gulph Mills

King of Prussia, PA 19406

Robert Buswick

Butler Ventamatic Corporation

P.O. Box 728

Mineral Wells, TX 76067

Terry Siegel, V.P.

John C. Byram, Jr. 615 W. 50th Street

Kansas City, MO 64112

Calmac Manufacturing Corporation

150 S. Van Brunt Street, Box 710

Englewood, NJ 07631

Calvin D. McCracken

Cambridge Development Group

Rt. 2, Yacht Cove Road

Columbia, SC 29210

Keith B. Belser

R. H. Bohman

Amana Refrigeration Inc. Amana, IA 52203

91
Carlisle Tire & Rubber Co.

P. 0. Box 99

Carlisle, PA 17013

Carrier Air Condition Co.

Carrier Parkway

Syracuse, NY 13201

Caster Development Co.

634 Crest Drive

El Cajon, CA 92021

Central Virginia Sunglow

4905 Radford Avenue

Richmond, VA 23230

Donald K. Hudson, Pres.

Certain-Teed Products Corp.

P. 0. Box 860

Valley Forge, PA 19482

Chamberlain Manufacturing Corporation

845 Larch Avenue

Elmhurst IL 60126

Charles H. Franke

Chamisa Solar Canmunity , Inc.

P. 0. Box 387

Lanham, MD 20801

Paul M. Emmons

Champion Home Builders Company

5573 North Street

Dryden, MI 48428

Henry H. Leek

Chemalloy Electronics Corp.

7949 Towers - P. 0. Drawer 10

Santee, CA 92071

Mr. Friedman

Chemex Corp.

211 River Road

New Castle, DE 19720

Cole Solar Systems , Inc. 440-A E street, Elmo Rd,

Austin, TX 78745

Warren Cole, Pres.

Columbia Gas System Svc. Corp.

1600 Dublin Rd.

Columbus, OH 43215

George W. Myler

Columbia Technical Corporation

Solar Energy Division

55 High Street

Holbrook, MA 02343

Walter H. Barrett

Comfort Master of Sacramento

1517 19th Street

Sacramento, CA 95814

Edward R. Atkins

COMSAT

Box 115

Clarksburg, MD 20734

Dr. E.S. Rittner

Connecticut Solar Systems, Inc.

72 Florence Road

Riverside, CT 06878

Seymour Polansky, Pres.

Conserdyne Corporation

4437 San Fernando Road

Glendale, CA 91204

Howard Kraye

Consolidated Aluminum Corp.

700 E. Godfrey Ave.

Philadelphia, PA 19104

Copper Development Association

405 Lexington Avenue

New York, NY 10017

George M. Hartley

Crayton Enterprises, Inc. 3924 W. Crest Avenue

Tampa, FL 33614

Gary F. Crayton, Pres.

Daylin, Inc. 9606 Santa Monica Blvd.

Beverly Hills, CA 90210

CSI Solar Systems Division

12400 49th Street

Clearwater, FL 33520

L. H. Sallen

Daystar Corporation

41 Second Avenue

Burlington, MA 01803

Clifton C. Smith

Daniel Green Associates

12909 Camphill Street

St. Louis, MO 63141

Daniel M. Green

92
Deko-Labs of Friberg-Dekold Corp.

Box 12841 University Station

3860 Southwest Archer Rd.

H-3, Gainesville, FL 32604

Donald F. DeKold

Del Sol Control Corp.

11914 U.S. 1 Juno, FL 33408

Rodney E. Boyd

Delta T. Company

2522 W. Holly

Phoenix, AZ 85009

James L. Hoyer

Diversified Solar Products/Engineering

285 Stratford Rd. Suite 207

Winston-Salem, NC 27103

Larry J. Folds

D. J. Products

Box 2292

North Canton, OH 44720

Ronald R. Brookes

Donald Johnson & Assoc.

2523 16th Avenue South

Minneapolis, MN 55404

Duncan Solar Co.

P. 0. Box 4923

Stanford, CA 94305

E. H. Ellis Inc. Box 1487

Homestead, FL 33030

Edward H. Ellis

East Greenbush Plumbing & Heating

34 Old Troy Road

East Greenbush, NY 12061

Frank J. Ginther

E.B.S. Inc. Tech. Center

19 West College Ave.

Yardley, PA 19067

Ecotope Group

2270 NW Irving

Portland, OR 97210

Eeothermia , Inc

.

550 East 12th Avenue

Suite 1801

Denver, CO 80203

L. Lore Wartes

ELCAM, Inc. 5330 Debbie Lane

Santa Barbara, CA 93111

Allen Copper, Pres.

Eltra Corp. C&D Batteries Div.

3043 Walton Rd.

Plymouth Meeting, PA 19402

EMCO Building Supply, Inc.

P. 0. Box 308

Bethany, OK 73008

James E. Emmert, Pres.

Eco-Solutions , Inc

.

P. 0. Box 4117

Boulder, CO 80302

Robert Hess

Ecotechnology , Inc

.

234 Barbara Ave.

Solano Beach, CA 92075

Candace G. Pettus

Ecotope Group

Box 618

Snohomish, WA 98290

Mr. Ken Smith

Electrasol Laboratories, Inc. 2425 Brengle Ave. #9

Orlando, FL 32808

Dr, Harold R. Dessau

Marvin E. Holgren, Mgr. of Engrg.

Elkhart Products Corp.

1255 Oak St.

Elkhart, IN 46514

Energy Conservation Systems

5932 Del Paz Dr. Colorado Springs, CO 80918

Peter 0. Wood

The Energy Conserver

2595 Barkman Drive

Colorado Springs, CO 80916

Donald Holzworth

Herbert J. Holmquist

Energy Rsch. Co.

P. O. Box 532

Flint, MI 48501

Energy Systems Consultants

7120 Hayvehhurst

Van Nuys, CA 91406

William P. Stevens

93
Energex Corporation

5115 Industrial Road

Las Vegas, NV 87118

Energex Corporation

957 Toni Avenue

Las Vegas, NV 89119

A1 Jenkins

Energy Design Associates, Inc. 3003 N.E. 19th Drive

Gainesville, FL 32601

Richard Rodgers

Energy Dynamics Corporation

327 West Vermijo Avenue

Colorado Springs, CO 80903

Peter 0. Wood

Energy Research Group, Inc.

P. O. Box 8025-A

Orlando, FL 32806

John J. Hobbs, Pres.

Energy Systems, Inc. 634 Crest Drive

El Cajon, CA 92021

Terrence R. Caster

Enersol Company

First International Bldg, Ste. 1800

Dallas, TX 75270

J.O. Carnes, Sr., Vice Pres.

Enertech Corp.

P. O. Box 420

Norwich, VT 05055

Edmund Coffin

Environmental & Ecological Products,

P.0. Box 155

Columbia, MD 21045

George W. Hunter, Jr.

Environmental Energies, Inc. 21243 Grand River Ave.

Detroit, MI 48219

Timothy J. Homing

Environmental Energy

121 Broadway, Suite 535

San Diego, CA 92101

Graham Hatfield

Environmental Future, Inc. 150 S. Los Robles St. 880

Pasadena, CA 91101

Environmental Research & Technology,

696 Virginia Road

Concord, MA 01742

Norm Geril

ERA Del Sol

5960 Manderin Dr. Goleta, CA 93017

Erwin & Sons, Inc. 110 Maple Street, N.E.

Albuquerque, NM 87106

Maynard L. Toensing, V.P.

EVOG

Box 36 Hebron, NH 03241

Paul S. Hazleton

FAFCO, Inc. 138 Jefferson Drive

Menlo Park, CA 94025

Freeman A. Ford

Falbel Energy Systems Corp.

472 Westover Rd.

Stamford, CT 06902

Gerald Falbel

Flagala Corporation

9700 West Highway 98

Panama City, FL 32401

Henry G. Swicord, Pres.

Filon

Vistron Corp.

12333 S. Van Ness Ave. Hawthorne, CA 90250

Floyd ' s Heating , Inc

.

P. 0. Box 175

Goleta, CA 93017

Robert Floyd, Pres.

Free Heat

P. 0. Box 8934

Boston, MA 02114

Fun & Frolic, Inc. Dept. S, P. 0. Box 277

Madison Heights, MI 48071

Edward J. Konopka

Future Systems , Inc

.

12500 W. Cedar Drive

Lakewood, CO 80228

William Thompson

Gaffigan Company

1217 S. Railroad Avenue

San Mateo, CA 94402

Garden Way Laboratories

Inc. P. O. Box 66

Charlotte, VT 05445

Dr. Douglas Taff

94
GASCO, Inc.

P. 0. Box 3379

Honolulu, HI 96842

Howard Lee, Sr., V.P.

Gaydart Industries , Inc

8542 Edgeworth Dr. Capital Hts., MD 20028

George R. Gaydos

General Atomic Co.

P. 0. Box 81608

San Diego, CA 92138

J.L. Russell, Jr.

General Electric Co.

P. 0. Box 8661

Philadelphia, PA 19101

B.J. Tharpe

General Energy Devices

2991 West Bay Drive

Largo, FL 33540

David DeSormean

General Solar Power Corporation

99 Park Avenue

New York, NY 10016

Earle W. Kazis, Pres.

W.A. "Bill" Starrs, Jr. Mktg. Staff Rep.

Georgia Power Co.

Box 4545

Atlanta, GA 30302

Glasteel

727 Buena Vista

Duarte, CA 91010

ATTN: Jim Christopher

Gleason Supply Company

9 Water Street

Biddeford, MA 04005

Thomas Gleason

Gorman-Lavelle Plumbing Co.

3459 East 52nd Place

Cleveland, OH 44127

Anthony E. Lavelle

Gould, Inc. 540 East 105th St. Cleveland, OH 44108

E.L. Thellman

Ronald C. Autenrieth, Mgr.

Distributor-Dealer Prod.

W.R. Grace and Co.

62 Whittemore Ave.

Cambridge, MA 92140

Grassy Brook Village

Box 121

Townshend, VT 05353

John T. Schenbly, Jr.

Grumman Corporation

1111 Stewart Avenue

Bethpage, NY 11714

Ronald B. Peterson

Gulf Thermal Corporation

P.O. Box 13124

2215 Industrial Blvd/Airgate

Sarasota, FL 33578

Dudley Slocum, Pres.

Haldeman, Inc. 2845 Supply Avenue

Los Angeles, CA 90040

Tom Haldeman

Halstead & Mitchell

Div. of Halstead Indus., Inc.

P. 0. Box 1110

Scottsboro, AL 35768

Otto J, Nussbaum, Director of Engineering

Rsch. & Devel.

Hansberger Refrigeration & Electric Co.

2450 8th Street

Yuma, AZ 85364

Edwin L. Hansberger, Jr.

Hatic Heating, Refrigeration & Air

Conditioning

619 29th Street South

Arlington, VA 22202

Richard C. Adams

Hatic Heating, Refrigeration & Air

Conditioning

P. 0. Box 221

Milford, OH 45150

Osman Hatic, Pres.

Arthur L. Hawk

Engineering Consultant

535 W. Great Falls Street

Falls Church, VA 22046

Hawkins & Anderson, Inc. 117 North Hamilton St. Richmond, VA 23230

95
Heat Recovery Systems, Inc. 233 Grand Boulevard

Westbury, NY 11590

Frank R. Stark

Helio Associates, Inc.

P. 0. Box 17960

Tucson, AZ 85731

Jeffrey R. Wootan

Heliometries

33 Stowe Lane

Menlo Park, CA 94025

Kim Mitchell

Heliopticon Corporation

One Pine Street

Nashua, NH 03060

David L. Thun, Pres.

Hussey Metals Division

Copper Range

Washington St. Leetsdale, PA 15056

Albert C. Kolesar, Product Mgr.

J. Hutchison

147 Parkhouse

Dallas, TX 75207

Hydro-Flex Corporation

2101 Northwest Brickyard Road

Topeka, KS 66618

Max L. Campbell, Pres.

IBM

150 Sparkman Dr. Huntsville, AL 35805

Ms. P. A. Cosper

Heliotherm, Inc

.

W. Ienni Road

Lenni, PA 19052

Don L. Kirkpatrick

Helter-Skelter Engineering

Box 479

Forest Knolls, CA 94933

William Wark-Swann

HEXCEL Corporation

117.11 Dublin Blvd.

Dublin, CA 94566

George P. Branch

Highland Manufacturing Company

1002 C.W. Gladstone Street

San Dinas, CA 91773

Peter J. Kalman

Stanley C. Hills

76 Sandy Neck Road

E. Sandwich, MA 02537

Hoffman Products, Inc.

P. 0. Box 975

Willmar, MN 56201

Gary G. Hoffman

Homecraft

2350 West 47th Street

Denver, CO 80211

Honeywell , Inc

.

Aerospace & Defense Group

2600 Ridgeway Parkway

Minneapolis, MN 55143

Jerry Mevissen/R2380

Honius Electric , Inc

.

846 Brown Street

Dayton, OH 45409

Howard W. Honious , Pres.

IDE Air Equipment, Inc. Box Hill M. , East

N.E. Station

Wilkes-Barre, PA 18705

Richard H. Paterson

Independent Power Developers

Box 167

Noxon, MT 59853

John R. Zlvhuska

International Environment Corp.

129 Halstead Ave.

Mamaronack, NY 10543

Mr. Richard D. Rothschild

International Environment Corp.

1400 Mill Creek Rd.

Gladwyne, PA 19035

Mr. Richard H. Kiley

International Rectifier

Semiconductor Division

233 Kansas St. El Segundo, CA 90245

International Scientific Energy, Inc.

P. 0. Box 537

Flagstaff, AZ 86001

Herbert Wade

International Telephone and Telegraph Co.

4711 Golf Road

Skokie, IL 60076

J. A. Lane

Iowa Solar , Inc

.

Rt. 1, Box 343

North Liberty, IA 52317

D. Dunlavy, Pres.

96
Independent Living , Inc

5730 Holiday Road

Buford, GA 30518

William T. Hudson

International Sunmaster, Inc.

P. 0. Box 129

Colorado Springs, CO 80901

Tcm Forster, Pres.

Intertechnology Corporation

Box 340

Warrenton, VA 22186

Dr. George C. Szego, Pres.

Irvin Industries, Inc. Structures Group

555 S. Broadway

Lexington, KY 40508

Lloyd Rain

Isothermics

P. 0. Box 86

Augusta, NJ 07111

Itak Corp.

10 Maquire Rd.

Lexington, MA 02173

Jack Berenholz

Janofsky Associates

P. 0. Box 48415

Briggs Station

Los Angeles, CA 90048

J & R Simmons Construction

2185 Sherwood Drive

South Daytona, FL 32109

Jessup Company

Box 9126

Greensboro, NC 27408

Kenneth D. Jessup

John J. McMullen Associates, Inc. One World Trade Center

New York, NY 10048

Louis H. Roddis, Jr., Pres.

Johnson Controls, Inc. Penn Division

2221 Camden Court

Oak Brook, IL 60521

J.P. Morrison, Product Manager

Johnson Service Co.

Research Division

507 E. Michigan St. Milwaukee, WI 53201

S.R. Buchanan

Johnston Manufacturing Co.

Solar Division

33458 Angeles Forest Hwy.

Palmdale, CA 93550

J. G. Johnston

Kaiser Aluminum

9501 West Devon

Rosemont, IL 60018

R.V. Paulson, Mgr. Finishing & Corrosion Engineer

Kalwall Corporation

P.0. Box 237

Manchester, NH 03105

Keith W. Harrison, V.P.

Kaman Sciences Corporation

P. 0. Box 7463

Colorado Springs, CO 80933

Douglas M. Jardine, P.E.

Kapp Alloy & Wier Co.

226 3A S. Normandie

Torrance, CA 90501

Kawneer Company, Inc. 1105 N. Front Street

Niles, MI 49120

Ben H. Fly

Kay University

11675 Sorrento Valley Road

San Diego, CA 92121

William K.R. Watson

Kaye Instruments , Inc

15 De Angelo Drive

Bedford, MA 01730

Newell F. Tillman

Kennard Industries , Inc

10961 Olive Boulevard

St. Louis, MO 63141

Sam M. Kennard, III, Pres.

Kessel Insolar System

2135 Mono Way

Sonora, CA 95370

Kenneth Kessel, Owner

Mel Kiser & Associates

6701 E. Kenyon Dr. Tucson, AZ 85710

Mel Kiser

K-Line Corp.

12300 Washington Ave.

Rockville, MD 20852

Ted Knapp

97
K. T.A. Corporation

12300 Washington Ave.

Rockville, MD 20852

Ted Knapp

Lambda Instruments Corp.

4421 Superior Street

P. 0. Box 4425

Lincoln, NE 68504

Joe H. Hultquist, Ph.D.

Libbey-Owens-Ford Co.

811 Madison Ave.

Toledo, OH 43695

D.R. Grove, Sales Mgr.,

Liberty Mirror & Aircraft Prod.

L. M. Dearing Associates, Inc. 12324 Ventura Boulevard

Studio City, CA 91604

Dr. LeRoy M. Dearing, Pres.

Lardic Solar Energy, Inc. 400 Agnew Road

Jeanette, PA 15644

Dick O'Neill, Pres.

Lennox Industries, Inc. 200 South 12th Avenue

Marshalltown, QA 50158

Gary 0. Hanson

Living Under the Sun

115 Millview St. Uniontown, PA 15401

Mr. & Mrs. L.S. Cooper

IO-K Medallion Systems, Inc. P.0. Box 188

Belmont, NC 28012

Robert Kincaid

MAF Mechanical Service Corporation

3304 Shore Road

Oceanside, NY 11572

M. Amsterdam, Vice Pres.

Mankind Research Unlimited, Inc. 7775 17th Street, N.W,

Washington, D.C. 20012

Dr. Carl Schleicher

Matrix Inc. 537 South 31st Street

Mesa, AZ 85204

M. Blecher & Sons, Inc. 9412 Buckeye Road

Cleveland, OH 44104

Edgar A. Blecher

MND , Inc

.

P. O. Box 15534

Atlanta, GA 30333

Monte V. Davis, Pres

McCombs Solar Company

1629 K Street, N.W. , Suite 520

Washington, D.C. 20006

John C. Engle, Vice Pres.

McDonnell Douglas Astronautics Company

5301 Bolsa Avenue

Huntington Beach, CA 92637

Frank F. Duquette

Meenan Oil Company, Inc. Levittown Parkway

Levittown, PA 19059

Bradley R. Davis

Mr. Mitchell

18391 N. Miami Ave.

N. Miami Beach, FL 33169

Chuck Missar

704 Birch Ave.

Cottage Grove, OR 97424

Mitre Corp.

1820 Dolly Madison Blvd.

McLean, VA 22101

Steven Bloom, A.T.X.

Mobil Tyco Solar Energy Corp.

16 Hickory Drive

Waltham, MA 02145

A. I. Mlavsky

Monsanto Research Corp.

1515 Nicholas Rd.

Dayton, OH 45407

Frank Winslow

Moore Fuels, Inc. 525 North High Street

Millville, NJ 08332

William Moore, III

Motorola , Inc

.

4039 E. Raymond, M-6

Phoenix, AZ 85040

Nalle Plastics Inc. 203 Colorado St. Austin, TX 78701

George S. Nalle, Jr.

NRG LTD. 901 Second Avenue East

Coralvilie, IA 52241

Dave Simms

98
National Solar Corporation

Novelty Lane

Essex, CT 06426

Anthony Easton, Pres.

Oden Brothers, Inc. 310 East Fourth Street

Frederick, MD 21701

R. Herbert Oden

National Solar Supply Co. Div. of Stamar, Inc. 1250 Winchester Parkway

Suite 200

Smyrna, GA 30080

Bryan Stansell

01in Brass

01in Corporation

East Alton, IL 62024

Sheldon H. Butt

Oregon Equipment Mfg . , Inc

.

165 E. Greenwood

Natural Heating Systems

207 Cortez Ave.

Davis, CA 95616

David A/ Springer

Bend, OR 97701

Mike Hollis

Owens-Illinois

Post Office Box 1035

NET.SCO, Inc. RD #1

Pittsford, VT 05763

Toledo, OH 43666

R.E. Ford

Owens Services Corporation

Niagara Blower Co. 405 Lexington Ave. New York, NY 10017

Erwin Lodwig

930 E. 80th Street

Minneapolis, MN 55420

Robert H. Owens, Pres.

OEM Products , Inc

.

Noranda Metal Industries, Inc. French Tube Division

108 Prospect Dr. Newtown, CT 06470

J.R. Russell

Solarmatic Division

214 W. Brandon Blvd.

Brandon, FL 33511

D. W. Barlow, Sr.

PPG Industries, Inc. North American Solar

2500 D Valley Rd.

Reno, NV 89502

One Gateway Center

Pittsburgh, PA 15222

Neil M. Barker

Northrup, Inc. 302 Nochols Dr. Hutchins, TX 75141

P.S.H. Construction Company

12430 Heather

Clovis, CA 93612

Philip Hickerson

Northwest, Inc. Box 384-Northgate Drive

Warrendale, PA 15086

Albert A. Bartos, Pres.

PAK-WELL Co. Colton & Opal Streets

P.O. Box 1129

Redlands, CA 92378

Nottingham MC Co. of Calif.

244 S. Bent

San Marcos, CA 92060

J. W. Nelson

PARCO Building Corporation

P. 0. Box 740

Oak Ridge Engineering & Associates

110 Peach Rd. , P.0. Box 3016

Oak Ridge, TN 37830

Vernon J. Hockman

Gloucester, VA 23061

Warren E. Parkhurst

Patterson Solar Systems

185 Magnolia Avenue

O' Boyle Plumbing & Heating

5300 Iroquois Road

Washington, D.C. 20016

Joseph V. O' Boyle

Floral Park, NY 11011

James B. Patterson

The Pendleton Company

8115 Central Expressway

Suite 425

Richardson, TX 75080

James D. Pendleton

99
PERFICOLD

50942 U.S. 31 North

South Bend, IN 46637

William R. Gallagher, Pres.

Phila. Electric Co.

2301 Market St. Philadelphia, PA 19101

George A. Hunger, Jr.

Pittsburgh Coming Corp.

800 Presque Isle Dr. Pittsburgh, PA 15239

Walter F. Lynsavage

Pomona Park, Inc. 71 Smith Hill Road

Monsey, NY 10952

Stephen Iser, Pres.

Portable Aluminum Irrigation Co. , Inc.

P.O. Box 878

Vista, CA 92083

Will C. Kinney

Porter Heating & Cooling

1801 Nottingham Rd.

Newark, DE 19711

PR Distributors

Aquasolar Pool Heaters

1232 Zacchini Ave. Sarasota, FL 33577

John Pickett

Pyramid Plumbing

1708 S. Congress

West Palm Beach, FL 33606

Ranco

601 W. Fifth Ave., Box 8187

Columbus, OH 43201

R.A. Townsend Company

1100 Bagley Street

Alpena, MI 49707

R. A. Townsend, Jr.

Raypack , Inc

.

31111 Agoura Rd.

P. 0. Box 5790

Westlake Village, CA 91359

R. M. Thornton, Inc. 1354 Florida Avenue, N.W. Washington, D.C. 20002

Frank M. Reaves

Raytheon Company

141 Spring Street

Lexington, MA 02173

Gerald F. Olsen

Remarch Company , Inc

.

4530 McPherson

St. Louis, MO 63108

James M. Darrish, Pres.

Research Consultants Cooperative

P. O. Box 407

Salem, NH 03079

Phoebe Rideout

Research Products Corporation

P.O. Box 1467

Madison, WI 53701

E. F. Rothe

Providence Community Action Program,

1082 Chalkstone Avenue

Providence, RI 02908

Thomas J. Rossi

Piper Hydro Incorporated

2895 East La Palma

Anaheim, CA 92806

James R. Piper

Quality Installation Services

12510 Winexburg Manor

Silver Spring, MD 20906

Paul Green

RAM Products Inc. Box 340

Sturgis, MI 49091

Paul Sorkoram

Inc. Resource Technology Corp.

151 John Downey Dr. New Britain, CT 06051

Revere Copper & Brass, Inc.

P. 0. Box 151

Rome, NY 13440

William J. Heidrich

Reynolds Metal Company

6601 W. Broad Street

Richmond, VA 23261

Chester H. Holtyn

RKL Controls, Inc. Hainesport Industrial Park

Hainesport, NJ 08036

100
Rheem Manufacturing Co.

7600 South Kedzie Ave. Chicago, IL 60652

Mr. D. W. Proulx

RHODIA, Inc. 1145 Towbin Avenue

Lakewood , NJ 08701

Matthew J. Napoli

E. F. Rockfeller

P.O. Box 13601

Philadelphia, PA 19101

Robertson Co. Resolite Div.

Zelienople, PA 16063

Rockwell International Corp.

2230 E. Imperial Highway

El Segundo, CA 90245

Douglas W. Hege

Rodgers & MacDonald

3003 N.E. 19th Dr. Gainsville, FL 32601

Forbes Howard

Rocky Mountain Air Conditioning

5010 Cook Street

Denver, CO 80216

Don ERickson

Schodorf Plumbing & Heating

24 E. Pearl Street

Willard, OH 44890

Harold J. Schodorf, V.P.

Scientific-Atlanta, Inc. 3845 Pleasantdale Road

Atlanta, GA 30340

Glen P. Robinson, Jr.

Jack S. Scovel

4220 Berritt St. Fairfax, VA 22030

Sea Solar Power, Inc. 1615 Hillock Lane

York, PA 17403

J . Hilbert Anderson

SENNERGETICS

18621 Parthenia Street

Northridge, CA 91324

James C. Senn

Sensor Technology, Inc. 21012 Lassen St. Chatsworth, CA 91311

Service Unlimited Inc. Second & Walnut Sts.

Wilmington, DE 19801

Richard W. Wolf

Rothenberger

7317 Cahill Rd.

Suite 261

Minneapolis, MN 55435

Rust Construction Co. , Inc. 210 South Payne Street

Alexandria, VA 22314

Thcmas L. Rust, Pres.

Sanders Associates, Inc.

95 Canal Street-MER12-1124

Nashua, NH 03060

James J. Connolly

SCHIBI Heating & Cooling

5025 Hubble Road

Cincinnati, OH 45239

Kenneth A. Schihi, Pres.

Schmitt's Heating & Air Conditioning

Service

211 Auburn Street

Ithaca, NY 14850

E. K. Glover

Sheldahl , Inc

North High #3

Northfield, MN 55057

Sheller-Globe Corporation

1641 Porter

Detroit, MI 48216

John D. Columbo

Sierra Solar Systems

P.O. Box 2634

Olympic Valley, CA 95730

Frank Lavue

Sierra Solar Systems, Inc. P.O. Box 310

Nevada City, CA 95959

Karl R. Stewart

Silicon Material, Inc. 341 Moffett Blvd.

Mountain View, CA 94043

John E. Lawrence, Pres.

101
J&R Simmons Constr. Co. Inc. 2185 Sherwood Dr.

South. Daytona, FL 32019

John Sinmons

SILTBC Corporation

3717 Haven Avenue

Menlo Park, CA 94025

Robert E. Lorenzini

Slack Associates

2904 Stafford Street

Baltimore, MD 21223

Howard C. Slack, Pres.

SOCAR Service Corporation

7400 N.W. 30th Avenue

P.O. Box 47-1238

Miami, FL 33147

James Carrano

Solar-Aire of California

80 S. Third Street

San Jose, CA 95113

Eugene L. Pfeiffer

Solaray Corporation

2414 Makiki Hgts. Dr. Honolulu, HI 96822

Lawrence M. Judd

Solaray, Inc. 324 S. Kidd St. Whitewater, WI 53190

Robert K. Skrivseth

Solar American

106 Sherwood Drive

Williamsburg, VA 23185

Robert J. Pegg

Solar Applications , Inc

.

7926 Convoy Court

San Diego, CA 92111

Edward Sorenson, Pres.

Solar Comfort, Inc. 249 South Grove Street

Venice, FL 33595

Paul A. Youngberg

Solar Corp.

9620 Royalton Dr. Beverly Hills, CA 90210

Solar Development , Inc. 4180 Westroads Drive

West Palm Beach, FL 33407

Don Kazimir

Solar Dynamics, Inc. 4527 E. 11th Ave. Hialeah, FL 33013

Solar Energetics, Inc. 2126 Willow Way

Ardencroft, DE 19810

William M. Anderson

Solar Energy Company (DC)

818 18th St. N.W. Washington, D.C. 20006

G. H. Hamilton

Solar Energy Components, Inc. 1605 N. Cocoa Blvd.

Merritt Island, FL 32922

Solar Energy Contractors, Inc. 3156 Leon Road, P.O. 16425

Jacksonville, FL 32261

Wallace W. Stewart

Solar Energy Development, Inc. 1437 Alameda Ave.

Lakewood, OH 44107

Mr. Nicholas Macron

Solar Energy Digest

P. O. Box 17776

San Diego, CA 92117

William B. Edmondson

Solar Energy Modules Company

1091 S.W. 1st Way

Deerfield Beach, FL 33441

David B. Aspinwall, Jr.

Solar Energy Products Co.

121 Miller Rd.

Avon Lake, OH 44012

Solar Energy Products, Inc. 1208 N.W. 8th Avenue

Gainesville, FL 32601

Jack C. Ryals, Pres.

Solar Energy Products, Inc. 680 Central St. (Rt. 12)

Leominster, MA 01453

Richard D . Rettberg

Solar Energy Research Corp.

1228 15th St., Suite 412

Denver, CO 80202

James B. Wiegand

Solar Energy Resources Corporation

10639 S.W. 185th Terrace

Miami, FL 33157

Scott Balmer

Solar Energy Structures , Inc.

P. 0. Box 225

Southbury, CT 06488

James R. Bette
Solar Energy Systems

1243 S. Florida Ave.

Rockledge, FL 32955

Roy C. Meade

Solar Energy Systems, Inc. 70 S. Chapel St. Newark, DE 19711

Robert 0. Johnson

Solar Energy Systems, Inc. 2492 Banyan Dr. Los Angeles, CA 90049

Kenneth I . Brody

Solar Energy Systems, Inc. 2101 Starkey Rd.

Largo, FL 33540

Ronald E. Gregg

Solar Energy Systems of Orlando

300 S. Semoran Blvd.

Orlando, FL 32807

Solar Environmental Engineering Company

P.O. Box 1914

Fort Collins, CO 80521

C. Byron Winn, Pres.

Solar Energy Systems, Inc. 9016 Collins Avenue

Pennsauken, NJ 08110

Nathan E. Brussels

Solar Energytics, Inc. P.O. Box 532

Jasper, IN 47546

Douglas A. Wassmer, V.P.

Solar Equipment Sales Company

Box 625-Sentry Place

Scarsdale, NY 10583

Patrick R. Sbarra, Pres.

Solar Heat Company

P.O. Box 42

Hesperia, CA 92345

Ralph Kipper

Solar Heat of Pennsylvania

Box 1056

420 W. Marion Street

Lancaster, PA 17604

Robert G. Ulmer

Solar Heating Services, Inc. 1112 Woodside Parkway

Silver Spring, MD 20910

James R. Mazzullo, Pres.

Solar Heating Systems Corp.

151 John Downey Dr. New Britain, CT 06051

Alvin L. Trumbull

Solar Homes Systems, Inc. 12931 W. Geauga Trail

Chesterland, OH 44026

Joe Barbish

Solar Homes , Inc

.

2 Narragansett Avenue

Jamestown, RI 02835

Spencer Dickinson

Solar Heme Systems, Inc. 3309 Estero Drive

San Ramon, CA 94583

Preston H. Hunter, Pres.

Solar Industries. Inc. 100 Captain Neville Drive

P. O. Box 3206

Waterbury , CT 06705

Andreas Duus, Jr.

Solar Industries , Inc

.

324 South Third, #1

Las Vegas, NV 89101

Robert Sharp, Pres.

Solar Innovations

412 Longfellow Boulevard

Lakeland, FL 33801

Ronald Yachabach

Solar Installation & Service Division

of Helios Corp.

1313 Belleview Avenue

Charlottesville, VA 22901

John Embree, Pres.

Solar Kinetics, Inc. 147 Parkhouse Street

Dallas, TX 75207

Joe A. Hutchison, Pres.

The Solar King

4002 East Grant Road

Tucson, AZ 85712

Herbert Lee

Solar Master

8624 De Soto Avenue

Canoga Park, CA 91304

Stan Nathanson

103
Solar Mechanical Systems

11380 Rocky Mountain Street

Reno, NV 89506

Lewis R. Keith

Solar Research

Div. of Refrigeration Research

525 N. Fifth Street

Brighton, MI 48116

E. W. Bottum, Pres.

Solar Science Industries, Inc. 512 E. Indian Spring Drive

Silver Spring, MD 20901

Jerry Robison

Solar Services, Inc.

P. 0. Box 2166

Hendersonville, N.C. 28739

Helen P. Bird

Solar Structures

1255 Timberlake Drive

Lynchburg, VA 24502

W. W. Hays, III, Pres.

Solar System Sales, Inc. 180 Country Club Drive

Novato, CA 94947

George Walters, Pres.

Solar Systems Company

103 Jackson Avenue

N. Plainfield, N.J. 07060

Douglas Miller

Solar Systems , Inc

.

P. 0. Box 611

Princeton, WV 24740

Nabeel H. Hamden

Solar Systems of Florida

2551 Ulmerton Road

Largo, FL 33540

Kenneth Keene

Solar Systems West

421 Court Street

Elko, NV 89801

Mark Chilton

Solar Technology Company

210 New Hackensack Road

Poughkeepsie, NY 12603

Marion A. Zimmer, Pres.

Solar Technology, Inc. 119 North Center Street

Statesville, NC 28677

Nelson Brown, Pres.

Solar Technology, Inc. 5730 Holiday Road

Buford, GA 30518

William T. Hudson

Solar II Enterprises

21416 Bear Creek Road

Los Gatos, CA 95030

M. A. Clifton

Solar Usage Now, Inc. 450 E. Tiffin Street

Bascom, OH 44809

Joseph W. Deahl

Solar Utilities Company

406 North Cedros

Solana Beach, CA 92075

Jack Schultz , Pres

.

Solar-West Construction Company

565 Mountain Green Drive

Calabasas, CA 91302

Rod Bergen, Pres.

SOLARCOA, Inc. 4647 N. Long Beach Blvd., #A

2

Long Beach, CA 90805

K. E. Parker, Pres.

Solaron Corporation

4850 Olive Street

Denver, CO 80022

Edward M. Redding

Solar Products , Inc

.

P. 0. Box S-2883

San Juan, PR 00903

Chaim Shurka

Solarific Water Heating Co. 709 N. Federal Hy.

Stuart, FL 33494

Mr. Stanley R. Borgman

Solar Power Corp.

23 North Ave. Wakefield, MA 01880

R. W. Willis

Solar Products Engineering Co.

3 Birch Lane

Pelham, NH 03076

Ronald A. McCracken

S olar Products , Inc

.

P. 0. Box S-2883

San Juan, PR 00903

Herbert J. Houtkin

Solar Research

120 Erbbe N.E. Albuquerque, NM 87112
Solar Supply Co. 7724 Girard Ave. La Jolla, CA 92037

Solar Systems Inc. 12500 W. Cedar Dr. Lakewood, CO 80228

Bill Thompson

Solar Systems Inc. 1500 Durand Ave. Racine, WI 53403

Paul E. Sobel

Solarsystems Inc. 1515 WSW Loop 323

Tyler, TX 75701

John L. Decker

Solar Systems Sales

180 Country Club Dr. Novato, CA 94947

George Walters

Solar Thermics Enterprises, Ltd.

Box 248

Creston, LA 50801

Byron C . Brown

Solar Utilization Systems

2716 Marion Ave. 3G

Bronx, NY 10458

Juan E. Repollet

Solar Water Heater Co.

Solarsystems , Inc

.

1802 Dennis Drive

Tyler, TX 75701

James Estes

Solartram Company

P. 0. Box 496

Escanaba, MI 49829

John Walbridge, Pres.

Solarway

P. 0. Box 217

Redwood Valley, CA 95470

Mr. Ben Piraino

Solergy , Inc

.

150 Green St. San Francisco, CA 94111

Ronald H. Smith

SOLCAN, LTD. 126 Wychwood Park

London, Ontario, Canada N6G 1R7

R.K. Swartman

Soltec

P. 0. Box 6844

Denver, CO 80206

Richard S . Speed

Soltek Associates

2467 Warring Street, Suite 305

Berkeley, CA 94704

Richard P. Hills

10021 Southwest 38th Terrace

Miami, FL 33165

Walter V. Morrow

The Solargizer Corporation

3444 Hudson Road

Lake Elmo, MN 55042

Bill Olson

Solargy, Inc. 1486 Friendly Drive

Pasadena, MD 21122

Frank Weiskopf, Pres.

Solarponics

P. 0. Box 1571

San Luis Obispo, CA 93406

Michael J. Emrich

Solartec Co. 1203 Sun Valley Rd.

Solana Beach, CA 92075

Sol-Therm Corp.

7 W. 14th St. New York, NY 10011

Southeastern Solar Systems, Inc

4705-J Bakers Ferry Road

P. 0. Box 44066

Atlanta, GA 30336

E. Moore

Southern California Edison Co.

P. 0. Box 800

Rosemead, CA 91770

Gerald A. Howell

Southwest Air Conditioning, Inc

7268 El Cajon Boulevard

San Diego, CA 92115

William F. Hampson

Southwest Solar Systems

650 North 6th Avenue

Tucson, AZ 85705

D. K. Bennett

105
Southwest Solar Systems, Inc. 5555 North Lamar Boulevard #J107

Austin, TX 78751

Daniel J. Dotson, Pres.

Spectrolab, Inc

.

12484 Gladstone Ave.

Sylmar, CA 91342

Spiral Tubing Corp.

533 John Downey Drive

New Britain, CT 06051

Robert W. Perkins

SSP Associates

704 Blue Hill Road

River Vale, NJ 07675

Jed Schaiman

Steam Power Systems, Inc. 7617 Convoy Court

San Diego, CA 92111

Dr. Rod Burton

Steelcraft Corporation

Environmental Design Division

2700 Jackson Avenue

P. 0. Box 12408

Memphis, TN 38112

Gary Ford, Pres.

Stolle Corp.

1501 Michigan St. Sidney, OH 45365

E. G. Beck, Jr.

Stone & Webster Engrg. Corp.

245 Summer St. Boston, MA 02107

J. W. Landis, Sr.

Strong Electric Corp.

87 City Park Ave. Toledo, OH 43602

Sun Century Systems

P. 0. Box 2036

Florence, AL 35630

Howard Craig, Pres.

Sundstrand Hydraulics

2210 Harrison Ave. Rockford, IL 61101

James H. Meyer

Sundu Co.

331.9 Keys Lane

Anaheim, CA 92804

A. J. Meagner

Sunearth , Inc

.

Box 99

Milford Square, PA 18935

Howard Katz

Sunhay Enterprises

1505 East Windsor Rd.

Glendale, CA 91205

Frank L. Sunhay

Sunglow Solar Systems, Inc. 12500 W. Cedar Dr. Lakewood, CO 30228

Bill Thompson

Sunpower

Rt. 4, Box 275

Athens, OH 45701

William T. Beale

Sun Saver , Inc

.

1611 Ninth St. White Bear Lake, MN 55110

Sun Stone Solar Energy Equipment

P. 0. Box 941

Sheboygan, WI 53081

Michael R. Marcheske

Sunstone

P. 0. Box 941

Sheboygan, WI 53081

Glenn F. Groth

Sun Store, Inc.

P. 0. Box 1385

Greenville, SC 29605

Sunstrand Aviation

Research Dept.

4747 Harrison Ave. Rockford, IL 61101

R. G. Mokadam

Sun Systems Company

512 Maple Avenue, West

Vienna, VA 22180

Robert T. Shea

Sun Systems

716 Main St. Berlin, PA 15530

Sun Systems, Inc.

P. 0. Box 155

Eureka, IL 61530

Dr. Y. B. safdari, Pres.

106
Sunburst Solar Energy, Inc.

15 Fairoaks Court

Atherton, CA 94025

T. Lawrence Newton, Pres.

Swedlow, Inc. 7350 Empire Drive

Florence, KY 41042

C. T. Hicks

Sunearth Solar Products Corp.

Rd. 1, Box 337

Green Lane, PA 18054

Howard S. Katz, Pres.

Systems Technology , Inc

.

P. 0. Box 337

Shalimar, FL 32579

William S. Cronk

Sunsav, Inc.

9 Mile Street

Lawrence, MA 01840

Peter H. Ottmar

Sylvanic Corporation

2015 Third Avenue East

Hibbing, MN 55746

Stanley J. Maleska, V.P.

Sunseeker Systems, Inc. 100 W. Kennedy Blvd.

Tampa, FL 33602

Robert W. Ellis

T-K Solar Distributors

63 Plandome Road

Manhasset, NY 11030

Thomas P. Kay

Sunsource Pacific, Inc. 832 Halekauwile Street

Honolulu, HI 96813

Guy Kittrell, Pres.

The Sky is Falling

1330 21st Street, N.W. Washington, D.C. 20036

Petter 0. Boe, Pres.

Sunspot Solar Products, Inc.

P. 0. Box 333

Carrboro, NC 27510

John R. Meeker

Teledyne Brown Engineering

207 Jones Valley Drive, S.W.

Huntsville, AL 35802

Dr. G. R. Guinn

Sunvert Systems, Inc.

Rt. 515, Box 288

Vernon, NJ 07462

Kurt J. Wasserman

Thomason Solar Homes, Inc. 6802 Walker Rd. S.E.

Washington, D.C. 20027

Sunwall, Inc.

P. 0. Box 9723

Pittsburgh, PA 15229

R. J. Gramm

3M Company

3M Center Bldg. 209-1

St. Paul, MN 55101

B. E. Johnson

Total Air

Sun Water , Inc

.

18754 Parthenia St. Northridge, CA 91324

40 Lakeview Street

Meriden, CT 06450

Louise Bartholomew

Sunwater Company

1112 Pioneer Way

El Cajon, CA 92020

Trane Co.

La Crosse, WI 54601

Mr. Bob Williams

Sunworks, Inc.

P. 0. Box 1004

New Haven, CT 06508

Rye Loope

Transfer, Inc. 735 E. Hazel St. Lansing, MI 48909

R. S. Rowland

Superior WJ Service

P. 0. Box 706

Holly Hill, FL 32017

Transparent Products Corp.

1727 W. Pico Blvd.

Los Angeles, CA 90015

Swedcast Corp.

7350 Empire Dr. Florence, KY 41042

Clark T. Hicks

TREMCO, Inc. 10701 Shaker Blvd.

Cleveland, OH 44104

Sanford M. Wohl

107
Tri-State Solar King, Inc. Box 503

Mams, OK 73901

Kenneth Fast, President

Tulare County Air Conditioning

Service

P. 0. Box 3245

Visalia, CA 93277

Richard A. Manley

Turbo Refrigerating Co.

P. 0. Box 396

Denton, TX 76201

Buster Smith

Underwriters Labs., Inc. 333 Pfingsten Rd.

Northbrook, IL 60062

C. B. Schram

Unit Electric Control, Inc. Sol-Ray Division

1815 North Hwy. 17-922

Maitland, FL 32751

U.S. Solar Corp.

6407 Ager Rd.

W. Hyattsville, MD 20782

Mr. John R. Harris

Unitspan Architect Systems

6606 Variel

Canoga Park, CA 91303

Universal 100 Solar Energy Systems

501 Elwell Avenue

Orlando, FL 32803

William Y. Ford

Universal Solar Systems, Inc. 3310 Southwest 7th St. Ocala, FL 32670

Michael S. L. Schweer

University Mechanical & Engineering

Contractors

4464 Alvarado Canyon Road

San Diego, CA 92120

Shayne McDaniel

Universal Solar Aids Inc.

30 Cobum Ave. Orlando, FL 32805

Norman Camow

Vactek Inc. 2423 Northline Blvd.

Maryland Heights, MD 63042

Vantage Solar Corporation

P. 0. Box 13097

Orlando, FL 32809

Harold Ross

Valley Oil Company

P. 0. Box 12249

Salem, OR 97309

Michael W. Delk

Video Listings

Suite 205

1299 Bayshore Hwy.

Burlington, CA 94010

Donald C. Bullock

Virginia Solar Components , Inc. Hwy. 29, South Rt. #1

Rustburg, VA 24588

Bob Savage, Pres.

W. A. Strutman & Associates

215 S. Warson Road

St. Louis, MO 63124

Western Hydroponics Inc. 25725 Jefferson Ave. Murrieta, CA 92362

Western Energy

454 Forest Ave. Palo Alto, CA 94302

Westwind Co. 309-1/2 W. Boyd Dr. Farmington, NM 87401

Geoffrey Gerhard

Wilcon Corp.

3310 Southwest 7th Street

Ocala, FL 32670

K. T. Wilson

Wilson Solar Kinetics Corp.

P. 0. Box 876

Hartford, CT 06101

Mr. James A. Pohlman

WINCO

Div. of DYNA Technology, Inc. East Seventh at Division St.

P. 0. Box 3263

Sioux City, IA 51102

John A. Clark

108
W. I.S.E. Managers, Inc.

P. 0. Box 322

Sandy Creek, NY 13145

Ms. Roberta F. French

Ying Manufacturing Corporation

1940 W. 144th Street

Gardena, CA 90249

Ying Nien Yu, Pres.

W. L. Jackson Manufacturing Co., Inc.

P. 0. Box 1168

Chattanooga, TN 37401

Bernard J. Brown

Zepher Wind Dynamo

P. 0. Box 241

Brunswick, MA 04011

Allen Lishness

W.M. Hall & Sons, Inc.

P. 0. Box 188

Belmont, NC 28012

W. M. Hall, Jr.

Zomeworks Corp.

P. 0. Box 712

Albuquerque, NM 87103

Steve Baer

W. R. Robbins & Son Roofing Company

1401 Northwest 20th Street

Miami, FL 33142

William R. Robbins, Sr.

Wallner Plumbing Company

P. 0. Box 726

Redding, CA 96001

Alvin Wallner

Wayne Manufacturing Corporation

P. 0. Box 550

Waynesboro, VA 22980

Frank L. Shiflet, P.E.

Whelchel Solar Enterprises

2050-C Carrol Avenue, Suite 2 Chamblee, GA 30341

Henry C. Whelchel, Jr.

Worcester Polytechnic Institute

Worcester, MA 01609

William A. Wright

Wright Air, Inc. 6305 Dougherty Road

Dublin, CA 94566

Edwin E. Wright

Eric M. Wbrmser

Wormser Scientific Corporation

88 Foxwood Road

Stamford, CT 06903

Wyle Laboratories

7800 Governors Drive

Huntsville, AL 35807

David R. Reese

109
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM. BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBSIR 77-13142. Gov’t Accession

No.

3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

Solar Energy Systems - Survey of Materials Performance

5. Publication Date October 1977

6. Performing Organization Code

7. AUTHOJl(S)

L. F. Skoda, L. W. Masters

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project/Task/Work Unit No.

11. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Energy Research & Development Administration

Division of Solar Energy

25 Massachusetts Avenue

Washington, DC 20545

13. Type of Report & Period Covered

Final

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant

bibliography or literature survey, mention it here.) A stud/ was performed to obtain data regarding the perfonrance of materials in

operational solar energy systems, to identify and assess available standards for

evaluating materials, to provide reconmendations for the development of test method

standards for materials and to provide guidelines to aid the selection of materials for use in solar energy systems. During the study, field inspections of approximately

twenty-five operational solar energy systems were performed and a questionnaire was

sent to 459 manufacturers and installation contractors to obtain materials performance

data. This report contains the findings of the study. A primary conclusion is that the

process of selecting materials for specific applications within solar energy systems

is hindered by the lack of an adequate data base of materials performance under the

conditions experienced in solar systems and subsystems. Recommendations are made that

would help in establishing an improved data base.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons

)

Absorber coatings; absorber plates; cover plates; enclosure; insulation; materials

performance; reflective surfaces; seals; selection of materials; solar energy systems;

standards

18. AVAILABILITY JQT Unlimited d For Official Distribution. Do Not Release to NTIS

I

^ Order From Sup. of Doc., U.S. Government Printing Office Washington, D.C. 20402, SD Cat. No. Cll

|X] Order F rom National Technical Information Service (NTIS)

Springfield, Virginia 22151

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF PAGES

113

22. Price

$6 . po

USCOMM-DC 29 04 2- P 74