NATIONAL BUREAU OF STANDARDS REPORT

5934

THE USE OF ANHYDROUS METHYL ALCOHOL

IN REFRIGERANT 12 AND 22 SYSTEMS

Uy

Paul R. Achenbach

C. W. Phillips

Report to

Mechanical Engineering Division

Headquarters, Quartermaster Research and Engineering

^ Natick, Massachusetts

Command

U. S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

for official use only
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NATIONAL BUREAU OF STANDARDS REPORT

NBS PROJECT NBS REPORT

1003-20-4832 June 19, 1958 5934

THE USE OF ANHYDROUS METHYL ALCOHOL

IN REFRIGERANT 12 AND 22 SYSTEMS

by

Paul R. Achenbach

C. W. Phillips

Air Conditioning, Heating, and Refrigeration Section

Building Technology Division

to

Mechanical Engineering Division

Headquarters, Quartermaster Research and Engineering Command

Natick, Massachusetts

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U. S. DEPARTMENT OF COMMERCE

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;? t ! mm

m i; : .: j. :Ae -m

.. . i «
THE USE OF ANHYDROUS METHYL ALCOHOL IN

REFRIGERANT 12 AND 22 SYSTEMS

by

Paul R. Achenbach and C. W. Phillips

Abstract

An investigation was made relative to the use of anhydrous

methyl alcohol as an antifreeze agent in refrigerating systems employing Refrigerants 12 and 22. The investigation

included a review of the literature, a limited amount of

laboratory work on the miscibility of methyl alcohol, water.

Refrigerants 12 and 22 and refrigerant grade oil, and a

survey of technical information and policy of manufacturers

of refrigerating equipment, refrigerants, and desiccants.

Information received in the survey indicated that five out

of six manufacturers of refrigerators who have experimented

with the use of one percent or less of methyl alcohol in

R-12 and R-22 systems indicate satisfactory performance providing the moisture content in the system is kept at a very

low level. Some of these manufacturers state that the discoloration and corrosion of metals is measurable but not

objectionable under these conditions. Two of the six manufacturers now use 1/2 percent or less methyl alcohol regularly in relation to the weight of refrigerant in these

domestic refrigerators and one other uses small amounts in

one of their home freezer models. One large manufacturer

of R-12 and R-22 refrigerants states that the use of methyl

alcohol by manufacturers in amounts of one percent or less

of the weight of refrigerant is acceptable based on sealed

tube laboratory tests of such mixtures. There is general

agreement that the use of methyl alcohol in larger amounts

in R-12 and R-22 systems will cause excessive corrosion with

or without the presence of water and that the initial moisture content of such systems should be kept at 25 ppm or

lower regardless of whether methyl alcohol is used or not.

Limited experimental data indicate that the moisture limit

in R-12 and R-22 systems with regard to corrosion is probably between 100 ppm and 300 ppm of water without methyl

alcohol being present. Thus in a system without an antifreeze, freezeup at the expansion device serves as a warning

against conditions that might produce corrosion. With as

little as 0.2 percent methyl alcohol in a system the moisture

content could exceed the corrosion limit many fold before a
••
- 2-

freezeup would furnish a warning of excessive moisture.

Since a little methyl alcohol can prevent freezing in a system containing considerable moisture the report recommends

that domestic refrigerators of all types and models be

dehydrated at the factory to a moisture content not to exceed 25 ppm. On the assumption that thermally-sealed hermetic

systems are not usually serviced in the field, their useful

life with respect to the effects of moisture is largely

determined by the initial condition created at the factory

and the length of time they remain leak tight. For such

systems it is recommended that the factory use of one percent

methyl alcohol or less in relation to the weight of the

refrigerant be considered acceptable. Since service operations can be performed in mechanically-sealed hermetic

systems and open systems and since such operations are

anticipated by their construction, it is recommended that

the use of methyl alcohol in such systems be prohibited.

It is further recommended that research be initiated to find

a suitable method of determining the alcohol and moisture

contents of new refrigerators as a part of the inspection

procedures and to study the effects of moisture and antifreezes in refrigerating systems as a basis for better

specification requirements.

I. INTRODUCTION

In response to a request from the Quartermaster Research and

Engineering Command, dated March 13, 1958, an investigation was

made regarding the use of anhydrous methyl alcohol in refrigerating

systems using Refrigerants 12 and 22 . The investigation was

directed primarily, but not exclusively, to the use of alcohol in

the hermetic systems of domestic refrigerators. Answers were

desired to the following questions:

a. Is the exclusion of alcohol from such refrigerating

systems scientifically tenable?

b. What is the quantitative maximum of alcohol allowable without incurring injurious acid and corrosion levels?

c. How can effective dehydration of the system at the

factory prior to the addition of alcohol be determined if the

limited addition of alcohol were permitted?

d„ What test method can be used to determine the moisture content of a system containing refrigerant, oil, and alcohol?

e. At what refrigerant temperatures, if any, might the

addition of alcohol be desirable?

-3-

II. PROCEDURE

The procedure used in this investigation consisted of the

following steps:

1„ Review of published literature on the subject of

corrosion of the materials in refrigerating systems as

a result of moisture, alcohol, or both,

2„ A survey of expert opinion from the manufacturers

of domestic refrigerators, (refrigerants, driers, refrigerant oils, desiccants, and other refrigerating equipment and individuals with special information related

to the problem.

3. A limited laboratory study of the miscibility of

refrigerant 12, methyl alcohol, water, and refrigerant

oil

In surveying the opinion and experience of manufacturers and

selected individuals, information was asked on the following

questions

1. Does methyl alcohol in quantities of one percent

or less in refrigerant 12 or 22 systems cause corrosion

either by itself or when combined with water over a long

period of time under typical operating conditions?

2. What is the moisture limit in R12 and R22 systems

with regard to corrosion of iron, copper, and aluminum?

3. What is the moisture limit in R12 and R22 systems

with regard to deterioration of the hermetic motor

insulation?

4. If the use of methyl alcohol were permitted in new

systems, what should the limit be?

5o If methyl alcohol were permitted in new systems,

how could the purchaser know that the initial dehydration

of the system was thorough?
.*
- 4 -

60 Would methyl alcohol and R12 or R22 remain mixed in

a refrigerant charging tank if mixtures were prepared

in large quantities in a manufacturer's plant?

7. Would the methyl alcohol and any water present in

a system tend to accumulate in the evaporator., or would

the oil circulation tend to return it to the compressor?

8 . Has your company done research on the corrosive

effect of methyl alcohol in refrigerating systems?

9. Does your company have an opinion or a policy for

or against use of methyl alcohol in new hermetic

refrigerating systems for operation at evaporator temperatures of zero F?

This inquiry was sent to the following companies and

individuals

Davison Chemical Company

Ansul Chemical Company

E 0 Io DuPont de Nemours & Company, Inc.

General Chemical Division, Allied Chemical and

Dye Corporation

Dow Chemical Company

Highside Chemicals Company

Admiral Corporation

General Electric Company

Amana Refrigeration, Inc.

Frigidaire Division, General Motors Corporation

Hotpoint Company

Kelvinator Division, American Motors Corporation

Norge Division, Borg-Warner Corporation

Philco Corporation

Servel, Inc.

Westinghouse Electric Corporation

Whirlpool-Seeger Corporation

Copeland Refrigeration Corporation

-5-

Carrier Corporation

Prick Company

York Division, Borg-Warner Corporation

Tenney Engineering, Inc.

H. F„ Spoehrer, Sporlan Valve Company

J. F. Butterworth, Socony Vacuum Oil

W. Oo Walker, University of Miami

III. RESULTS OF SURVEY OF MANUFACTURERS AND OTHERS

Question 1

Does methyl alcohol in quantities of 1 % or less in Refrigerant 12 or 22 systems cause corrosion either by itself or when

combined with water over a long period of time under typical

operating conditions?

E. I. DuPont de Nemours & Company

"Based on laboratory tests and industry experience, it

appears that methanol in amounts of one percent or less based on

refrigerant is acceptable in systems using ’Freon-12’ or ’Freon22’ refrigerants. However, larger amounts, especially in

systems containing aluminum, should not be used. The methanol

problem lies with its uncontrolled use in field service.

"Some manufacturers of refrigeration compressors regularly

add methanol in amounts up to about one percent by weight based

on the refrigerant „ Experience with this procedure over a

period of years has been good. Apparently, the use of methanol

under these conditions with strict manufacturing control is not

harmful. Units produced by these manufacturers are warranted

for the same periods of time as others who do not use methanol.

Limited laboratory tests tend to confirm the conclusion that

small amounts are acceptable. In tests at 250°F for 115 days,

the effect of one percent methanol was not significant (Refrig.

Eng. 65, 40, Nov. 1957 )."

-- Ansul Chemical Company --

"The most recent information available to us is published by

DuPont which shows that Freon-22 stored in sealed glass tubes containing 1 % by weight methanol and in contact with copper, iron and

refrigeration grade oil will show very little decomposition at

temperatures of 250° and 300 °F.

- 6 -

"We have always taken the stand that no methanol should be

used since even anhydrous alcohol will introduce moisture into

the system in which it is used. Furthermore methanol itself is

quite a reactive compound and can readily react with the component

parts of the system, especially in the case of aluminum in which

case trimethyl aluminum can be formed. Again, if a drier or

dehydrator is in use in the system, the desiccant can adsorb the

methanol thereby reducing its capacity for water.”

E. W. McGovern, DuPont Company --

’’Antifreezes, such as methyl alcohol, act merely as antif reezes--they do not prevent other moisture effects, such as

corrosion. As a matter of fact, methyl alcohol itself, when mixed

with a dry halogenated hydrocarbon refrigerant, produces a

slightly corrosive mixture.”

-- Highside Chemicals Inc. --

’’The test data which we have been able to locate indicate that

the use of methyl alcohol in quantities of 1% or less does cause

some corrosion over long periods of time.”

-- Westinghouse Electric Corporation --

’’Westinghouse does not use any type of anti-freeze in refrigerator compressors. We have run laboratory tests using methyl

alcohol and have entered into discussions and compared test

results with others on many occasions. The answers to your

questions, however, are based on experience with these tests and

are not the result of long-term field experience.

”1 do not think that methyl alcohol in quantities of one per

cent or less in refrigerant 12 systems will cause corrosion

either by itself or when combined with water over a five or ten

year period of time under typical operating conditions. This

refers to one per cent by weight of the refrigerant. We have had

no experience with alcohol in refrigerant 22 systems.”

-- Whirlpool Corporation --

”We do not use methyl alcohol in our system as it serves no

purpose as we have no ’freezeups'.

"We feel that alcohol serves no useful purpose and offers

another element to the chemical stability problem and, therefore,

should not be used."

- 7

-

-- Admiral Corporation --

"Result is from extended life tests on units having one percent of alcohol indicate that the amount of corrosion on components

is dependent to a great extent on the operating pressures and temperatures. Extensive copper plating was deposited on bearing surfaces in approximately six months on those units operating under

accelerated test conditions of 235# head pressure and 250° motor

winding temperatures. Similar units having a small fan in the

circuit to maintain compressor housing temperatures below 150°F

were comparatively free of plating after 12 months operation.

"At the present time Admiral does not use alcohol in refrigeration systems since we use Tecumseh compressors and addition of

alcohol to a system automatically voids the Tecumseh warranty,,"

-- Kelvinator Division --

"We have been successfully employing methanol for over twenty

years as an additive to refrigerant 12 for the purpose of preventing freez-up at the capillary inlet to the lowside. We have

experienced no trouble relating to corrosion or compressor breakdown due to methanol, and our compressors and systems have been in

continuous operation for the same length of time in the field.

We use less than 1$ methanol in our refrigerant; actually, it

is less than 0.5$. We have never found it necessary to use methanol

in refrigerant 22 to prevent freez-up. At no time has corrosion

been found to be a factor even under twenty years of typical

operating conditions in the field."

-- Hotpoint Company --

"The answers given herein will be based on experience with

only one refrigerant; namely, R-12 or F-12 as you choose. Answers

are given under the same numbers as your questions.

"1. Extended life tests (Hotpoint units with Kelvinator Compressors) on operating systems with less than 1$ alcohol have shown

no signs of corrosion. These tests included units with greater

than 1$ alcohol and to date, they have not shown any evidence of

corrosion. These tests are still in progress. These tests included

units with normal and excessive quantities of moisture also."
.

.
-8 -

-- Frigidaire Division --

"Methyl alcohol in quantities of 1% or less in R-12 or R-22

systems over long periods of time can cause visible corrosion and

staining and iron and copper compound formation . If similar systems are test-run side by side, one dry and one with 1/2 to 1%

methanol, the alcohol system can always be picked out as having more

stain, corrosion, copper plating, and debris on fine filter screens

than the dry system. However, for proper perspective, it does not

necessarily follow that alcohol may never be used. There have

been and are many instances of practical use of alcohol.

"Household refrigerators and vertical food freezers have a

dry desiccant which is CaSOj, (special coating). We have found

other desiccants very satisfactory but are using this one at the

present

"Ice cream cabinets and horizontal food freezers are charged

with 3 c.c. of methanol.

"We have a substantial knowledge on the rate and amount of

corrosion on a methanol charged system when quantities are excessive. However, excellent statistical results as to performance

and life have been obtained with a 'minimized 1 methanol charge of

3 cubic centimeters."

-- Norge Division —

"With the advent of aluminum tubing and evaporator assemblies

for household systems the use of liquid desiccants is a greater

hazard than ever before. The corrosion potential is increased

many times and Norge does not recommend its use under any circumstances . "

-- Copeland Refrigeration Corporation --

"We recommend that nothing be put into a hermetic refrigeration system except pure refrigerant, refrigerating oil and a

suitable dehydrating agent - such as activated aluminum. Silica

Gel, Molecular Sieve, etc., (no liquid dehydrants.)

"We have in years past added liquid dehydrators to the condensing units and/or compressors and we have some large manufacturers at this time who add small amounts of pure anhydrous

methyl alcohol to the systems and our experience has been quite

satisfactory providing the alcohol is used to take care of an

- 9

-

extremely small amount of moisture. We have, of course, encountered

corrosion in large amounts where large quantities of alcohol was

added to act as an anti-freeze in a system containing very large

amounts of moisture. Just what these limits are I cannot say,

but we consider the use of an anti-freeze an easy way of covering

up for poor workmanship, improper dehydration, etc. We believe

the use of alcohol leads to sloppy workmanship because to a

service man if one cc is good for a given amount of refrigerant

four cc is four times as good. This leads to trouble." — Bendix Westinghouse --

"It has been our practice to void the warranty when this or

other foreign substances are used in the refrigerating system.

We have definitely found that methyl alcohol in our hermetic

systems is injurious and have therefore ruled against it."

-- Frick Company —

"We have used Methyl Alcohol in varying quantities in field

installed plants. We also have reports from many of our agents

regarding the use of such material.

"The results of all such experiments have brought us to the

conclusion that the use of Methyl Alcohol with any refrigerant is

improper and should be avoided."

-- York Division —

"We have consistently recommended against the use of methyl

alcohol in refrigerant systems and, consequently, we have no

experience which we could offer to you in answer to your inquiry." — Tenney Engineering, Inc. --

"This is to advise that our company is under the impression

that methyl alcohol is considered a contaminant at this time in a

refrigerant system, and its use is frowned upon by hermetic compressor manufacturers.

"Our company does not employ methyl alcohol as an antifreeze.

We utilize a process of gas charging and evacuation for dehydration

of our refrigeration systems."

-- Carrier Corporation --

"We have no test data on the effect of methyl alcohol, however

we are considerably influenced by the work done at duPont which

shows that methyl alcohol under certain circumstances is harmful,

and we are willing to accept their data."

- 10 -

-- Dr. W. 0. Walker --

’’Tests indicate that methyl alcohol in quantities less than

1 % probably does not cause corrosion in Refrigerant 12 and possibly might not in 22 although there are no tests on the latter

that I am acquainted with. If moisture is present, its effect will

be additive to the alcohol."

Question 2

What is the moisture limit in R12 and R22 systems with regard

to corrosion of iron, copper, and aluminum?

Very little factual information was obtained on this question.

The DuPont Company comments as follows:

"We do not believe that a permissible moisture limit in

Refrigerant 12 and Refrigerant 22 systems with respect to corrosion of metals has been established. Laboratory sealed glass

tube tests indicate that in the absence of motor insulation

materials, the effect of small amounts (5 to 80 ppm) of moisture

on refrigerant decomposition is negligible (Refrig. Eng. _65, 40,

Nov. 1957). The quality of the oil is probably of more significance . ’’

R. J. Thompson, Kinetics Chemicals Inc. reporting in Industrial and Engineering Chemistry Vol. 24, 1932, states that:

Freon, saturated with water at 80F, when sealed in glass tubes

with specimens of aluminum, brass, cast iron, copper. Dural metal,

bronze, galvanized iron. Babbitt metal, lead, monel metal, magnesium alloy, silver, steel, tin solder, zinc, and Y metal for

four months at 235F corroded only Y metal and magnesium alloy.

Brass, copper, and lead were somewhat discolored, but not corroded.

(Freon, saturated at 80F, contains about 98 ppm of water.

)

Highside Chemicals Company reports in 1940 that a compressor

valve plate in a Freon-12 system showed corrosion after eight

months’ operation with a water content of 300 ppm.

Ansul Chemical Company reported the following data in

response to this question:

"This is a highly controversial subject. Our main emphasis

hag been in determining the corrosion limit for moisture in an

open type F-12 operating system. Small quantities of moisture

were added to this system and a specially designed filter block

containing Whatman No. 1 filter paper was installed in the liquid

-11

line. Whenever a moisture concentration of 15 ppm was reached

corrosion solids collected on the filter paper within 24 hours.

The above test does not indicate whether corrosion would occur

with lesser amounts of water in Freon-12 over a prolonged period

but does indicate that corrosion can occur within a very short

period at 15 ppm water in Freon-12. This system contained copper

and steel but no aluminum. This same test was repeated very

recently and corrosion occurred at 16 ppm as analyzed by the

Model W water analyzer.

"Our most recent experience with Freon-22 has been that

corrosion solids collected on a filter in 24 hours when a

moisture concentration of 135 ppm was reached. This, too, was

an open type unit having a discharge pressure of 185 psig and

35 psig suction pressure and a liquid line temperature of 82°F.

To our opinion this test is not conclusive since it is composed

of only one run. Furthermore the test conditions to our opinion

were very mild and corrosion solids could occur at a much lower

moisture than 135 ppm."

Question 3

What is the moisture limit in R12 and R22 systems with

regard to deterioration of the hermetic motor insulation?

Practically no data were obtained on this subject. Generally,

manufacturers believed that it depended on the type of insulation

and that the limit was higher than the limit for corrosion.

Question 4

If methyl alcohol were permitted in new systems, what should

the limit be?

Nine manufacturers recommended that no methyl alcohol be permitted in refrigerating systems; five manufacturers stated that a

limit of 1/2$ by weight or less was an acceptable limit; and one

person stated that 1 % by weight was probably an acceptable limit.

Question 5

If methyl alcohol were permitted in new systems, how could the

purchaser know that the initial dehydration of the system was

thorough?

- 12 -

All but two manufacturers replied that the customer would not

know what the initial water content of the system was. One manufacturer believed that the moisture content and alcohol content

could be shown in the manufacturer’s literature. Another manufacturer replied that the moisture in the refrigerant could be

determined by the gravimetric method, the Karl Fischer method, or

by DuPont’s electrolytic water analyzer.

The DuPont Company commented as follows:

’’The purchaser of refrigeration equipment has to depend on

the integrity of the manufacturer as far as initial dehydration

of the unit is concerned. Those manufacturers who use methanol

provide the same warranties as those who do not. There are many

problems connected with the analysis for water in assembled units

including getting a representative sample and recharging the unit

with new refrigerant (and oil) or returning the analyzed sample.

Methanol will not interfere with the analysis for water by the

Karl Fischer method. This method has been used for analyzing

assembled units, but it is not as adaptable as the Electrolytic

Analyzer or the Weaver conductivity method. Alcohol is known to

interfere with these methods.”

Question 6

Would methyl alcohol and R12 or R22 remain mixed in a refrigerant charging tank if mixtures were prepared in large quantities

in a manufacturer’s plant?

All respondents believed that mixtures of R12 or R22 with

methyl alcohol would remain mixed in storage.

An analysis by the Quartermaster Research and Engineering

Command indicates that the percent alcohol in the remaining

refrigerant in a drum would gradually increase as increments of

liquid were drawn off. The difference in vapor pressure of the

two refrigerants and methyl alcohol would cause proportionately

more refrigerant to be evaporated into the vapor space as the

tank was emptied by repetitive withdrawals.

Question 7

Would the methyl alcohol and any water present in a system

tend to accumulate in the evaporator, or would oil circulation

tend to return it to the compressor?

-13-

Most respondents believed that the .methyl alcohol and water

would not tend to accumulate in the evaporator. There were two

exceptions

-- Kelvinator Division

’’Some moisture, depending upon the concentration could

accumulate as ice in the lowsides held at extremely low temperatures, while methanol will tend to circulate with the refrigerant

along with that water held in solution by the circulating refrigerant at the prevailing temperature. The circulating oil in the

system does not directly effect the distribution of methanol

and/or moisture.”

-- Frigidaire Division --

”In an operating system at proper charge moisture and alcohol

will be circulated in similar manner to the oil. In a system shut

down after running, the moisture and methanol can concentrate in

the evaporator.

’’Alcohol causes less damage while the equipment is running

than it does in storage. The alcohol will tend to concentrate In

the evaporator and during storage, when freon flow has practically

ceased, pin-point corrosion Is bound to exist at the point where

the alcohol/water concentrates in the evaporator. This is a particular hazard with the new Roll-Bond aluminum evaporators. If

the corrosion should not completely penetrate the wall, the wall

is weakened; also the corrosion by-products are a serious hazard.

He feels that this storage condition would be of particular concern in Army use since the refrigerators are run before acceptance,

and then they are often put into storage for extended periods.”

IV. LABORATORY STUDIES OF MISCIBILITY

Some limited studies were made at the National Bureau of

Standards of the miscibility of R12, chemically pure methyl alcohol

water, and refrigerant grade oil. The mixtures were made in unsilvered Dewar flasks at atmospheric pressure so any separation of

the liquids could be observed. Under these conditions the refrigerant gradually evaporated at a temperature of about -20F. The

following results were observed:

1„ Refrigerant 12 and methyl alcohol were miscible

„

2, When 1/2$ water and 1/2$ methyl alcohol were added to

R12 in that order, beads of ice were formed as the

water was poured in and the ice beads were slowly dis

solved after adding the alcohol with constant

-14-

stirring. Finally, the mixture of alcohol and

water floated on the surface of the refrigerant in

a broad, flattened puddle.

3. When the alcohol was added to the R12 first, small

flaky ice crystals were formed temporarily on adding

the water, and the mixture of alcohol and water

floated on the surface of the refrigerant the same

as before.

4. When 1/2$ methyl alcohol and 0,1$ water were added

to R12 in that order the alcohol-water mixture

floated on the surface as in the other tests.

Increasing the amount of alcohol five-fold did not

disperse the floating liquid, but appeared to

spread it out. Increasing the ratio of alcohol to

water to 50 to 1 by weight dispersed the floating

liquid, leaving an apparent homogeneous mixture.

5. Methyl alcohol and refrigerant oil do not mix.

6. When 1/2$ alcohol and 1/2$ water were added to a

half-and-half mixture of R12 and oil the mixture of

alcohol and water floated on the surface of the oilrefrigerant mixture. Increasing the proportion of

alcohol did not disperse the alcohol-water mixture

into the refrigerant and oil.

7. A 60 to 40 ratio of water to methyl alcohol has a

freezing temperature of about -20F. When such a

mixture was added to R12 in an amount equivalent to

1/2$ water to weight of R12, no ice was formed, but

the mixture floated on top of the refrigerant. When

increments of 1/4$ of pure water by weight were

added ice crystals were formed and later dissolved,

but the floating liquid gradually took on a consistency like creamy, partly-crystallized honey. No

hard ice crystal formation was evident until the

water content was slightly in excess of 3 1/2$ of

the weight of refrigerant and about seven times the

weight of alcohol.

8. When successive increments of this 60 to 40 mixture of

water to methyl alcohol were added to R12 the floating

material gradually took on this same creamy, partlycrystalline consistency observed when excess water

was added.

-15-

V. NBS TESTS OF A WAREHOUSE UNIT CONTAINING

METHYL ALCOHOL AND WATER

In August 19^7 the National Bureau of Standards made tests

of a one-ton warehouse unit to determine the effectiveness of

methyl alcohol as an antifreeze when operating at -10F evaporator

temperature. The system held about 25 lb of Freon-12 and was

charged with 0.2$ methyl alcohol. It was found that 0.8$ water

by weight could be added before any difficulties with freezing

at the expansion valve occurred. After 30 hours’ operation of the

system considerable rust was found on the valves and valve plates.

A water content of 0.8$ corresponds to 8000 ppm and is well above

the corrosion limit of iron in an R12 system.

VI. DISCUSSION AND CONCLUSIONS

The information obtained during this survey does not provide

overwhelming evidence either for or against the use of small percentages of alcohol in domestic refrigerators.

Five out of six manufacturers of refrigerators who have

experimented with the use of 1$ or less of methyl alcohol In R-12

and R-22 systems indicate satisfactory performance providing the

moisture in the system is kept at a very low level. Some of

these manufacturers state that the discoloration and corrosion of

metals is measurable but not objectionable under these conditions.

Two of the six manufacturers now use 1/2$ or less methyl alcohol

regularly in their domestic refrigerators and one other uses

small amounts in one of their home freezer models.

One large manufacturer of R-12 and R-22 refrigerants who has

conducted sealed tube tests with mixtures of these refrigerants

and 1$ methyl alcohol states that the use of methyl alcohol by

manufacturers in amounts of 1$ or less of the weight of refrigerant is acceptable.

There is general agreement that the use of alcohol In larger

amounts in R-12 or R-22 systems will cause excessive corrosion

with or without the presence of water. There is general agreement

that the initial moisture content of such systems should be kept

at 25 ppm or lower regardless of whether methyl alcohol is used

or not.

Data received from several manufacturers on their factory

dehydration processes indicate that the principal difficulty Is

the moisture retained in motor windings and in the mechanical

components of the system after assembly. Three manufacturers

- 16 -

quoted residual moisture contents ranging from 0.10 gram to 0.135

gram in their assembled systems after dehydration and before adding

oil and refrigerant. No difficulty was cited in obtaining oil and

refrigerant with 10 ppm of water or less in each. In a system with

residual moisture in the range from 0.10 gram to 0.135 gram and

charged with 6 lb of refrigerant and oil of 10 ppm moisture concentration,, the total moisture would average 40 to 50 ppm concentration „ A part of the residual moisture would remain in the motor

windings under normal operating conditions,, but if the operating

conditions were such that the moisture in the windings were transferred to the refrigerant the moisture content of the circulating

refrigerant could exceed 25 ppm.

The use of methyl alcohol makes the initial dehydration procedure less critical and potentially could permit poor quality

control with regard to factory dehydration. It probably reduces the

dehydration cost a little. Small percentages of methyl alcohol in

a refrigerating system permit at least 1 1/2 times as much water as

alcohol to be present in the system before freezing occurs at

evaporator temperatures from -10F to -20F. This ratio may vary with

the type of expansion device used. Thus 1 percent of methyl alcohol

(equivalent to 10,000 ppm) in a system would permit a moisture concentration of 15;, 000 ppm before a freezeup would occur at -20F.

Laboratory tests show that, unless the percentage of alcohol

exceeds the percentage of water by a ratio of more than 25 to 1, a

mixture of alcohol and water will float on the refrigerant surface

when the water content is 0,1/ by weight of the refrigerant or more.

Experiments with lower percentages of water were not made. Laboratory tests and some manufacturers’ experience indicate that the

alcohol-water mixture could accumulate in the evaporator on the

surface of the refrigerant during storage conditions or when the

unit was not running and might produce accelerated corrosion in

that area.

Limited experimental data indicate that the moisture limit

in R-12 and R-22 systems with regard to corrosion is probably in

excess of 100 ppm of water, but less than 300 ppm without methyl

alcohol being present. Thus in a system without an antifreeze,

freezeup at the expansion device serves as a warning against conditions likely to produce corrosion. With as little as 0.2$

methyl alcohol in a system the moisture content could exceed the

corrosion limit many fold before a freezeup would furnish any

warning of excessive moisture.

There is apparently no simple method by which the Federal

government can test a production unit for moisture content as a

part of its inspection procedures. Manufacturers state that the

Karl Fischer method can be used for moisture analysis on a system

containing alcohol, but it is not readily adapted to inspection
» •
-17-

procedures. Both the DuPont electrolytic analyzer and the Weaver

method are affected by the presence of alcohol. There are colorchange moisture indicators appearing on the market at the present

time., but their adequacy as inspection devices has not been

evaluated by the National Bureau of Standards,

Neither the National Electrical Manufacturers Association

nor the Air Conditioning and Refrigeration Institute has recognized the use of methyl alcohol in refrigerating systems as good

practice nor has there been any standard adopted by these associations for the application of liquid antifreezes to refrigerating

systems

More technical data is needed on the effect of liquid antifreezes in refrigerating systems and on the corrosion limits of

various materials of construction in the presence of moisture in

such systems. Based on the data available it would appear that

there might be a small margin of moisture content in R-12 and R-22

systems between the upper limit which will not cause freezing at

the expansion device and the lower limit for corrosion. If

small percentages of methyl alcohol have any place in such refrigerating systems it would be as an antifreeze within this range

of moisture content. It should not be used in any system where

normal operation or maintenance procedures could permit even

small percentages of alcohol (less than 1%) to cover up or accommodate excessive amounts of moisture in the system.

The useful life of a thermally-sealed hermetic system depends

almost entirely on whether or not the system remains leak-tight

and on the initial condition created at the time of assembly

insofar as the effects of moisture are concerned. This indicates

that a low moisture limit should be specified for such systems

whether or not alcohol is permitted. Assuming that the Federal

government does not typically repair thermally-sealed hermetic

systems when they fail, there is little opportunity to introduce

excessive amounts of alcohol or moisture in these systems as a

result of servicing and repair procedures.

This line of reasoning does not apply to mechanically-sealed

hermetic or open type systems which by their design permit compressor repairs, leak repairs, and recharging by service groups.

In such systems small amounts of methyl alcohol (less than Vfo)

could accidentally or deliberately be used to cover up or accommodate moisture in amounts that would produce corrosion.

Based on the information accumulated during this survey and

on the above analysis our opinions are as follows:
. - *
-18-

1. All types and classes of domestic refrigerator

systems should be dehydrated at the factory to a

moisture content not to exceed 25 ppm„

2. Thermally-sealed hermetic systems in domestic

refrigerators containing Vfo or less of methyl

alcohol in relation to the refrigerant charge

when new should be considered acceptable.

3. The introduction of methyl alcohol in new mechanically

sealed or open type systems at the factory should

be prohibited^

4. Investigations should be initialed immediately to

find a suitable method for determining the alcohol

and moisture contents of new domestic refrigerators

as a part of the inspection procedure at the time

of purchase

„

5. Further research on the effects of moisture and

antifreezes in refrigerating systems should be

undertaken to provide a sound basis for specification requirement So

USCOMM-NBS-DC

ESTABLISHED 1802

E. S. du Pont de Nemours & Company

INCORPORATED Wilmington 98, Delaware

RGANIC CHEMICALS DEPARTMENT

FREON* PRODUCTS DIVISION) June 18, 1956

Ref. File No. 10.

Mr. Paul R. Achenbach, Chief

Air Conditioning, Heating,

and Refrigeration Section

National Bureau of Standards

Washington 25 , D. C.

Dear Mr. Achenbach*.

This is in reply to your letters to R. C. McHarness and B. J - Biseman of our

"Freon" Products Division. We have prepared some comments on the use of methanol

as an antifreeze in refrigerating systems using the "Freon" refrigerants. A copy

is attached to this letter.

In answering your specific questions, we have the following additional comments.

1. We have no firsthand knowledge concerning the corrosive effect of one percent

or less of methanol in "Freon-12" or "Freon-22" systems over a long period of

time under typical operating conditions. Some manufacturers have reported

good experience with its use (ASRE Meeting in Boston, 1956), hut we know of

no published data on unit tests. In limited laboratory sealed glass tube tests

at 250°F for 115 days, one percent methanol had no significant effect on refrigerant decomposition {Refrig. Eng. 6^, 40, Nov. 1957)*

2. We do not believe that a pemisslble moisture limit in Refrigerant 12 and

Refrigerant 22 systems with respect to corrosion of metals has been established.

Laboratory sealed glass tube tests indicate that in the absence of motor insulation materials, the effect of small amounts (5 to 80 ppn) of moisture on refrigerant decomposition is negligible (Refrig. Eng. 65^, ^0, Nov. 1957)*

quality of the oil is probably of more significance,

3. Little has been published on the effect of moisture on hermetic motor insulation.

We would not expect a harmful effect on conventional insulation materials from

isma.1

amounts of moisture.

i

1

I

4.

If methanol is used as an antifreeze, it should be limited to one percent on the

weight of the refrigerant. The purchaser of refrigeration equipment has to

depend on the Integrity of the manufacturer as far as initial dehydration of une unit is concerned. Those manufacturers who use methanol provide the same warranties as those who do not. There are many problems connected with the

analysis for water in assembled units including getting a representative sample

and recharging the unit with new refrigerant (and oil) or returning the analyzed

FREON and combinations of FREON- with numerals are Qu Ront’e registered trademarks for fluorinated hydrocarbons

BETTER THINGS FOR BETTER LIVING . . THROUGH CH EM IS^RY

- 2 -

sample. Methanol will not interfere with the analysis for water by the Karl

Fischer method. This method has been used for analyzing assembled units, but

it is not as adaptable as the Electrolytic Analyzer or the Weaver conductivity

method. Alcohol is known to interfere with these methods.

6a Methanol is miscible with liquid refrigerant and there would be no reason to

expect separation in a charging tank.

To Methyl alcohol, water or oil will not accumulate in a properly designed

evaporator and suction line. Turbulence of the refrigerant liquid and velocity

of the gas are usually sufficient to carry along other liquids that might be

present.

A reprint of some of the work we have carried out at the "Freon'" Products

laboratory bearing on the above questions is attached. It was published in REFRIGERATING ENGINEERING 65 , **0, (1957) • We hope the information will be of help to you

in considering the advisability of using methanol as an antifreeze agent. If we

can be of assistance to you on the application of our "Freon" refrigerants, please

let us know.

Very truly yours,

"FREON" PRODUCTS DIVISION

o^L/<C> :

D. E. Kvalnes

Manager

Technical and Sales Development

DEK/ba

Enel.

METHANOL IN REFRIGERATION SYSTEMS

Based on laboratory tests and Industry experience, it appears that

methanol in amounts of one percent or less based on refrigerant is acceptable

In systems using "Freon -12" or "Freon -22" refrigerants. However, larger

amounts, especially in systems containing aluminum, should not be used. The

methanol problem lies with its uncontrolled use in field service.

Some manufacturers of refrigeration compressors regularly add

methanol in amounts up to about one percent by weight based on the refrigerant.

Experience with this procedure over a period of years has been good. Apparently,

the use of methanol under these conditions with strict manufacturing control is

not harmful. Units produced by these manufacturers are warranted for the same

periods of time as others who do not use methanol. Limited laboratory tests tend

to confirm the conclusion that nraa.1

1

amounts are acceptable. In tests at 250°F

for 115 days, the effect of one percent methanol was not significant (Refrig. Eng.

65, 1*0, Nov. 1957)

While methanol may be safely added to refrigeration equipment by manufacturers, its use is often abused under field service conditions. It may serve

as a temporary expedient for the prevention of ice formation in capillary tubes

or expansion valves but it can lead to serious trouble. We do not recommend the

use of methanol under field service conditions for the following reasons.

1. It is generally better practice to remove the cause of trouble rather than

to provide temporary relief by curing the symptoms. If excessive water is

a current or potential problem in a system, effective and inexpensive driers

are available for removing it. Current manufacturing procedures assure good

dehydration, and good performance without alcohol has been well demonstrated.
.
2. Laboratory tests have shown that the presence of large amounts of methanol

greatly increase refrigerant decomposition and metal corrosion in a relatively short period of time. Also, it is difficult in practice to resist

the feeling that if a little is good more is better.

3 . Addition of methanol does not remove water. Both the water and methanol

remain in the system and over a period of time may chemically react not

only with refrigerant, metals or oils but also with insulation materials or

with foreign material that may have inadvertently entered the system.

4. Water and methanol (along with same air) contribute to the formation of

metal oxides. Iron and copper oxide are catalysts for the decomposition

of "Freon-12" and "Freon-22" (Refrig. Eng. 65 , 33, Sept. 1957)*

5 . Many laboratory tests show that methanol can react with aluminum regardless

of its effect on refrigerant or other metals present. This reaction produces a grey gelatinous mass and the presence of hydrogen has been demonstrated. In one test "Freon -12" containing four percent methanol with oil,

aluminum, copper and steel was stored for 60 days at 250°F. At the end of

the test a vapor sample contained over 50 percent hydrogen by volume. In

similar tests containing two and four percent methanol with "Freon-12" and

"Freon -22" there was a greater degree of copper plating and attack on the

aluminum than in the control tests without methanol.

The reaction of aluminum with ethanol has also been demonstrated

(Soap and Sanitary Chemicals, Vol. XXVI, No. C.S.M.A. ( 2 ), 1950).

ft "Freon" Products Division

E. I. du Pont de Nemours & Co. (Inc.)

PH1LCO CORPORATION

REFRIGERATION & RANGE ENGINEERING DIVISION

TIOGA & C STREETS

PHILADELPHIA 34

PENNSYLVANIA

May 6, 19^8

D, S. Department of Commerce

National Bureau of Standards

Pile Number 10.3

Washington 25>, D. C.

Attention; Mr. Paul R. Achenbach, Chief,

Air Conditioning, Heating,

and Refrigeration Section

Dear Mr. Achenbach:

In reply to your inquiry of April 17 regarding

"Methyl Alcohol in Refrigerants", please be advised

that we feel that the questions you asked should be

answered on an Industry basis. Accordingly, we are

asking our Company Representative to bring this matter

up with the proper Committees of both NEMA and ASRE.

Yours truly,

PHILCO CORPORATION* • *

C. R. Quinn - Manager

Refrigerator & Freezer

Engineering

CRQibg

GENERAL ELECTRIC

COMPANY

APPLIANCE A no TELEVISION RECEIVER DIVISION

APPLIANCE PARK . . . LOUISVILLE 1, KENTUCKY . . TELEPHONE GLENDALE 4-7511

May 8, 1958

Mr. P. R. Achenbach, Chief

Air Conditioning, Heating,

and Refrigeration Section

National Bureau of Standards

Washington 25, D.C,

Re: File No. 10.3

Dear Mr. Achenbach

I have made some inquiries regarding the questions contained in

your letter of April 17, 1958 Unfortunately they lie 'for the most

part outside our experience in the field of refrigeration for home use. The following summarizes findings corresponding to the questions which

you enumerated

1. The effect of methyl alcohol has not been investigated.

2. The presence of water results in capillary "freeze-up"

at levels below that at which any corrosion problems

appear with our present design.

3. The chief source of moisture is in cellulosic motor

insulation and plastic wire insulation. With both R12

and R22 systems, our problem is to remove the water to

prevent the failure noted above. A dryer is included in

the system to maintain low moisture levels throughout

service life.

4. We have no information as to a limit for methyl alcohol.

5. No help.

6. Methyl alcohol and freon mixed within miscibility limits for

the temperatures involved would be stable.

7. We believe in our system that the mixture would circulate.

This would depend on design.

We know of no policy for or against methyl alcohol for this use.

GENERAL ELECTRIC

P. R. Achenback (con't) * -2-

A likely source for a great deal of this information is the duPont

Company and their publication such as Kinetic Technical Bulletin B-5.

I hope this information proves to be of some value.

Very truly yours,

. V / / //.

Manager

Metallurgy & Ceramics Laboratory

MAJOR APPLIANCE LABORATORIES

RL HADLEY :cc

DAVISON C H E

DIVISION OF

BALTI MOR E

: a l c

:race a co. M A R Y L A N

O M P A N Y

Hay 2, 1$>58

Mr. Paul R® Achenbach, Chief

Air Conditioning, Heating,

and Refrigeration Section

U. S. Department of Commerce

National Bureau of Standards

Washington 25, D.C.

Dear Mr. Achenbach:

I am writing in reference to your letter of April 17th,

your File 10.3

Davison Chemical Company has conducted no research

relative to the corrosive nature of alcohol in refrigeration

systems . However, in view of the several published papers in

which it is indicated that this material is quite undesirable,

we do not recommend its use to any of our customers.

You indicated in your letter that you had access to some of the information published by Ansul Chemical Company.

To our knowledge, they have probably published more data on

this subject than any other firm, and I am sure they will be

able to provide you with much information in addition to what

you obtained in their ’’News Notes.”

Cordially yours,

S// J£.-<•*•***-. *.».' • Wra. P. Cummings > ' Technical Service Representative

Industrial Chemicals

VJPC/vb

p M I S T R Y
.
CARRIER CORPORATION

CARRIER PARKWAY, SYRACUSE 1, N E W YORK

April 28, 1958

Mr, Paul R. Achenbach

U, S. Department of Commerce

National Bureau of Standards

Washington 25, D. C,

Dear Mr, Achenbach:

Subject: Methyl Alcohol in Refrigerants

Your File No. 10.3

This is in reply to your letter of April 17 regarding the practice of using

methyl alcohol as an antifreeze agent in Refrigerant 12 and 22 systems.

I am sorry that we do not have data which relates to many of your questions,

however we will try to do the best we can with the information we have available. Our comments to the questions you have listed are as follows:

1. We have no test data on the effect of methyl alcohol, however

we are considerably influenced by the work done at duPont

which shows that methyl alcohol under certain circumstances

is harmful, and we are willing to accept their data.

2. This question, as far as I know, has not been specifically

answered by our industry. We have ran extensive tests on the corrosion of metals in Refrigerants 11 and 113, arriving

at the conclusion that water below saturation is not detrimental to metals in any way. We are inclined to believe

that the same applies to Refrigerants 12 and 22, This fact

seems to be borne out by the paper by Divers and Beacham

which is attached, and which shows that the volume resistivity of saturated refrigerant is not affected by moisture

up to 100/S saturation.

3. The answer to this question depends to a certain extent on the insulation system considered. For example, a Lecton

coated magnet wire- Mylar slot liner system is currently

under consideration by Carrier, and I suppose by others in our industry. This system would be highly satisfactory in

perfectly dry systems or in systems where the motor operating

temperature is below 105°C and some moisture is present. In

equipment operating above 105 °C with moisture present, the

Mylar slot liners would have to be coated to prevent

deleterious hydrolysis reaction. In other words, various

Page No. 2

Mr, Paul R. Achenbach April 28, 1958

materials have different degrees of resistance to

hydrolysis, and moisture level in the system would have

to be adjusted to suit the materials used,

A. We would not tolerate the use of methyl alcohol in new

systems, largely because we can see no reason why the

original factory processing should leave residual moisture

in an amount which would require its use.

5.

We do not know. This would be a very difficult analytical

6. The best information we have on this is in duPont’s Kinetic

Technical Bulletin B-7 which indicates that methyl alcohol

is quite soluble in R-12 and R-22.

7. We believe that the alcohol would not necessarily accumulate

in the evaporator. We are not sure whether it would return

to the compressor and stay there, however.

We have not done research work on methyl alcohol. We have a broad policy

which recommends against its use for any purpose. We do find, however,

that in isolated cases, some of our field people will resort to its use.

job.

Very truly yours.

V

RS/lg

Materials and Processes Department

Research and Development Division

Att.

WkOlSpCot CORPORATION

EVANSVILLE DIVISION

EVANSVILLE, INDIANA

May 27, 1958

U. S. Department of Commerce

National Bureau of Standards

Washington 25? D. C.

Attention: Mr. Paul R. Achenba oh, Chief,

Air Conditioning, Heating,

and Refrigeration Section

Dear Sir:

File 10.3

Item 1. We do not use methyl alcohol in our system

as it serves us no purpose as we have no "freeze-ups."

Item 2. and 3* We have found that by dehydrating to

a limit of 0.1 gr. per assembly under 250YF. of heating

and 200 micron or less pressure gives us a unit that when

using F-22 is chemically stable and a unit plus dryer

(silica gel) when using F-12 is stable.

Item 4, 5 j 6, and 7* See Item 1.

We feel that alcohol serves no useful purpose and

offers another element to the chemical stability problem

and, therefore, should not be used.

Yours truly,

WHIRLPOOL C ORPORATI ON

Evansville Division

John S. Wright, Chief Engineer

JSW: jb Engineering Services

cc: Messrs. F. J. Hausfeld

E. T. Morton

PRaicott 7-0626 UKUSIDE CHEMICALS INCOftPOftATED

Manufacturing Chemists

10 COLFAX AVENUE, CLIFTON, N. J. June 5, 1958

U. S. Dept, of Commerce

National Bureau of Standards

Washington 25, D. C.

REF: File #10.3

ATTN : Mr. Paul R. Achenbach, Chief,

Air Conditioning, Heating,

and Refrigeration Section.

Dear Sir:

This refers to your letter of April 17, addressed to

our predecessor corporation, Stewart Industries, Inc., on

the subject of methyl alcohol in refrigerants. You will

note from the enclosed that we manufacture a liquid dehydrant containing a water destruction agent which actually

destroys the moisture. Methyl alcohol alone is only an

anti-freeze, which permits the water to remain in the

system.

We have reviewed the laboratory files of our predecessor corporation in an attempt to answer your specific

questions. Unfortunately, we are not able to find sufficient information to give a complete answer.

Regarding question one, the test data which we have

been able to locate indicates that the use of methyl alcohol in quantities of 1% or less does cause some corrosion over long periods of time. We are unable to answer

questions number two and three regarding the moisture

limit in refrigeration systems, due to practical side of

both the corrosion and insulation problems. In other

words, any moisture will tend to corrode the system and

will tend to damage the insulation, but the degree of

this damage might or might not be serious enough to

cause the system to stop. Any moisture can be considered harmful, and should be removed.

June 3 , 1 958

Mr. Paul R. Achenbach, Chief Air Conditioning

Heating and Refrigeration Section

National Bureau of Standards

Washington 25, D. C.

Dear Mr. Achenbach:

Your letter with regard to the use of methanol in refrigerating systems and moisture corrosion limits has been referred

to me for reply. We will attempt to answer each question in

order as listed.

1 . Our investigations on the use of methanol were carried

out in the 1 940s and did not involve the use of operating equipment. The most recent information available

to us is published by DuPont which shows that Freon-22

stored in sealed glass tubes containing by weight

methanol and in contact with copper, iron and refrigeration grade oil will show very little decomposition

at temperatures of 250° and 300°F. In this regard your

best source for information would be such manufacturers

as General Electric, Westinghouse , Carrier or Techumseh.

We have always taken the stand that no methanol should be

used since even anhydrous alcohol will introduce moisture

into the system in which it is used. Furthermore methanol

itself is quite a reactive compound and can readily react

with the component parts of the system, especially in

the case of aluminum in which case trimethyl aluminum

can be formed. Again, if a drier or dehydrator is in use

in the system, the desiccant can adsorb the methanol

thereby reducing its capacity for water.

2. This is a highly controversial subject. Our main

emphasis has been in determining the corrosion limit

for moisture in an open type F-12 operating system.

Small quantities of moisture were added to this system and

a specially designed filter block containing Whatman No. 1 filter paper was installed in the liquid line. Whenever

a moisture concentration of 1

5

ppm was reached corrosion

solids collected on the filter paper within 24 hours.

The above test does not indicate whether corrosion would

occur with lesser amounts of water in Freon-1 2 over a

prolonged period but does indicate that corrosion can

occur within a very short period at 15 ppm water in Freon-1

2

This system contained copper

Hr. 1-Haul Achenbacb

Pago Two

June 3

and steel but no aluminum . This same test was repeated

very recently and corrosion occurred at 16 op; as analyzed

by the Ho del :/ water analyzer

.

Cur most recent experience •• »i th Freon- 22 has been that

corrosion solids collected on a filter in 2b hours '.hen a moisture concentration of 135 ppm was reached. This,

too, was an open type unit having a discharge pressure of

1 o5 psig and 35 psig suction pressure and a licuid line

temperature of 82° F. To our opinion this test is not

conclusive since it is composed of only one run. Furthermore the test conditions to our opinion were very mild

and corrosion solids could occur at a much lower moisture

than 135 ppm.

We have always maintained that all refrigeration systems

be kept as dry as possible. This is especially true of

Freon-22 upon which more rigorous operating conditions

are imposed.

We specify that water content should be below 1 5 ppm in

F-1 2 units and below 25 ppm in F-2 2 units.

3 . We have no data on the effect of moisture on hermetic

motor windings.

4. To our knowledge, if methanol is used in new systems the

purchaser would- have no means of knowing whether the

initial dehydration is thorough. It should be pointed

out, however, that most of the manufacturers are very

thorough in this respect since they are obligated to

stand behind their warranty which in some case run as high as 5 years.

5. We have no information with regard to mixing of methanol

and refrigerants. Our only experience in this regard

is that methanol is miscible with F-1 2 and F-22 in all

proportions to temperatures of -90° F.

6. It is our opinion that if the saturation level is not

reached the moisture will be the same throughout the

system. ;e have determined the desiccant moisture equilibria of alumina in both Freon-1 2 and Freon-22. The

desicc nt is preloaded with water and placed in a

cylinder which is charged with refrigerant. After several

days the refrigerant is analyzed for moisture content.

Results are plotted on an adsorption isotherm. Je have

also installed driers preload with water into operating

systems and analyzed these systems for moisture. The

results of the two types of tests agreed within the range

of experimental error.

This would indicate that moisture does not accumulate in

the evaporator.

Mr. Paul Achenbach

Page Three

June 3

V/e believe that VJ. R. Brisker of General Electric and

H. M. Mlsey of Wes tinghouse have done some work in this regard.

Yours very truly

Walter 0. Krause, Section Head

Refrigeration Applications Research

WOK: jmh

K E L V I N A T C

AND 1 E O N A f

1

111 HUDSON AUTOMOBILES

. S H AUTOMOBILES

ECIAL PRODUCTS

American Motors Corporation

14250 PLYMOUTH ROAD

DETROIT 32 MICHIGAN

May 13, 1958

APPLIANCE

H

H

H

1

I

1

U.S. Department of Commerce

National Bureau of Standards

Washington 25, D.C.

File No. 10.3

Subject: Methyl Alcohol in Refrigerants

Attention: Mr. Paul R. Achenbach, Chief

Air Conditioning, Heating,

and Refrigeration Section

Gentlemen

Your questions relating to the above subject have been referred to

the writer for consnent.

We have been successfully employing methanol for over twenty years

as an additive to refrigerant 12 for the purpose of preventing

freez-up at the capillary inlet to the lowside. We have experienced

no trouble relating to corrosion or compressor breakdown due to

methanol, and our compressors and systems have been in continuous

operation for the same length of time in the field.

!• Does methyl alcohol in quantities of 1% or less in refrigerant

12 or 22 systems cause corrosion either by itself or when com- bined with water over a long period of time under typical

operating conditions?

A. We use less than 1% methanol in our refrigerant^ actually, it is

less than 0.5$. We have never found it necessary to use methanol

in refrigerant 22 to prevent freez-up. At no time has corrosion

been found to be a factor even under twenty years of typical

operating conditions in the field.

2. What is the moisture limit in R12 systems with regard to corrosion

of iron, copper, and aluminum?

A. According to extensive tests by du Pont as related in their technical bulletin #B-5 Table #11 wet refrigerant 12 containing 98

ppm water does not attack iron, copper or aluminum. We do not

feel that the moisture content of the circulating refrigerant

in our systems should exceed 25 ppm run under specific conditions,

which is far below the 98 ppm noted in du Pont' s data.

File Mo. 10.3

Attn: Mr. Paul R. Achenbach

-2- May 13, 1?5«

In Table VI of du Pont’ s report "Sealed Tube Tests with Hermetic

System Components", stability of Al-Cu-Fe metals is siinilar to

Cu-Fe at 250°F., and better at 3uO*'F.

The specifying of a moisture limit in a Rl2 refrigeration system

must at the same time specify the manner of sampling, details of

system operation prior to sampling, basis of moisture calculation

aiia method of moisture determination.

In our systems, we specify maximums of 0.135 g moisture for the

total of mechanical parts, 10 ppm oil moisture and 10 ppm

refrigerant. These values are sound practical manufacturing

limits which are necessary to produce high quality products ; they do not imply that the absolute moisture content is stable to

these limits after the system is in operation due to cellulose

water of hydration, nor do they imply that random checking of the

oil or refrigerant will remain at these specified limits.

In the processing of a system, care must always be exercised to maintain the low moisture limit of the mechanical parts, for a proper

evacuation of the system cannot be obtained if a "wet" system is

produced. At present, we evacuate to a balanced pressure of 2^0

microns which would not be possible if our moisture content of the

system was not within specifications.

As to corrosion of metals in a system of the qualities noted above,

there is no danger under normal operating conditions. If operating

conditions change to the extent of catalyzing chemical reactions or

provo Icing material failure, moisture values will change as well as metal attack.

3. VJhat is the moisture limit in R12 and R22 systems with regard to

deterioration of the hermetic motor insulation?

A. From our information, there is no ham to the motor insulation at

the moisture limits which we specify.

Properly processed and cured wire film insulation such as Formex

is impervious to moisture vapor as found in a hermetic compressor;

and even during operation when submerged in oil having 7b ppm

moisture content, no deterioration of the film has been observed

by the writer. Both refrigerants 12 and 22 do penetrate the film

to some extent with 22 having a definite deteriorating affect, but

the refrigerant moisture content has not been considered by refrigerant or motor manufacturers to be a contributing factor; the

writer concurs in this. It is the writer’s belief that any limit

of system moisture content which is set by specification to prevent

oil or refrigerant breakdown and rust, would be sufficiently satisfactory for the wire film.

With regard to the other motor insulating materials such as cellulose and twine; these do have present, both, absorbed moisture
:
File No. 10,3

Attn 2 Mr„ Paul R. Achenbach

3- May 13, 1958

which is influenced by humidity, and water of hydration, which is

part of the organic matter*

During compressor dehydration, the absorbed water of 2 to 3 grams is

almost completely removed and in some cases, a small portion of the

water of hydration is removed. Replacing this, water does not impair

the dielectric properties of the insulators. It has been found that

during the compressor operation, system moisture will be absorbed

from the freon and oil by this dry insulation during the ,}o ff

period, and released again during the "on" period. No harm to either

the cellulose or twine insulation is expected from moisture present

in the 12 or 22 systems which is within the specifications controlling corrosion or refrigerant and oil breakdown.

4. If the use of methyl alcohol were permitted in new systems, what

should the limit be?

A* We specify 2 ml methanol per pound refrigerant 12 (0.35$ by weight)

which is sufficient methanol for our systems which have less than

0.135 g of water remaining after dehydration, du Font have stated

in their test results of "Sealed-Tube Tests witn Hermetic System

Components" that "the effect on F-12 decomposition of 1% of methanol

(on the weight of the refrigerant) was determined to be insignificant in copper and mild steel systems (Table VI)".

5® If methyl alcohol were permitted in new systems, how could the purchaser know that the initial dehydration of the system was thorough?

A* Moisture in oil can be titrated by the Karl Fisher method.

Moisture in refrigerant can be determined by gravimetric check;

titrated by a modified Karl Fisher method, or measured by du Font* s Electrolytic Water Analyzer. If the moisture in these components

is below 25 ppm when operated and sampled to specific specifications,

the system can be considered to have been properly dehydrated by the

manufacturer. Methanol does not interfere in these last two methods.

Here again, the migration of moisture and its amount at some point

in a system is a variable depending upon operating conditions and

charges, among others. The sampling of a system under a specific

operating condition will furnish an empirical value of moisture

present at the point of sampling which may not have any bearing on

the total moisture of the system. Even with driers present in the

system, tneir capacities may be exceeded at some time due to operating conditions and the system fail due to inadequate protection.

The use of methanol on the other hand will furnish continued protection from freez-up under all conditions of operation due to its

migration with the refrigerant.

6. Would methyl alcohol and Rl2 or R22 remain mixed in a refrigerant

charging tank if mixtures were prepared in large quantities in a manufacturer8 s plant?
'

>
File No. 10.3

Attn: Mr. Paul R. Acnenbach

May 13, 1958

A» We have always mixed metnanol witn the refrigerant and nave never found separation to exist.

We have always added methanol to the ton drum of refrigerant 12.

As tne result is a homogeneous solution of methanol in refrigerant, there is no separation. The exact amount of methanol is

added under pressure and the drum either rocked for four (U)

hours, or allowed to stand for 7

2

hours $ either method will insure complete homogeneous mixing of the methanol throughout the

refrigerant.

7* Would the methyl alcohol and any water present in a system tend to

accumulate in the evaporator, or would the oil circulation tend to

return it to the compressor?

A« Some moisture, depending upon the concentration could accumulate

as ice in the loxjsides held at extremely low temperatures, while

methanol will tend to circulate with the refrigerant along with

that water held in solution by the circulating refrigerant at

the prevailing temperature. The circulating oil in the system

does not directly effect the distribution of methanol and/or

moisture.

Q. Has your company done research on the corrosive effects of methyl

alcohol in refrigerating systems? Does your company have an opinion or a policy for or against the use of methyl alcohol in

new hermetic refrigerating systems for operation at evaporator

temperatures of zero F?

A. Our company has determined by laboratory tests on compressors and

systems made to our specifications that no corrosive effects of

methanol result in typical operating conditions. We strongly

support the use of methanol as an antifreeze in hermetic systems

for operation in household or commercial application. Our present practice follows our contention and our field record supports

our judgment that methanol does not create corrosive conditions.

It is hoped that the foregoing discussion has made our thinking clear

and has relieved any doubts in your mind as to the advisability of

permitting the use of methanol as an antifreeze in hermetic refrigerating systems under the conditions described.

Very truly yours.

AMERICAN MOTORS CORPORATION

Kelvinator Division

George *r. Bauer

Assistant Chief Engineer

GTB/eh

FREON, A REFRIGERANT

R. J. Thompson, Kinetic Chemicals, Inc., Wilmington, Del.

Corrosive Action

Test specimens of aluminum, brass, cast iron, copper, Dural metal,

bronze, galvanized iron, Babbitt metal, lead, monel metal, magnesium alloy,

silver, steel, tin solder, zinc, and Y metal, after being sealed in glass

tubes 'with Freon under its own vapor pressure for 5 months at a temperature

of 235°F. (ll2.8°C. ), showed no visible evidences of corrosion except for

a slight darkening of the surfaces of the aluminum, brass, copper, bronze,

lead, and zinc. There was no perceptible pitting of the surfaces of any

of the specimens.

Freon, saturated with water at 8o°F. (112. 8°C. ) for A months with the

above metals, corroded only Y metal and magnesium alloy. Brass, copper,

and lead were somewhat discolored but not corroded.

In refrigerating equipment there may be present a small amount of

free water, but there will never be a sufficiently high temperature under

normal operating conditions (109«5°F., or 43°C. compression temperature--

standard ton conditions) to cause corrosion of any of the metals used in

compressor construction. Freon is only slightly soluble in water, and

the solution formed will not corrode any of the common metals used in

refrigeration construction.

Industrial & Engineering Chemistry

Volume 24, 1932

CHEMICAL EFFECTS IN REFRIGERATING SYSTEMS

By E. w. McGovern

E. I. duPont de Nemours & Co., Inc.

Antifreezes, such as methyl alcohol, act merely as antifreezes--they

do not prevent other moisture effects, such as corrosion. As a matter of

fact, methyl alcohol itself, when mixed with a dry halogenated hydrocarbon

refrigerant, produces a slightly corrosive mixture. If an antifreeze is

used to open a frozen system, it should be followed by a chemical dryer.

A liquid moisture scavenger differs from an antifreeze in that it

chemically reacts with water to form another compound. The scavenger itself,

in the quantity used, and the. water reaction products should be harmless to

the refrigerating system. One such liquid drying agent is reported as giving good results when used in small amounts to take care of small amounts

of water, but as being unsuitable for removal of large quantities of water.

Excerpt from article appearing in Refrigerating Engineering, May, 19^+2.

Westinghouse

ELECTRIC CORPORATION

ELECTRIC APPLIANCE DIVISION

Mr c Paul R. Achenbach, Chief,

Air Conditioning, Heating, and Refrigo Section

U. S. Department of Commerce

National Bureau of Standards

Washington 25, D. C«

Subject: File Mo. 10.3

Methyl Alcohol in Refrig erants

Dear Mr. Achenbach:

PHONE BROADWAY 9-731 1 300 PHILLIPP! ROAD

BOX 2199, COLUMBUS 16, OHIO

June U, 1958

Your letter of April 17 has been referred to me for reply.

I would like to point out at the beginning that the answers which you

receive to your letter will contain more opinions than facts. Just as methods of manufacture vary from one manufacturer to another so do the

processing specifications. This does not mean that one method is right

and another is wrong, but does indicate that, with the many differences

in detail design and application of a refrigerating system., there is more than one way to accomplish a satisfactory long life. If a manufacturer has had satisfactory service experience with a specific method

of processing, he is reluctant to change his methods even if another

method appears to be equally good.

Westinghouse does not use any type of anti-freeze in refrigerator compressors. We have run laboratory tests using methyl alcohol and have

entered into discussions and compared test results with others on many

occasions. The answers to your questions, however, are based on experience

with these tests and are not the result of long-term field experience.

| With this background statement and explanation, I will attempt to answer your specific questions as follows:

1. I do not think that methyl alcohol in quantities of one per cent or less in refrigerant 12 systems will cause corrosion either by itself

or when combined with water over a five or ten year period of tiirie under typical operating conditions. This refers to one per cent by

weight of the refrigerant. We have had no experience with alcohol

in refrigerant 22 systems.

2. In household refrigerators and freezers the amount of moisture which

can be tolerated is governed by the tendency to freeze up at the

YOU CAN BE SURE ... IF it s W OS 1 i IlglM) IISC

Mr 0 Paul R. Acbenbach - 2 - June la, 19^8

expansion end of the capillary tube rather than by corrosion* As

insurance against freeze up, we dehydrate to a point where there is

less than one hundred mg. op moisture left in the compressor, and then

place a desiccant in the system to scavenge any moisture which might

enter during assembly.

3. Here again the moisture limit is determined by the tendency to freeze

up rather than by damage to the motor insulation.

U. It has been fairly well established that one half per cent methanol in

systems has not been harmful.

5. The purchaser would have to rely entirely upon the reputation of the

manufacturer that dehydration of the system had been thorough.

6. It has been my finding that methanol added to large quantities of

refrigerant 12 in the amount of one half per cent, and thoroughly

mixed, will enter the system as a true solution. We have had no

experience with refrigerant 22.

7 . I would not expect any problem with the methyl alcohol and water solu^

tion accumulating in the evaporator.

For further information of a more specific nature you may want to contact

one of the following persons:

Dr* D. E. Kvalnes

Freon Products Division

E. I. du Pont de Nemours and Co., Inc,

Wilmington, Delaware

Dr. H« M. Parmelee

Freon Products Division

E. I. du Pont de Nemours and. Co., Inc.

Wilmington, Delaware

Dr. W. A. Knapp, Research Consultant

General Chemical Division

Research Laboratory

P. 0 o Box Uo5> Morristown, New Jersey

Very truly yours.

/m

cc

/

/ \ /7

James B. Kelley

Advanced Engineering Section

Refrig-Freezer Engrg. Dept.

Columbus Works - Mr* A. J, 'Pfeiff er. Mgr. Refrig- Freezer Engrg.

Mr. R. D. Smith, Secretary, Household Refrig-Freezer Section

National Electrical and Manufacturers Association, 1|?5> E. birth Street

New York 17, N. Y.

Midwest manufacturing CORPORATION TELEPHONE 4751 GALESBURG. ILLINOIS

SUBSIDIARY Of Mdmttll CORPORATION

May 21, 1958

Mr. Paul R. Achenback, Chief,

Air Conditioning, Heating & Refrigeration Section.

U. S. Dept, of Commerce,

National Bureau of Standards,

Washington 25, D.C.

Dear Mr. Achenback:

Your letter of April 17, 1958 with reference to the usage of Methyl

Alcohol in refrigerants has been referred to the writer for reply.

As you are probably aware the corrosive effect of alcohol in a refrigeration system has been discussed pro and con for many years

in the refrigeration industry, and I am sure the views expressed

here will not be in agreement with many of the experts from other

manufacturers

.

The answers are listed in the same sequence as the questions in

your inquiry, and are based on experience with F-12 systems.

1. Results from extended life tests on units having one percent of alcohol indicate that the amount of corrosion on components is dependent to a great extent on the operating pressures and temperatures. Extensive copper plating

was deposited on bearing surfaces in approximately six

months on those units operating under accelerated test

conditions of 235# head pressure and 250° motor winding

temperatures. Similar units having a small fan in the

circuit to maintain compressor housing temperatures below

150°F were comparatively free of plating after 12 months

operation. The terminology "typical operating conditions"

will vary with the unit designs of the individual manufacturer and it is the writer's opinion that the phrase

should be more specific so there would be a common basis

for comparison.

2. With reference to the minimum amount of moisture in a system that may result in corrosion of iron, copper or aluminum components in the compressor the manufacturers

usually have definite ideas as to the allowable moisture

content permitted based on past experience in the field.

2 - Mr. Paul R. Achenback

Admiral specifications permit a maximum moisture content

of 10 P.P.M. in a system employing a dessicant, and to

date this has proven satisfactory. However, it should be

noted that the moisture limits are usually below 5 P.P.M.

in the hourly checks of systems on the production line.

3. The rate of deterioration of motor insulation in the presence of moisture depends greatly on the operating temperatures of the windings during unit operation. It is an accepted fact that moisture migrates between the liquid

and vapor phases of the refrigerants as well as between

the refrigerant and motor insulation.

The compressors as received from the manufacturer are dehydrated and contain less than 0.10 gm moisture. Upon

completion of final processing in our plant the moisture

content is further reduced.

4. If Methyl alcohol were permitted in new systems it is recom- mended that the amount be not more than l/2 percent of the

refrigerant and oil charge.

5- To the best of my knowledge the consumer would have no idea

as to the degree of dehydration the system has been subjected

by the manufacturer as long as the unit functions properly.

6. To the best of our knowledge F-12 and Methyl alcohol will

remain mixed in large quantities, but suggest you contact

Gibson or Kelvinator as they have had several years ex- perience in this process.

7 . Inasmuch as the refrigerant, oil and alcohol are miscible

there is little possibility that the alcohol would accumulate in the evaporator.

At the present time Admiral does not use alcohol in re- frigeration systems since we use Tecumseh compressors and

addition of alcohol to a system automatically voids the

Tecumseh warranty.

Hoping this information may be of some value, we remain

Sincerely yours,

MIDWEST MFG. CORPORATION

W. F. Helsel

Chief Engineer - Applications

iiOTPOLIT COMPANY

56OO Went Taylor Street

Chicago 44, Illinois

April 29, 195^

Mr. Paul R. Achenbacli , Chief,

Air Conditioning, Heating, & Refrig. Section

U. S. Department of Commerce

National Bureau of Standards

Washington 25, D. C.

Re: File lo. 10.

3

SlfLJ JCT: Methyl Alcohol in Refrigerants

Dear Mr. Ache nbach

Your letter of April 17th has been referred to the writer for an answer. You

state you have been asked to "survey expert opinion relative to this subject.

We would like to suggest tuat you contact three other men in our industry who

I am sure vAi.ll give you the results of yeiers of experience:

(1) Dr. Howard M. Elsey, Cnemical Consultant, 212 - Fifth Street, Oakmont,

Pennsylvania. Dr. Elsey, now retired, was cnief research chemist for

Westinghouse and did a great deal of work with refrigerants and oils.

(2) Dr. George Bauer is chief chemist for Kelvinator Division of American

Motors Corp., 14250 Plymouth Road, Detroit yl, Michigan.

(3) Dr. Ross, Sun Oil Co., l603 Walnut St., Philadelphia 3; Penn.

Kelvinator, as you may or may not know, has been using alcohol in their household,

F-12 systems for a great number of years. I am sure that Dr. Bauer will have information which will be of interest to you.

The answers given herein will be based on experience with only one refrigerant;

namely, R~12 or F-12 as you choose. Answers are given under the same numbers as

yo\ir questions.

1. Extended life tests (Hotpoint units with Kelvinator Compressors) on operating systems with less than 1 . alcouol nave shown no signs of corrosion.

These tests included units jith greater than 1$ alcohol and to date, they

have not shown any evidence of corrosion. These tests are still in progress.

These tests included units with normal and excessive quantities of moisture

also.

2. It is doubtful whether you will get an answer to this question. Any moisture

beyond the limits now imposed by the Engineering Departments of the manufacturers is based upon the amount of moisture permissible without causing a "freeze-up" of the system while operating . Therefore, the limits are based

on tne projected amount of tuis residual moisture in the system before it is

charged with refrigerant and tne amount of money eacli manufacturer cares to

invest in a desiccant which is inserted to "mop up" this residual moisture

and preventing it from causing a "freeze-up".

Mr. Paul R. Achenbach 4/29/5«J

-pR-.1P as it Is sold to tue industry has a maximum moisture limit of ten parts

per million. A3 it is delivered to the customer, their product usually runs

five to seven parts per million. With the addition of the residual moisture

in the refrigerating units us they are charged, most manufacturers set a total moisture limit for their systems as sold at less than twenty-five parts

per million.

3. 'Hie possible deterioration of hermetic motor insulation is closely connected

with the neat this insulation is subjected to during tue cycling of the mechanical unit. As the stators, vmich contain hygroscopic material such as pager

and cotton are delivered to the manufacturer, they have apjiroxjj ciate ly 2g, to

3-y grams of water. Good processing by the unit manufacturer will bring this

residual moisture down to approximately 0.10 grams. Si ion id the cycling of

the units after charging, release tuis residual moisture (due to operating

teiaperature ) , it is possible to snorten tue life of tne motor due to breakdovm

of the hygroscopic materials mentioned.

4. It would be our suggestion that tne amount of alcohol peed should be held to

leas than 1/2/ based on tne total cnarge (by volume). All dotpoint refrigerators for the past two years have been charged with R-.L2 vita less than 1/2/

alcohol. Field Service indicate no difficulty from "freeze -ups" and there

have been no failures of motors attributable to alconol addition or residual

moisture.

In asking your question concerning the IX of alcoiiol, you did not state whets cr you were tillliking of tills as I of total charge (oil and refrigerant) or I of

oil or refrigerant charge only. You can readily understand that based on tinamount of oil and/or refrigerant used in some systems, tne basis for the 1$

might make quite a difference. If it is your ultimate plan to establish a standard, it should be clearly stated on what the 1 is based; namely, total

charge, oil or refrigerant separately.

In our case here at ilotpoint, we have several different chargee of both oil

and refrigerant. Given below, we have taken the niaximum and minimum charge,

percenting the alcohol used all three ways to give you some Idea of the possible

variation percentage -wise

.

oil p-12 both:

Maximum / O.lo 0. 36 0.15

minimum /, 0.09 O.03 0.06

5* Your question is not quite clear. if your interpretation of "purchaser” .aeons the ultimate customer (the louse wife), then we can say taere is no manufac turer

at present using alcohol wl»w designates on tue unit in anyway the tiioro\*g.aie ss of tiie unit dehydration prior to refrigerant cuar^ing.

0. We believe the answer would be that the u.Lco sol does remind 1 mixed if ap} Lied to

large quantities of freon before c uur in, . We strongly rocoimuend taut you get

a more complete answer from Ur. . vuier at iCelvlaator since this company has used

this method for adding alcoiiol for a number of years.

For your information, vie aero at Uotpoiut add the alconol at tne chorgin, board,

automatically, with each measured c marge 01' refrigerant, as it is delivered

directly to tne unit. A very accurate dispensing device adds 1.9 ce of alconol

to each refrigerant ciiarge.
-

‘

•

'
TO: Mr. Paul R. Acheribach V29/5'-

7* Since the alcohol, refrigerant and oil are miscible, there would be no uccurnulatioji of either of these separately. This may depend coiaowhat on tne type

of system, whether it is a "high pressure " or "low pressure" crankcase.

With reference to your last two questions (not numbered ) , I believe your first question is answered in my number one of this letter, find my statement verifying that

we iiave used alcohol for the past two years, answers your second question.

In conclusion, we would be interested to know tue reason for tne survey you are making.

If there is some thought of establishing a standard for permissible methyl alconol additions, we would like to know the comments from the lingineerinq Departments of all the

other manufacturers. Since all have representatives as members of our National Society

ASRE, and since tills Society lias active committees for formulating standards for our

industry, we strongly recommend tuat you contact Mr. Frederick J. Reed, Engineering

Professor, Duke University, College of Engineer in, , Durnam, north Coi'dina, who is at

present tne chariman of the ASRE Standards Committee.

Yours very truly,

: / Henry W. Deuker - Manager

Materials 1 Processes

Refrigeration Engineex' i ng

HOTPOIHT COMPANY

lIWD:pl

Mr* Paul R* Achenbach, Chief

Air Condit .toning. Heating,

and Refrigeration Section

U#S* Department of Commerce

National Bureau of Standards

Washington 25* D*C.

Doar Mr* Achenbach:

Subject: Methyl Alcohol in Refrigerants

We know of no conclusive data which will answer the questions listed in

your -letter of April 1?* We have, however, had considerable experience in

the use of Methyl alcohol in hermetic compressors over the past fifteen

years*

We recommend that nothing be put into a hermetic refrigeration system except

pure refrigerant, refrigerating oil sad a suitable dehydrating agent - such

a>- activated aluminum, Silica Gel, Molecular Sieve, etc*, (no liquid

dehydrants* j

We have in years past added liquid dehydrators to the condensing units and/or

compressors and we have some large manufacturers at this time who add small

amounts of pure anhydrous methyl alcohol to the systems and our experience

has been quite satisfactory providing the alcohol is used to take care of an extremely small amount of moisture* We have, of course, encountered,

corrosion in large amounts where large quantities of alcohol was added to

act as an anti-freeze in a system containing very large amounts of moisture*

Just what these limits are I cannot say, but we consider the use of an antifreeze an easy way of covering up for poor workmanship, improper dehydration,

etc* We believe the use of alcohol leads to sloppy workmanship because to

a service man if on« cc is good for a given amount of refrigerant four cc is

four times as good* This leads ' > trouble*

Yours very truly.

COPJSIjAND R£FRIGARATIG^/^JRPORATI OU

Rey /fio^iley / /

dime Appl-ip a t i on' i&tg inee r

HM:ss

'\l

AUTOMOTIVE AIR BRAKE COMPANY

050 EAST VIRGINIA STREET

EVANSVILLE DIVISION EVANSVILLE 11. INDIANA

April 25, 1953

Mr. Paul R. Achenbach, Chief,

Air Conditioning, Heating,

and Refrigeration Section

U. S. Department of Commerce

National Bureau of Standards

Washington 25, D. C.

Dear Mr. Achenbach:

In reply to your letter of April 1? on the subject of methyl alcohol

in refrigerants, it has been our practice -to void the warranty when

this or other foreign substances are used in the refrigerating system.

We have definitely found, that methyl alcohol in our hermetic systems

is injurious and have therefore ruled against it.

However, I think it would, be well if you got the specific answers to

your questions from DuPont who have gone into this matter much more

thoroughly than we havej in fact, we have followed their recommendations

in ruling against it.

I would suggest that you write to:

Mr. R. C. Mciiamess

E. I. DuPont d.e Nemours <h Company

"Freon” Prod. Laboratory

Chestnut Run

Wilmington 93, Delaware

or

Dr. B. J. Eiseman

• E. I. DuPont de Nemours &. Company

"Kinetic” Chemicals Division

Wilmington 98, Delaware

C. L. Ploeger

Director of Engineering

CEP: js

SUBJECT

TO

APPROVAL

BY

AN

EXECUTIVE

OFFICER

OF

THE

COMPANY

AT

WAYNESBORO.

PENNSYLVAN

i . JL DICT. Phi t\ G i AUBREY, v P a a . ROSCH LI . Sec y d Tula a A DETWILER. Ass tSkr

ADDRESS ALL COMMUNICATIONS TO THE COM PAN

Y

M <

. H

ESTABLISHED 1853

AIR CONDITIONING. REFRIGERATING.

ICE MAKING tt QUICK FREEZING EQUIPMEl POWER FARMING MACHINERY

PORTABLE SAWMILLS

TELEPHONE 1245 CABLE ADDRESS

FRICK (WAYNESBORO. PENNA j Waynesboro, Penna.. U S.A. May 21, 1958

"Wednesday"

U. S. Department of Commerce

National Bureau of Standards

Washington 25, D. C.

Attention: Mr. Paul R. Achenback, Chief,

Air Conditioning, Heating, and

Refrigeration Section •

Subject: Methyl Alcohol in Refrigerants

Gentlemen:

This will acknowledge receipt of your letter of April 17th

reference the above subject and we can reply to same in a general

manner only.

We have never attempted the use of Methyl Alcohol in any

factory assembled units.

We have used Methyl Alcohol in varying quantities in field

installed plants. We also have reports from many of our agents re- garding the use of such material.

The results of all such experiments have brought us to the

conclusion that the use of Methyl Alcohol with any refrigerant is

improper and should be avoided.

Where moisture was present in a system we did not secure freedom from freezing troubles at expansion valves until the quantity

of Methyl added was increased to a point where it seriously and adversely affected evaporating temperatures.

Where a system had contamination such as, small copper cuttings we seemed to experience more copper plating and oil sludging when Methyl

Alcohol was added to the refrigerant.

We have never attempted any precise measurement of moisture

percentage.

U» S. Department of Commerce

Washington 25, D„ C„

DATE; May 21, 1958

"Wednesday

PAGE #2

In our overall experience we have found no substitute for a clean system wherein moisture has been eliminated by the proper initial

evacuation or the inclusion of a proper dryer in the liquid supply line.

Field installations subject to maximum moisture contamination

because of open lines during erection are made trouble free by the

careful use of a liquid line dryer which is kept in service only for

that length of time necessary to dry the refrigerant and then bypass.

We consider the continued flow of refrigerant through a desiccant dryer is improper.

While the above does not answer your questions in chronological

order, we trust that it will give you our general experience in this

matter.

Very truly yours.

FRICK COMPANY

M. W. Garland, Chief Engineer

Air Cond«& Refg* Mchy, Biv*

MWGsBJSP

YORK YORK, PENNSYLVANIA

DIVISION OF BORG-WARNER CORPORATION

May 13, 1958

Mr. Paul R. Achenbach, Chief,

Air Conditioning, Heating,

and Refrigeration Section

National Bureau of Standards

Washington 25, B. C.

Subject: Methyl Alcohol in Refrigerants,

Dear Mr, Achenbach:

This is in reply to your letter of April 17.

We have consistently recommended against the use

of methyl alcohol in refrigerant systems and, consequently, we have no experience which we could

offer to you in answer to your inquiry.

We would suggest that you contact Kinetic Chemicals

Division of E. I. du Pont deNemours &. Co. We feel

sure that they can supply you with considerable of

the information which you are seeking.

Yours very truly

\

RFL:M

R, F. Lauer

Vice President

MEMBER OF ENVIRONMENTAL EQUIPMENT INSTITUTE AND A R !.

1090 SPRINGFIELD ROAD 2235 SISSON ST. UNION, NEW JERSEY BALTIMORE II, MARYLAND

TELEPHONES MURDOCK 6-7870 NEW YORK BELMONT 5-5522 WORTH 2-0332

TELETYPE UNVL 433 BA 168 Union, New Jersey

April 28, 1958

U. Sc Department of Commerce

National Bureau of Standards

Washington 25, D. C,

References Methyl Alchohol in Refrigerants

Attentions Paul R, Achenbach

Chief, Air Conditioning, Heating, and Refrigeration Section

Gentlemen;

With reference to your letter of April 17, 1958, this is to advise that our

company is under the impression that methyl alcohol is considered a con-» taminant at this time in a refrigerant system, and its use is frowned upon

by hermetic compressor manufacturers.

Our company does not employ methyl alcohol as an antifreeze. We utilize a process of gas charging and evacuation for dehydration of our refrigeration systems,

I am enclosing a copy of a letter from the American Society of Refrigerating

Engineers describing a task force group studying the problem of contaminants.

1 feel sure that they would cooperate with you in supplying available information on the questions which you have put forth. Another source of information

would be the Freon Refrigerant Group of the Du Pont Company, which has

conducted extensive studies in this area.

Very truly yours,

TENNEY ENGINEERING, INC,

Bernard Friedman J

' ^ *'» ’ Technical Director

BF: JS

Enclosure - 1

UNIVERSITY OF MIAMI

CORAL GABLES 46, FLORIDA

May 6, 1958

OFFICE OF THE DEAN

KSION OF RESEARCH AND INDUSTRY Fil© No . 10.

3

Mr* Paul R , Achenbach, Chief

Air Conditioning, Heating,

and Refrigeration Section

National Bureau of Standards

Washington 25# D. G.

Dear Mr* Achenbach? Subject? Methyl Alcohol in

Refrigerants

I have your letter of April 23rd relative to the subject.

At the outset, 1 can tell you that very little is known

relative to the questions propounded in your letter.

Where anything is known, the information is quite general*

Following is a quick run down on each of the questions

contained in your letter,

1. Tests indicate that methyl alcohol in quantities less

than 1 % probably does not cause corrosion in Refrigerant

12 and possibly might not in 22 although there are no

tests on the latter that I am acquainted with. If

moisture is present, its effect will be additive tc

the alcohol.

2* Not known.

3* Not known.

if,. Probably 1 % by volume.

So Not known.

6* Methyl alcohol will remain mixed with Refrigerant 12

indefinitely unless there is a distillation operation

in which case it might or might not behave like water*

At room temperature, certain Refrigerant 22 and methyl

alcohol would remain mixed, I do not know whether they

would separate into two saturated layers at lower

temperatures. Nothing is known about the distillation

characteristics of this mixture.

7. See remarks under No, 6,

UNIVERSITY OF MIAMI

CORAL GABLES 46, FLORIDA

OFFICE OF THE DEAN

IVTSSON OF RESEARCH AND INDUSTRY

Mr- Paul R e Achenbach , Chief May 6* 1958

I cannot refer you to publications on any of these questions

since , as far as I know, there is nothing covering the field.

It seems that a large amount of research would need to be

don© in this area. Perhaps your government agency could

finance such research,

I hope this information is of some value to you.

Kindest personal regards.

Very truly yours

W/m

Walter 0, Walker

Dean,

May 9, 1958

U, S„ Department of Commerce

Mational Bureau of Standards

Air Conditioning, Heating and Refrigeration Section

Washington 25? D.C,

Attentions Mr, Paul R, Achenbach, File No, 10,3

Dear Sir:

The following are our comments in answer to the questions which you

raise in your letter of April 17, 1958, We regret that in all too

many cases the answers cannot be absolute or precise but must be

estimates and opinion extrapolated from the data and experience at hand*

1 , Methyl alcohol in quantities of 1$ or less in R-12 or R-22 systems

over long periods of time can cause visible corrosion and staining

and iron and copper compound formation. If similar systems are test-run side by side, one dry and one with l/2 to 1$ methanol,

the alcohol system can always be picked out as having more stain,

corrosion, copper plating, and debris on fine filter screens than

the dry system. However, for proper perspective, it does not

necessarily follow that alcohol may never be used. There have been

and are many instances of practical use of alcohol,

2* Although we presently operate below 25 ppm moisture in R-12 systems

yet there are many thousands of systems that were operated satisfactorily

at the 25 ppm level or even a bit higher. In R-22 systems in air

conditioning units, the refrigerant may on occasion reach as much

as 200 ppm HpO, though generally 60 to 100 ppm is the practical

level. Certain amounts of staining and corrosion can be observed

particularly in condensers but this has had no significant effect

on operation or life,

3* We make no distinction between allowable moisture levels for hermetic

motor insulation deterioration and allowable: levels for the rest of

the system.

4* Where the use of methyl alcohol can be demonstrated to be safe and

practical a level of l/2t» by wt. of the refrigerant charge should

be adequate for household refrigerators. For other types of systems

the design and operating conditions may require a higher level.

- 2 -

5© If methyl alcohol is present in a new system,, there is no way of

knowing whether initial dehydration was thorough except by analyzing

the total refrigerant charge for moisture and alcohol and the compressor

stator for free moisture*

6* Anhydrous methyl alcohol makes a true solution with dry R-12 or R-22

and would remain mixed in large charging tanks,,

7® In an operating system at proper charge moisture and alcohol will

be circulated in similar manner to the oil* In a system shut down

after running* the moisture and methanol can concentrate in the

evaporator*

8® Frigidaire has done research on the effects of methanol in refrigerating

systems* Frigidaire current practice is to use desiccants instead of

methanol in the household refrigerating systems* Other products receive

drier or methanol depending on economics and design requirements*

VAMsgmh

ocs G* R* Long

F, I* Payne

W® H® Smith

J* So Dom

V* A« Williamitis

Materials & Process

Engineering Division

/

SUuJAUX 0,' SUMV.IiX OP HbFFJfllv AT1GH Myjfnl T M\nUFA0iU;*EE6, 3 MiBCH 53

The following Information wao developed in accordance with directive

of Mr. J« W. Millard, that survey conducted An 1936 be reviewed for

current validity.

On 25 February, at 1600 hours, Mr® W. F. Kelly, E. X® DuPont, 40

Worth Street, E. Y., called in reopens© to an inquiry submitted by Mr®

Vogol to their local Office on a matter not genaan© to this laomo* Mr®

Kelly was asked whether the opinion of DuPont had changed from that expressed in their letter in report dated 3 February 1956. Mr® Kelly stated

that DuPont still took the same stand in opposition to methanol, and added,

without my knowledge of the motivation for the question, * "In spite of

what Kolvinator might soy." He will gather together further documentation

of DuPont’s position end will give it to Mr. Vogel during his visit to

W. Y. vicinity on 2B Fobruary 1953*

General Chemicals, Oenotron Division, was contacted on 26 February

1953, end Hr. Melon stated that although so» manufacturers believe that

alcohol doe© no hum, Conotran opinion is that, a city system and a mechanical

dryer Is preferred® If the system moisture is kept below 29 ppm, alcohol

will not b© needed. If a system hao alcohol and is latex opened by a

service man, additional alcohol may be added and would exceed the clangor

limits® They do not have fim information on what the danger limits are,

but they are Investigating; at the University of Miami, and will forward

such information as it is developed.

Mr® Zi* 0. Crouch, Forge Plant, Muskegon Haights, Michigan, stated that

tha Horge position of 1956 is still firm. They are strictly opposed to the use of alcohol®

Mr® E* H. Swart, Sr., Carrier Corporation, Syracuse, K. Y., stated

that Thou&ono, a sodium alcohol compound, is slightly alkaline - and therefor©,

not as potentially corrosive as methanol. However, no liquid desiccant is

recommended® Tecuioeeh will allow Carrier to uoo alcohol under extremely

careful quality control and moisture levels, but extra cost of such control

would bo prohibitive® At host, alcohol is undesirable since the oafo limits

could be exceeded by a mechanic on the first repair job® Carrier does not

uco it, although Mr. Swart said ha had excellent success with it when ho

was with Kelvinstor 25 years ago, and he believes they a till us© it® Ho

believes it is used chiefly & a production cost consideration sines it

caves about 40$ in materials alone per end item. Ho states that colid dryer

had lidded advantage of removing acids somewhat, a function directly opposite

that of methanol

®

In conversation with l.'endoll Smith and Vic .iilliaaitis of Fripicaire,

Dayton, Ohio, they stated that in some applications, whore a designed-in
*
proasuro drop required compensation, they have obtained practical results

using; 3 cc*a of methanol. They now only use methanol on ©no model horizontal

food free. -.or, and in 1959 all their items will uoo mechanical dryers# Thoy

state that in all their failures of equipment using alcohol, thoy can identify corrosion stains on all defective items and approximately 5.# of

the failures con be attributed to iron-salt by-products of alcohol on the

motels of the system# They are writing on new dryers which will absorb

prototype compounds and acids as well as water, a function that methanol

cannot perform. They fuel that 1 cc of alcohol will pickup an equal volume

of water dovn to minus iOf, and that below this temperature, alcohol is

ineffective. Although their dryer exceeds the cost of alcohol and a filter

by about 15#, they fuel that in a period of over 10 years per item, without

corrosion failure, the 15# la saved, but they cannot prove this except by

their experience, hr# fcilliurtiiis stated that his personal opinion is that

alcohol causes less damag® while the equipment la running then it does in

storage. The alcohol will tend to concentrate in the evaporator end during

storage, when froon flow has practically ceased, pin-point corrosion is

bound to exist at the point where ths elcohol/wator concentrates in the

evaporator, This is a particular hazard with the now Roll-Bond aluminum

evaporators. If the corrosion should not completely penetrate tho wall, th®

wall la weakened} also tho corrosion by-products are a serious hazard. He

fools that this storage condition would be of particular concern in Army

uoo sines the rofrigeratora arc run before acceptance, and then they are often put into store go for extended periods.

ho further effort will be axle to secure additional information at

this time sines it would bo a duplication of tho work assignment which has

been made to KBS, If the information obtained thus far can bo considered

to bo representative of the Industry, alcohol has very few advocates.

Documentary evidence la on hand from various compressor manufacturers stating

that uso of alcohol will void compressor guarantees.. Tho data to be furnished

by DuPont as stated above was picked up by Mr, Vogol from Robert B. £en.roton.

District f>alo8 Supervisor, L« I. DuPont, Do Kotaouro & Company, Inc., on 23

February. Thao© documents are available for study and thoy support tho above

statements of Mr. Rally. Mr. Sangston stated that DuPont has evaluated

over 200 different liquid additives and finds that their opinion la applicable

to all of them.

PAUL L » J , t OOuiXi

Cy furnished*

JViMlllard (Chf, RED)

2

U. S. DEPARTMENT OF COMMERCE

Sinclair Weeks, Secretary

NATIONAL BUREAU OF STANDARDS

A. V. Astin, Director THE NATIONAL BUREAU OF STANDARDS

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