# ., ' * ^ -;~~~~~;4 IeAppendix B Supplement Technology Assessment and Screening Analysis

... . ... j::::- :'

Aft X ,f,~~~~~~:i~:'- ::SST7 j~ii::i .'::

. ........-. F f ....-........... :i 7

........... ~ ~ ~~~~~~~~~~li:il~lli~:-li:::::.

.......... ~~~~~~~~~~~~~~::-- is~ ~ ~~~~~~~~~~~~~~~~~~~::::j~::::~::::::::

. 'ii4~i:lil-Iiri'.~~~~~~~~~~~~~. ........ A 

# ·~,~iiii!~ ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~!iiiii;

*.....

....E E .Wh

X~ ~~~~~..... ~ ,~~~~~~~~~....iiiiiii~ iiiiiiiiiii ~ f~ ~ !~ ~iiii~~~~~~ii~~i~i~~i~11i~~~i!~!!!i~~~ii~~iiii~~i~~i~ · ~i!!iiiiilli~ ~ -Xv:

... ...... .......~ ~~~~~~~~Klllliii8.

.................. .~.t :"ii~~ii~ 3~3~il''

MIZZ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~t~~~;·

.... .............. ~ ~~~~~~~~~~~~~~~~~~~~~~~~~ii~~iiiii''

................. ~ ~ ~~~~~~~~~.:iiii~(DRAFT TECHNOLOGY ASSESSMENT AND SCREENING ANALYSIS REPORTON DESIGN OPTIONS FOR WATER HEATERS 1.INTRODUCTION This report defines water heater product classes and discusses possible design options for improving theenergy efficiency ofresidential gas-fired, oil-fired and electric residential storage-type water heaters. ' 

### :.i

ii: ~.. iiiii The procedure used inthis design option analysis is ba. on a 'i Tuit ofEnergy (DOE orDepartment) rule outlining process improvement measuresfrocess Ru 'l ier the different appliances subject to possible regulation are defined, potendtiaesign op s aeid as thnext step in the process ofpromulgating appliance efficiency: :dards.iScreening fa'":si used to determine ifany design options should be eliminated 

### fro' ii her consideration:.:'.!'.. 2. PRODUCT CLASSES Appliance features that provide utility to the.onsumer areg o.. rated into the analysis through the creation ofproduct classes. Classes .iai'giof appliancei:pes. For example, water heaters arean appliance type, but a gas-fired storage"wt. 

### e.is a product class. Appliance types are segregated into separate classes to wfhi different ' iiency standards apply. DOE differentiates classes by fuel type or othrperformnce-re iii ures that provide utility to the consumer and affect efficiency. Ingenea:classes are defined using data collected in discussions with appliance manufacturers, trade assoiaions, anbother interested parties. This section specifies.the i-'duct clag..:irnsd"ed inthis analysis. Those classes for which no DOE t l...icedure hii' .ecified A to ned but omitted from further analysis. 2.1 Product'l Under Ci:ieration Cure;n a i. air---.:i-

-- e. Curreil' !iihaate rs arise:parated into the product classes shown in Table 1.The correspondiii mnimum'i ncY requirements which became effective April 15, 1991 are also listed

....

. .. $
. : -. "Table 1.CurrentProduct Classes & Efficiency Standards

Product Css Efficiency Standard a .ii:: EF > 0.62-(.0019x Rated Storage Volume [gallons]) EF >0.59-(.0019 , Rated Storage Volume [gallons]) Electric EF 0.93-(.00132 <Rated Storage Volume [gallons])

Draft screen.005 June 23 1997 B-lTable 2 lists product classes and their current market shares.

Table 2. ProductClasses forWater Heaters (31 Product Class Market Share Year I Gas-fired Storage 52.3% 1995 2 Electric Storage 47.3% 95 3 Oil-fired Storage 0 4% i9 5 - - * , ; .^

^ : ?w

^*
. .. ......... ; :;: ;....

.. ;

- - . ...

. 2.2 Product Classes Not Under Consideration | . ' 1 : ' ''-I 8''-"'': '....R . ... : There are otherclasses ofwater heaters manufactu.re.the Department will'not consider in this rulemaking for reasons described below. The typeso.ter heaters ofwhich the DOE is aware, but for which a new standard will not be issued are.::.i et. instantaneous, gas-fired instantaneous, and gas-fired outdoor auxiliary water heaters. ' ''-l
.. 2.2.1 Electric instantaneous water heaters ......... ::8 Typical electric instantaneous water heatersdlo nit 

## h|v|the capacity to supply an entire residence with hot water. A 20-amp 

### Q(22 volt) cireuit will spplyonly enough energy to heat a 3.0 gallon per minute flow by 10.30F. Th-isisnot sufficient to supply enough water at the 120 to 140°F range expected in most residences.ctric inistataneous water heaters are often installed as booster heaters or to supply a single lavMatycin commialib ;,l gs such as small offices. These heaters are essentially reiVstance heat'ing |ents install,||i |pipe. 1Thei| 

### irecent m'ding, offered that will supply enough energy to heat a 3.0 gallon per minute fl1ihesired teat 

### .This unit has a peak rated input of28 kW and thus may not be appropriat.M l||l s househotd escially homes with lessthan a 200 amp electrical service. The variable syistlem on this heater does not in itselfimprove efficiency.

.-..

No design optios found that would improve the efficiency ofelectric instantaneous water heaters. For thisi reason and because so few are installed for residential use, electric instaneous water heaters are not included inthis analysis.

±2;a.s-fired instntaneous water heaters -'irX ."ed instantaneous water heaters are not studied in this analysis because ofthe small number ofannual shipments and because they will be covered by the same standards written for gasfired storage-type water heaters.

Draft screen.005 June 23, 1997 B-22.2.3 Gas-fired outdoor auxiliary water heaters Anotherproduct class covered bythe standards for gas-fired storage water heaters are gas- fired outdoor auxiliary units. Due to the small number ofunits sold, no analysis will be done forthis product. Water heaters designed for outdoor installation in mild climates have a significant share ofthe Australian market. The Gas Research Institute and a US water heater manufact:r are testing a product for the US market.[4] Because units are not yet available and ."'ilibe covered by the standards for traditional gas-fired storage water heaters, n eiarate a s l be done for this product. 3. BASELINE MODELSS

.

....... .... Baseline models for this analysis were determinei e most commonly sold models currently on the market. The features for each baseline .ledescribed in manufacturers' product literature for their standard models. The efficiency an i, gs were taken from the Consumers' Directory ofCertified Efficiency Ratings 

### ].

.. 3.1. Gas-Fired Storage-Type Water Heater.'
. .... The baseline model gas-fired sto e-type wer he en for this analysis is a bottom- fired, 40-gallon, glass-lined steel tank a 3-iccnter fluehe inlet and outlet water connections are at the top of the tank. The in e is 34iiBtu/hr, h a pilot rated at 400 Btu/hr. It has an energy factor (EF) of.56 and a :.'ery effl cy of 6. The tank is insulated with one inch of polyurethane.foam. The ba:s..*iodel usedii ni;ysis is based on the units listed in Table 3. These are t c a identl tributors and manufacturers. The average EF forthese i.. 56 an " ee rec0very efficiency (RE) is 0.76. For this analysis, the low end oftheE -iR. -ranges"-1 :-d. High i

.. i the odels currently available on the market with EFratings at theminimumffinSe'c n :fo""r tainks rated at 40 gallons. The lowest efficiency standard models ofgas-f.i storage type ':~i}ith eers readily available onthe market from all major manufacturers arelisd with an EF of.5 i7. This is above the minimum EF allowed under current standards. [6]The minimum efficie''ry for a gas-fired water heater with a rated volume of40 gallons is 0.54. T:NAECA standard fr gas-fired water heaters is given by the following equation: EF= 0.62

- (0.0019 K Rated Volume) (1) Manufacturers have used some ofthe design changes that were considered as potential methods for reducing heat leaks in the Notice ofProposed Rulemaking [7] to reach these EF levels. A variety of design options are currently used, none universally[8]. Some ofthese are discussed here. Draft screcn.005 June 23. 1997 B-3

### While it isnot directly associated with the efficiency ofthe product, manufacturers have improved qualitycontrol. They are currently designing for and building better products. Examples ofqualityimprovements that might affect efficiency would befewer metal to metal contacts between feed through andthejacket, better control and placement, and fewer gaps in, the insulation, etc. Using alongerdip tubeis alowcostmethod ofachieving ahigher first hourrating. Hot water inthe upper region ofthe tank is mixed less with the incoming cold water as the dipube length is increased. , : I" Instead ofgetting a higher first hour rating manufactu.eirs..can afli'eati |;derate theburner and still get the same first hour rating. A smaller burner ithe same flu i ii.n configuratia means a higher recovery efficiency, because the same heattransfer sutce ar'easisi. dfor alower amount ofheat.

..... ... 

### Plasticdrainvalves can save about 15-20 Btu/hr iria' isses. There is,however, arisk ofreduced reliability and the danger ofleakage betweeptlai: h and plastic valve because of different expansion coefficients. Also the cost ofaplastic d"rain va".il. is than the cost ofametal drain valve.
_ .. Some manufacturers cover the top oftheianode :i: 

### .;insulatio.' This reduces the amount 

### ofheatthatcan be lost through a gap inthe i.sulationl:iiE...i ufacturer covers the topof theanode rodwithinsulation without leavg any holdien thejhis i a cost saving measure for the manufacturer, which gives a slighitefficiency.increase. .:is, however, much more difficult for consumersto replace the anode rodi eydessiE Another.method ofreducing the numberoffeedthroughs that isused by some rrnm facturers, nsists iattaching the anode rod to the hot water outlet '.
ncurers mayiAls : te sing other echniques we are not aware ofto improve EF. The baseI....ildel EF u tis analysis is above the NAECA minimum standards to reflect current mmodel ethese increases were achieved primarily withtechniques that reduce tlieaks, rtment has dropped this design option' from further analysis.

Table 3CurrentMarketlaseline Models forGas-Fired Storage Water Heaters. ', .:., i.-
. tank rated first .^ mufacntrer iMp Number size input hour EF RE

________ ji_____s___(gallons) (kBtu/hr) rating 

### a ... "51-40T34-3N 40 34 63 0.57 77 [9] " "FSG-40-230 40 32 62 0.56 76 [10] ji'l4irte M-I-40T***N-10 40 34 66 0.57 77 [11] Rheem

- 21V40-7 40 34 62 0.56 76 [12] State PRV 40 NORT-*** 40 35.5 62- 0.56 76 [131 baseline 40 34 62 0.56 76 Draft scren.005 June 23, 1997 B-43.2. Electric Storage-Type WaterHeater Typical electric storage-type water heaters usually have two resistance heating elements inserted from the side ofthe tank. One element is close to the top ofthe tank. The other heating element is mounted much lower in the tank. Each element is typically rated at 4,500 watts, but circuit. 086

_-------....4:. ?:~iiii~?::?~:,::, The electric resistance storage water heater chosen oXfi ae teb5 galon, glatsi lined steel tank with two 4500 watts elements. The doubleeements a erloc shat on ne element may be energized at any time. The tank is insula wth nch offo

Manufacturer Model Number size inpi hurt

. EF American E52-50R-045D 4........... 58 0.87 [14] AOSmith DEN-52 50 5 58 0.86 [15] Bradford White M-I-50T***T-13. 5 64 0.86 [16] Rheem 81V52D 0 4.5 57 0.86 [17] State PV 52 2 R 

### 60 52 4.5 56 0.88 [181 baseline i.' 4.5 56 0.86 

### 3.3. Oil-FidStageTyeater The leviatioia fl-fired storage-type water heater product features among hmanufacfortr electric or gas-fired storage products. The product descriptions presented in Table 5 are facturers product literature and the GAMA directory.[19] Not all manifacturers are listedii eGAMA directory. For oil-fired storage-type water heaters, the baseline model considered is a center-flue model w.itioia rated volume.of" 32 gallons. The tank is insulated with 1" offiberglass insulation. Water -.nom__.ons for thiiimodel are also atthe top ofthe tank. The rated input is .65 gph. AnEF of.50

~andi 'r:- · c.~:~cii env of75% are specified. These are the lowest ratings listed for comparable mitA·MA directory. The average first hour rating of 106 gallons per hour isassumed for the baseine moodel.

Draft screen.005 June 23. 1997 B-5Table 5 Current Market Baseline Models for Oil-Fired Storage Water Heaters. 

### tank rated first Manufacturer ModelNumber size input hour EF RE (gallons) (gal/hr) rating 

### Aero CF-32T/A 32 0.65 n/a n/a n/a [20] Bock 32PP** 32 0.75 131 0.68: 282 [21] Bradford White M-I-32L*OF-10 32 0.65
. 0.4 76 [22] GSW JWF 307 32 O'65 1 76 Heat Transfer Products SJ-30 CWB 30
.. .. t5 2:: 75 .: Lochinvar BRE 32-B 32 0.75 ia a [23 baseline 32 iii.


### . 0.65.. 106 o:':


### 4. DESIGN OPTIONS

. ,:y .. .. ::::::::: : '';::: 

### Design options are changes inwater heaterdesig tatmay haie ?i tential to save energy. This section describes design options known atif.i:L;. : i. The Department issued a Techni"l Suuppoi.t =D) in November 1993 that proposed design options forincreasing watifheatereFciency Many ofthe design options listed inthat document areincluded here alaonlWith desig'options suggested by commenters on the NOPR and further research by the LawrenleBrkele ational L oratory (LBNL). Table 6 shows the 

### disig' options this analysis. Not all design options are applicable faiisproduct classe e produc 

### asssto which each design option may be applicable are indi 

### l table

Draft scmren.005 June 23, 1997 B-6Table 6 Design Options for Gas-Fired, Oil-Fired and Electric Storage-Type Water Heaters Design Options Description gas eec oil Heat Traps X X X Plastic Tank X ~ X
. R-16 Insulation X
. X R-25 Insulation X 

### xi: Vacuum Insulation X .- :..X Gas Filled Panel Insulation

- X

. . Aerogel Insulation

. X Evacuated Panel Insulation !-:I-
.. 

### X... X :::: x x Forced Draft 

### .X 

### .. ,:il.lll. , - i:= Improve Flue Baffle 

# AX x: Submerged Combustion Chamber

....... 'i Multiple Flues :X: :1" X 

### X Air-Atomized Burner :i
. . Sl

### oo very X X
Flue Dl..'

........ 3-- X Flue pa 

### -rBOperatehd) X Jdirect Heating (Sie rHeater) X

. Two Phase Thernisiphon X 

### Flue GasDilutiio X on X u:t.pe.. B ed Ignition 

### x Thermophotovoltaic Generator X X Thermoelectronic Generator X X Draft screen.005 June 23, 1997 B-7

### Condense Flue Gases X X Pulse Combustion X X Condensing Secondary Heat Exchanger X X Add-On Heat Pump X Return AirHeat Pump

_____ x Integral Heat Pump Submerged Combustion Directly Fired " X Off-Peak XU" Solar Pre-Heat
. ' ii.X x:: Drain Water Heat Recovery X X Tempering Tank
. X X Regular Maintenance Xi
. X X X Sediment Removal Features .X :X X g A~~~id: i:: ; .... ^i s...:... i.i.:i'
. . Some ofthe design options insjtbile 6 arepliminated iom further consideration (later inthis report) ifany ofthe following criti isted ii'dte Processrtule are not met[25]: 1) .:Tjinologica! ~bf. .i.iy..y.
.
. :'hnolg* iorate diniomercial products orin working prototypes will be

.....

^Ilidered tech Illcally feasible." 2) Practi t:i;oManuJft.ut nstall and Service.

.. '..M::io n of technology in commercial products and reliable installation

. and serv"i"n" '":fit:chnology could be achieved on the scale necessary to serve the relevant i fi thetime ofthe effective date ofthe standard, then that technology

... l will be considered practicable to manufacture, install and service." ::.i 3) No adverse.impacts onProduct Utility or Product Availability. i 4 Niiiiii:er;i.eN. I se Impacts onHealth or Safety. t hi" e reasons for eliminating a design option shown in Table 6 (or keeping for further consideration) arediscussed in the individual descriptions ofthe design options outlined below. The design optionsthat are not recommended for elimination in this report will be further analyzed. The efficiency and cost ofdesign options not eliminated, and combinations ofthese design options will Draft screen.00S June 23. 1997 B-8

### be analyzed. Later analysis may reveal which design options should be eliminated for economic reasons. In certain 'cases the proper application of a design option may require substantial modifications to other elements within the water heating system (e.g. chimney). The cost of performing these modifications will be included within the future economic analysis. Included inthe discussion ofdesign options are concerns raised bvcommenters on the NOPR. Comments do not necessarily exclude a design option from further analysis but descibe issues that are affected by a design option and should be taken into consideration fao~irther:analysis. Heat Traps

..i iiiiii Heat traps are anti-convection valves installed att,.e inletad outlet ofA.e 

## t""water heaters. Without some method to prevent it,convectiona-ioi.l develop inside I 

### i s leading out ofthe water heater. These convection loops are slo.iOw ofwater driven by the different densities ofhot and cold water. Buoyant hot water rises .in'e seide ofthe pipes leading out of the water heater. As it flows up thepipes, heat islost to:the surrotndiatir. When the water cools off, itincreases indensity. The cooler water then sinks.b¢c along the -de 

### ofthe pipe and back into the water heater tank. Anti-convection valves are one-wayvalves w h
.. fi':ii into the tank from the cold water inlet pipe and out ofthetank intofthe hot water outli" but keep convection loops from transporting hotwater out ofthe tank. vention.heat trap are currently made intwo styles. The first stylehas afloating plasticball th.itblocks thecold water. ilet. The buoyancy ofthe plastic holds itinplace,until water isdrawn. TIforcees sti' g enoughtopush the ball out oftheway as

water enters the tank.Th~:Zec:"~ : - trt style the bllot wa as water enters the tank. Theecond style is 

### e ehot water outlet. Inthis heat trap, the ball ismore: d ia::.n wa :ter. a ::twi..ght oftf lls the outlet until hot water isdrawn and the water pinlet' out Fi ea 6] A smabypass channel isleft for water to escape back into the inlet line ank as.._after a large drawfills the tankwith cold water. Other.:heat" : 

### ":sins also Iha"been invented and produced. These include U-shaped pipes [27], flexib i-'ls '[ flapssprings, and othermechanisms. .l:heDepartment: i:::: :: that this design option should not be screened out. .iic Tank :i At~

least....manufacturer ismaking water heaters with plastic tanks. The technology, a i

...... '"':::'"'''dedpolybutylene innertank with afilament wound fiberglass outer tank, issimilar to::th F o' : :gy used to make tanks for water softeners. [29] The lower heat conductivity ofplastic compared to metal, reduces theamount ofheat conducted through the tank wall to the insulation and to the feed-throughs. This technology can not be used with standard center-flue gas-fired water heaters, oroil-fired water heaters. The plastic can not withstand the high temperatures produced by the flames. This technology isused with electric water heaters without any problems. Side-arm water Draft screen.005 June23, 1997 B-9

### heaterand heat pipetechnologies canavoid flametemperature problems with gas-fired water heaters. Side-arm gas-fired water heaters with plastic tanks are currently available. [30] Plastic tank water heatersusing heat pipesto transfer heat from the burner are expected to be onthe market by the end ofthisyear. [31] The Department believes that this design option should not be screened out. R-16 Insulation 

### Thejacket insulation on the baseline model ofgas ain ectricijc : eaters isone inch of foam insulation. The baseline model for oil-fired water heiars usesfibe 

### lasin sulation. The R-46 designoption increases the insulation thickness totwo inche of oam ins'iiation : ii"e side:ahd top ofthe tank.All manufacturers offer bothgas and electri nmodelswith thicker le::::liii lation. The Department believes that this design option shiA not:fbe screened out. R-25 Insulation '
. 

### Thisdesign optionuses three inches offoam i :''' atni around ':ides and top ofthe tank. The costs and energy savings are calculated a:?.mc rei: .anges feom the R-16 (two inches of foaminsulation) design option. This design onin increstlof water heaters four inches fromthe baseline. Additional installation csts will biadded t i nt forthose cases where water heaters areinstalled intight locations tiat require :emodeling to fit. There will also be an increase in shipping costs as fewer heaters willfitin a truk etc. 

### TheDepartment beli
. e tlat this dSioinl'shoud not be screened out. Vacuumi .... ll . 

### A"hardaiii iwith inftetiai r ctive surfaces is a very good insulator. It has beenused foryears inThe'sibtl"' 

### e" and Dewa'-tnks for cryogenic applications. While this technology could be applied:t'wat"er heates th-lDepartment isnot aware ofany attempts to do so. '.The Department beie:esithat this design option should be screened out dueto problems with proditt availability. :| ' : 

### s9Flillled Panels :.. :iijIii^'" "' :'P'aneis (GFP), are thermal insulating devices that retain a high concentration ofa loNiii'::.iv:ity gas. at atmospheric pressure, within a multilayer infrared reflective baffle. The thermal performance ofthe panels depends on the type ofgas fill and the baffle configuration. Calorimetric measurements have shown total resistance levels ofabout R-12.6 for a 1inch thickkrypton panel, R-25.7 for a 2 inch krypton panel, and R-18.4 for a 1inch xenon panel. GFPs Draft screen.005 June 23, 1997 B-10

### areflexible. self-supporting and can be made inavariety ofshapes and sizes to thoroughly fill most types ofcavities. [32] The Department believes that this design option should not be screened out at this time but seeks additional information onthis design option. Aerogel Insulation Aerogels are transparent, low density, and highly porous mater 

### i very good thermal insulating properties. I > New manufacturing processes have been developed that ca dutb e blankets or clamshell forms ofthis material. At cryogenic temperaturs -valueserinch greai .40 have been observed at high vacuum. R-value per inch greater ambient pressien have also been measured. [33] Commercial applications ofthisi `1pgy with a high vacuum achieve R-20 in a 1"thick panel. [34] i. foam i n W..: ."'": "'j:~'~ i~!i~ii?~iiii:i
.... The Department believes that this design option should not e screened out at this time but seeks additional information on this design option. Evacuated Panels Inaddition to aerogels, other Mai s witilightwe en structure can create very good 

### insulators at "soft" or low vacuumi.The materials canie enclosed with metals or plastic. One company manufactured panels for in refligrtors. T design used hermetically sealed stainless steel skins tosrround a layerf secial higW fiberglass A vacuum (10' torr) is drawn inthis pr s rigid fibea eps the vacuum panel from compressing with the vacmzm 

### p5) Other tedj insulation panelsfeature fine powders contained within an envelope composed of teP wt.erse an ffer five to ten times the R-values ofstandard fiberglass or foam insulac iiie. u 3,

- .Jyhe Department i s that this design option should not be screened out at this time but seeksadditional informationn on this design option. 

### FDraft Draf Sevua l anufacturrers are currently making water heaters with induced-draft blowers. Howevr, it's feature isusually added to allow sidewail venting and may not be accompanied by any increase in flue baffling. Using a fan to force the flue gases through the baffle with either an induced-draft blower (downstream ofthe water heater) or a forced-draft blower (upstream ofthe water heater), often Draft screen.005 June 23, 1997 B-ll

### called power vent, can increase the recovery efficiency and reduce the standby flue losses. The offcycle fluelosses are reduced bythe additional restrictions to airflow from both theblower and the increased baffling. Increased recovery efficiency from this design option may necessitate relining vent systems. The Department believes thatthis design option should not be screened out.

... ii Improve FlueBaffle , .:

.. 2 .,-. 

### The standard flue baffle isa twisted strip ofmetal ,'ied int"i fithat increases the turbulence offlue gases and improves heat transferto the .als ofthe fleiiiO::: manifacturer: uses aflue with many small rectangular fins attached onthe insie surface i'J!their 

### midefficiency mael The arrangement and size ofthese fins increasesthe reco;::ry effieiecy ofthe wti:;:


### . 'iierOther baffle configurations that increase recovery efficiency are|| -. .. ilable. i

- Iftherecovery efficiency istoo high, water heaters wit:i iign option vented to masonry chimneys or otherolder venting may cause problems. Intihat case hhmneys must be relined to prevent problems caused by the condensation offlue gases. To avoid ms from condensation itisalso possible to use sidewall venting. A?:li}
... Potential health and safety proble.m associat ' effi ciencies that are too high will be addressed by increasing the ins.flation cQ.t to ac iifr modifications to the venting system. This design option will be spit to threeidesign options, a slightly improved flue baffle, an improved fluebaffle,-anda greatlyimov'ed flueaiffe. Thedfeails ofthe geometry are not specified. The slightimprovement inthe flue:i"te woulidve an R ofaround 80%. and is assumed towork with existingvent systems. teimprovedl: wuld have an RE ofaround 82%, and is assumed ti vent.re venit.i n a sigrii mount ofinstallations. A greatly improved flue baffle is:assm to have ::B.. and would require power venting for safe operation. :bis~

" -~i'bi::. ha v >::: . .. ":::eo:pera:t:i:on.*::::.::::
. 

### The Dep ibelieves 'i^design option should not be screened out atthis time but seeks additionai oon ' -n

: on thisi'n option. ' ..... .....~iii
. " ~i >b: ::,. "%'" SubmergedCombustioCi0mW r Thecombustion chamberin a standard gas-fired storage water heater isbelow thewater tank. Thi bottom ofthe taki 'is suspended directly above the burner. The sides and bottom of the

... iustion chamber are not surrounded by water. By inserting the combustion chamber into the e 'atnk. morg the combustion energy can berecovered. Standby losses are reduced somewhat "b" s"' ei".ictions on the air flow throughthe combustion chamber and flue. This designoption can increase recovery efficiency sufficiently so that condensation islikely to occur inventing systems that are not double-walled sheet metal. To avoid problems caused by condensation on other venting systems, masonry chimneys must be relined orsidewall venting must be used. Ifvented properly, no health and safety problems exist. Draft screen.005 June 23, 1997 B-12TheDepartment believes that this design option should not be screened out. Multiple Flues This design option uses three smaller flues in place ofone large central flue in the middle of the storage tank. The greater surface area ofthe flues yields an increase inrecovery efficiency. This isa consequence ofthe increased surface area for heat exchange between the flue gasesand the water inthe tank. Onemanufacturer is currently offering this design option in a residentiu gas-fired water heater. a TheDepartment believes that this design option sh l be s .. t. Air-Atomized Burner

.... ' i

.......... : This is a different type ofburner for oil-fired equipt nstea d ofrelying on pressure to create a spray offine oil droplets prior to combustion, this s stream ofairto atomize oil This design allows better control of droplet size and rixing w i t wer oil flow rates than conventional burners. Downsizing the burner with the sameflue and ba-goetrv will give a higher recovery efficiency. The combustion process is AlW Nth this. uier. Working water heaters have been m with sp Therewould beno impacts

seeks add:i'..... informatuiorhs deig o m
... ... Slow Reco ry iiiiii:.. *

- m. .No

- There .. be no im pact Redi while ng fle baffle and tank geometry the same will increase the ratio ofheati fer s ' per BTUinput thereby increasing the recovery efficiency. The lower input means therecovery: is lower. The first hour rating would probably be reduced as well, 

### although some ofthis firs: ihorating reduction could possibly be offset by changing the dip tube design.

"U" Tube Flue Draft crn.5 June23. 1997 B-13...... 

### .". There should no pro blem with technological feasibility or impacton practicabilit to Ar eaendtierviceoexcept ifthe recovery oft erecby increas 

### es to 

### me point of c ausin g 

### l~input:iiii!":- tmg systems. No adverse impacts woul d be expected on health and safety. TheDepartment believes that thisdesign option shouldno t bescreened out at this time but seeks additional information on this design option. "U" Tube Flue Draft scrcen.005 June23. 1997 B-13One commenter to the 1994 NOPR mentioned an old water heater design that uses an inverted U-shaped flue within the tank ofthe water heater. This design could increase the recovery efficiency andwould reduce standby losses. Unfortunately no working models are currently available and it is not clear whether it would meet modem safety standard. There is also a lack ofworking prototypes. The Department believes that this design option should be screened out dueitb uncertainty about availability and safety ofthis design option. ;^ 1 FlueDamper (Electromechanical) Flue dampers are offered by several manufacturers a? an option;n co'mml iater hder. These dampers are electrically actuated dampers mountdi.at the tip ofthe flue. :!T d'i| s are opened when the water heater is firing and closed duri |ffiicle. When the da :iis closed, standby losses byair flow up the flue are reduced. Safetyinite " are required to assure the damper is openbefore the burner can come on. It shouldbe noted tha lii:de.in option requires electricity to operate a gas-fired storage type water heater.
. Because these devices are currently bei. .|.'|i com.m cpm erer heaters, this design option passes all the screening criteria. It shouldi'noted i l iadditiot the increased installation cost for electrical supply, maintenance costls re expe.ted o| hi.i' The Department believes that.s design iption shold not be screened out. FlueDamper(Buoyancy Operaed) Y Thij: s.kd.amnper ivs: ::';¥ery ligh' ":::: l:uminum dome-shaped poppet that slidesup and down'r'e placei" " ::: ofthe flu ofa gas-fired water heater. The buoyancy ofa cycle combustion
... 

### lifts theii l alowing flue gasses to enter the venting system. Working prototypes have: ilt and tes iid |AGA. This`ifl`"lg otioni ould reduce off-cycle standby losses, but would have no effect on recoverefficiency. This 

### ' i er may not work with high RE water heaters as there may not be enoug 'waste heat in the eO .ion products toprovide sufficient buoyancy to liftthe poppet. There aren' known obstacles i this design option, although it has not passed safety certification yet. TheDepartment believes that this design option should not be screened out at thistime but 

### s'ti:ik tionalinrmtation on this design option. I':" e ''""'': (Side Arm Heater) This design option avoids the large flue losses by removing the flue from the center ofthe tank. Wateris withdrawn from the bottom ofthe tank and heated in a small separate heat exchanger over a burner. Water is returned to the top ofthe tank. A small circulation pump moves water through theheat exchanger when the burner is on. The burner has electronic ignition. Auxiliary power Draft screen.005 June23, 1997 B-14can be supplied by a low-voltage plug-in transformer. Further reductions in standby loss can be achieved by using electronic ignition on the burner. There is a commercially available water heater using this design option in combination with electronic ignition and a plastic tank. The Department believes that this design option should not be screened out:i Two Phase Thermosiphon (TPTS) Thisisa heat pipe like mechanism to transfer heat fr'omI the burna ge tank. Tihe working flue is partially vaporized at the evaporator whi is mountedver thThe.v or along with some ofthe heated liquid is propelled to the :denser:ich is insi if'""' ank. At the condenser, the vaporized working fluid is conde'"ri:ains back throurgiaate restricted tube tothe evaporator, where it is reheated. The -:':iciiOprevents the heated vapor and liquid from flowing tothe condenser on the return path there isvery little heat transfer through the TPTS system. This reduces standbyosses teat Working prototypes have been developed A major':heater manufacturer is planning to bring a version to market soon..
.. :: TheDepartment believes that th esign se screened out at this time but seeks additional information on this eAin option .ai iox

-.'.:..

. ... ; SA ufactaking with induced draft fans that in addition to 

### pu~lling t sbaIon prd through the water heater, also draw excess air into the flue gases prior to ve additio drawn in cools the flue gases leaving the water heater to a low enough tpefj so thatSt 4lastic piping can be used for venting. This eliminates any problems rwithob astic pi is often cheaper and easier to install than sheet metal or masonry chimneys" H hile this design es not necessarily increase water heater efficiency, when combined wTh design options thatr e crease recovery efficiency, it can help avoid venting problems. uThe Departmebelieves that this design option should not be screened out

Intermittent or electronic ignition systems can be installed to replace a standing pilot. Not only isthe pilot replaced with new equipment, but so are all the required burner control and safety devices. This design option requires electricity for the gas-fired water heater. There are three different technologies available to electronically ignite the burner. These are hot-surface ignition. spark-to-pilot Draft screen.O05 June23, 1997 B-IS

### ignition, and direct-spark ignition. The hot-surface ignition heats a ceramic oxide element to ignition temperature usinglinevoltage. Bothspark-to-pilot and direct-spark ignition use a-spark to ignite the gas. The spark-to-pilot ignites a pilot whichin turn ignites theburner. The direct-spark ignition uses a spark to directly ignite the main burner. Both ofthese designs can be built to use low voltage supplied by a 24 volt transformer. Low-voltage electricity can be supplied by a 24 volt plug-in transformer. Aplug-in transformer reduces wiring and other installation costs. It should benoted thata large portion ofthe heat from the pilot light
. elpst. maintain water temperature inthe tank. Without aflue damper or some other restriction n-ycle fluelosses, the reduction ofgas consumption issmall. The cost ofthe electri i for th: ignition, and the standby lossesinthe transformer, ismore thanthe cost ofthegas that is '. :having a pilt light. This design option used alone will actually increase'Ibtal energrConsum'ion' Mpare a standing pilot.

. 

### TheDepartment believes thatthis design option s l ' tybe screened out.

.... . .... Interrupted Ignition · iI 

### The sparkignitor for oil-fired burners isus 'l. nwhen e"ite burner ison. With the right controls, the spark can be activated onlyi '':s':i:'me isestablished. This design option not onlyreduces electricity consumption, but i:so reduces' iiiosts , because the electrodes do not have to be replaced as often.
. . The Department believes this desig. option shuild not be screened out at this time but seeks additional information on t'ihadesign q.n. 

### " Thermon:poA.! taic Ge*a'- 

### Ath*p voltaic" -i ter uses a special light-emitting burner coupled with silicon photovoltaic ce'i'. " 'G'erate auxti y ' "i||wer to run a fan, electronic ignition, controls, and charge a battery. This i"*Is ::.erquire mn iof auxiliary electrical supply, while offering the efficiency advantagesait eiectrrc.t i i-onand forced-draft combustion. .TheDepartment :iSll-ded development ofprototypes ofthis design option.

The Departmentblieves thatthis design option shouldbe screened out due to concerns about :itiacticability to Manufacture. 

### TI '-'-' 

### ,nei:t aGenerator Another method ofgenerating electricity at the water heater that isbased on thermocouple technology. Thermoelectric generators are available, but none havebeen used in water heaters.

Draft screen.005 June 23. 1997 B-16The Department believes that this design option should be screened out due toconcerns about the practicability to manufacture. Condense FlueGases To extract the maximum heat out ofthe fuel ofa gas-fired appliance, the combustion products in theflue gases must be condensed. To do this in a storage water heater, the flue musthbe lengthened bycoiling it around inside the tank. The flue exit must be lowwhere itcan;:-wntact h:' coolest water in the tank. The flue gases must be forced through the water heater, :' draft provided by buoyancy forces is not strong enough. Three manufacturers crtly ma 

### eheater using this technology. It is typically designed to provide both dome:st:hot water. .ndihating. I The condensate in flue gases is acidic. Special Sting sytms must be:tj'. lf: can handle this condensate, and the condensate must also be' e':iisafely. The installai ost in this analysis must include the cost for adding electric service, 

### li conduit, re-venting, and adding a condensate drain. The high sulphur content offuel oil means':, tc densate is much more acidic for oil-fired equipment. This design option has not been demonstrat4. i r::: t!fired storage type water heaters.

. .....'.:.. -wi i :'i: '' The Department believes that this desgn tid not bScreened out for gas-fired water heaters. TheDepartment believes t.i:this design p be screened out foroil-fired water heaters due to concerns about the:practicabit' to maJ re. - Pulse Combustion . Pulse.combustion burers erate onii ronating pressure waves that alternately rarefy the tion cha j ing a eir mixture into the chamber) and pressurize it (causing .e. cormp 0 .reo the mixtiire to its flash point). This process is initiated by a blower s-up-i..... ntieal fuet niuxture to the combustion chamber. The mixture is ignited with a spark l i.et rtmes b atiiis produced, the process becomes self-sustaining. Pulse frsequencies areil r ''of 10e s per second
. Pulse combustion systems feature high heat transfer ra,,'are 

### c ':'i.'.oself-venting, and can draw outside air for combustion even when installedinside. Americ'"'iAiociation Laboratories (AGA Labs) built several prototype pulse combustion water heaters-'asp:.'fart ofa study ofpulse combustion residential water heaters. [39] This technologyhas not been developed for oil-fired equipment. T:.....e De..:ent believes that this design option should not be screened out for gas-fired wa hii" ""'"'

### t-'is time but seeks additional information on this design option. The Department 

### bel.iesi:... sdesign option should be screened out for oil-fired equipment due to problems with product availability. Add-On HeatPump Draft screen.005 June 23. 1997 B-17

### This design option involves a separate heat pump that can be attached to an existing electric storagetypewater heater, Asmall pump circulates water from the tank, through theheat pump..This design option could also theoretically be applied to either gas-fired or oil-fired storage type water heaters as well. [40] The Department believes that this design option should be screened outdue tothe lack of demonstrated practicability to manufacture, install and service and lack ofproduct.availability. ReturnAir HeatPump .:W " 

### Another technology somewhat similar to add-on ;eat pumps hloae at porator in the return air duct of the household heating and cooling '.isystem. RieranM i|i edt......he 

### evaporator.[41] I,, 1: The Department believes that this design option s h 

### uldbe screened outdue to the lack of demonstrated practicability to manufacture, install and seraicek. l k ofproduct availability. IntegralHeatPump 

### The integral heat pump uses a heat|ie.xchangeth.. :ia .buit the| inner wall ofthe tank as the condenser. This design increases the'efficienctofthe cohi er and eliminates the need for a pumpto circulate the er. Ts based onwater. his des ion i seon ater heater currently on themarket. [42] .:'. :

. The Department beeehat this Al should be screened out due to the lack of demonstr

### atdracticabily ttiaufactur rt- 

### aid service and lack ofproduct availability. Submerged C'~whiion ' it~te r~ e fll ^ ^ | | || |!6 (o w ' <::: ^ 1 1 11s,.
.. Inthis 

### 4ig|the flue.products are bubbled through a small volume ofwater by the pressure fro eburnie r. This small amount ofwater is heated by direct contact with the 

### flame and flue products. -tllatewater isre-pressurized by a circulating pump and returned to the storage tank. . g



### ...

.i Apotentialhealthiproblem isthe contamination ofdomestic water by the flueproducts. This di:.may conflict wit plumbing codes. [43] *'il..

.erti" " -iment believes thatthis design option should be screened out dueto potential health probleis:' :s:sed bythis design option. DirectlyFired

Draft screen.005 June 23, 1997 B-18In this design option, water is sprayed through a series ofbaffles above the burner. Flue products are in direct contact with the water, which is re-pressurized by a circulating pump and returned to the storage tank. Apotential health problem isthe contamination ofdomestic water by the flue products. This design may conflict with plumbing codes. The Department believes that this design option hould be screened dueopotential health problems caused bythis design option. Timer Controlled This design option limits the time ofday when the ments .n electric t ater heater may be energized. These are most often use.d.. of eectc tind side management programs for load shifting Field tests show a f :ie"t energy savings, from allowing the water in the tank to remain at a reduced temperature .fRi il day. The Department believes that this design pi uld d out at this time but seeks additional information on this design optioni.. .i, 

### SolarPre-Heat iii. This design option uses solart cllectors. ~as pre-heas to a standard electric storage type

This e s a heat hanger to recover waste heat from the drain. In effect this 

### becomes a. ter standard electric storage type water heater, but could be used with

wfossil-fif water heaters T eearirem a few designs currently available.d c . t be screened out at this timbu

The Department lieves that this design option should not be screened ou.:t at this time but seeksadditional information on this design option. Drain !. .... o"er

.....



### Teprain T-:k A tempering tank is an un-insulated storage tank plumbed in the water line before the water heater. When it is installed in a conditioned, or semi-conditioned space, it will raise the inlet water temperature to the ambient temperature. d 

### b wi th Draft scrcn.005 June23, 1997 B-19

### The Department believes that this design option should not be screened out at thistime but seeks additional information onthis design option. Sediment Removal Features 

### Several manufacturers offer models with dip-tubes designed to create turbulent water flow that prevents or limits the build up of sediment on the bottom ofthe tank. Ti.s'may reduce degradation ofefficiency overthe life ofthe water heater. A ': .. : * 

### The Department believes thatthis design option shou[liot be:i ::ut at thistime but seeks additional information onthis design option. ....... . :: 4. CONCLUSIONS .. 

### Forpreviously stated reasons, the design options :ina were eliminated from further consideration.

.::Draft c . .: . ,,005 June23,
.... B c....::,"'- : : : : :::::'
........ .. >:',''



## . ..........

Draft screen.005 June23, 1997 B-20Table 7.Design Options Department Proposes to Eliminatefrom FurtherAnalysis Vacuum Insulation "U"Tube Flue Thermophotovoltaic Generator Thermoelectronic Generator

. Condense Flue Gases (oil only) Pulse Combustion (oil only) Add-on Heat Pump Return Air Heat Pump

..... iiiiji&.......* ; *** Integral Heat Pump Submerged Combustion Directly Fired

. .......... *S irii Table 8 shows the design optis remaii' g for furtfr analysis. Table 8. Remaining Desi n Otions.: Heat 'Ti i
R16 Insulation R25 Insulirion "iiiii:i Gas:,illed Panel InsulatiO gel Insulation ated Panel li'ation ImproveiFue Baffle Submerged Combustion Chamber Multiple Flues Draft screen.005 June 23, 1997 B-21

### Air-Atomized Burner Slow Recovery FlueDamper (electromechanical) FlueDamper (buoyancy operated) Indirect Heating Two Phase Thermosiphon , Flue Gas Dilution

. ,::: , .' Electronic Ignition | ' ' . liiii:ii 

### Interrupted Ignition
.. Condense Flue Gases (gas only)
. . . . R,,R : 

### Pulse Combustion (gas only)

.. .. . Timer Controlled ' Solar Pre-Heat Drain Water Heat Recovery System::

.. f ;' .::... Tempering Tank .f , Sediment Removal Features

.. i

Draft
. ... 005 June23,1997 B-

* '.>,.>lss,;S:g :::

Draft screen.005 June 23, 1997 B-22

### REFERENCES 1. U.S. Department ofEnergy, Office ofEnergy Efficiency andRenewable Energy (U.S. DOE). 1996a. Energy Conservation Programfor Consumer Products: Proceduresfor Consideration of New orRevised EnergyConservation Standards forConsumerProducts, 

### Notice of final rulemaking.. Federal Register. Vol. 61 No. 136, July 15, 1996. pp 36974-36987. [http://fr.counterpoint.com/fr/1996/0715/00014.html] 2. U.S. Department ofEnergy, Office ofConservation and Renewa lergy (U.S. DOE). 1990. EnergyConservationProgram for ConsumeAro OductsPiWR leRegardingTest Procedures andEnergy Conservation Standards fa* aterHeRegister, 

### V. 55, No. 201, October 17, 1990. pp 42162-42177^ Aixi 3. US Department of Commerce, Bureau of sus, Economicsi Statistics Administration. 1996. Current Industrial Repor usehold Appliances-MA36F, Annual 1995. [http://www.census. gov/industry/ma3.l 4. What 'stheLatestSplashin WaterHeating?,GRID Gas 

### Ritu te Digest, Summer 1996, Gas Research Institute, Chicago, IL.X,
...... 5. Gas Appliance Manufacturers Asso'iation,nsu r' Directory of Certified EfficiencyRatings.Arlington, VA iOctobere196 6. Code of Federal Regulations CF 430.32 ergy ConservationStandardsand Effective Dates. [http://cfre nterpoiucom/cfr/L 

### i997/0228/0002859.html#§ 430.32] 7. U.SDOE. 1993 Oiitp. I-6 8. iions 1ii Lannes adford-White Inc., Middleville, MI, (12/16/94); 

### Ml M xttin, Cafi3i t Ei^ergy Commission, Sacramento, CA, (12/19/94); and Larry Weinga i| ental E|Monterey, CA, (12/15/94) 9. 

### AmiGoup1994. ResidentialGas&Electric,RGE-1 1/94, Johnson City, 9. 10.' A.O. SmithWateiPriducts Company, 1994. EnergySaverGasResidentialWaterHeaters



### :il FSG,FSGL,FGiH, FSGT, A 713.1, November 1994, Irving, TX.

.Bradford 

### W.e Corporation, 1996. FullLine WaterHeaterPocket Catalog,Rev 8/96, 

### 12.'R^i; em Manufacturing Company, Water Heater Division, ResidentialGas WaterHeater ProductGuide,6-93 BP Form No. 1366, Montgomery, AL 13. State Industries, Inc. 1994. ResidentialGas WaterHeaters,Censible,copyright 1990, STG 

### 5/494, Ashland City, TN Draft screen.005 June23, 1997 B-2314. American WaterHeater Group, 1994. Residennal Gas&Electric,RGE- 1/94, Johnson City, TN 15. A.O. Smith Water Products Company, 1994. A.O. Smith FullLine Catalog:Residential. CommercialWaterHeaters,BoilersandStorageTanks, Form No. CPD-9150E 60M-59A,, 1994, Irving, TX 16. Bradford White Corporation, 1996. FullLine Water HeaterPacketCatiog,Rev 8/96, Ambler, PA. .i ::!. 17. Rheem Manufacturing Company, 1995. Water -H'er "Divisioi'::"tiial Gas Water HeaterProductGuide, 10-95BP Form No. 105-6.Montgom A
...... L::. 18. State Industries, Inc. 1990. ResidentialElectrici :.erHeters,Cerinsiblie,iv g: 1990, STE 16/1-90, Ashland City, TN : 19. GAMA, 1996, Op. cit.
..... 1^ .i..!iiiB:::,,

-. * . .. "...R,''..I.'. " ''".' 20. Aero, 1996. WaterHeaters,HighEfficiency Oil., red Waterl :gWH 03/96 30M DKT 2641, Mississauga, Ontario, Canada
... S 21. Bock Water Heaters, 1996, Oil Wat~ 'Heate"rs 1-t, Madison WI 22. Bradford White Corporation, .1996 Ful.iLine Waeir'Heater Pocket Catalog,Rev 8/96, Ambler, PA.
. 23. Lochinvar Corporation, il93, Res a O- .- ,:"Fired Water Heaters, Litho 2M 10/93, 

### Na..:i.e, TN ii

....... 24. t "J'e-m:nent of'- Oice ofEnergy Efficiency and Renewable Energy (U.S. DOE). 199J':":St:uppo

. : " : EnergyEfficiency Standards for ConsumerProducts: RoomAIr:i"':""Mers. Wa: i" ters, Direct HeatingEquipment,MobileHomeFurnaces, 'Kitc i"i'i-. : .. ens, PotHeaters, FluorescentLampBallasts& TelevisionSets. No.

... DO'E-000II;'"::p- . by Lawrence Berkeley Laboratory, Energy Analysis Program. November 1993 Vl3'F 25' U.S. DOE. 1996 i 

### Op.cit.

M. U.S. DOE 

### 1.9. Op. cit. p 1-5 27.ifli."NieiD. Ned. ed.. "Simple HeatTrapfor WaterHeaters",Energy Design Update, vol. '.i4lno. ' 10, October 1994, New York, p14. 28. Harvsy, Jane Allison, "MakingYour WaterHeater MoreEfficient", Home Mechanix, March 1994, p 14
Draft screen.005 June 23. 1997 B-2429. Rheem Manufacturing Company, Water Heater Division, "MarathonHigh Performance, HighEfficiency, Lifetime GasWaterHeater", form no. 101-41, 10-93 BP, Montgomery, AL. 1993. 30. Rheem, 1993. Op. cit. 31. Communication withRon Swenson, TPTS Development Company, Santa Cru;:CA, (3/4/97) 32. Griffith B.T., Arasteh D., and Turler D., Gas-Filled Panels:Anf.4:t WApplications in the Building Thermal Envelope., Lawrence Berkelerationa. :atory, LBL-38093, October 1995, Presented atthe BETEC Fall Symposi u, Washi . ieC, November 1:4i 1995. <http://eande. bl. gov/BTP/papers/38093..pdf:'B i e a'so <http://eande.lbl.gov/BTP/pub/INpub.html>
. ii
.. 33. Williams, B., TechnologyOpportunity:Aerogel-Ba"" rinsulation, NASApril 1997, <http://technology.ksc.nasa.gov/WWWaccess/Oppoi i..el .html> 34. Glacier Bay, Inc. SuperInsulationPanels.BARRIER 20Mii... 1 1997, San Mateo, CA <http://www.glacierbay.com/BARRIER.htiii :,ii, m... 35. VacuumInsulationaReality,Environmental B bilSi&Nws, vol.-4, no. 1,January/February 1995,

.. : . .... i'
.... ^ <http://www.ebuild.com/Arc hivcves "roduct:-Review /AUR
_ VacuumInsulation.html> 36. ORNL, Powder-Evacuated ias, OaiRidge Natnal Laboratory, <http://www.orn.gov/%7'k/succe ep.htmit
37.
.. 

### ob~ Therm"ls'"j"WaerHaterater <http://ecotopia.com/tpts.htm> 38. Unitei:^':titi.: atent 439.-3,66. <http:// "r t".gov/c "i:fetch4?/mount2/PTO/INDEX-+PATBIB-83+0+2 1797+4 +0+-,27 iS*1+J IN%^runes> 39.
..ifThrasher, W.H., ""|CombustionResidentialWater Heater,Prepared by American Gas Association Labori o , Cleveland, OH, forGas Research Institute, contract no. 5080-345- 0369, October, 986
: j. .Heat pump w.er heater models B 108 and WH-6BX manufactured byE-tech, Atlanta, GA.

: : :iilka: : P.B:i i: , A ; :: ; 4." " ir Conditioning is developing a heat pump water heater ofthis type. 42. model #TS-HP-52 HR, manufactured by DEC International, Therma-Stor Products Group. 43. International Association ofPlumbing and Mechanical Officials, Uniform PlumbingCode, 10, section 1002, Walnut, CA, 1991 Draft screen.005 June 23, 1997 B-25