Full report

Original page 1

I 3 1176 00168 0991 ,, DOE/NASATECHNICAL MEMORANDUM )'I/,4.YA7.,,"zA..,Zq',, DOE/NASATM-82415 DEVELOPMENTANDTESTINGOFTHERMALENERGYSTORAGEMODULES FORUSEIN ACTIVESOLARHEATINGANDCOOLINGSYSTEMS , (FinalReport) l By John C. Parker I 19810015070 SoGeolarrgeEneCr.gyMarshallApplicatiSpaonsce PFrloigjehtct CenOffticere NASA-TM-82415 Marshall Space Flight Center, Alabama 358t2 A..,,,_, FOR REFE_NClg U.S. Department of Energy Solar Energy

Original page 2

,,,, ......... IOTICE ............... TIlLs epo t8 p_epa_ed !:o doc_nen vo_k sponsored b? the hL_l:ildhate8 Goiter. Ne_l:he he Uu:l.tml States not ttl lSt_ll h!l Uttered 81:lt1:eal)ep!t_l:lmnl: of Enerlye the ;a_ted |tti_tl8 tqet_Loul l_e_l:u 8td Space kiu_tst_tttoo, not any ltedt_e2 eu_o?eeeb uo m7 oft l:he_r €ontractor8, subcontractors OZ_hllt IlqtlO_Mlell_Iulllll _ m_ml:y, express o lmpltede ot UINIi m? Zqld. Z_Ltb_L_L;:ot? teepmuJ.b_l.tl:yfo ;:he accuracy, l)l_du_ o_ p_eH d_ec2oeed., o_teptee_t that 1t8 ue vou_d uO_ _tnit_tnle p_L,e:e_L7_ed _441ht8. munrlmllulnlm - ! iII Jill .........

Original page 3

1, REPORT NO. I2. GOVERNMENT .D AS A TM-824i5 I 4, Tr'FLE AND SUBTITLE Development And Testing Of Thermal TECHNICAL REPORT STANDARD TITLE PAGE ACCESSION NO. 3. RECIPIENT'S CATALOG NO, 5. REPORT DATE Energy Storage April 1981 Modules For Use In Active Solar Heating and Cool-s. PERFORMmGORGANIZATIONCO_E .__ing,tLems - Fin.al Report :'7. AUTHOR(S) John C. Parker '97 PERFORMING ORGANIZATION NAME AND ADDRESS George C. Marshall Space Flight Center Marshall. Space Flight Center, AL 7Z SPONSORING AGENCY NAME AND ADDRESS 8, PERFORMING ORGANIZATION REPORT # 10. WORK UNIT. NO. 35812 I. CONTRACTORGRANTNO. 13. FYPE OF REPOR%" a PERIOD COVERED National Aeronautics and Space Administration Technical Memorandum Washington, DC 20546 15, SUPPLEMENTARY NOTES Prepared by Solar Energy Applications 16, ABSTRACT This Document summarizes the 4. SPONSORINGAGENCCYODE Projects Office final results of contract NAS8-32254 with Artech Corporation, Falls Church, Virginia, for the additional development work on thermal energy solar heating and cooling systems. storage modules for use with active It discusses the intended use of the final report, describes the deliverable end items, lists program objectives, relates how they were encountered and their solutions. accomplished and deals with problems The report shows that the product developed and tested is marketable and is recommended as 17. KE WORDS Solar Test Container Phase Change Salt Molded F,ut ect ics Polyethylene Chamber Plastic being suitable for public use. 18. DISTRIBUTION STATEMENT "UC590 Unclassif ied-Unlimited 19. SECURITYCLASSIF.(ofthl=report 120. SECURITY CLASSlF. (of this page) 121. NO. OFPAGES 22. PRICE Unclassified I Unclassi£ied I 34 NTIS MSFC - Form 32 92 (Rev. December 19 72 ) For sale by National Technical Information service, Springfield, Virginia 2215 1

Original page 4

Original page 5

TABLEOFCONTENTS PAGE SUMMARY..........................,...................I INTRODUCTION..................,,,.,,,,,....,,,,,,,. ,, 3 PROGRAM BACKGROUND AND GOALS,,,,,,,,,,,, ....,, ,, 3 PURPOSE OF THIS PRODUCT DEVELOPMENT AND TESTING CONTRACT................. ...... ................ .. 3 DESCRIPTION..............................,,,,,..,,. ., 3 PROJECT DEVELOPMENT REQUIREMENTS AND CRITERIA, .. 3 DEVELOPMENT OF THE THERMAL ENERGY STORAGE MODULES....... 5 TECHNICAL DATA FOR TIIETIIERMALENERGY STORAGE MODULES,,, 8 PERFORMANCETESTS,,,....,.......,,.,.....,,..,,,.....,.......9 THERMAL ENERGY STORAGE ASSEMBLY................... .... . 9 • DUCTING lllllillJllllllllllllllllllllllllllllllllllllll 9 TEMPERATURE, PRESSURE AND AIR FLOW MEASUREMENTS......° II DRY AND WET BULB TEMPERATURE.......................... Ii TES MATERIAL TEMPERATURE..........................,... II TEMPERATURE DIFFERENCE MEASUREMENT ACROSS TIIE TES UNIT II DUCT PRESSURE MEASUREMENTS.. ..... ..................... II AIR FLOW MEASURING APPARATUS.......................... ii AIR RECONDITIONING APPARATUS.......................... 12 PERFORMANCETESTRESULTS.... ,,,,,,,,,,.,,,,,,,,,,,,,,,,,,, 12 PROBLEMSENCOUNTEREDANDTHEIRSOLUTIONS..................17 CONCLUSIONS,,.........,,,,........,,,,,,,,,,,,,,,,....... 17, RECOMMENDATIONS...........................................18 o GENERAL,,,,,,,,,,,,,,...........,,,,,,,,,,,,,,,,,,.,,,,,,,2o INSTALLATION. OPERATION. AND MAINTENANCE INSTRUCTIONS 20 iii

Original page 6

LISTOFFIGURES FIGURE # TITLE PAGE Figure 1 Tubular Concept (In direction of Air Flow) Prior to Contract Implementation ....... 4 Figures 2-4 Container Configurations ..................... 6 Figure 5 Final Design: Hardware - "As Built" Configuration ................................ 7 Figure 6 Instrumentation Setup ....................... I0 Figure 7 TESmod (TM) Thermal Energy Storage Modules .................................... .19 Figure 8 Disassembly of Module ....................... 26 Figure 9 Parts Identification iv ........................ 27

Original page 7

TECHNICAL MEMORANDUM DEVELOPMENTANDTESTINGOFTHERMALENERGYSTORAGE MODULESFORUSEINACTIVESOLARHEATING ANDCOOLINGSYSTEMS- FINALREPORT SUMMARY The intended use for this report is to provide product development information as an aid to the solar heating and cooling systems manufacturing industry the products suitability for use cooling systems for residential This report will also in their effort to determine in active solar heating and/or and commercial applications. serve as an aid to those who desire to remain abreast of the state-of-the-art of solar energy heating and cooling projects. In October of 1976, Artech Corp. entered into a contract with the National Aeronautics and Space Administration (NASA)/ Marshall Space Flight Center (MSFC) for the additional development and testing and subsequent delivery of thermal energy storage modules consisting of sealed containers filled with salt hydrates or eutectics which can provide latent heat or coolness at certain desired temperatures, after being heat or cooling source. thermally charged from an outside The deliverable end item under this contract was to be three identical subsystems. Each subsystem was to consist of modules which when combined would constitute a volume of approximately 6' x 6' x 6' However, in mid 1977 the contractor began experiencing fabrication problems. in the air passages of the plastic Numerous pin holes were found containers. The container was redesigned and certain improvements made in the molding techniques. This resulted in added costs; and to maintain the funding limitation as established at contract implementation the scope of work was adjusted by changing the n_Iber of products to be delivered from three identical subsystems to one subsystem. The one subsystem consists of modules which when combined constitutes a volume of approximately 2' x 2' x 6' 1

Original page 8

The thermal capacity was also changed as a result of the reduced volume of the containers. Initially, the thermal energy storage subsystem was to be able to store 7@_0@0 Btu's of heat under certain temperature conditions. The smaller volume subsystem can store approximately 100,000 Btu's of heat under the same temperature conditions. At contract completion (over a 48-month period), the 2' x 2' x 6' thermal energy storage modules were delivered to the Marshall Space Flight Center, Huntsville, Alabama. These modules, containing the phase change material, have a specific storage capacity of versus 6 Btu/lb :for rocks, masonry, solid material. Thus, for the same as much storage material is required, approximately 70 Btu/lb concrete or other heavy storage capacity, on!y 1/12 resulting in reduced space which is a big factor in building costs.

Original page 9

INTRODUCTION PROGRAM BACKGROUND AND GOALS The problems of energy availability and increasing cost have lea t0 a major national effort to develop alternate energy sources. One such source is the energy in solar radiation, which can be used for heating and cooling buildings, domestic hot water, and other applications. The National in the Solar Heating and Cooling 409), of which the effort described Energy Policy, as established Demonstration Act of 1974 (PL 93in this final report is a part, provided for the demonstration within a three-year period of, " the practical use of solar heating within a five-year period of the technology, and demonstration practical use of combined heating and cooling technology. Responsibility for implementing the Demonstration Act was given to the Administration (now the Department a large part of this work. Energy Research and Development of Energy). NASA/MSFC manages PURPOSE OF THIS PRODUCT DEVELOPMENT CONTRACT The purpose of this contract Corp. for further development of was to provide funding to Artech an existing thermal energy storage subsystem (Figure i) for solar heating or combined heating and cooling subsystem to make a marketable product and for the procurement of the developed subsystem. CONTRACT Contract performance period September 30, 1980. was from October I, 1976, through DESCRIPTION PROJECT DEVELOPMENT REQUIREMENTS AND CRITERIA During the development of the thermal energy storage subsystem, the contractor was required to: A) Meet, to the greatest extent possible, the parts of the interim performance criteria for solar heating and cooling systems, as specified in the contract. B) Meet, to the greatest extent possible, the Subsystem Performance Specifications, C) Provide test data/analyses as specified ifi the contract. to verify that hardware, to the greatest extent possible, meets the Subsystem Performance Specifications. l i 3

Original page 10

22.5 CONCEPTA 26.75 3ONCEPT B •'-3.75" TUBE72" LONG. 4. ,._,F I-'- _ __,. TUBULARCONCEP(ITN DIRECTIONOFAIRFLOW) PRIORTOCONTRACTIMPLEMENTATION NO._SCALE FIG. '1 4

Original page 11

D) Prov].de O_:'awings and specifications in sufficient detail to deliine the configuration repeatabi]ity. and to ensure manufacturing E) Have provisions to monitor performance. F) Provide Installation, Operation and MaintenanceManual s G) Provide, to the greatest extent possible, subsystem and/or component hardware certified by independent test laboratory (such as Underwriters Laboratory and American Gas Association) to meet nationally recognized standards and o codes (such as American Society of Heating', Refrigeration and Air Conditioning Engineers; American Society of Mechanical Engineers; American American Refr'igeration National Standards Institute and Institute). DEVELOPMENT OF THE THERMAL ENERGY STORAGE MODULES TESmod TM is ARTECII's trademark for a series of modular thermal[ energy storage units that make use of the phase change principle for' storing heat by melting the storage material. When the module is charged with thermal energy, the material melts. It solid[ies again as the energy is removed from storage. The phase change enables the material to store much more heat than a similar quantity of an inert material. The phase change material is a proprietary salt hydrate m,ixture based on ordinary G]auber's salt, sodium sulfate deca.hyd.rate or Na2SO4.1OH20 , whfch melts at; about 90°F. The mixture contains special additives to insure nucleation and prevent se_regation, and had been tested for'the equivalent of many years ()factual use. The salt hydrate mixture is permanently sealed in specially desi[,<ned containers molded of high-density polyethylene. Each container is designed with ribs or air passages for maximum heat transfer to or from the air flowing through the system. (See Figure 7). Artech Corp. was originally contracted to deve].op, fabricate;, and deliver three identical thermal energy storage subsystems. F,ac.h subsystem was to consist of modules which when combined would consti.tute a volume of approximately 6' x 6' x 6'. l,]ach module was to be composed of sealed trays filled with salt hydrates, which provide latent and sensible heat or coolness at desirable temperatures and temperature ranges. Initially, the thermal energy storage subsystem w_s to be able t;o store 700,000 B[u (36 percent of theoretical) of heat al}()ve a minimum temperature of 70°F and not to exceed a temperature ()f ].26°F. A mJn.i.mtml of' 60,000 Btu's per hour would be acc.umu]ated witI_a constant st)t.tr.('.(.,[']owof 3,000 cfm at a temperature not to exceed 150°F. 5

Original page 12

!n July of 1977, the contractor in fabricating the plastic containers began experiencing problems required for the thermal energy storage modules. (The rotational molding technique was used to fabricate the containers). in the air passages of the plastic Numerous pin holes were found containers. Figures 2, 3, and 4 show 3 different air passage configurations. All three had 18 air passages. All three had the same "pin hole" problem. Finally, Artech Corp. consulted manufacturers of molding machinery, molds for the rotational process, i the McNeil-Akron Company, and several producers of and then redesigned the container to meet the requirements of all aspects of the production sequence. Figure 5 shows the redesign. Essentially, it involved reducing the number_of air passages from 18 to i0 and increasing the "air passages" radii. Artech then conducted a new design analysis ° on the redesigned thermal energy storage containers. A summary of the results follows: This change and other necessary the ratio of heat transfer area to from 250 to about 190. This ratio governing the heat transfer rate. calculated heat transfer efficiency culated rate of heat accumulation somewhat lower than the target of Subsystem Performance Specification, dimensional changes reduced cross-sectional air flow area is an important parameter For a 500-cfm air flow, the dropped, reducing the calto 81,000 Btu. This is I00,000 Btu stated in the but the widening of the fins and the reduction in the number of air passages led to a compensating increase in the volume of salt hydrate mixture in each container. This increased the calculated thermal capacity of the subsystem to slightly more than 130,000 Btu, somewhat higher than the I00,000 Btu called for in the The added cost of this design Subsystem Performance Specification. change, together with the costs inherent in the delays, required an adjusted scope of work, so that the funding could remain the same. This was done by changing the number of products to be delivered from three identical subsystems to one subsystem. The one subsystem consists of modules which when combined constitute a volume of approximately 2' x 2' x 6' After the changes, the subsystem I00,000 Btu of heat above a minimum was designed to store temperature of 70°F and not to exceed a temperature of 126°F, and a minimum of i0,000 Btu per hour was to be accumulated with a constant air flow of 500 cfm at a temperature not to exceed 150°F. The convenient two-foot cube modules were found in the standard ASIIRAE 94-77 test to have a storage Btu each. They can be assembled in capacity, and in series to increase capacity of a minimum of 27,000 parallel to increase storage heat transfer efficiency, in any suitable insulated enclosure connected to a horizontal air circulating system. TECHNICAL DATA FOR THE THERMAL ENERGY STORAGE MODULES (See "Installation, Operation, on page 20). 6 and Maintenance Instructions"

Original page 13

.31 R_, /.25 R 3.5 ° DRAFT ANGLE-"" ' ,1 _ PIN HOLES DEVELOPED DURING MOLDING PROCESS / ,SAIR .22 R ON PASSAGES • t 1.88 .k 120. 3.5 ° DRAFT ANGLE ON ALL FINS UNLESS -1 r 3.50.... 4..... L,4ALLFINS .31 R ON '11.22L OTHERWISE STATED. DRAFT ALL FINS BETWEEN FINS ANGLE EXCEPTING OUTSIDE FINS .12R (TYP) _ ....................... (TYP) _ .74 NOM (TYP) ,/.5!16"'R . 3/16"'R _ I./ . 11 '/ UNLESS OTHERWISE 7/32" R ON .-/ STATED ALL FINS FIG. 2 ,- PIN HOLES DEVELOPED DURING / MOLDING PROCESS J"............................... ] 3° DRAFT ANGLE (TYP) FIG. 3 3.5 ° DRAFT ANGLE" - . ...... .__..#('("_ PIN HOLES DEVELOPED DURING t 318" _ ; FIG. 4 NOTE: CONTAINERS MADE FROM MOLDS IN ACCORDANCE WITH THESE THREE (3) CONFIGURATIONS ALL HAD PIN HOLESAND POROSITY IN THE RADII AND CORNERSOF THE AIR PASSAGES.

Original page 14

114" R R oo _ 11/64" PASSAGES 1/2" R 1/2" R INCREASED I 11/64'--,- I Jl--ON ALL ON ALL RADII.o,,-'".c,L,..so-o. '/__ il-- FINS FINS FINAL DESIGN STATED --_ 5° DRAFT ANGLE UNLESSOTHERWISE HARDWARE- "AS BUlLT'" -- CONFIGURATION FIG. 5_ \

Original page 15

PERFOR NCETEST THERMAL ENERGY STORAGE ASSEMBLY Tests were performed on an assembly of three 2x2x2-ft modules in series, having an area at the air entry and exit faces of 2x2 ft and a length in the air flow direction of 6 ft. This assembly, with duct transitions to ixl ft at the inlet and exit ends, is termed the TES unit in the following discussion. It was enclosed in an insulated chamber designed to prevent short-circuiting flow cedures essentially conformed to Standard 94-77. To determine the heat transfer around the modules. Test prothe recommendations of ASHRAE rate in flowing air, the TES unit was monitored with thermocouples in a closed heating and cooling loop instrumented according to the requirements of ASHRAE 94-77 _See Figure 6 ). T_e heated to 128UF ' for charging the to 65 ° for discharging. The flow inlet and outlet air temperatures be performed with a step increase temperature, but the step changes owing to inadequacy of the heating air flowing in the loop was heat storage material and cooled rate and the difference between were recorded. Tests were to and decrease of inlet air were not achieved in practice and cooling capacity of the air reconditioning system. In a significant portion of each test, the heat exchange rate was impaired the desired incoming air temperature. by this inability to reach In Charge Test No. 2, the incoming air did not reach the desired temperature until after the two-hour test period specified by ASHRAE 94-77 was over. The heat transfer rate was determined by multiplying the change in temperature by the mass flow rate and the specific heat of air. The heat transfer rate was integrated over the charge and discharge periods to obtain the storage capacity. Correction was made in the manner for heat flow through the walls of DUCTING The test loop specifications specified by ASHRAE 94-77 the storage chamber. called for an air inlet test duct, between the air flow measuring apparatus and the TES unit; and an outlet test duct, between the TES unit and the air reconditioning apparatus, to have the same cross-sectional dimensions as the outlet of the TES unit. The test section ducting satisfied this requirement. 9

Original page 16

AIR PRESSURE DIFFERENTIAL MEASURING ORIFICES • .DIFFUSION BAFFLE CALIBRATEDNOZZLE__. DIFFUSION BAFFLE WET& DRY THERMOCOUPLES HEAT CONTROLSENSOR • © sEcrzoN THERMOI LEP JUNCTIONS "--' "J WET g DRY THERNOCOUPLES " • _ : EVAPORATOR HEATERS BYPASS BYPASS BLOWER • " WET & DRY THERHOCOUPLES AIR PRESSUREDIFFERENTIALMEASURINGORIFICES INSTRUMENTAT ION SETUP THERMOPLEI • FIGURE 6. " OUNCTIONS

Original page 17

TEMPERATURE, PRESSURE AND AIR FLOW MEASUREMENTS All temperature measurements or a thermopile constructed from constantan) thermocouple wire. were made wifh thermocouples calibrated type J (copper- No extension wires of other : materials were used in the fabrication or installation. The wire diameter was no larger than 0.51 Temperatures indicated by output of the thermopile, were mm (No. 24 AWG). thermocouples, and the millivolt recorded on strip chart recorders during the tests. The thermocouple-recorder combination was ° calibrated with an ice bath and of the latter being measured by 0 DRY AND WET BULB TEMPERATURE a hot water bath, the temperature a calibrated thermometer. The air flow temperature was determined with thermocouples located at the air inlet and at the outlet of the TES modules in the test loap. A wet-bulb thermocoaple, whose reservior was kept filled with distilled water by a siphon arrangement, was in close proximity tQ each of the dry-bulb thermocouples. TES MATERIAL TEMPERATURE Two spaced thermocouples were provided near the trailing edge of the stack Qf co_ta_pers _n each of the three modules. TEMPERATURE DIFFERENCE MEASUREMENT ACROSS TIIE TES UNIT The temperature difference mined by a thermopi!e whose nine located at the center s of equal inlet and out!et ducts. These inlet and outlet Qf the TES unit. DUCT PRESSURE MEASUREMENTS across the TES unit was deterjunctions on each side were cross sectional areas in the j_unctions were located at the The static pressure drop across the TES module was measured at 500 cfm using a manometer with a measuring sensitivity of 0.005 inches of water. Each side of the manometer was connected to four pressure taps on the air external manifold. The pressure inlet or outlet duct via an taps were 6.4-mm (i/4-inch) nipples soldered t the duct and centered over l-mm (O.040-inch) holes. All inside duct surfaces were free of surface irregularities and hole burrs. The pressure drop at I000 cfm was estimated from the 500 cfm value. AIR FLOW MEASURING APPARATUS The air flow rate was determined by measuring the pressure drop across a calibrated nozzle 37-69. as specified by ASHRAE Standard ii

Original page 18

AIR RECONDITIONING APPARATUS The reconditioning apparatus, within the limits of its heating capacity of 9 kW and cooling capacity of 27,000 Btu/hr, was capable of controlling the dry bul_ temperature of the air entering the TES module to within _i.0 sired test value during the tests. C (_i,8 F) of the de- PERFORMANCETESTRESULTS Tests were run at air flow rates four and two hour charge and discharge of 500 and i000 cfm, for periods respectively, as specified by ASHRAE 94-77. In addition, each charge or discharge test was continued until the system reached essentially a steady state, as required in preparation for a subsequent test, and the temperature difference representing heat input or output was integrated over the entire period (5-16 hr) to determine the total storage capacity of the heat storage unit. Results of the two-and four-hour tests are summarized on the data sheets, prescribed by ASHRAE 94-77, which follow. 12

Original page 19

Grnrral Information Manufacturer ,., ,,..o,,,., ARTECH CORP• •.,.0.°,.• •..,,.,. •, .,. • .t .o, o**oQ,.,, 4 Q,,l,.,,,,.e ,,oloo.,,,o, • ,, • o,i..., •,, J • ,, • o. ol Mode,Number..........Wg.S..99.-2...(qu.t.i.t.y.....3..in..ser.ies.)................................................. SerialNumber.......... 11..2! _ 3 " " S,o,geMedium,....... .._..TI}...CH....Tg.S..9.0...(.S.o.d.i..u_n..s.u.l.f..a.t.e...d.e..c.a..by..d..r.a.t..e._i .t.h..pr?p.r.i..e.t.a..f".addiT..t.i.yes).. Air Transfer Fluid ...................................................................................................... Container Material High density polyethylene ,.,, ...... .,.o, .......... ..o,.,o,..°....,..o.°...,.:o,.,.,,..,°.,,°,.,....,.,....,.,.,,.,,o.l,°. 6 ft Length ........................................................................................................... 2 ft Width ............................................................................................................ 2 ft, plus 5-1/8 in. dolly height ' Height .............................................................................. .............................. 4305 lb Weight of Storage Device, W ........................................................................................... 24 ft3 ' Volumeof StorageDevice,V............................................................................................ 50- 150°F Normal Operating Temperature Range ................................................................................... MinimumT,ansfcrFluiFlowdRate....... .2.5.0..C..fi?..................................................................... MaximumTransfer FluidFlowRate ...... 1.00Qcf.m...................................................................... MaximumOperatingPressure.......... N!A ..................................................... i ..................... Flow Configuration Tested.. :.......... see.. s.k..e.t.c..h.. .F,g1..1.1'.e...) .................................6 (pictureor diagram) Heat Loss Rate Test 75.7°F tit ,.........°..,. ..... ,,......,.,..., .... o.....,**o.o. 123,000 BTU TSC L ................................................. 2.4°F Average of(tin - tout) .................................... w,.................,.......<...................../.,.r. 0. 240 BTU/(I_.°F) t ,o,,,.,. °oo.o.,,,.,,.-.,,°o.,. ....... . .... ,- L.................. z_:4B:u/::..............nr) TransientTests 77°F t i ..... o,,,.,,,o,,°, ..... ,o .... -°-.,o ............ ,,* 65°F |i "''''''''''°°'''''''''' ''''''' ....... " .... ° ...... ''' 63°F o t, ,,,,..,,,o,..,°..,,-,.,, ........... ,, .......... ,-°. 4hr 20 min Tg. o,,,,..,.,°°,,,.,,.., ,..,, ............. ° ..... ,,,,.. , w,................. 1..8.9.9..--'£5..o.0...c...)-.,.t.n.r......... Ap .................. 0: p.4.8..in: Ha0 .................... 1,................. Q.24.0.B.TC...bm:.W............°F) TSC .................................................136_700 BTU c:, .................. .5.5.1.0.Q..B.,.Tfl..................... 4 hr 20 rain •rd•. ,,,,. ,,,,,,o,..o,,..,.oo,.,..,,.,,, ....... ,. ...... w..... ...........ZZ_Q_bm/hr(599....)....... c, ................. 4a,40013'U 13

Original page 20

Central Inform_lloa Manufactu.rero.e, eot oe4o t__oTE('otoo__eeleoo.oeCORPee.t° t oooeoeeoeeeoeeeoooomet o jteo_t oe • o o o • e o o • o e o • • o # eeeeeot ooeoo. • e o o • • e Molumbe...........,s.i.9.Q..u,2..O.,....txA.x..r.i.l .. SerialN.mb............, .L...Z.,.......................................3. TransfeFrluid. AiT " " • Con,a_Matener........ (-I,i,,..a_b..n.s.i..×.pol..e............... ...........................................l;..h×l..e.n.e. Le,,V................. Oh..f:;. Widih .................. .2. ........ .............................................................. : ........ ........ e_g..................t .2ft.,..l..us..s.]L8 .in,..do],yh_:,gb:..............................................; wei_hofSto,rageDe.iceW...... 430,S.lb ............................................................................ ' Volume of Storage Device. V.° ..o......0 24 ft 3_.... • o......°......................o..o..................o.t.,*oo..°....._ oF NormaIOpcratingTem.peratureRange ..... _..0. - _._0 ............... ......................................... ............ Mi,,imT_a,,,,sFlruiFdIo_a,,.......2..S.0..:............................................:.f:n..,. :............ ..,... .... MaximumTransferFluidFlowRate..... .1.q0.0..c.fin ..... : ................................................... .......... Maximum OperatingPressure...... ".... .N! ... : ..................................... ."................................. ... Flow Configuration Tested..: .......... S.., S.. rich,, .1_1 u Ire.. 9). (pictureor diagram} Heat Loss RateTest t°................... 7.S-7.°........................... TSCL............... :,Z.3.000.I!T....................U ^.rageor(t,.-1o,,)..2.4.°...........................F ................:m: o ................... , .................. o."z4Q_axl/l.M:?£).......... L................... 2.4.:.4...B.L/.C°.:r)............. " Transien_Tests 73°F t............. ...........*.. °. .... ......=-.........o . ,.................. ? ............................ ,, 63°F .......... 2 hr I0 rain g ° ....... o...,...,.... °°,. ° °.. -. °............... ,,,,................. ..2..l_/b:r .11.o9.c_m.]o..... p.................. .0.:1.8.o.i.n:.tJ20...(.e.s..t...).......... c,,................. .0.0.2:.o..U/(I.h..: .oF)........... vsc ................ L;6o,O.O.7...I...................T_ c, ................... 4_L..'./O.O.....................°_ _ .................. ..h..o..................... ,,................. .4A.4.4.L/hx. il, OO.O..€.f!)..... c_................. :5,300.B.T..................... 14

Original page 21

l(st perl'ormcd a l an :.Lit' flow rate of' AStIRAE T_-,t duration Cha:r[int rato • Capac. it;y Dis('.har,ino',., v;t, Capacil;y 500 efm 1000 c, fro 4 hr 2 hr 13,800 Blu/hv 21,,.11 1-tu/hv 55,100 B|.tl 41 , 7()0 1:I.iz 10,60r). B1.u/hr ]7,(300 l_t.u/hr, 42,400 Btu 35,3o0 l_tt U]t:i.mate cap,tt..]l".''":y , cha.l,a':in,, 80,r_r.q...... Pi,I.1 7(; 700 !lu . Time.allowed for '<luilibrat;ion U1.t i m.al: e e a p a c i t: y, d _ ,qchargTing Timo al.lowed for oquilibration 12 hr 5 hr 81,600 Bt;u 69,d(10 Blt 16 hr 5 hi' Thus the subsystem a(thievt.'d o°c'/,of/ t.h( tarm,l:.., va.]ue of lO0,O00 Btu tTor ulti.matc st.orage (:a.pacity and an av,ra:q'e of' 1.22,:_o:[-," the -t:ar,,o-et val ue or 10, o00 rate clurin_f the AS!{RAI,; test period :1.5 Bt:u/hr for hr, al t. ran,l',r a.l; a flow rate t_l' 5(10 {,i'm.

Original page 22

INDUSTRIAL Azr CondttzonZngCompany Dr. Fred Ordway Artech Corporation 2901 Telstar Court Falls church, Va. 22042 Subject: TES Test Dear Dr. Ordway: Sep.te_er 24, 1980 The undersigned, having been "certified" by the National Environmental Balancing Bureau (NEBB) for the testing, balancing and adjusting of heating, ventilating and air conditioning systems, both as a technician and a supervisor, you recently requested that I examine your current TES testing and report to you accordingly. NEBB standards encompass five major categories, as follows: i. Instruments and measurement accuracy. 2. Preliminary procedures. 3. Equipment and system checks. 4. Testing, balancing and adjusting procedures. 5. Test reporting. Having examined the TES test setup on two occasions, on September i0, 1980, prior to the actual testing but with instrumentation complete, and on September 25, 1980, during the actual testing, I am pleased to report that the testing equals or surpasses all NEBB standards in my judgment. Very truly yours, GRS:mk e Smith, P.E. P.O. BOX 2076 2824 FALLFAX DRIVE FALLS CHURCH, VIRGINIA 22042 (703) 573-7700 16

Original page 23

PRO3LEMENCOUNTEREDSANDTHEIRSOLUTIONS::,, ' Initially, the period of performance of this contract. Was From October 1, 1976, through September 30, 1977. Around mid 1977, problems were_.encountered in fabricating the pl.ast:ic containers. This problem continued for the best part of three years. Finally, after resolving the difficulties, the period of performance was extended through September 30, 1980, at no cost to the Government. The plastic containers for this project were fabricated using the rotational molding technique. This method is commonly used in the plastic industry, but its use is limited to the fabrication of parts that are regular in shape such as hollow cyl- - inders, hollow spheres, or hollow containers that have generous radii in the corners, ends or sides. As can be seen from Figures tainers 'have rather sharp radii 2, 3, and 4, the or:iginal conin the fin areas, and the fins are close together. It was found that this configuration was "pushing" the state-of-the-art, as it were. After several attempts at molding containers by changing fin radii and the distance between them, a product with uniform wall thickness and free of porosity was finally achieved (see Figure 5). The end item delivered has this cont'iguration and is satisfactory. CONCLUSIONS A common alternate to the thermal ener_,y storage module for heal-, storage in an air circulating system is a large mass of rocks, masonry, concrete, or similar heavy, inexpensxve solid material. These materials store only sensible heat--that is, the temperature goes up as heat is added, and goes back down as heat is recovered. It can't go too :fardown or there won't be any heat transfer into ,, the circulating air. It can't go too far up because the sol.at collectors become less and less ture increases. For a reasonable 30°F and a typical specific heat specific storage capacity is 0.2 efficient as their outlet temperaoperating temperature range of figure of 0.2 Btu/lb.°F, the × 30 = 6 Btu/lb. The phase change material in the thermal energy storage module, on the other hand, stores energy mostly as latent heat-that is, the heat can be put into storage and recovered without any significant change in temperature. The material stays near its melting point of 90OF. The specific storage capacity in this case as 70 Btu/lb. Therefore :for the same storage capacity only 1/12 as much inaterial is recluired. This size reduction factor capacity of 300,000 Btu can fit means that a typical storage in a closet-size space, anywhere 17

Original page 24

the designer finds convenient, rather than in a whole basement filled with 25 tons of rocks. Saving space is saving money. Further, adding solar heat to an existing building by this method may be the only heat storage system that space will allow. It has been determined that the product developed under this contract is marketable and suitable for public use. RECOMMENDATIONS For this type of thermal energy cation and one requiring a minimum storage, an immediate appliof retrofit installation effort, Could be in existing greenhouses, both domestic and commercial. 18

Original page 25

TE Smo d (TM ) THERMAL ENERGY STORAGE MODULES FIGURE 7.

Original page 26

GENERAL TESmod (TM) THERMAL ENERGY STORAGE MODULES MODEL NO. 7750 INSTALLATION, OPERATION AND MAINTENANCE INSTRUCTIONS IMPORTANT i. IMMEDIATELY ON RECEIVING i.i Lift from the base, or from a suitable sling through the lifting rings on the top. Never pick up module by plastic containers or steel cross pieces. FRAGILE. DO NOT DROP. 1.2 Examine for damage. If found, file claim with transportation company immediately. 1.3 Remove the shipping covering plastic containers for any (if any). Check the cracking or leakage that may have been caused by mishandling. If found, mop up any spilled thermal energy storage material with water. Contact ARTECH for damaged container. repair or replacement of 1.4 If it is necessary to remove one or more containers, see paragraph 3.4.2. 1.5 Store under cover. Protect from contact with other objects. 2O the plastic containers

Original page 27

1. DESCRIPTION 2.1 Each thermal energy storage module is composed of high density polyethylene plastic containers filled with thermal energy storage material. Each container is supported by a steel frame unit 24 in. (610 mm) square and 3 in. (76 mm) high. The frame units are joined means of vertical to make a module two feet high by connecting rods through the four corners of the frame units. The standard 2x2x2-ft (0.6x0.6x0.6-m) module consists of eight frame units rods are attached dolly wheels. At and containers. The corner to a steel base having four the top, the corner rods are attached to a lifting frame provided with eyebolts so that the module can be lifted by means of a chain or cable sling. The module should be lifted only (1) by a sling attached to all four eyebolts, oT to a pair of them on opposite corners, so that the module remains vertical when lifted, or (2) by a fork lift or similar equipment under the steel base. 2.2 The containers can be removed and reinstalled by disassembling the module. See paragraph 3.4.2 for disassembly procedure. 2.3 The thermal energy storage material in the plastic containers absorbs latent heat, and melts, at approximately 90°F (32°C). The module must not be subjected to a temperature greater than 150°F (65°C). 2.4 Each module is shipped assembled on its steel base. The base has four heavy-duty wheels, two in swivel mounts and two in rigid mounts. For flexibility in installation, one-third of the modules are assembled with the two swivel wheels on one side, and the remainder with the swivel wheels on one end, the customer. unless otherwise specified by 2,5 The eye bolts may be removed from the lifting frame to facilitate a close fit between the module and the enclosure. 21

Original page 28

1. INSTALLATION 3.1 DUCTWORK 3.1.1 The module is designed to be placed with its base horizontal plastic containers and the ribs on the in the direction of air flow, inside a close fitting, insulated plenum designed as part of the heating/ cooling system. The module can be placed alone, or with other modules in parallel and/or in series (tandem), to provide the combination of storage capacity and heat transfer efficiency 3.1.2 External dimensions (0.6x0.6 m) in plan desired by the designer. of the module are 2x2 ft and 2 ft (0.6 m) in height, plus the depth of the dolly (5-1/8 in. or 130 mm) and the height of the lifting frame (3-3/8 in. or 86 mm). See figure 9 on page 27 of these instructions. allow no more then between modules, or and the enclosure, through the modules. must be provided to Plenum dimensions should 1/8 in. (3 mm) laterally between an outside module to ensure proper air flow Suitable spacer material prevent air flow past the dolly wheels and lifting frame, if these are present in the installation. If any air spaces exist between _ the sides of parallel modules, or between modules closed at intervals with a suitable material. 3.1.3 Ductwork and plenum and plenum, they must be of 2 feet (0.6 m) or less should be in accordance with good design practice, and should provide for uniform distribution of the inlet air flow over the cross section of the module assembly. Uneven air flow distribution will result in decreased thermal charging and discharging rates. Plenum and ductwork should be air- i tight for efficiency. ! 3.1.4 The modules, like any heat exchange device, must be accessible for periodic inspection and cleaning. If the temperature of the module may be below the dew point of the incoming air at times, provision for collecting and removing the condensate must be incorporated 22

Original page 29

in the plenum. The containers are designed so that any condensate will drip from their inlet and outlet faces. 3.1.5 The inlet air temperature must not exceed 150°F (6S°C). " 3.2 SUPPORTING STRUCTURE 3.2.1 The plenum must be supported or suspended in • a manner consistent with the weight of the modules. Each 2x2x2-foot (0.6x0.6x0.6-m) module weighs 470 lb (213 kg), plus 12 lb (5.5 kg) if 16 lb (7.3 frame. 3.2.2 Each module level within 3.2.3 Each module equipped with doily wheels and kg) if equipped with a lifting must be placed horizontally and 1/4 in. per foot (20 mm per meter). must be oriented with the indicator arrows pointing in the direction of the air flow during the thermal the operating the discharge (i.e., freezing o_ energy storage material) part of cycle. Air flow during charging may be in either direction. 3.3 INSULATION 3.3.1 This discussion is based on the physical units customary in the U.S. air conditioning trade. Conversions to other units will be supplied by ARTECH on request. 3.3.2 The following quantity depends on the materials used in the storage plenum: R = insulation value of plenum walls, top, bottom and The R value sides (ft 2 • hr • °F/gtu) is usuall_ obtainable from the maker ° of the insulating material or from handbooks. 3.3°3 The following ment of modules: quantities depend on the arranges = number of modules in series (tandem) p = number of these tandem groups in parallel h = number of series-parallel groups stacked vertically 23

Original page 30

3.3.4 To compute the area to calculate A = 8(sp + sh) = 8s(p This is the area around be insulated, + h) the top, sides, and bottom of the enclosure. The inlet and outlet ends are presumably occupied by the duct connections. 3.3.5 To compute the temperature differential, subtract the average ambient temperature outside the plenum from 90°F: T = 90 - TA (OF) , 3.3.6 The rate of heat loss from the storage plenum is approximately Q = AT/R = 8s(p + h)r/R (Btu/hr) 3.3.7 The total storage capacity is approximately C = 27,000sph (Btu) 3.3.8 The half-retention time (i.e., the time required for half the stored heat to be lost) is thr = C/(2Q) = 13,500sphR/[8s(p + h)T] = 16g7phR/[(p• + h)T] i! 3.3.9 The required R value of the insulation is R = thr (p + h) r/(1687ph) (ft2 • hr • °F/Btu) i 3. 3. i0 EXAMPLES i" 3.3.I0.i A small heat storage unit in a basement space maintained at 65°F modules in series. has three 2x2x2-ft What insulation value is required to retain half the stored heat for seven days? The numerical values are thr = 168 hr p = I module (width of array) h = 1 module (he'd'1=nt of array) T = 90 ° 65 ° = 25°F The calculated insulation value is R = 168 (1 + 1)25/(1687., 1- 1) = 5,0 (ft2 • hr . °F/Btu) 24

Original page 31

3.3o10o2 A heat storage unit for a home, consisting of three parallel sets each having nine modules in series, is exposed to outside air at an average temperature of 30°F and is required to retain at least half of its stored heat for four days. What insulation value is required? thr = 96 hr ° p = 3 modules in parallel h = 1 module high T = 90° - 30° = 60°F The calculated insulation value is R = 96(3 + i)60/(1687 . 3 • I) = 4.6(ft2 . hr • °F/Btu) 5.4 SETTING THE MODULE IN PLACE 3.4.1 DO NOT lift module by the containers or the am-e--elementsaround them. Lift by the eyebolts on the lifting frame (with a suitable sling so the module remains horizontal)or by the base or dolly. 3°4°2 If necessary, some or all of the containers may be removed to facilitatemoving the module into position. To remove the containers, remove the four nuts at the top corners and lift off the lifting frame. Then remove each plastic container, followed by the frame elements that supported it. Note carefully the position of each component as you remove it. DO NOT DROP THE PLASTIC CONTAINERS. In reassembling the module, make sure that the plastic containers are correctly oriented with respect to the dolly wheels and that each container is supported at the inlet and outlet ends by its frame elements. The arrows on all containers should point in the same direction. When all parts have been replaced, tighten the nuts on the corner rods to a torque of approximately15 Ibf_ft. (20 N.m). (.See figure 8) 25

Original page 32

QI 0 I Disassembly of Module (Figure 8) 26 I • ! I

Original page 33

LIFTING FRiV_E .SEEDWG 7750,.50 ROD SEE DWG 7750.44 '_ FULL FRAME SEE DWG 7750.40-2 m _ o_ CONTAINERS (OTY 8) _ SEE DWG 7750.30 t_ r+ t-_ o QUARTER FRAME (QTY 12) SEE DWG 7750.40-I : It FULL FRAME SEE DWG 7750.40-2 ! DOLLY SEE DWG 7750.42

Original page 34

1. OPERATING INSTRUCTIONS 4oi INITIAL CIIECK 4oioi Inspect for leaks of thermal energy storage material or damage to the plastic containers. 4.1.2 Verify that the position of the module(s) is horizontal and level, 4.1.3 Verify that each module is oriented with the ._ caps of the plastic containers toward the i entering air during the discharge (i,e., j freezing of the thermal energy storage ._ material) part of the operating cycle. 4ol.4 Verify that any air spaces between the sides of parallel modulesp between module(s) and plenum, or below the module base have been blocked off at the inlet and outlet of each module. 4.1.5 Verify the presence and operation of system controls to prevent the air inlet temperature from exceeding 150°F (65°C). 4.2 AIR FLOW RATE 4o2.1 Determine the desired air flow rate from system design calculations. The rate will normally be between 300 and I000 cubic feet per minute (0.15 and 0.5 m3/s) for each 2x2x2-ft (0.6x0.6x0.6-m) module. 4.2.2 Check actual flow rate with suitable instruments such as a flow meter and stop watch. 4°2°3 If actual flow rate differs from required flow rate_ make necessary adjustments, of ' fanCs) and/or damper(s). _ 28

Original page 35

1. _INTENANCE 5.1 Inspect module(s) after every three to six months of operation for container leaks and cleanliness. If a leak is found, mop up with water and contact ARTECH regarding repair or replacement of the leaking container assembly. If dust has accumulated in the container air passages sufficiently to impair heat transfer, remove it with a vacuum cleaner, water spray, or compressed air. 5.2 If provision for condensation in the storage plenum is required, make certain that the condensate drain • is not clogged. Verify that the provisions for control of theair DUCT WORK", are still flow, listed under "INSTALLATION, effective. 5.3 Check that system controls prevent the inlet air temperature from rising above 150°F C65°C). 9.9

Original page 36

TESMOD TM LIMITED WARRANTY -i! The thermal energy storage modules used for residential or commercial heating and/or coolingshallbe warranted against defective materials and workmanship for a period of five years. Replacements will be made FOB the contractor's plant, subject to receipt of defective items, shipment prepaid, and the contractor's examinationconfirming the defect. This warranty specificallyexcludes failure due to over- ° heating or mechanical damage, usage in research or experimental applications, or installationsother than those made under the supervision of an authorized representativeof ARTECH CORP. This limited warranty supersedes any other warranty, express or implied. _" U.S GOVERNMENT PRINTING OFFICE 1981--740-006/407 REGION NO. 4 30 • } } , • i ....... • ..... . ..................... , .................................. ,,, Q ! I

Original page 37

APPROVAL DEVEL_T ANDTESTINGOFTHERHALENERGYSTORAGEHODULES FORUSEIN ACTIVESOLARHEATINGANDCOOLINSYSTEHSG F[#ALREPORT By John C, Parker The Information in thls report has been revlewed for technical content. Revlew of any information concerning Department of Defense or nuclear energy activities or programs has been made by the MSFC Security Classification Officer. This report, in its entirety, has been determined to be unclassified. _ WILLIAMA. BROOKSBANK"JR., Manager, Solar Energy Applications Projects

Original page 38

U'I_ ":"' ...., : " . .. : :',..."__,.:,"_.....;.... ::" :.. ';' ......., . ,f'" ;.. '... .;... : "?: ': . . s" , ...... :', ":'"X, i" ,: ... • • i L" ,v : " " ,,,.,, ..... • ,,,:,, ,: , ::, ,,,

Original page 39

Original page 40

f