Midtemperature Solar Systems Test Facility Predictions for Thermal Performance Based on Test Data
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Midtemperature Solar Systems Test Facility Predictions for Thermal Performance Based on Test Data Solar Kinetics T -700 Solar Collector With Glass Reflector Surface Thomas D. Harrison DISmtBUTION OF THIS DOCUMENT IS UNUMIT£0 DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. Issued by Sandia National Laboratories, operated for the United States Department of Energy by Sandia Corporation. NOTICE: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, nor any of their contractors, subcontractors, or their emplo.yees, makes any warranty, express or implied or assumes any le~al liability or responsibihty for the accuracy, completeness, or usefUlness of any informat10n, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or othcrwisebdoes not necessarily constitute or imply its endorsement, recommendation, or favoring y the United States Government, any agency thereof or any of their contractors or subcontractors. The views and opinions expressed herein do not necessarily state or reflect those of the United States Government, any agency thereof or any of their contractors or subcontractors. Printed in the United States of America Available from National Technical Information Service u. S. Department of Commerce 5285 Port Royal Road Springfield, VA 22161 Price: Printed Copy $6.00; Microfiche $3.00 1 2 ?AND80-1964/7 Category Unlimited Release uc 62 Printed March 1981 MIDTEMPERATURE SOLAR SYSTEMS TEST FACILITY .PREDICTIONS FOR THERMAL PERFORMANCE BASED ON TEST DATA SOLAR KINET~CS T-700 SOLAR COLLECTOR WITH GLASS REFLECTOR SURFACE Thomas D. Harrison Experimental Systems Operation Division Sandia National Laboratories Albuquerque, NM 87185 ABSTRACT Thermal performance predictions based on test data are presented for the So~ar Kinetics T-700 solar collec tor, with glass reflector surface, for three output temper~tures at five cities in the United States. This boOk was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor anv agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for th~ accuracy, completenCY.I, or uOO!UIMU t)l lilliV mlllllllAIIWt, lllJllfttntu~. l)f\l\,ly~t, vr pre~t41 dtiDIQM'd,. ~· represents that its usc would not infringe privately owned rights. Reference herem to any. spec1ftc commercial product. PfOCCSS, or service by trade name, trademark, manufacturer, .or Otherwtse, ~oes 001 necessarily constitute or imply in endorsement. recommendation, or favonng by th~ Unned ~l::tl<K Go•nunu~nt ru o~ny ~nr\1 thr.r~m!. The viom "nQ Qp]niC?n~ ol authors l!vprpo;V'tl hermn cln 001 necessarily state or reflect those of the United States Government or any agency ther~f. I'WTRIBUTION OF THIS DOCUMENT IS UNUMI~O 3,4 f1 CONTENTS Page Introduc·tion 7 Description of the Collector 8 Results of the Test Program 8 Prediction of Thermal Performance 12 Previously Published Predictions 18 Reference 19 ILLUSTRATIONS Figure 1 Solar Kinetics T-700 Collector 9 2 Peak Efficiency Plot for the Solar Kinetics T~700 Solar Collector with Glass Reflector Surface 10 3 Heat Loss Plot for the Solar Kinetics T-700 Solar Collector with Glass Reflector Surfaqe 11 4 Thermal Output of the Solar Kinetics T-700 r.nll P.r.t.nr. with Glass Reflector Surface w:i, th E-W and N-S Orientation and Fresno TMY Solar Data 13 5 Thermal Output of the.Solar Kinetics T-700 Collector with Glass Reflector Surface with E-W an~ N-S Orientation and Albuquer.que TMY Solar Data 14 6 Thermal Output of the SnlRr. Kinetic~ T-700 Collector with Glass Reflecto~ Surface with F.-W nnn N-S Orientation and Fort Worth TMY Solar Data 15 7 Thermal Output of ·the Solar Kinetics T-.700 Collector with Glass Reflector Surface with E-W and N-S Orientation and Charleston TMY Solar Data 16 8 Thermal Output of the Solar Kinetics T-700 Collector with Glass Reflector Surface with E-W and N-S Orientation and Boston,TMY Solar Data 17 5 TABLE Table. 2 1 Predicted Annual Thermal Output (kWh/m ·yr) 18 .. 6 MIDTEMPERArURE SOLAR SYSTEMS TEST F~CILITY PR~DJCTIONS' FOR THERM~L P~RFORMANC~ aASEQ 0~ TEST DATA SOL~R KINETICS T~700 SOL~R COLLECTOR WJTa GLA§S R~fLECTOR SURFACE rnt:rodqction Sandia National Laboratories, Albuque:rque (S~L~), i$ cqrrently conducting a prog:ra~ to predict the performance and measqre the char acteristic$ of comme:rcially available solar collectors that have the potential for U$e in industria~ process heat and enhanced oil recovery applications. A detailed account of the methods used to make the predictions is given in Reference 1. For the convenience of the reader, some of this information is repeated in thi$ document. rhis document presents the thermal performance predictions for the Solar . I Kinetic$ solar line-focusing collector. The program is limited to thermal-performance only and does not include consideration of other factors, such ~Ei 1. Losse$ q.t the ends, q.t 913.ps, and from shadowing due to pq.cking, 2. Collector warm-up penalties, \. 3! Degrq.qq.tion of performance, 4. Cost of the collector, 5. LO$$.eS in the energy tran$port $.ystem and system warm-qp penq.lties, 6. Reliability, 7. Cost of iqstallation, 8. Cost of oper.qtion and m13.intenance~ and 9. Wind effects. The program is apthorized by the Department of Energy, Division of Solar ThermaL Energy System~, c~.nc.l pa:Ltially funded through the Solar Energy Research Institute. 7 Description of the Collector A photograph of the Solar Kinetics collector is shown in Figure 1. The module. has the. following chara'cteristics. Reflector configuration Parabolic trough Reflective surface , ·Glass Aperture dimensions 2.13 m x 6.10 m (7.0 ft x 20 ft) Aperture area 13.00 m2 (140 ft 2 ) Support structure Aluminum monocoque Tracking system Shadow band (DeLevan) .Drive mechanism Hydraulic Heat transfer·fluid 'l'herminol-66® Operating range 100° to 300°C (212° to 572°F) Manufacturer .solar Kinetics, P.o. Box 4'1045 Dallas, Texas . 75247 ', f 1 t Results of the Test Program This collector was tested at the Collector Module Test Facility (CMTF) at SNLA. From the test data, three parameters were defined. , 1 . Peak efficiency (n ) _:.. the efficiency of the collector when . p the sun's rays are at normal incidenc~ to the aperture plane (equivalent to solar noon) expressed as a funct~on of At/I. :t.t is the temperature difference between the heat t·rahsfer fluid outlet temperature and the ambient temperature in dParePs rentigra~e. T is the i.rrarliance of the suh in watts per square meter. 2 np = 80.7 - 67.6 At/I. - 33.4 (At/I) • (%) Peak efficiency is plotted in Figure 2. 2. Receiver thermal loss (QL) ~- the.heat lost per unit aperture area expressed as a function of At. 8 Solar Kinetics T-700 Collector Figure l. I-' 0 ,-.... 60 ~ 0... ~.. 50 >- u z l.J..I 40 ....... u ....... I..L. I..L. l.J..I 30 ::.<:: ex: l.J..I 0... o~--------~--------~----------._--------~--------~----------._--------~ 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Figure 2. Peak Efficiency P: ot for the Solar K i n~tics T-700 Solar Collec~or w ~ th Glass Reflector Surface oL = o.o + 0.233 At + o~oo129 (At)2 (W/m2) Heat ioss is plotted in Figure 3. 150 c:'l- .....,._E 3 ._j cr .. .. V') 100 V') 0 --.1 i- <( w :I: 50 0 . 0 100 200 300 Figure 3. Beat Loss Plot for ·the Solar Kinetics T-700 Soiar Coiiector with Giass Reflector Surface 3i Optical loss coefficient (k ) ~- K , in conjunction with the 0 0 ehd"""loss coefficieht; :KE' and the ;,cosine effect;;; determine the incident angle modifier, K. Specificaily; K. KEcos8 • = K0 See Re:ferei'lt:e l• Th~ vaiues of K as a fUnction of e are 0 ·K K e (degrees)· 0 e. {degrees)- ·.o 0 1. 00 . 35 '1. 00 5 . 1.00 40 . u. 95 10 1. 00 45 0.90 11 .K K a (degrees) 0 a (degrees) 0 15 1.00 50 0.88 20 1.00 ·ss · o·. 86 25 1.00 60 0.82 30 1.00 Thes~. values of the incident angle modifier were verified on the SNI.A Coll~ctor Module Test Facility turntable. Pre~ic~i.on of Thermal Perfor~ance :. A computer program calculates the predicted thermal performance of the collector.