Task Vi Performance of Solar Heating, Cooling and Hot

Home , Central solar heating

~ :1~~~~--~\·~···" · ~t'..\/. INTERNATIONAL ENERGY AGENCY program IEA to develop and test SOLAR R&D solar heating and cooling systems

TASK VI

PERFORMANCE OF SOLAR HEATING, COOLING AND HOT WATER SYSTEMS USING EVACUATED COLLECTORS

ANNUAL PROGRESS REPORT

JANUARY 1982 TASK VI: PERFORMANCE OF SOLAR HEATING, COOLING AND HOT WATER SYSTEMS USING EVACUATED COLLECTORS

ANNUAL PROGRESS REPORT

JANUARY 1982

Operating Agent: U.S. Department of Energy Report prepared by Task VI Chairman:

Professor William S. Duff Solar Energy Applications Laboratory Colorado State University Fort Collins, Colorado 80523 USA TABLE OF CONTENTS

EXECUTIVE SUMMARY INTRODUCTION 2 Background 2 Objective . 2 Approach 2 Task Duration 3 Publications Policies and the Role of Evacuated Tubular Collector Manufacturers in Task Activities 3 PROGRESS REPORT 4 Status of Task 4 Task Meetings 13 Work Plan for 1981 13 Milestone Chart 15 Level of Participation and Task Assessment 16 APPENDIX A List of Participant Countries, National Contact Persons and Responsible Researchers 18 APPENDIX B Mountain Spring Bottle Washing Facilities Solar Project, Canada 19 APPENDIX C Sanyo Osaka Solar House, Japan 22 APPENDIX D Solar House of the Eindhoven University of Technology, The Netherlands 25 APPENDIX E

The Knivsta District Heating Project, Sweden . 28

; ; APPENDIX F Geneva SOLARCAD District Heating System Project, Switzerland 32 APPENDIX G Solar Test Installation at Bracknell, England 36 APPENDIX H

Colorado State University Solar House I, USA . 40 APPENDIX I Solarhaus Freiburg, West Germany 45

iii EXECUTIVE SUMMARY The objective of Task VI of the IEA Solar Heating and Cooling program is to further the understanding of the performance of evacuated collectors in solar heating, cooling and hot water systems, and to study, document and compare the performance characteristics of such collectors in various systems and climates. The execution of the task emphasizes common reporting requirements, a variety of installations covertng important evacuated collector applications, a comprehensive use of available evacuated collectors, use of the same collectors in several installations and some duplication in end uses. Cooperation in the task will provide a means of reducing duplication in each participant's national program and a reference point for future evacuated collector systems research, development and corrmercialization activities. The task participants and applications are: Canada - Industrial Process Heat CEC - The CEC's participation is pending Executive Committee approval, but will involve cooling of a small office building. Japan - Single Family Heating, Cooling and Hot Water Production The Netherlands - Single Family Heating and Hot Water Production Sweden - District Heating Switzerland - District Heating The United Kingdom - Simulated Load, Domestic Hot Water Emphasis USA - Single Family Heating, Cooling and Hot Water Production West Germany - Multifamily Heating and Hot Water Production Exchange of performance results within the task has been greatly enhanced by adoption of a mandatory common reporting structure utilizing the IEA performance reporting format that has been modified and made more specific and prescriptive. 2

INTRODUCTION Background Based on the demonstrated need for a coordinated approach to resolve energy problems, certain members of the OECD agreed in September 1974 to develop an International Energy Program, which included cooperation on energy R & D Programs. The International Energy Agency (IEA) was established within the OECD to administer, monitor and execute this International Energy Program. Solar Heating and Cooling was one of the technology fields, which were selected for multilateral cooperation. A number of project areas, called Tasks , were identified for cooperative activities within the overall IEA Solar Heating and Cooling Program. The details of the cooperative projects, as well as the administrative and management procedures, responsibilities of the signatories, and special financial and legal conditions, are contained in a 11 Implementing Agreement for a Programme to Develop and Test Solar Heating and Cooling Systems". By signing this agreement, the contracting parties (governments or organizations designated by governments) agree to actively participate in one or more of the tasks. A lead country, called the Operating Agent, was selected for each project and is responsible for maintaining the schedule and quality of work required to meet the objectives of the project. The tasks and the respective operating agents are: I. Investigation of the Performance of Solar Heating and Cooli ng Systems -- Technical University of Denmark. II. Coordination of R & Don Solar Heating and Cooling Comp onents Agency of Industrial Science and Technology, Japan III. Performance Testing of Solar Coll ectors -- Kernforschungs anlage JUlich, Federal Republic of Germany IV. Deve lopment of an Insolation Handbook and Instrumentation Package -- United States Department of Energy (Comp1eted) V. Use of Existing Meteorological Information for Solar Ene rgy Application -- Swedish Meteorological and Hydrological Institute. VI. Performance of Solar Heating, Cooling, and Hot Water Systems Using Evacuated Collectors -- United States Department of Energy VII. Cen tral Solar Heating Plants with Seasonal Storage -- Swedish Counci l for Building Research VIII. Pas sive and Hybrid Solar Low Energy Buildings -- U.S. Depart- ment of Energy This report deals with the subject matter of Task VI. The remaining projects are covered in separate annual reports. Objective The objective of this task is to further the understanding of the performance of evacuated collectors in solar heating, cooling and hot water systems, and to study, document and compare the performance characteristics of such collectors in different systems and climates. 3

It is intended that tbe conduct of tb-is tC\Sk. will involve; . - Requtred cammonaltties in d~ta co11ection and reporti".ng, 1~ A comprehensive variety of dtfferent tnsta11ation types, collectors and other components, 3) Some simtlartttes tn tnsta11ation types and co11ectors, and 4) Interaction with other IEA tasks. Thus, each participant will have as easy access to , and gain as much information from, each of the Task VI insta11at1ons as though a11 installations were part of his national program. Perfonnance comparisons will be made and reported that would be difficult or impractical from separate, non-coordinated projects. Approach

Each participant in this task is responsible for the oper~tion and analysis of at least one evacuated collector solar heating and/or cooling system. At the first meeting, the participants agreed on: a. General requtrements for partidpating installations, b. Desired features of participating installations, c. Requirement for instrumentation, data collection and performance reporting and d. Procedures for reviewing proposed installations. Details were included in the January 1981 Annual Progress Report. Task Duration In view of the timing requirements of some of the installations proposed for the task, the participants agreed it would be desirable for the program to be extended from a three year term to a five or six year duration. An extension of the task to December 1985 was approved at the October 1981 Executive Conmittee meeting. Publications Policies and the Role of Evacuated Tubular Collector Manufacturers in Task Activities Collector manufacturers are encouraged to take part in task activities with supply of hardware, advice, evaluation and review. In such arrangemets, the responsible participant in the task shall give full consideration to the manufacturer's advice and opinions and provide the manufacturer with the opportunity to review and advise on reports and papers. The findings and reports shall be t he sole responsibility of the participant. A list of national contact persons and responsible researchers is appended as Appendix A. 4

PROGRESS REPORT Status of Task The task participants, their applications, their status and the collectors they use as of J~nuary 1, 1982 are shown i'n Tao1e 1. Appendices B through I provide additi'onal detai'ls for each participant's installation. Schematics of a representative group of the evacuated collectors used by the parttctpants are shown in Ptgures 1 through 4. Tne latest meeting of the task was tn August 1981. At the meeting a detailed outline for the first Task VI interim report was approved and information to be provided by the partici'pants was establtshed. All participants will provide descriptive infonnatton on their installations and Japan, the U.S. and the FRG will provide data and results for the winters of 1979-80 and 1980-81 and the summers of 1980 and 1981. Examples of typical performance results are shown in Figures 5 through 7. Other installations will provide data and results at their discretion. The meeting produced further standardization of analysis and reporting procedures. These included a collector capacitance correction for reconciling non-steady state collection data with steady state tests, an agreement which will establish task standards for specifications of collector area bases and a statistical procedure to estimate experimental parameters. Task III/V measurement accuracy studies were also a meeting topic. Conclusions and observations from the Boulder pyranometer workshop were presented and discussed. Future Task III/V activity in this area will be watched with interest, especially since some Task VI analyses, reporting and comparisons are made on an hourly basis. A number of evacuated collector manufacturers were present at and contributed to the meeting. In addition to Sanyo and Philips, who are Task VI participants , Corning, Owens-Illinois and Sunmaster attended. A new task goal of making careful and convincing performance comparisons between the Task VI installations using evacuated collector systems and the same systems equipped with flat plate collectors was unanimously endorsed at the August 1981 task meeting. Detailed component by component validations of computer simulation models against data from each installation will be conducted. Performance curves typical of good flat plate collectors will be substituted into the models. The different designs will be simulated and comparisons will then be made between optimum systems for each installation. The new goal arises from the Task VI general characteristics of acceptable installations and detailed program of work. Its methodology is also in confonnance with the express recommendation of Task I that future validation work should emphasize on-site validation at experimental facilities. The second task interim report, planned for 1983-84 will focus on the new goal. System characteristics to which perfonnance is sensitive will be given special emphasis in the modeling. One characteristic is the improved performance of tubular collectors compared to their flat plate analogues at off-normal solar incidence angles. So that these effects may be better incorporated into the validation, the Task VI installations that are starting data collection will begin measuring diffuse and direct radiation. Investigations of evacuated tubular collector incident angle effects conducted for Task III will be utilized. In addition, energy collection tests at off normal solar incidence angles will be made by Task VI participants to expand the data base on these effects. Table 1. Task VI Installations

Applications Evacuated Collectors Status as of Used or Planned January 1, 1982

Canada Industrial Process Heat Solartech (0-I tubes) Operating and collecting data Japan Single Family Heating, Sanyo Operating with a thoroughly Cooling and Hot Water Sanyo Heat Pipe* tested data system Production General Electric TC -100 Netherlands Single Family Heating Philips MKI Heat Pipe Being converted to evacuated and Hot Water Production (Isobutane working fluid) collectors Sweden District Heating Philips MKI Heat Pipe Operating and collecting data (Isobutane working fluid) General Electric TC-100 Owens-Illinois Switzerland District Heating Corning Operating and collecting data Sanyo Owens-Il 1i noi s* Swiss Evacuated Flat Plate Collector* (J1 Sunmaster (0-I tubes)* United Simulated Load, Philips MKI Heat Pipe Operating and collecting data Kingdom Domestic Hot Water (Isobutane working fluid) Emphasis United Single Family Heating, Corning Operating with a thoroughly States Cooling and Hot Water Corning Large Tubes* tested data system Production Philips MKIV Philips MKI Heat Pipe (Isobutane working fluid) Philips MKI Heat Pipe (Water working fluid and longer tubes) Owens-Illinois Sunmaster (0-I tubes)* West Multifamily Heating and Corning Operating with a thoroughly Germany Hot Water Production Philips MKIV tested data system Philips MKI Heat Pipe* (Isobutane working fluid) *Planned or under consideration 6

Unit assembly

Outer glass Vacuum Contact end \ with heat Cylindrical copper fin U-tube fl ow channel

Selective film on inner tube Reflector (absor~ing substance)

Figure 1. The GE TC-100 Collector .;---Heat pipe condenser End cap--~c::_~- Soft connection ,~-....,,.,r--Support plate PHILIPS HEAT PIPE EVACUATED TUBE /;.---Evacuated glass tube COLLl="CTOR --Selectively-coated ab~~r pbte Overall length- 1135 mm. n=-et:::=-Absorber alternately over Outside diameter 65 mm. and urder heat pipe

Evacuated glass tube Heat pipe Ab90rber

~--Sup~t plate .~""----Erd cop

Figure 2. The Philip Mark I Heat Pipe Collector 8

~v e r glass \

cover tube--._

insu_lation

Figure 3. Philips Mark IV Evacuated Tubular Collector 9

Molded Plastic Mounting with Manifold Tubes

Selective Surface

Absorber Support Clips

Copper Tubing Section A-A Tube Cross Section

Molded Plastic Mounting Typical Tube Detai I

Figure 4. Corning Evacuated Tubular Collector 10

102 z

PUM' ENERGY CQLECTCJl LOSSES T!ERl-\1\l

EXCESS HEAT

COLD ~l/\TER PREHEAT GAltl BY DUILDI NG

5 %LOSSES PREHEAT TAllK <1500 LITER TAl'a<)

f\ UX ILIMY Et/CRGY ;;: :::;;;::::::::::::::::::;;;;;;;;;;;;;;;;:::;;;;;;:::::::::::::::::::: ELECTR IC I Oil ... :::::::::::::::::::m:::m::::iiliiiliiiiiil!tiii!!iiii!i!iiiiiliiim ::rn:::::::n:::~7, : :~H::::: 11: 1::1: ::::1mm1m1:1::1m1m1mm1m: m1111m 1:1::1::1:m:1111::1:

lilililJ:, LOSSES DHrl TAtl< LITER TANK) illiliilllllillillilllllillllllllliillilliiliilll~lillliliiliilillllililillllllllllllilll,lllllililil,f (l(XXJ :1::1:m:::::::m.1::_1:.::!:11:1111:1:1:::1111111:111:1111:11111111:1::1:: m1m:11:: 1111:111:1::::11m1

1111111 CQLECT0'1 SYSTEM

DISTRll.VTIO!l SYSTEM

lll!i!!!!l1f! SCUR TNI< <1500 LITER)

CIRCULAT IOU LCXJ' AIID WARM HATER LOAD 100 % mmm

Figure 5. Energy flow for the Solarhaus Freiburg for the Eleven Mo nths Beginning February 1980 -

l.O 0 EFFICIENCY Clf ' SOLAR CClLLECTClR CP 0 GE-COLLECTOR PERIOD :1981.2.3.--1981.2.28. EFFICIENCT: T•0.58~-0.36X-8.99X 1

>. u c QJ .. u °'0 4- 4- QJ - (J1 en o . . ... c . • ...... ~ . • I . . . , u ...... QJ ..,,. - . : ...... 0 . - r- . . . 0 . . . . u ...... ~ w ...... ~ 0 - .. . :r: .

N 0

0.030 C11l/I 0.015 0 . .045 0.060 0.075 0.090 0. l 05 0. 1 2 2 m • ·c tiT/I w fi:gure 6. Efficiency of the GE Co11ector on the Sanyo Osaka House 12

T STORAGE-l75

65 53.2) 43.7~] ~] 4().81 48.T l41.0 39.2 44.2 f39.5 TAMBIENT_l_O_ 9:5 -- -- _7_1_ 1000 I.I -- 1.3 . 22 -5.0 942 928 !APERTURE AREA: 44.7 m2 I 888 900 20 Em TOTAL INCIDENT SOLAR >- c .,, • SOLAR WHILE COLLECTING :::; 800 787 ~ 762 • ENERGY COLLECTED (/) w 708 704 !;t 700 a: 15 >- 642 a: w :::: 600 590 ...J w Cl c>- Cl .,, 495 ~ 500 "'e ..... '.'.:i Q._ 10 :IE Q._ ~ 400

>-(.!) a: w z w 300 a:

0'-----""- ~~__..,...... ,....___...... ~...... ___.., OCT '78 NOV '78 DEC '78 JAN '79 FEB '79 MAR '79 SEASON

Figure 7. CSU So1ar House I Energy Monthly Availability and Co11ection for the 1978-79 Heating Season 13

Task Meet i ng s Four Task VI meetings have been held on: October 3-5, 1979 in Fort Collins, Colorado, USA April 22-24, 1980 i'n Stuttgart and Frei burg, West Germany December 2-5, 1980 tn Kobe and Osaka, Japan August 17-19 and 24, 1981 in London and Brighton, England In addition, a small wo rking group meeting on Task VI internal reporting structure was held on September 28-0ctober, 1980 tn Pingree Park, Colorado. USA. The next Task VI meeting t~ scheduled for May 14, 17:-19, 1982, Geneva, Switzerland. A small 1. wo~king group meeting on modeling and a small working group meeting on the Task VI format are scheduled respectively for May 10, 11, 1982 and May 20, 21, before and after the main task meeting. Work Plan A major task activity for the coming year is preparation of the first task interim report. Dates for the sequence of activities leading to submission of this report are given below. Flow of Infonnati6n for the First Interim Task VI Rep6rt

August 1981 May 1982 · August l 982 Meeting Meeting Meeting Discuss out- Review first Finalize draft 1ine and draft of of report for agree on re- report executive com- port struc- mittee considera- ture. Decide tion what infonnation participants will provide

I~------June 1981 July 1981 February 1981 I Apri 1 1982 July 1982 . i Detailed Partici- Information Draft of re- , Final draft outline pants re- from par~ from , of report of report turn their participants chairman to I from from conmen ts to chairman rparticipants I chainnan to chairman to chair- participants to parti- man cipants 1 14

Four days are necessary for tb~ next task meeting due to the materi.al th.at must be covered ~nd in li~ht of the ina~e.quacy of t h.e scheduled three day duration of the 1a.st meeting. About one day of the next meeting w·tl 1 be devoted to rnodeltng ~nd vaHctation, a,bou.t one day to the intertm report draft, about one day to reporttng each tnsta11 atton's yearly results and the rematntng time to dtscusstng coordi'natton wi'th other tasks, evacuated tubular co11ector tnctdent angle effects, task planning and a stte vtstt. For the next meeting the 11 new"' parttctpants wi11 send a full report of their insta11ation 1 s yearly results to the other parti'ctpanh one month before the meeting. The reports will use the IEA Task ~I modified format. Report fog of results at the meetl'ng wt11 l:)e functionally organized. That ts, results of each insta11ation will be reported in a session focused on collection, then in a session focused on storage and so forth. Two special small, two-day working group meetings will be held in conjunction with the next task meeting, one for modeling and validation and another to finalize the Task VI format. The modeling working group will meet before the main meeting to study ways to improve each tnsta1- lations 's modeling and validation effectiveness and wl'11 recommend task wide oojecttves an ct procedures. The format worki·ng group, meeting after the main meeting, wil 1 use the experience of just having written and presented full reports on their insta11attons to make any needed changes to Task VI reporting requirements. Evacuated tubular collectors have a much higher degree of sensitivity to incidence angle effects than do flat plate collectors. Seasonal variations in collection performance, probably due primarily to this effect, have been observed. Some research has been done in this area, but there is more needed. A part of the task activity for the next period will focus on this matter. Several participants will arrange to have evacuated tubular collectors tested at off-normal incident angles in their countries' test facilities. Task III results 1n this matter will be utilized. Tests at the Task VI tnsta11ations themselves will alsd be made. Evacuated collector manufacturers will be invited to attend and actively participate at the next meeting. 15

Milestone Chart 1982 Jan June July Aug Sept Oct Nov Dec Participants' annual reports sent to other participants Participants' interim report information sent to chairman Draft of interim report to participants Task Annual Report Semiannual Task Meetings A Modeling and validation working group meeting A Format working group meeting Submission of Interim report to Executive Committee 16

Level of Participation and Task Assessment All task members are now performing, or have assurance of being able to perform, according to both the requirements of the Annex and the elaboration of responsibilities given in the January 1980 Task VI Annual Report. All participants are actively contributing to task meetings.

~ 0 N Cl >- V> Cl (.!) z Cl z z ct: z ct: ..... ~ ct: _J ~ c::: _J c::: LLJ ct: c::: z LLJ Cl (.!) Cl z: LLJ LLJ N l.JJ $ ct: :c. 0 I- I- I- a.. I- LLJ ...... ct: V) ;:c ct: l.JJ 3: 3 z: V) LLJ u '":> z V) V) ::::> ::::> 3 l. Task Meetings Attended October 19791 x x x x April 1980 x x x x x x x September 19803 x x x x December 1980 x x x x x x x x August 1981 x x x x x x x x 2. Annual 1980 Task Report Submitted x x x x x x x 3. Presentation on Special Topics at the 1980 Task Meetings x 4. Presentation on Special Topics at the 1981 Task Meetings x x x x x x x x 5. Task Meetings Hosted x x x x

Notes: 1Several of the countries had not yet organized their participation or were otherwise unable to attend. 2The Netherlands joined the task after it started 3A small working group meeting was held to establish a reporting format for the Task.

No major problems are anticipated in attaining the 1982 task goals. 17

The following are the significant accomplishments for the current period: l) An additional task goal was identified. 2) A detailed outline and participant input obligations were established for the first interim task report. 3) Further standardization of analysis and reporting approaches were achieved. 4) An adjustement procedure for reconciling non-steady state collection data with steady state collector test results was developed. 5) A greater level of evacuated collector industry participation was achieved. 6) The functional approach of the last task meeting was successful and will be used in the next meeting. 7) All task tnsta11ations are operating and collecting data. 18

AP PEND IX A

List of Participant Co untries, Natio1a· CJ t ~ct Persons and Responsible R ese ~~c h e~: · CANADA NETHE LA NDS Mr. W.E. Carscallen Responstble Researc~er: c/o National Research Council of Professor C.W.J. van Koppen Canada Eindhoven University- of Tech nology Montreal Rqad aox 513 Building M~23q, Roo~ 147 Ei'ndhoven Ottaw.a, Onta.rto Kl,I\ QR6 · Neth.erlands Canada · SWEDEN CEC 0 Mr. Lars Astrand Dr. E. Aranovitch Uppsala Kraftvarme A-B European Comrnis.si.on Box 125 Joint ·Re.s .ea.rch. Center Eura tom 575104 Uppsala 1~21020 !spra, ~taly Sweden FEDERAL REPUBLIC OF GERMANY SWITZERLAND National Contact Person: Professor O. Guisan Dr. K.R. Schreitrntlller University of Geneva DFVLR Section de Physique Pfaffenwaldring 38-40 32 Bd d'Y voy D-7000 Stuttgart 1211 - Geneva 4 Federal Republic of Germany Switzerland Responsible Researcher: UNITED KIN GDOM Mr. K.H. Vanoli IST Energtetec.h.ni k ~mbH MY'. Graeme Baker D- 7842 K~nd. ~rn-WQ 11 bach BSRIA. federal Republic of Germany Old Bracknell Lane Bracknell, Berkshire JAPAN United Kingdom Mr. Katsuh.iro Hinotani Research_ Ce.nter Tech.nica,1 -Qpera,ttons Professor William S. Duff Sany{) E1 ectrtc . Co. , I.. td. Solar Energy Applications Laboratory 1-18~13 Hashi'ridant, Htrakata Colorado State Uni versity Osak.a 573 Port Collins, CO 80523 Japan USA NnHERLANDS OPERATING AGENT - USA

Natton~1 Contact Person: Professor William S. Duff Mr. J.C; DeGrij~ · Solar Energy Applications Laboratory Ph.il i. pS. L. tgh.ting IJi'vi s ion Colorado State University Develqpment Opt. - Solar Collectors Fort Collins, co 80523 Butlding ·EB5 USA Eindh.oven · Netherlands 19

APPENDIX B Mountain Spring Bottle Washing Facilities Solar Project, Canada 20

APPENDIX B Mountain Spring Bottle Washing Facilities Solar Project, Canada The solar system installed in the bottling plant, a 2230 m2 single story building, of Mountain Spri'ng Beverages in Edmonton, Alberta was designed to assist in matntaining at a temperature of 75°C a caustic soda solution used for the washing of reusable empty soft drink bottles. The bottle washing process consists of the following stages: a) spray washing the bottles in warm (=49°C) weak caustic solution. The heat necessary to keep this solution warm is obtained from the main soaker tank via a liquid to liquid heat exchanger. b) In order to sterilize the bottles they are mechanically passed through soaker tank (14000 1) where the bottles are sprayed, both internally and externally with a 3.5-4% caustic soda solution. The temperature of the caustic soda is maintained between 72°C and 82°C by a Schaffer gas fired heater. The fluid in this tank is continuously circulated through a filter and the gas fired heater when the bottle washing process is operative. A bypass has been inserted in the return line to the gas heater to divert the fluid through the shell side of a tube-in-shell heat exchanger where it is heated by the hot solar fluid circulating in the tubes. c) Washing of the bottles is completed by a rinse in fresh water ( 21°C). The load on the working facility is composed of two components the standby losses and the sensible heat required to raise the temperature of the glass bottles from the outdoor ambient temperature to a nominal 75°C. On a monthly basis approximately 80,000 cases of one dozen 1.065 litre bottles pass through the rinse and soaker tank. The through put of bottles is seasonal. The soaker operating time is approximately nine hours per day (higher in summer, lower in winter) with the summer work weeks being six days and the winter work weeks being five days. The gas fired heater and circulating pump are connected to a timer which initiates the heating of the soaker tank four hours prior to the first bottle washing shift. The approximate annual load for the plant is 550 MWh. The Solartec collector array is composed of two groups, one to the north end of the building roof and one to the south end. The northern and southern banks have 106 and 110 collector modules respectively. This presents an active area of 281 m2 . The spacing between rows of collectors is 2.7 m, the tilt of the collectors is 50°, and the orientation is due south. Each group is independently plumbed to the storage tank to permit operation of only half the system in the event of a shutdown for repairs. Control of both portions of the array is by a corrmon control unit and one control collector located in the extreme northwest corner of the northern array. A spare control collector resides in the extreme southeast corner of the southern array. 21

The plumbing system consists of two pairs of header pipes, one for each of the northern and southern groups. The plumbing runs are internal to the building with a total of 22 branches penetrating the roof for the individual supply and return lines for each bank of collectors. As the system depends on open channel flow for drainage, all of the plumbing is sloped toward the accumulator tank. All the interior piping is covered with 10 cm of fiberglass insulation and as the supply and return lines are parallel they are bundled in a 2.5 cm thick alumi num-backed fiberglass blanket. Water flow to the collector array is not continuous but rather intermittent; they array operating on a batch process principal. Pumping ts accomplished by two collector pumps (76 L/s @ 15 mH 20), one for each of the collector groups, sourcing a 5700 L accumulator tank. Drain down is initiated by two normally oepn solenoid valves located between the supply and return pipes (these are not illustrated in the blue- prints), this allows the water in the collector supply lines to drain back by bypassing check valves located immediately downstream of the collector pumps. Energy transfer from the accumulator tank to the bottle washing facility is by means of a circulating pump and a tube-in-shell heat exchanger. This energy transfer is on a continuous basis if the accumulator water is of a higher temperature than the return caustic soda solution to the gas heater. The evacuated tube collector module is a drain down, liquid collector capable of delivering fluid temperatures up to 90°C. The module consists of eight evacuated glass tubes which are arranged in parallel flow, with a one-sided supply and return header. Behind each of the tubes is a parabolic cusp reflector. Due to the nature of this application in which the load occurs concurrently with available solar energy the necessity for a.storage tank does not arise. Instead an accumulator tank (5700 liters) is needed. The capacity of this tank is to fill the entire collector l-0op and still have enough residual fluid in the tank such that the heat exchanger circulating pump can operate satisfactorily. During periods when the bottle washing facility is not operating (i.e. weekends) and solar energy is available heat can be transferred from the accumulator tank to the soaker tank effectively increasing the storage capacity of the system by 14,000 liters. 22

APPENDIX C Sanyo Osaka Solar House, Japan 23

APPENDIX C

Sanyo Osaka Solar House, ~i3.p~n Osaka Sanyo Sohr House is a two-started retnforced concrete building for a stngle famtly res;·dence. The solar house is destgned prtrnartly for energy savtngs for space cooling, space heattng and domestic h_ot wa.ter supp1ytng. Besides so1ar energy uti'lization for space cooltng, space h~attng and DH~ supp1ytng, energy savtng designs are adopted tn the structure of the house and air ctrculation equip- ments ;·n the house. One of them ts external insulation of 100 nm thtckness for the walls and floors. The solar system consists of evacuated glass tube solar collectors, three ·storage tanks, an absorption chiller, two auxiliary electric heaters, circulation pumps, four fan coil units and pipings. Collected heat by the evacuated solar collectors is stored in the first storage tank. The evacuated solar collectors is stored in the first storage tank. The stored heat is distributed in hydraulic form to the DHW storage tank and to the second storage tank in a heating season or the absorption chiller in a summer season. Chilled water produced in the chiller is sent to the second storage tank in summer. Hot water for DHW supply is obtained through a heat exchanger in the first storage tank and domestic hot water is supplied from the DHW storage tank. Space cooling or space heating is made by cold or hot air through fan coil units placed in rooms, respectively, and chilled or hot water is supplied into fan-coil units from the second storage tank. Solar fraction for space cooling, space heating and DHW supplying for Osaka Solar House is expected to be more than 0.85. The solar house is a two-storied residential building for a single family with living area of 118.52 square meters. The solar system in Osaka Sanyo Solar House consists of evacuated glass tube collectors, three storage tanks, auxiliary electric heaters and a heat exchanger in the first storage and fan coil units. The auxiliary heater for cooling and heating is placed after the first storage tank and the axui1iary heater for DHW is built in the DHW storage tank. The solar system schematics is shown in Figure C-1. Hot water from the collectors is stored in the first storage tank at about 85°C in summer, 50°C in the winter and 60°C in spring and fall. In cooling season the hot water from the first storage tank is supplied to the generator of the absorption chiller. The chilled water (10°C) produced in the chiller is supplied to the second storage tank and stored there. In heating season the hot water of higher than 45°C in the first storage tank is supplied to the second storage tank . For the operation with the axuiliary heater, the hot water temperature from the auxiliary heater to the second storage tank is controlled at 45°C by a three way valve. For cooling and heating inside the house, chilled (10°C) or hot (45°C) water stored in the second storage tank is supplied to the fan coil unit depending on the requirement. Domestic hot wate r supplying system consists of the hot water supply coil in the first storage tank. The hot water for the domestic hot water supply can be obtained by heat exchange with the heating coil in the first storage. If hot water in the DHW storage is lower than 50QC, it is heated by the auxiliary heater built in the tank. Ts : 50'C

\\'ater Sm'

0.92L/s Ts W : 60'C (0. 75K\\') l'I. Ts \\" : 4 5 'C s :85'C S: lO'C

Figure C-1. Solar System Schematics 25

APPENDIX D Solar House of the Eindhoven University of Technology, The Netherlands 26

APPENDIX D Solar House of the Eindhoven University of Technology The Netherlands At present the Solar House of the Eindhoven University of Technology is equipped with a conventional solar heating and hot water system. The 3-yrs monitoring period for this system having expired it is intended to equip the solar house with Philips evacuated tubular collectors in order to demonstrate their applicability and potential in a humid, mesa thermal marine climate. The Solar House of the Eindhoven University of Technology, a rather spacious, detached house is situated in the outskirts of Eindhoven. The house was completed in November, 1976. In the design of the house both the architectural and the mechanical engineering implications of the utilization of solar energy were taken into consideration. As such the house was the first integral solar house in the Netherlands. The solar collector roof is tilted at an angle of 48° to the South. The cooling medium is water. In the 4.1 m3 solar heat storage tank the advantages of thermal stratification are exploited to the limits of their potential. The solar system serves both the space heating and the domestic hot water supply. The performance of the solar system is monitored continuously, readings of the 30 measuring points being taken each minute and recording being executed each half hour. A simplified schematic drawing of the current solar heating system is given in Figure D-1. The system differs in three aspects from the usual water-filled systems: The auxiliary heater keeps the temperature in the upper part of the storage tank at a constant value, there is no heat exchanger between the collectors and the storage vessel and a fully developed thermal stratification is applied in the storage tank. The system heats a thermally well insulated, rather spacious detached house and also supplies the hot domestic water. The house is occupied by a family consisting of the parents and a daughter; frequent guests however bring the average number of occupants up to about four. The heated floor area amounts to 220 m2 . An air heating system provides the heat for the living spaces (living room, study, kitchen, pantry, 5 bedrooms, 2 bathrooms). The garage is heated by injection of the was t e ventilating air. The total outside wall area is about 172 m2 , the t otal outside roof area about 141 m2 . In order to achieve a low unintentional ventilation numerous measures had to be taken to eliminate air leaks in the envelope of the house. The system conversion currently being carried out will also simplify the system by incorporating the auxiliary heater in the storage vessel, improve the thermal insulation of the storage and the heat transfer capability of t he air heater, and apply a newly developed control strategy which promises a 5% performance improvement compared to the present on-off control. The retrofitting is expected to give valuable additional information of a practical nature . ~} ~/~

AUXILIARY-HEATER \\\

COLLECTORS

N ......

AIR HEATER

Figure D-1. Simplified Scheme of the Solar Heating System 28

APPENDIX E The Knivsta District Heating Project, Sweden 29

APPENDIX E The Knivsta District Heating Project, Sweden Sweden is to a large extent depending on oil as a source of primary energy. About 70 percent of the primary energy used consists of oil and petroleum products. For the community of Uppsala the situation is even worse. More than 90 percent of the primary energy is oil and petroleum products. The main part of the electrical power supply is produced in an oil fired cogeneration plant. Today 80 percent of the buildings in the town of Uppsala are connected to the district heating system. In 1985, 95 percent of the heating demand will be covered through district heating. Present plans call for a reduction of the dependence upon oil to 40 percent in 1985 and lower in the 1990's. This to be accomplished through increased energy recovery from the incineration of garbage, use of biomass and conversion to coal/oil or even coal/water mixtures instead of oil. Solar energy will give a rather insignificant contribu- tion by 1985 but is expected to contribute approximately 10 percent in 1990 and 20 to 30 percent at a later stage. In the Swedish climate solar energy can supply up to 10 percent of the demand for heating and domestic hot water by feeding directly into a district heating network . In order to reach a higher percentage, seasonal storage must be applied. In order to learn more about the use of solar energy on a large scale UKAB is designing a central solar heating plant with seasonal storage for 500 flats with construction start in 1982. It will con- sist of a solar collector array of 20,000 m2 (200,000 square feet), a rock storage of 100,000 m3 and a distribution system for heat and domestic hot water supply. For that project, called the Lyckebo project, evacuated tube collectors are an interesting product. This conclusion is valid for the application of solar collectors to a district heating network. As a first step the performance of such collectors should be studied in the actual environment. Therefore we have installed evacuated collectors from three different manufacturers at our Knivsta heating plant. The three collectors are mounted on the flat roof of a district heating plant built for biomass. See Figure E-1. Each collector form two rows totaling 40 m2 . The rest of the equipment, such as heat exchangers and control valves, are located inside the building. The solar system is connected to an existing district heating system of 12 MW peak demand. The three different collector makes form three separate systems. They are connected to the return piping of the district heating network. The collectors are General Electric TC-100, Owens Illinois Sunpak TM Series Modules with shaped specular reflectors and Philips Mark I Heat pipe with 15 tubes per module and no reflectors and Glycol is used as freeze protection. To prevent freezing of the district heating side of the heat exchanger a three way valve is used to by-pass the glycol-water mixture if it has too low temperature by mistake. There is no storage in the system as the heat load is always much bigger than the energy production from the collectors. 30

During the first year the operating mode "running the collector system against a seasonal storage" will be simulated. The second year the mode, "solar collectors connected to a district heating system with just short time storage in the district heating net", will be simulated. w_.

A Boilerbuilding with roof-mounted solar collectors

B Silo

( Receiving hopper

-·--.L. -- · --- · --- · ~1·

Fi gure E-1 32

APPENDIX F Geneva SOLARCAD District Heating System Project, Sw·i tzerl and · 33

APPENDIX F Geneva SOLARCAD Dtstrict Heating System Project, Sw'i'tzer1 and · , The Swiss national objectives in this project are to: 1) Build a large system ( ~ 1000 m2} with evacuated collectors and as soon as possible demonstrate the fe asibtli'ty of such a system 2) Favor some eventual Swiss product. (A few studies in Switzerland are being made on flat or other types of evacuated collectors}. 3) Coordinate the different Swiss activities connected to the field of evacuated collectors. The construction of a large system is being preceded by tests of small areas of different collectors working in rea1 conditions. The fina1 project w·ill have a collector fi'eld of about 1000 .m2 , a temperature range of about 90-13QQC, ~ peak power output of about 500 kW and a mean annual output of aoout 400,000 kWh/year. Sanyo evacuated co11ectors havtng 19.5 m2 aperture area were mounted in 1980. This installation has operated since the beginning of 1981. A second test area with 18.7 m2 of Corntng France evacuated collectors were mounted at the end of 1981. The design of the final installation and the choice of collectors will be made at the end of 1982. Construction will take place in 1983. Operation and measurements would start in 1984 with results available at the end of 1984 or in 1985. The solar energy system has a design maximum power of 0.43 Gcal/h (500 kW), far below the minimum power delivered by the district heating s·ystem. In consequence no storage has to be considered and the solar energy system can be connected directly to the return branch of the district heating system or to one of the three separate networks. The solar energy system is therefore correlated to the temperature behavior of the return branch. And the situation is dramatically different from that of a solar energy system connected to a storage with very slowly evolving temperature. Temperatures can vary by 10 or 20°C in less than one hour and variations up to 30°C can occur during a day. Thus the solar energy system must 11 follow 11 such variations. The maximum temperature reached by the three different return branches were scanned for a 3 year period. Only a few days a year was this maximum temperature higher than ~0°C. Thus, due to temperature differences in the heat exchanger, in the collector loop and in the plumbing, temperatures up to ~120°c at the collector must be allowed for. · The connection to the district heating system is shown on Figure F-1. For simplification, the pump is ~ctivated all the time (even during the nights) . Each test loop is conceived with one heat exchanger in order to avoid correlations between different test loops (what would be the case with only one heat exchanger for the different 1oops). 34

2 The ei·ght Sanyo modules wi. th 9. to ta 1 area of 22. 2 m are oriented South at a tilt ~ngle of 30Q from bortzontal. The absorber plates, whtch cou1d be ttlted~ are tn the same plan~ as the co11ector. So far no white reflecting surface has been mouhted behtnd the tubes. The collectors are on a ~ut1dtng roof, the rest of the installation is one floor below. T~e roof is htgh and the solar avai1abili'ty for co11ectors is qui'te good i'n thts test area. 35

Figure F-1. Connection to District Heating S,ystem Test Arrangement

START BRANCH 130° / CENTRJ..L 1------~------~------.,,,____, USERS ST/\TION RETURN HHANCH 90°

PUMP 2 1113/h

TEST LOOP l

TEST LOOP 2

TEST LOOP 3

EXCHANGERS

TYPICAL TEMPERATURES AHI:; INDICATED 36

APPENDIX G Solar Test Installation at Bracknell, England 37

APP ENDIX G Solar Test Installation at Bracknell , England

The purpose of the proposed project is to determine system and component characteristics for evacuated systems both from practical tests and by the use of mathematical models, to assess their potential application for the UK, to provide data for cost effective calcul ations and to produce data to support the design of optimized systems for particular applications. The initial two yea r program of work will concentrate on systems designed for the production of heat for space heating and domestic hot water in dwellings, water will be used as the he at transfer fluid. Dependent upon the outcome of this project further studies will be made to extend the work to include industrial applications and use of alternative hea t transfer fluids. The proposed project is in two parts: The construction and operation of a test installation to provide operational experience , data for model validation and . a test bed for system development and component appraisal studies. The development of a mathematical model of evacuated collector system performance. The design concept of the PTF is that it is a facility that can accommodate a number of separate solar heating systems, each system is as close to reality as possi ble with the collectors installed outdoors subject to preva iling weather conditions and the system complete with all piping controls and storage. The load on the system is provided by a physical simulator on-line computer controlled. The computer is programmed to produce a load for any specified house and heating system active with the weather conditions and the solar heating system storage temperature, the load program also takes account of the supposed living habits of the occupants and the thermal response of the house and its heating system. In selecting the most appropriate form that practical trials should take, both trial house installations and total laboratory trials with simulated insolation were considered. However trial houses are very inflexible in terms of com ponent or load changes and measuring of all the parameters affecting load is difficult and total laboratory trials were considered too unrealistic for real confidence in the relevance of the data procured. These and other considerations led to the PTF approach which has already been shown capable of being easily modified and preliminary model validation using the data obtained has been very encouraging. The evacuated collector system which is the third system to be incorporated into the UK PTF is shown in Figure G-1. The physical load simulator or interface is intended to enable a load calculated by the compute r to be imposed on the solar system. It is designed so that with the appropriate co1TV11and from the computer the prescribed load in terms of the fluid flow rate from the solar store and its return temperatu re to the store can be achieved. The principle of design of the simulator is that it consists of three loops linked by two mixing cylinders, each loop having its own 38 pump. The first loop, between the solar store and the first mix.ing cylinder controls the flow rate from/to the store by means of a motorized valve controlled directly by the computer. Rotameter and turbine flow measuring devices are included in this loop. The second temperature control loop, between the two mixing cylinders, have a higher fluid flow rate compared with the outer loops and provides fluid at the required temperature for return to the solar store. The required temperature is achieved by removing hot water from the temprature control loop to the third cooling loop. A small heater is included in thts loop to facilitate good control of the return temperature to the solar store. The flow rate through the third cooling loop between the second mixing cylinder and the reject heat exchanger is regulated by a motorized valve controlled by a PIO controller with its set point signal provided by the computer. OHie/ coil Pressure Over heat vessel Pressure cooler relief valve Store 75 l/m 2 collector

w l.O

I House I load Freeze prptection 1By- pass heater 1 I I l I I I '

I L---- 1 : i r '------,I I ~ I I I I I I I : L ______il I I I * for use if primary/ ______j storage circuit ;_ ~-=:.::. .=-_-_-_-_-_-::__ ~ -_ -_-_- _:- _-:-.:: _:- ::_:. Contra 11 er ~----- separation required

Figure G-1. ~c hematic of Proposed System 40 APPENDIX H Colorado State University Solar House I, USA 41

APPENDIX H Colorado State University Solar House !, USA

Solar House I is a residential-type building located in the Solar Village at the Foothills Research campus of Colorado State University in Fort Collins, Colorado. The building is a three- bedroom house, although the interior is utilized for offices. The first floor is the 11 livingtt area, with 126 square meters floor space, exclusive of the unheated vestibule and separately heated garage area. The full basement, with 123 square meters floor area has additional offices as well as space for the solar equipment. The south side of the basement is entirely above grade while the north wall is all below grade. The garage has been converted to offices that are heated and cooled by a separate electric supply not associated with the solar system. Solar collectors are mounted on the south side of the 45 degree roof. The roof is partially supported by four walls which extend outward 1.83 m from the south wall of the building. A 1.83 m overhang shades the south-facing windows on the first floor in the summer and admits sunlight during the winter. Shading of the south- facing windows in the early morning and late afternoon is provided by vertical support walls (fins) extending from the south wall. The actual heating load is less than 80 percent of the anticipated value because of departures from the design on which the load was based. The principal differences are due to the use of triple glazed windows rather than double, reduced infiltration by use of a vestibule entry, and higher interior heat generation resulting from lighting, electric equipment, and occupants. Internal heat generation and heat lost from storage into the house also increase the cooling load significantly. The current program in Solar House I involves evaluation of systems which included an experimental heat pipe evacuated tubular collector supplied by Philips, Eindhoven, Netherlands, a sectional heat storage tank supplied by the Bally Case and Cooler Company, second and third generation chillers supplied by Arkla Industries, an off-peak electric heat storage unit supplied by the TPI Corporation, and other heating, cooling, and hot water equipment. There were four distinct solar energy systems in CSU Solar House I from October 1979 to September 1980. The configuration of the experimental house provides many options. Heat may be supplied from a flat-plate liquid collector on the roof or from an evacuated tube liquid collector on an adjacent platform. Two storage tanks and two tube-and-shell heat exchangers are available for storing heat from both collectors. Heated water may be supplied from either tank to the heating, cooling, and service hot water equipment in the house, while heat is rejected from the other tank to the atmosphere. In the period l October 1979 to 30 September 1980, both a heat pipe evacuated tube collector and a flat plate collector was used to supply heating and cooling requirements of the building. The evacuated tubular collector systems are shown in Figures H-1 and H-2. Principal system components are an experimental heat pipe evacuated tube collector, a drain back single glazed selective flat plate collector, a modular 42 heat storage tank with stratification enhancement, an off-peak electric auxiliary heater, a lithium bromide absorption chiller with integral cooling tower, a heat exchanger and tank for solar water heating, and a heat exchanger for storage-to-warm air transfer. Solar collection was accomplished by operation of the collector pump transferring heat in water directly to storage. For solar space heating, hot water was pumped from storage to a heating coil through which house air was circulated, water being returned to the tank. Auxiliary space heating was supplied by an off-peak electric heat storage unit through which air passed before distribution to the rooms. Service hot water was heated in a tube-and-shell exchanger through which hot water was supplied in a conventional electric water heater. Chilled Solar /Auxiliary Water Valve Pump

Main Absorp- Aux- Pump ..------___,, tion ---+--1 iliary Water Elec- Chil ler tric Air to House Boiler Floor Return Air Registers--_,__r------Heat Storage

Cooling Tower (Outdoors)

Figure H-1. System Three: Cooling and Hot Water with Simple Loop Heat Pipe Evacuated Tubular Collector and Absorption Water Chiller with Separate Cooling Tower Heat Pipe Evacuated Tubular Collector

Solar I Auxiliary Valve

Absorption Main Vent Aux- Pump .--+---' Water 1----+---+-__,,i liary Chiller with Elec- Integral tric Cold Water Cooling Tower Boiler From Main (Outdoors)

Heat Storage

Air to House Return Air

.Figure H-2. System four: Cooling and Hot Water with Single Loop Heat Pipe Evacuated Collector and Absorption Water Chiller with Internal Cooling Tower 45

APPENDIX I Solarhaus Freiburg, West Germany 46

APPENDIX I Solarhaus Freiburg, West Germany

The 11 Solarhaus Freiburg 11 is an apartment-house with 12 flats (areas ranging from 40 to 90 m2 ). The scheme of the overall energy system is shown in Figure I-1. In addition to two modules of evacuated tubular collectors for DHW and heating purposes it is equipped with an improved thermal insulati'on and with various energy saving installations. The experimental phase covers the years 1979 to 1982. The objectives of the experiment can be sunrnarized as follows: Test of evacuated tubular collectors with different climatic conditions (Colorado and Freiburg) and realistic operation conditions (main task Freiburg: domestic hot water preparation) the detailed recording of all relevant data as the basis for computer simulation of solar energy systems the comparison of analytic models with the experiment the specification of the influence of various energy saving components and methods on the gross energy consumption of the house and on the convenience of the occupants.

'"' ~ 0-::~ J ·~·~ ...,. ..te,, ... 000000

Figure I-1 . Simplified Scheme of the Energy System 47

The structure ts heavily built with a higher thennal capacity (outer wall 24 cm limestone blocks) . The efficient thermal insulation on the outside of the wa11s and the additional insulation of the partitions and the roofs of the apartments 1ead to a we11-ba 1anced indoor radiation climate. The construction of the windows with threefold panes and two continuous sealings reduces both radiation, convection and ventilation losses. Two ventilation systems of di'fferent design have been installed in the hous·e, For three apartments delivery of fresh air is ac- comp1 ish.ed by a channe1 system with clean, preheated fresh air. The other apartments have venttlation boxes which delivered filtered outside air. In both systems the amount of fresh air delivered can be manually controlled. The exhaust air ts being sucked out by a separate ventilation system. The balconies are pre-hung by means of a special construction to avoid thermal bridges. The entry has been equipped with an air lock. The walls and the ceiling of the cellar have been equally insulated as the roof of the attic. The two Corning and Philips MKIV collector modules are operated up to now (within the experimental phase A) independently, that means, one is furnishing the DHW system, the other one the heating system. This coupling may be exchanged by means of hand-driven valves. In a latter phase B of the experiment, both collectors will be operated jointly, that means, both will supply first that con- sumer which calls for highest priority. In order to do that, a highly flexible control system with 44 different operation modes has been installed.