Session 3— Solar Energy

SOLAR ENERGY IN ISRAEL — UTILIZATION AND RESEARCH

Y. ZVIRINl and S. ZAMKOW*

'Technion — Israel Institute of Technology, Haifa, and %rael Ministry of Energy and Infrastructure, Jerusalem

ABSTRACT. The State of Israel has been a pioneer in solar energy development andutilization since it was founded. In the 50's, Solar Domestic Hot Water Heaters (DHWS)became commercially available. At the same time research work was started in differentareas of solar energy, which led to more advanced solar systems for additional applications.The presentation includes some details on commercial utilization of solar energy and a briefdescription of the main R&D projects in industry, universities and research institutes.

INTRODUCTIONCurrently, solar energy accounts for over 3% of thetotal energy consumption in Israel, mainly by DHWSuse. It makes Israel the world's largest solar energyuser per capita. The share of solar power in theenergy market is expected to rise to 4.5% by the year2000. Local industry provides the components forDHWS and other applications of solar energy. MostDHWS use natural circulation systems for hot watersupply to small residential units. Forced flowinstallations have become common as well and areused in high-rise buildings, hotels and in agricultureand industry. About 65% of all households in thecountry have DHWS. Their reliability isdemonstrated by the fact that their manufacturersguarantee them for up to 8 years. Israeli legislationrequires that every new apartment building up to 9stories will employ a DHWS.

While Israel does not yet have a commercial solarpower plant, the Jerusalem-based Luz Company hasmanufactured concentrating trough collectors for theconstruction of thermal power plants in the USA.The company has installed a number of electricitygeneration units with overall capacity of more than350 MW; these comprise about 95% of the world'selectricity supply produced by solar energy. TheNegev Desert is the region best fit for solar powerstations in Israel due to abundant sunshine andextensive undeveloped space. A solar radiation andland survey is being carried out there to choose thebest location for future solar power stations.

Two types of Solar Ponds have been investigatedin Israel. The first large-scale efforts to utilize solarenergy trapped in salt-gradient Solar Ponds, bymeans of organic Rankine cycle turbines andapplications to solar desalination, were done bySobnat (a subsidiary of Ormat Industries). The other

was a Thermal Diode Solar Pond based on use offresh water and developed by the Arel/ArgamanCompany. Various solar thermal units with novelsolar collectors (Paz/Pimat), selective coatings andcooling systems have been constructed. Thetechnology of solar space heating and absorption airconditioning (Paz-Gal) has been developed,demonstrating technological feasibility in variousapplications.

Solar energy is extensively utilized on a largescale for industrial evaporation at the Dead SeaWorks and in sophisticated greenhouses all over thecountry. The use of photo-voltaic systems is rapidlyincreasing, mainly in small-scale systems. Theapplications include an experimental project for thesupply of electricity to single houses in a smallcommunity, spot illumination and emergencycommunication. Passive climate control principleswere developed and are being increasinglyconsidered in designing new buildings.

At present, advanced R&D is being carried out byresearch institutes, universities and industry. Some ofthe projects are close to commercialization. Twolarge facilities for solar R&D, the Sde Boqer TestCenter and the Weizmann Institute Solar Tower, arein operation — investigating various methods ofelectricity production and thermal utilization. Thispresentation describes the main areas of solar energyutilization and current solar research in Israel.

UTILIZATION OF SOLAR ENERGYIsrael was the first country to utilize solar energy ona commercial basis. Considering the lack of fossilfuels, the very limited hydro-power potential, and therelatively large number of clear days during the year,the orientation towards solar energy developmentwas natural.

39

ISRAR — USS(i ENERGY CONFERENCE MAV 13-15.1991

1. Solar Hot Water SupplyPeople in Israsl began to buy solar flat platecollectors for heating water about 40 years ago.These systems were based mainly on naturalcirculation (thermosyphon) and served individualfamilies. With the growth of high-rise buildings,forced circulation systems have become increasinglycommon. The energy crisis following the YomKippur War in 1973 caused the acceleration of R&Dactivity to improve the performance of existingcollectors and to develop more advanced systems. Itis interesting to note that 16 years ago, theinstallment of solar heaters and water tanks onbuilding roofs was forbidden in severalmunicipalities, due to esthetic reasons. Today, roofscovered with DHWS systems are a common sight inIsrael (Fig. 1).*

Thermosyphon systems of variable sizes, forsingle family homes, are marketed extensively. Thecommon system includes a 2m2 flat plate collectorwith a 160 liters tank. Since there is no pump and nomoving parts, little maintenance is required,involving mostly occasional cleaning of thecollectors.

The common collector is constructed of atransparent cover, an absorber plate and blackpainted steel tubes. The leading manufactures(Chromagen, Miromit, Amcor, etc.) have made someimprovements, like selective coatings on theabsorber plate to reduce radiation losses, finnedstructure in the air gap between the cover and theabsorber to decrease neat convection losses, andcopper tubes to increase heat conductivity.

Natural circulation systems are obviously notsuitable for large-scale applications, i.e. high-risebuildings and industry. Thus, the development fromthermosyphon systems to a forced circulation wasnecessary. Forced circulation systems are controlledby differential thermostats which activate the pumpswhenever the temperature of the liquid in thecollector exceeds that of the storage tank. Many suchsystems have been built for hotels, hospitals, militarycamps, dormitories and kibbutz communities. Thecost of additional components, such as the pump,controller and piping, is quite small per family unit,and therefore in many cases forced circulationsystems are used in apartment buildings as well.

Today, solar hot water systems are extensivelyused in Isnwl. There are a few dozen firms thatproduce and market collectors or systemsincorporating them. Many of the systems meet therequirements of Israel Standards Institute's (ISI)codes and are manufactured under ISI supervision.DHWS systems are reliable and their prices have

gone down. The leading manufacturers guarantee thesystems for 8 years and have sold millions ofcollectors in Israel and abroad. The price of acomplete theimosyphon system ranges between $600to $800, about half of it for the collector. The forcedcirculation central system is priced in the range of$800 per apartment Experience shows that thepayback period is in the range of 4-7 years for mostfamilies. It is noted that in the mid-seventies, theuniversities and research institutes, especially theTechnion, Ben-Gurion University and WeizmannInstitute, cooperated with industry in developing thiskind of systems.

The government has encouraged the installation ofsolar heating units by reducing taxes and bypromulgating regulations requiring solar systems inall new buildings having up to 9 floors (excepthospitals and industry). The Ministry of Energy andInfrastructure gives partial financing for solar energyconservation in the public and private sectors. TheMinistry also provides information to the pubr ;through the printed and electronic media andindividual consultations in Advisory Bureaus.

2. Swimming Pool HeatingSwimming pool heating seems to be one of the mostfeasible applications of solar energy, due to lowtemperature requirements and the built-in energystorage in the pool water. Since pool watertemperature does not exceed 28-29*C, the outletwater temperature of the collector can remain below40'C. There are two possibilities of delivering heat— by using regular flat plate collectors at relativelyhigh efficiency (over 60%), or by using inexpensiveplastic collectors at lower efficiencies. The secondoption is becoming more popular in Israel andseveral companies produce and install these plasticcollectors. Plastic collectors can also be used forpre-heating water in open systems.

3. Natural Evaporation and Utilizationin AgricultureOne of the Israel's main natural resources is theDead Sea, with its very high concentration of salts.The Dead Sea Works, one of the most successfulIsraeli chemical industries, processes and exportslarge volumes of potassium chloride produced bynatural solar evaporation of the Dead Sea brine. Thesalt solutions flow into large evaporation ponds. Thefirst one, about 70 km2, is used to deposit sodiumchloride, which is not marketed in such largequantities. The brine is then transferred to smallerponds to deposit the main raw material, camallite —for production of potassium chloride and otherchemicals.

* All color figures appear at the end of the article; the pages have been misnumbered

40

Y. ZvRtN AND S. ZAMKOW SOLAR ENERGY n ISRAEL

The abundant solar energy, coupled with a severeshortage of water in Israel, has led to very advancedagricultural production in greenhouses. Solar heatinghas been adapted to enable the export of vegetablesand flowers during the winter. Israeli researchershave developed several types of solar greenhouses,which can absorb and store the excess energy duringthe day and release it as heat at night (Fig. 2).Different design techniques have been adopted tomaintain temperature and humidity at the requiredlevels: sloped greenhouses, soil and space heating,natural and forced ventilation, storage of energy inwater pool or in rock bed, etc. As a result, theaverage energy requirement of a greenhouse hasbeen reduced by a factor of two over the last 30years. On-site computerized systems for greenhousecontrol, including irrigation, have been developed tooptimize growth of various crops.

Several agricultural products, such as tobacco,spices, herbs and vegetable seeds require air-dryingat moderate temperatures and are natural candidatesfor innovative solar drying systems (Fig. 3).

4. High Temperature Hot Water and SteamProductionThe solar heated water systems discussed in theprevious sections are based on flat plate collectors.

Fig. 2. Storage of solar heat in salts to cool and heat agreenhouse

Fig. 3. Low-cost thermosyphon dryer

To produce hot water at higher temperatures orsteam, concentrating collectors are necessary. In thepast such systems were too expensive, but today theycompete quite favorably with other energy sources.

Paz Oil and Pimat have together developed andinstalled several novel fixed concentrating systemsfor heating water to temperatures of 80-90'C andtracking systems for producing steam at 150-200'C.These systems are suitable for laundries, hotels,hospitals, apartment houses and industry.

Hot water heaters, based on an original design fora low-profile collector which is similar to acompound parabolic concentrator with a workingfluid tube at the focus of the mirrors, have beendeveloped (Fig. 4). This system consists of analuminum mirror reflecting a beam onto a selectivelycoated steel pipe at the line focus and has a collectorefficiency of about 50% at 90"C (Fig. 5). Thecollector stand allows simple adjustment oforientation to summer and winter positions.

Figure 6 shows a steam generation system withhigher concentration ratio than the water heater, ithas modules of parabolic mirrors positioned on arotating axis which reflect sunlight onto a glass pipelocated above them.

Recently, a system combining 300m2 of collectingareas was installed to supply hot water and steam tothe Hillel Yaffe Medical Center in Hadera (Fig. 7).In all, 20 such units are now in operation in Israel.

5. Solar Cooling, Refrigeration and DesalinationA unique solar-powered cooling system has beendeveloped at Ben-Gurion University. This systemuses solar energy at 90-95*C; the heat drives anabsorption cycle by using an organic working fluid(Fig. 8). The system is able to lower the refrigeratetemperature below 0'C, in contrast to conventionalsystems which are limited by the freezing point ofwater. The Paz-Gal firm applies this technology toindustrial systems with up to 120 tons ofrefrigeration (Fig. 9).

A desalination process which can be powered bysolar energy was developed by Israel DesalinationEngineering (IDE) and has been used in differentlocations over the world. However up to date, IDE'slow-temperature multi-distillation desalination unitshave been powered by fossil fuels due to economicreasons. Such a system at an installed capacity of20,000m3 of fresh water per day has been operatingnear the southern Israeli city of Ashdod, adjacent to acoal power station.

6. Solar-Thermal Electricity ProductionThree main concepts have been tested in the world toproduce electricity by solar thermal processes. Theonly one which has succeeded on a large scale is the

41

— USSR ENERCV CONFEHENCE MAV 13-15,1991

COOLINCWATER

GENERATOR

HOTWATER

SEPERATOR

ECONOMIZER

i

wCONDENSER

EVAPORATOR

JET

AISOR1ER

"S= ICOOLING

WATER

Fig. 8. Flow chart of the Pazgal Absorption Machine

Luz parabolic trough collector system. The Luzcorporation has constructed eight power plants inSouthern California, USA (Fig. 10), with a totalcapacity of more than 350 MW. The collectors havebeen developed and manufactured by the Luz plantin Jerusalem, Israel, which continuously unproved itstechnology from one generation to the next Theseimprovements include the type, size, shape andmaterial of the mirror, the tracking system, thevarious coatings and materials for vacuum tubes,vacuum technology, connections between metal andglass, etc. (Fig. 11).

Figure 12 is a schematic presentation of a Luzplant. The unit consists of a series of modular solarthrough collectors (large parabolic mirrors), whichtrack the sun and concentrate the solar radiation on aheat-collecting pipe placed at the linear focus of thereflectors. The working fluid is oil, which can reachtemperatures of about 380'C. The hot oil is pumpedthrough a heat exchanger to produce superheatedsteam. The steam then powers a conventional,electricity generating, Rankine-cycle steam powerplant. A natural gas fired boiler provides back upsteam for the turbine.

Today, the Luz power plants are the only large

scale solar thermal powerproduction in the world — a 10MW power plant using the solartower concept was shutdown someyears ago in Southern Californiaand the operation of a 5 MW SolarPond at the Dead Sea in Israel wasalso stopped. The last two conceptsare further discussed in the R&Dchapter. Finally, Luz has carriedout feasibility studies in India,Mexico and Italy and has beennegotiating additional programs inseveral countries, including Israel.

7. Direct Sunlight Conversion toElectricity by Photo-VoltaicSolar CellsAlthough the price of photo-voltaic(PV) systems has considerablydecreased in the last few years,they are still too expensive toreplace electricity obtained fromthe national grid. Since theelectricity supply network is highlydeveloped in Israel, the market forPV systems is rather limited and itdoes not appear that it will becomevery attractive in the near futureeither. Several applications doexist, however, where it is not

cost-effective to invest in an electricity distributionsystem. These include communication systems inremote areas; illumination of bus stops, cross roadsand even street lighting (as shown in Figure 13);control elements in large irrigation systems; cathodicprotection to prevent piping corrosion, etc.

The Ministry of Energy and Infrastructuresupports a demonstration project to supply all theenergy needs by solar energy to 18 private houses atthe small village of KUI, in the Galilee. Each housereceives 2.5 KWh per day entirely from PV panels.The hot water is provided by solar DHWS. Batteriesare used to store the power. Recently PV panels havestarted to appear in the market for several privateapplications, such as garden and front-house illumin-ation, water pumps, etc. These are affordable tomany people, showing that the cost of PV systems is,indeed, going down and a potential of increasingutilization exists.

Unlike the solar thermal applications, there is noreal effort towards large scale commercialproduction of solar cells in Israel. Two Israelicompanies (Manor and Sonerco) have designed andinstalled imported solar cell systems for publicorganizations, like the government and local

42

Y . ZVWN AND S. ZAMKOW SOLAR ENERGY N ISRAEL

municipalities. The companies have also developed asmart system, which increases the illumination whenit senses the presence of people at a bus station. Thisdevice helps to reduce the size of both panels andbatteries, as well as the cost of the whole system.

SOLAR RESEARCH AND DEVELOPMENTSolar research in Israel started in the early 1930's.During the SO's research and development begun onselective coatings for DHWS, parabolic-troughtracking concentrators and solar ponds. After the oilcrisis of 1973, solar R&D picked up considerablemomentum. In 1977, the new Ministry of Energy andInfrastructure took over responsibility for energyprograms, including solar energy. Since its founding,the Ministry has spent more than $50 million onsolar R&D and a comparable investment has beenmade by the industrial and academic sectors.Currently, research and development in solar energyis carried out by many Israeli organizations —universities, research institutes and industry. Even inareas where solar systems are used on a commercialbasis, industry continuously works to improvedesign, materials, coatings and production methodsto develop more efficient, less expensive systems.

1. Test FacilitiesIn 1987, the Sde Boqer Solar Test Center was builtin the Negev Desert by the Ministry of Energy tofacilitate the comparative evaluation of solar

powered technologies under actual field conditions.Today, the facility is operated by the Ben-GurionUniversity. Several Israeli firms utilize the center totest various units, using on-site computerizeddata-logging and processing systems. The layout ofthe site is shown in Figure 14.

Another facility for R&D is the 3 MW SolarTower at the Weizmann Institute of Science, inRehovot (Fig. 15). Sunlight is reflected to a target atthe focus of 64 concave, computer controlledheliostats arranged in a field (Fig. 16). The heliostats2-axes tracking system makes it possible to obtainhigh concentration of solar radiation at the centralreceiver aperture, generating working gastemperatures of up to 600-1000'C (Fig. 17). Since1988, the facility has been used for high temperaturesolar research, such as methane reforming with solarenergy providing "chemical storage" in a solar"chemical heat pipe" (Fig. 18). The product gas(syngas) can be transported at ambient temperatureby pipeline to a distant terminal and reacted torelease heat for various applications. The SolarTower can provide sunlight at a concentration ratioof more than 10,000. The facility can also be usedfor testing high temperature gas turbines (a furtherdescription follows in Section 3), oil-shalegasification and converting solar radiation tomonochromatic laser light, required for efficientphoto-chemical reactions.

The following sections describe briefly the mainR&D projects.

Fig. 75. The Solar Tower at the Weizmann Institute

43

ISRAEL — USSR ENERGY CONFERENCE MAY 13-15,1991

Fig. 16. Heliostats arranged in afield at the Weizmann Institute

HOW THE SOLAR TOWEH FUNCTIONS

F;>. 77. The Solar Tower Functions

2. Climate Control in Buildings:Room Heating and CoolingIn principle, solar panels for heating water can alsobe used for home heating. However, this applicationis not yet economical due to the large investment incollectors and storage needed for only a few wintermonths with many cloudy and rainy days. A largesystem to supply heat for a library, constructed at theTechnion, was the first attempt at solar space healing

in Israel. This demonstrationfacility has been operating forabout 15 years, much longer thanwas previously estimated. Theaccumulated experience from theTechnion unit was used later forthe design of more advancedforced circulation solar heatingsystems.

Solar-powered air conditioningis also not economical, because thetemperature provided by flat platecollectors is barely sufficient tooperate an absorption system.Furthermore, a large collector areais needed for a limited period oftime. A demonstration system witha nominal cooling capacity of 200tons of refrigeration, powered by a3000 square meters of solarcollectors, was built about 12 yearsago by Tadiran — to supply air

conditioning at the Sheba Hospital in Tel-Hashomer.This system has proven to be technologically sound,but not economical. A more realistic concept wouldbe the use of the same collectors for heating in thewinter and air conditioning in the summer. Indeed,the Paz Corporation is experimenting with a novelabsorption system of concentrating collectors whichis described under Utilization of Solar Energy,Sections 4 & 5. The first demonstration project has

44

Y. ZVMN AND S. ZAMKOW SOLAR ENERGY n ISRAEL

HP STEAM FOR INDUSTRIAL USE

PIPING STORAGE

AND TRANSPORT

SOLAR

REFORMERPOWER /DISTANCE/

HP STEAM

METHANATORWATER

CH4 /CO2-*-CO/H2 CO/H2-*-CH4/CO2

DISTRIBUTED

POWER

PRODUCTION

Fig. 18. Chemical energy storage and transport system

been built for the Visitor's Center in the Sde BoqerTest facility. Initial calculations indicate that thissystem has the potential to be economical. Moreover,it is possible to integrate a solar panel with a back-upbiomass combustion system. The simplicity, easyinstallation and low operating cost could be useful atsmall combined facilities in remote locations.

Another approach to space heating is solar airheaters. Unlike water heaters, this kind of units is notcommercially available, although it seems that quiteefficient collectors can be produced at a low cost.Several designs of solar air collectors, whichsignificantly reduce the heat convection losses,including reflective-fins and capillary-tubestructures, are being tested at the Technion (Fig. 19).

hotter zone—

— cooler zone

mi

r—solar radiation

5;;^ p a i r flow

rr<</Fig. 19. Reflective-Fin or Capillary-Tubes for solar airheater

3. Research in Solar ThermalElectricity Production and DesalinationAs mentioned under Utilization of Solar Energy,Section 6, the Luz Company worked to improvecollectors, tracking systems, structures, coatings,production and treatment methods. Moreover, Luz

tested a new concept, in which direct steamgeneration occurs in the collector itself. Thisapproach would eliminate the use of thermal oil andsteam generator, thereby increasing the overallefficiency and reducing the cost of the system.Further experiments were planned in the Sde BoqerTest Center.

Another approach to thermal electricityproduction is the salt-gradient Solar Pondinvestigated and developed by Ormat/SolmaL In thispond, a salinity gradient (and therefore a densitygradient) is created and continuously maintained.The density of the water-salt solution increases withdepth. The heat is "trapped" in the bottom layer andtemperatures of 85-90'C can be reached there. Thetop layer has relatively low salinity at temperaturesnear those of the ambience. The hot bottom brine iswithdrawn for the extraction of thermal energy bylow temperature turbine. The organic fluid chosenprovides the optimization of overall efficiency. Thepower module consists of an evaporator, a vaporturbine coupled to a generator, a condenser and afeed pump (Fig. 20). Several test facilities ofincreasing scales have been built with differentcombinations of solar pond size and power blockcapacity. A 5 MW Solar Pond power plant wasconstructed in Beit Haarava at the Dead Sea shoreand was operated at partial capacity for a certainperiod of time (Pig. 21). The project showed thecapability of a solar pond to act as a large collector,including its own built-in storage, and demonstratedthe technological feasibility. A solar pond powerplant can be built, properly maintained and operatedfor many years. Also, such a plant can be coupledinto a grid, supplying either peak or base-loadelectricity. The size of the pond and the powermodule can be tailored to match the power profilerequired. Currently, however, a power plant based ona solar pond does not seem economical, mainly dueto its low thermal efficiency. The Qrmat organic

45

ISRAEL — USSR ENERGY CONFERENCE MAY 13-15.1991

vapor low-temperature turbine, developed for solarponds, has been used in several countries for powerproduction from geothermal sources.

Another concept for solar thermal electricityproduction is that of a central receiver located on aSolar Tower, coupled with a gas turbine, asmentioned here in Section 1. A ceramic receiver(Fig. 22) heats pressurized air to about 1000'C. Thehot air is expanded through a gas turbine, whichdrives the generator. An experimental 250 KWOrmat gas turbine is now installed at the WeizmannInstitute Solar Tower to test this method. IsraelElectric Corp. is also participating in the project.

The Ormat Company is also examining several

MainIraow

Fig. 22. Artist's sketch of the ceramic receiver

desalination processes, using heat and electricityprovided by a solar pond (Figs. 23 & 24). Asmentioned above, water shortage is a severe problemin Israel, so large scale desalination will be needed inthe near future.

Other methods of desalination, based on theextension of the solar still concept (evaporation andcondensation under a transparent cover), are beingstudied at Ben-Gurion and Tel Aviv Universities(Fig. 25).

4. Additional R&D ProjectsAnother concept of a solar pond, based on the use offresh water, has been developed by Arel Energy Ltd.,a subsidiary of Argaman. This pond is created bycovering the surface of the water with specialthermal diode panels, comprising a transparentpolycarbonate encased within a glass box. The paneltransmits solar radiation downward, but preventsupward heat losses that would normally be caused bynatural convection and radiation. The depth of thepond can be tailored to provide storage for daily,weekly or seasonal cycles. The thermal diode solarpond can store energy in the form of hot water at 60-90'C. The energy is suitable for commercial spaceheating, absorption refrigeration cycle, hot watersupply, greenhouse glazing, etc. Today, several unitsof up to 400m2 surface area are in operation.

A very brief summary of additional current R&Dprojects on solar thermal processes, methods andequipment is given below, listed by research centers.

FLASHCHAMBER

£> LY TOP cojjv«Ttve_ JOKEJ

v " -^°— c5!lvE£Tlw.e£?HLV STOWAOE ZONE 1

FEED HEATERS L

TTTEVAPORATORS

SEA WATER n

CONDENSER

COOLANT

•HINE

PROOACr

MAKE-UP

Fig. 23. Dual purpose M.ED, solar pond plant

4 6

Y . ZVMN AND S. ZAMKOW SOLAR ENERGY N taAa

FLRSHCHRMBBR

rcca uttneas

EVAPORATORS

J

nrcmiry

COHVEHSER

Wio'/M JM iNtrex m >

Fig. 24. Omar dual purpose M.ED, sea water plant

GkmPorw

Solar Desalination

Porom Fabric

Distilais Trough

Aflltsd-wfcliMI

DouOU GKsiog

F»j. 25. Afrove; A tilted-wick stillBelow: A simple double-effect solar still

• Technion and Rafael: Improvement ofintermediate and high temperature sytems —concentrators, evacuated collectors, reflectiveheat mirrors and various selective coatings,anti-reflective for solar radiation (Figs. 26 & 27).

• Ben-Gurion University (BGU): novel

A

plate glass

• 1 %

35%

regular

2%

38%

83%

regular

plate glass

8 9 % * 6 %

reflective:Heat Mirror(HM)

anti-reflective(AR)

Fig. 26. Glass radiation properties and improvements bycoatings

concentrators; hybrid systems; radiationmeasurement methods (equipment and dataanalysis); stochastic modeling; orientation ofcollectors and efficiency determination methods.

• Tel Aviv University (TAU): Improvedthermosyphon configuration; thermodynamicanalysts and system optimization; phase changematerials for solar pipe energy storage; ejectorcooling.

47

ISRAEL — USSR ENERGV CONFERENCE MAY 13-15.1991

600

500

200

100 -

Coalingsshield

HM. both

360 420 460Tp(K)

500 540

Fig. 27. Effects of heat mirror and anti-reflective coatings(HM.AR)

• In the 80's, research programs were also carriedout at the Hebrew University in Jerusalem insuch areas as fluorescent glass solarconcentrators, storage of thermal energy inphase change materials, improving theelectronic properties of amorphous silicon,hydrogen production by solar radiation andphoto-chemical reactions.

5. Photo-Voltaic SystemsAs mentioned under Utilization of Solar Energy,Section 7, solar cells are not manufactured in Israelon a commercial basis. However, R&D projects onmaterials, coatings and production methods arecarried out in all the universities mentioned above, inthe Jerusalem Technical College and in industry.Paz, for example, is testing the concept of increasingcell array efficiency by using side-mirrors, whichreflect additional radiation onto the solar PV panels.Other projects include combined thermal and PVsystems, as well as irrigation applications. A group atTAU is investigating satellite electric power andsolar radiation on Mars. Finally, a group at the SdeBoqer campus of BGU developed the PV-ISRAELsoftware to design photo-voltaic power productionsystems.

6. Passive SolarPassive solar principles, together with other means ofenergy conservation in buildings, can beincorporated in the design stage to save energywithout compromising comfort The principles ofpassive solar include conservation, orientation,materials, windows, shading, illumination and manyothers. The R&D projects have included numericalsimulations, computer aided design and promotionalprograms. Researchers have found that passive solar

features, which add 10-20% to the construction cost,can save 60-80% of winter heating expenditures.Energy saving of 20% can also be achieved throughproper building orientation and placement ofwindows. Two groups at the Technion (Architectureand Civil Engineering) and one at the Sde Boqercampus of BGU have developed the principles formore efficient buildings and have issued guidelinesfor planners. The guide covers existing buildings,new constructions and regional planning, especiallyin desert areas. A Climatic Atlas of Israel forplanners, which includes data from 40 weatherstations, has also been completed. A number of"solar houses" have been built in Israel, employingthese principles (Figs. 28 & 29).

Regulatory efforts have focused only on rules forthermal insulation of residential and publicbuildings. Unfortunately, the scope of regulatoryefforts has yet to be extended to cover the thermalmass of buildings and regional planning based onclimatic factors. As a result, passive solar principlesare not yet implemented on a large scale byarchitects and civil engineers. It is believed thatgovernment incentives and legislation could changethe picture, similar to the success in implementingsolar water heating, as described under Utilization ofSolar Energy, Section 1.

EDUCATIONThe rapid R&D progress and the large scaleutilization of solar energy in Israel has beensupported by educational programs all over thecountry. All universities offer teaching and trainingcurricula in solar energy and related areas on bothundergraduate and graduate levels. Theses on avariety of solar energy subjects have been written,including experimental and theoretical studies,numerical simulations and optimizations, technicaland economical evaluations.

The Ministry of Energy and Infrastructure hasbeen conducting numerous educational programs,including courses, workshops, conferences,promotion in the media and consulting in advisoryoffices.

The Israeli Section of the International SolarEnergy Society (ISES) holds various workshops andconferences, providing information on local andinternational activities. Israeli experts in solar energyparticipate in the international solar energyconferences and present the latest developments inthe international journals.

SUMMARYThe presentation attempted to describe, briefly, theachievements and advancement of solar energy inIsrael, both in utilization and R&D.

48

Y. ZVHN AND S. ZAMKOW SOAR ENERGY WISRAE

6m'TrombeWall

6m ! Solar Air Collectors

7m2IrombeWall

13m2 Green House

14mJ Solar AirCollectors

Under Roor Hear

Storage—9m1 Pebbles

Fig. 29. Passive Solar in Jerusalem

As mentioned above, solar energy supplies over3% of the energy consumed in Israel, which makesthis country the world's largest solar energy user percapita. Solar energy has the potential to supplementor replace conventional energy in a variety ofapplications, such as water and space heating,cooling of buildings, steam production in industryand electricity generation.

Israel is among the world's leaders in theapplication and development of solar energy. Astrong capability exists to supply a variety of solarenergy technologies. About $38 million have been

invested between 1979-1990 in a number ofindustrial scale solar demonstration facilities (Table1) throughout the country. Most of them are still inoperation. Local industry provides systems forDHWS, concentrating collectors and equipment forsolar power utilization, exporting complete panelsand systems. Different projects are at various stagesof development, including some at or nearcommercialization.

Advanced R&D is being carried out in variousuniversities, research institutes and in industry,encouraged by the Ministry of Energy andInfrastructure.

Y. ZvifflN AND S. Z A M K O W SOLAR ENERGV IN ISRAEL

Ser.No.

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10111213141516171819202122232425262728293031323334353637383940414243444546474849505!525354555657585960616263

D e s c r i p t i o n

Solar toot & collectors heating swimming poolHerb dryingWater heating for kibbutz laundryCooling by absorption in hospitalWater healing in an industrial processHydrosolar greenhouseFruit dryingSanitary waler heatingSanitary water heatingSanitary waler heatingSanitary water heatingSanitary waler heatingSanitary water heatingSanitary waler heatingWa'.er heating (addition)Sanitary water heatingSanitary water healingSanitary water heatingSanitary water healingWaler healing in student's quartersSanitary water heatingSanitary water heating

Solar passive homesWater heating for dairy farmSanitary water heatingWater heating in restaurantSanitary water heatingWater heating for swimming pool

Water heating for communal kitchenWater heating for communal kitchenWater heating for dairy farmWater heating for hotel kitchenStorage for space heating5 MW solar pond demonstrationWaler heating for dairy farmWaler heating lor plating processWaler heating tor hotel kilchenSanitary water healing by solar pondWaler healing lor hotel kitchenSteam tor comm.unal kitchenSanitary water heatingSanitary water heatingSwimming pool healingPhotovoltaic lighting systemsWater heating for hotel kilchen

Village electrification by photovoltaic systemsWafer heating tor communal kitchenVarious small remote photovoltaic systemsDemonstration project—photovoltaic—by PazHydrosolar greenhouseHydrosolar greenhouseSanitary water heating in boarding school

Sanitary water healing in boarding schoolSanitary & community kitchen water healingSolar pond for greenhouse healingSchool dormitory heating by solar pondDemonstration project — heal — by luzSolar tower tor fl&DDemonstration proiecl — steam — by PazWater heating for guest houseWater healing for communal kitchenSteam and hot waler for hospitalDemonstration project — PV — Israel Elec. Corp.

L o c a t i o n

Weizmann InstituteMaon DistrictKibbutz GevalTel HashomerKefar Sava

Tiral YehudaRishon-Le-ZiyyonJabotinsky boarding schoolHaifa UniversityBelYonaEshkol Regional CouncilTel Aviv UniversitySenior citizens home at Be'er-ShevaNaval school al AkkoHaifa UnivrsilyKibbutz 'En GevIskar Blades Plant

Technion - Israel Institute of TechnologySenior Citizens home at Ramal-GanHaifa UniversityBeit Hachayal at Be'er-ShevaGirls' Institute al Bene-Beraq

Ir-GanimKibbutz Giv'al HayyimKibbutz AlumotKibbutz DovrafSenior Citizens Center at AkkoILAN — Disabled Sports CenterDovrat HostelKibbutz Nir YizhaqKibbutz UshaElatJerusalemBet ha'AravaKibbutz Ma'agan Mikha'elRa'anannaElalKibbutz Ma'oz-HayyimJerusalem

Kibbutz Nir EliyahuGiv'ai-ShemuelKibbutz AlumimMizpe-Ramon MunicipalityNatural Reserve AuthorityElatMizpe KelilElatHundreds; dispersedSede Boqer Test CenterGiv'al KhenKefar BialikGiv'al Washington

<efarBalya<ibbutz Shetayim3et ha'Arava'etah Tiqwa

Sede Boqer Test CenterWeizmann InstituteSede Boqer Test Cenler<ibbutz Kefar-Blum

Kibbulz Neliv-haLamed-HeHillelYaffe HospitalSede Boqer Test Cenler

Year ofstart-up

1979197919801980198119811981198119811981

1981198119811981198219821982198219821982198219821982

198219821983198319831983

19831963198319841984

1984198419841984198519851985198519851985198619861986

1987-901987198719871987

1987198B1988198919891989

19891990199019901990

Total

Capitalinvest

$1000"

805016

4629

253748

20253542356998

6722454

186287

3450622

2212

21000

851305015351416201727

27127

81018025203540427627

78312000

7205846

750220

38654

' Cost at the time of investment.

Table I. List of induslrial scale solar inslallalions in Israel

ISRAEL — USSR ENERGV CONFERENCE

original ecu T

color HlustfoiMAV 13-15.1991

Fig. 1. Roofs covered with DHWS system

Efficiency %

JO

60

50

4U

3D

20

10

5^^-^-j :xv...._^^^N»jte.

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: ! ; t ;

- • L -

! i• _ L _ . ±

X : -' X

i

I

01 02 03 04 05 06 07 OS 09 10x T (collator)-T(«nbl«nt) . rn ' iC ,

Mtermllition lKwh '

Fig. 5. Efficiency diagram ofThermo-Si Collector

Fig. 4. Cross section ofThermo-Si Collector

Y. ZVIRIN AND S. ZAMKOW SOLAR ENERGY IN ISRAEL

Support From

Fuel-Fir«d Boiler Steam

Consumer.

^D—\ICondintittVPump

Fig. 6. Schematic diagram ofCS 112 solar steam generating system

Fig. 7. Hot water and steam supply unit at the Ilillel Yaffe Medical Center

ISRAEL — USSR ENE(?GV CONFERENCE MAY 13-15.1991

Fig. 9. Pazgal Absorption 40 RT Machine including Circumferential Equipment

Fig. JO. Aerial view ofSEGS plants, Kramer Junction, California

Y. ZVIRIN AND S. ZAMKOW SOLAR ENERGY IN ISRAEL

Fig. II. Collectors, Kramer Junction, California

Fig. 12. The Schematic Luz System - SECS VW-IXXXl-XIl

ISRAEL — USSR ENERGY CONFERENCE MAV 13-15,1991

LUZ DIRECT STEAMGENERATION FACILITY

F - { ( i f^—f.

f-J-4 J J / J J J J f-i~ry V f V f v u f 7 r r r '

Fig. 14. List of existing and planned installations:

1. Photovoltaic — by Paz Oil Co. (operating)

2. Solar Thermal — by Paz Oil Co. (operating)

3. Solar Thermal — by Luz Industries Israel (operating)

4. Two-axis photovoltaic system—by Israel Electric Corp. (SEC) (operating)

6. Base for future photovoltaic program— by IEC

5. Photovoltaic solar modules testing facility — by [EC (operating)

7. Cooler Absorber— by Pazgal (operating)

8. Solar Thermal Direct Steam—by Luz Industries Israel (planned)

9. Central data logging and processing — computerized systems

10. Meteorological Station

11. Visitors' Center

Y. ZVIRIN AND S. ZAMKOW SOLAR ENERGY IN ISRAEL

Fig. 13. PV Unit - Commercial Utilization

must i MI.ONDISSIH

Fig. 20. Schematic diagram ofOrrnal Solar Pond Power Plum

ISRAEL — USSR ENERGY CONFERENCE MAY 13-15,1991

Fig. 21. Ormat Solar Pond Power Plant in Beit Haarava. Aerial view.

ibn I

• ' • > ' . • ; • !

i a

Fig. 28. A House in the desert