Patent Publication Number: US-2011061719-A1

Title: Solar electricity generation system

Description:
FIELD OF THE INVENTION 
     The present invention relates to solar electricity generation systems generally. 
     BACKGROUND OF THE INVENTION 
     The following U.S. patents and published patent applications are believed to represent the current state of the art: 
     U.S. Pat. Nos. 7,173,179; 7,166,797; 7,109,461; 7,081,584; 7,077,532; 7,076,965; 6,999,221; 6,974,904; 6,953,038; 6,945,063; 6,897,423; 6,881,893; 6,870,087; 6,831,221; 6,828,499; 6,820,509; 6,818,818; 6,803,514; 6,800,801; 6,799,742; 6,774,299; 6,750,392; 6,730,840; 6,717,045; 6,713,668; 6,704,607; 6,700,055; 6,700,054; 6,696,637; 6,689,949; 6,686,533; 6,661,818; 6,653,552; 6,653,551; 6,620,995; 6,607,936; 6,604,436; 6,597,709; 6,583,349; 6,580,027; 6,559,371; 6,557,804; 6,552,257; 6,548,751; 6,541,694; 6,532,953; 6,530,369; 6,528,716; 6,525,264; 6,515,217; 6,498,290; 6,489,553; 6,481,859; 6,476,312; 6,472,593; 6,469,241; 6,452,089; 6,443,145; 6,441,298; 6,407,328; 6,384,320; 6,384,318; 6,380,479; 6,372,978; 6,367,259; 6,365,823; 6,349,718; 6,333,458; 6,323,415; 6,291,761; 6,284,968; 6,281,485; 6,268,558; 6,265,653; 6,265,242; 6,252,155; 6,239,354; 6,227,673; 6,225,551; 6,207,890; 6,201,181; 6,196,216; 6,188,012; 6,178,707; 6,162,985; 6,140,570; 6,111,190; 6,091,020; 6,080,927; 6,075,200; 6,073,500; 6,067,982; 6,061,181; 6,057,505; 6,043,425; 6,036,323; 6,034,319; 6,020,554; 6,020,553; 6,015,951; 6,015,950; 6,011,215; 6,008,449; 5,994,641; 5,979,834; 5,959,787; 5,936,193; 5,919,314; 5,902,417; 5,877,874; 5,851,309; 5,727,585; 5,716,442; 5,704,701; 5,660,644; 5,658,448; 5,646,397; 5,632,823; 5,614,033; 5,578,140; 5,578,139; 5,577,492; 5,560,700; 5,538,563; 5,512,742; 5,505,789; 5,498,297; 5,496,414; 5,493,824; 5,460,659; 5,445,177; 5,437,736; 5,409,550; 5,404,869; 5,393,970; 5,385,615; 5,383,976; 5,379,596; 5,374,317; 5,353,735; 5,347,402; 5,344,497; 5,322,572; 5,317,145; 5,312,521; 5,272,570; 5,272,356; 5,269,851; 5,268,037; 5,261,970; 5,259,679; 5,255,666; 5,244,509; 5,228,926; 5,227,618; 5,217,539; 5,169,456;5,167,724; 5,154,777; 5,153,780; 5,148,012; 5,125,983; 5,123,968; 5,118,361; 5,107,086; 5,096,505; 5,091,018; 5,089,055; 5,086,828; 5,071,596; 5,022,929; 4,968,355; 4,964,713; 4,963,012; 4,943,325; 4,927,770; 4,919,527; 4,892,593; 4,888,063; 4,883,340; 4,868,379; 4,863,224; 4,836,861; 4,834,805; 4,832,002; 4,800,868; 4,789,408; 4,784,700; 4,783,373; 4,771,764; 4,765,726; 4,746,370; 4,728,878; 4,724,010; 4,719,903; 4,716,258; 4,711,972; 4,710,588; 4,700,690; 4,696,554; 4,692,683; 4,691,075; 4,687,880; 4,683,348; 4,682,865; 4,677,248; 4,672,191; 4,670,622; 4,668,841; 4,658,805; 4,649,900; 4,643,524; 4,638,110; 4,636,579; 4,633,030; 4,628,142; 4,622,432; 4,620,913; 4,612,488; 4,611,914; 4,604,494; 4,594,470; 4,593,152; 4,586,488; 4,567,316; 4,559,926; 4,559,125; 4,557,569; 4,556,788; 4,547,432; 4,529,830; 4,529,829; 4,519,384; 4,516,018; 4,511,755; 4,510,385; 4,500,167; 4,494,302; 4,491,681; 4,482,778; 4,477,052; 4,476,853; 4,469,938; 4,465,734; 4,463,749; 4,456,783; 4,454,371; 4,448,799; 4,448,659; 4,442,348; 4,433,199; 4,432,342; 4,429,178; 4,427,838; 4,424,802; 4,421,943; 4,419,533; 4,418,238; 4,416,262; 4,415,759; 4,414,095; 4,404,465; 4,395,581; 4,392,006; 4,388,481; 4,379,944; 4,379,324; 4,377,154; 4,376,228; 4,367,403; 4,367,366; 4,361,758; 4,361,717; 4,354,484; 4,354,115; 4,352,948; 4,350,837; 4,339,626; 4,337,759; 4,337,758; 4,332,973; 4,328,389; 4,325,788; 4,323,052; 4,321,909; 4,321,417; 4,320,288; 4,320,164; 4,316,448; 4,316,084; 4,314,546; 4,313,023; 4,312,330; 4,311,869; 4,304,955; 4,301,321; 4,300,533; 4,291,191; 4,289,920; 4,284,839; 4,283,588; 4,280,853; 4,276,122; 4,266,530; 4,263,895; 4,262,195; 4,256,088; 4,253,895; 4,249,520; 4,249,516; 4,246,042; 4,245,895; 4,245,153; 4,242,580; 4,238,265; 4,237,332; 4,236,937; 4,235,643; 4,234,354; 4,230,095; 4,228,789; 4,223,214; 4,223,174; 4,213,303; 4,210,463; 4,209,347; 4,209,346; 4,209,231; 4,204,881; 4,202,004; 4,200,472; 4,198,826; 4,195,913; 4,192,289; 4,191,594; 4,191,593; 4,190,766; 4,180,414; 4,179,612; 4,174,978; 4,173,213; 4,172,740; 4,172,739; 4,169,738; 4,168,696; 4,162,928; 4,162,174; 4,158,356; 4,153,476; 4,153,475; 4,153,474; 4,152,174; 4,151,005; 4,148,299; 4,148,298; 4,147,561; 4,146,785; 4,146,784; 4,146,408; 4,146,407; 4,143,234; 4,140,142; 4,134,393; 4,134,392; 4,132,223; 4,131,485; 4,130,107; 4,129,458; 4,128,732; 4,118,249; 4,116,718; 4,115,149; 4,114,592; 4,108,154; 4,107,521; 4,106,952; 4,103,151; 4,099,515; 4,090,359; 4,086,485; 4,082,570; 4,081,289; 4,078,944; 4,075,034; 4,069,812; 4,062,698; 4,061,130; 4,056,405; 4,056,404; 4,052,228; 4,045,246; 4,042,417; 4,031,385; 4,029,519; 4,021,323; 4,021,267; 4,017,332; 4,011,854; 4,010,614; 4,007,729; 4,003,756; 4,002,499; 3,999,283; 3,998,206; 3,996,460;3,994,012; 3,991,740; 3,990,914; 3,988,166; 3,986,490; 3,986,021; 3,977,904; 3,977,773; 3,976,508; 3,971,672; 3,957,031; 3,923,381; 3,900,279; 3,839,182; 3,833,425; 3,793,179; 3,783,231; 3,769,091; 3,748,536; 3,713,727; 3,615,853; 3,509,200; 3,546,606; 3,544,913; 3,532,551; 3,523,721; 3,515,594; 3,490,950; 3,427,200; 3,419,434; 3,400,207; 3,392,304; 3,383,246; 3,376,165; 3,369,939; 3,358,332; 3,350,234; 3,232,795; 3,186,873; 3,152,926; 3,152,260; 3,134,906; 3,071,667; 3,070,699; 3,018,313; 2,904,612; 2,751,816; 514,669; RE30,384 and RE29,833; 
     U.S. Published Patent Applications 2007/0035864; 2007/0023080; 2007/0023079; 2007/0017567; 2006/0283497; 2006/0283495; 2006/0266408; 2006/0243319; 2006/0231133; 2006/0193066; 2006/0191566; 2006/0185726; 2006/0185713; 2006/0174930; 2006/0169315; 2006/0162762; 2006/0151022; 2006/0137734; 2006/0137733; 2006/0130892; 2006/0107992; 2006/0124166; 2006/0090789; 2006/0086838; 2006/0086383; 2006/0086382; 2006/0076048; 2006/0072222; 2006/0054212; 2006/0054211; 2006/0037639; 2006/0021648; 2005/0225885; 2005/0178427; 2005/0166953; 2005/0161074; 2005/0133082; 2005/0121071; 2005/0091979; 2005/0092360; 2005/0081909; 2005/0081908; 2005/0046977; 2005/0039791; 2005/0039788; 2005/0034752; 2005/0034751; 2005/0022858; 2004/0238025; 2004/0231716; 2004/0231715; 2004/0194820; 2004/0187913; 2004/0187908; 2004/0187907; 2004/0187906; 2004/0173257; 2004/0173256; 2004/0163699; 2004/0163697; 2004/0134531; 2004/0123895; 2004/0118449; 2004/0112424; 2004/0112373; 2004/0103938; 2004/0095658; 2004/0085695; 2004/0084077; 2004/0079863; 2004/0045596; 2004/0031517; 2004/0025931; 2004/0021964; 2004/0011395; 2003/0213514; 2003/0201008; 2003/0201007; 2003/0156337; 2003/0140960; 2003/0137754; 2003/0116184; 2003/0111104; 2003/0075213; 2003/0075212; 2003/0070704; 2003/0051750; 2003/0047208; 2003/0034063; 2003/0016457; 2003/0015233; 2003/0000567; 2002/0189662; 2002/0179138; 2002/0139414; 2002/0121298; 2002/0075579; 2002/0062856; 2002/0007845; 2001/0036024; 2001/0011551; 2001/0008144; 2001/0008143; 2001/0007261; 
     SUMMARY OF THE INVENTION 
     The present invention seeks to provide improved solar electricity generation systems. 
     There is thus provided in accordance with a preferred embodiment of the present invention a solar electricity generation system including a solar energy-to-electricity converter having a solar energy receiving surface including at least an electricity-generating solar energy receiving surface and a plurality of reflectors arranged to reflect solar energy directly onto the solar energy receiving surface, each of the plurality of reflectors having a reflecting surface which is configured and located and aligned with respect to the solar energy receiving surface to reflect specular solar radiation with a high degree of uniformity onto the solar energy receiving surface, the configuration, location and alignment of each of the reflectors being such that the geometrical projection of each reflecting surface is substantially coextensive with the electricity-generating solar energy receiving surface. 
     Preferably, at least 90% of the specular solar radiation reflected by the reflectors is reflected onto the electricity-generating solar energy receiving surface. 
     Preferably, the solar energy receiving surface also includes a heat-generating solar energy receiving surface. Additionally, nearly 100% of the specular solar radiation reflected by the reflectors is reflected onto the solar energy receiving surface. 
     Preferably, no intermediate optics are interposed between the reflecting surfaces and the solar energy receiving surface. 
     Preferably, the solar electricity generation system also includes an automatic transverse positioner operative to automatically position the electricity-generating solar energy receiving surface and the heat-generating solar energy receiving surface relative to the plurality of reflectors, thereby to enable precise focusing of solar energy thereon, notwithstanding misalignments of the reflector assembly. Additionally, the automatic transverse positioner receives inputs relating to voltage and current produced by the solar energy-to-electricity converter and is operative to fine tune the location of the plurality of reflectors to optimize the power production of the system based on the inputs. 
     Preferably, the solar electricity generation system also includes a dual-axis sun tracking mechanism for positioning the solar electricity generation system such that the plurality of reflectors optimally face the sun. Additionally, the dual-axis sun tracking mechanism includes a rotational tracker and a positional tracker. 
     Preferably, the dual-axis sun tracking mechanism receives inputs relating to voltage and current produced by the solar energy-to-electricity converter and is operative to fine tune the location of the plurality of reflectors to optimize the power production of the system based on these inputs. 
     Preferably, the electricity-generating solar energy receiving surface includes a plurality of photovoltaic cells. Additionally, the photovoltaic cells are individually encapsulated by a protective layer. Alternatively, the electricity-generating solar energy receiving surface is encapsulated by a protective layer. 
     Preferably, the solar electricity generation system also includes a reflector support surface and the plurality of reflectors are attached to the reflector support surface using clips. Additionally, the reflector support surface includes a plurality of slots for inserting the clips to assure proper placement of the plurality of reflectors. 
     There is also provided in accordance with another preferred embodiment of the present invention a solar electricity and heat generation system including a solar energy-to-electricity converter having an electricity-generating solar energy receiving surface, a heat exchanger coupled to the solar energy-to-electricity converter and having a heat-generating solar energy receiving surface, a plurality of reflectors arranged to reflect solar energy directly onto the electricity-generating solar energy receiving surface and onto the heat-generating solar energy receiving surface and a selectable positioner providing variable positioning between the plurality of reflectors and the electricity-generating solar energy receiving surface and the heat-generating solar energy receiving surface, thereby to enable selection of a proportion of solar energy devoted to electricity generation and solar energy devoted to heat generation. 
     Preferably, no intermediate optics are interposed between the reflecting surfaces and the solar energy receiving surface. 
     Preferably, the solar electricity and heat generation system also includes an automatic transverse positioner operative to automatically position the electricity-generating solar energy receiving surface and the heat-generating solar energy receiving surface relative to the plurality of reflectors, thereby to enable precise focusing of solar energy thereon, notwithstanding misalignments of the reflector assembly. Additionally, the automatic transverse positioner receives inputs relating to voltage and current produced by the solar energy-to-electricity converter and is operative to fine tune the location of the plurality of reflectors to optimize the power production of the system based on the inputs. 
     Preferably, the solar electricity and heat generation system also includes a dual-axis sun tracking mechanism for positioning the solar electricity and heat generation system such that the plurality of reflectors optimally face the sun. Additionally, the dual-axis sun tracking mechanism includes a rotational tracker and a positional tracker. 
     Preferably, the dual-axis sun tracking mechanism receives inputs relating to voltage and current produced by the solar energy-to-electricity converter and is operative to fine tune the location of the plurality of reflectors to optimize the power production of the system based on the inputs. 
     Preferably, the electricity-generating solar energy receiving surface includes a plurality of photovoltaic cells. Additionally, the photovoltaic cells are individually encapsulated by a protective layer. Additionally or alternatively, the electricity-generating solar energy receiving surface is encapsulated by a protective layer. 
     Preferably, the solar electricity and heat generation system also includes a reflector support surface and the plurality of reflectors are attached to the reflector support surface using clips. Additionally, the reflector support surface includes a plurality of slots for inserting the clips to assure proper placement of the plurality of reflectors. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be understood and appreciated more fully from the following detailed description, taken in conjunction with the drawings in which: 
         FIGS. 1A ,  1 B and  1 C are simplified illustrations of solar electricity generation systems constructed and operative in accordance with a preferred embodiment of the present invention in three alternative operative environments; 
         FIGS. 2A &amp; 2B  are simplified exploded view illustrations from two different perspectives of a preferred embodiment of a reflector portion particularly suitable for use in the solar electricity generation systems constructed and operative in accordance with a preferred embodiment of the present invention; 
         FIGS. 3A &amp; 3B  are simplified assembled view illustrations corresponding to  FIGS. 2A &amp; 2B  respectively; 
         FIG. 4  is a simplified pictorial and sectional illustration showing a preferred method of attachment of reflectors to the reflector portion of  FIGS. 2A-3B  in accordance with another preferred embodiment of the present invention; 
         FIG. 5  is a simplified pictorial illustration of a preferred arrangement of mirrors in the solar electricity generation systems of the present invention; 
         FIG. 6  is a simplified pictorial illustration of a solar energy converter assembly constructed and operative in accordance with a preferred embodiment of the present invention; 
         FIG. 7  is a simplified pictorial illustration of beam paths from some of the mirrors of the reflector portion to the receiver portion of the solar energy converter assembly of  FIG. 6 ; 
         FIG. 8  is a simplified exploded view illustration of a solar energy converter assembly constructed and operative in accordance with a preferred embodiment of the present invention; 
         FIG. 9  is a simplified assembled view illustration of the solar energy converter assembly of  FIG. 8 ; 
         FIGS. 10A ,  10 B and  10 C illustrate impingement of solar energy on the solar energy converter assembly of  FIGS. 8 and 9  for three different positions of the solar energy converter assembly relative to the reflector portion of the solar electricity generation system; and 
         FIGS. 11A ,  11 B and  11 C illustrate impingement of solar energy on the solar energy converter assembly of  FIGS. 8 and 9  for three different positions of the solar energy converter assembly relative to the reflector portion of the solar electricity generation system. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Reference is now made to  FIGS. 1A ,  1 B &amp;  1 C, which are simplified illustrations of solar electricity generation systems constructed and operative in accordance with a preferred embodiment of the present invention in two alternative operative environments. Turning to  FIG. 1A , there is seen a solar electricity generation system, generally designated by reference numeral  100 . Solar electricity generation system  100  preferably includes a solar energy converter assembly  102 , a preferred embodiment of which is illustrated in  FIG. 6 , to which specific reference is made. 
     As seen with clarity in  FIG. 6 , solar energy converter assembly  102  includes a solar energy receiving assembly  104  and a reflector assembly  105 , including a plurality of reflectors  106  arranged to reflect solar energy directly onto a solar energy receiving surface  107  of the solar energy receiving assembly  104 . Each of the plurality of reflectors  106  has a reflecting surface which is configured and located and aligned with respect to the solar energy receiving surface  107  to reflect specular solar radiation with a high degree of uniformity onto the solar energy receiving surface  107 . The configuration, location and alignment of each of the reflectors  106  is such that the geometrical projection of each reflecting surface is substantially coextensive with the solar energy receiving surface  107 . 
     It is a particular feature of the present invention that no intermediate optics are interposed between the reflecting surfaces of reflectors  106  and the solar energy receiving surface  107 . This is shown clearly in  FIG. 7 . 
     Turning now additionally to  FIG. 8 , it is an additional feature of a preferred embodiment of the present invention that the solar energy receiving assembly  104  includes a solar energy-to-electricity converter  108  having an electricity-generating solar energy receiving surface  110  and a heat exchanger  112 , which may be active or passive, thermally coupled to the solar energy-to-electricity converter  108  and having a heat-generating solar energy receiving surface  114 . Both solar energy receiving surfaces  110  and  114  are arranged to lie in a collective focal plane of the plurality of reflectors  106 . 
     Returning to  FIG. 6 , it is seen that preferably there is provided a selectable Z-axis positioner  116  providing variable Z-axis positioning along a Z-axis  118  between the plurality of reflectors  106  and the solar energy receiving surface  107 , thereby to enable selection of a proportion of solar energy devoted to electricity generation and solar energy devoted to heat generation. 
       FIGS. 10A-10C  show the impingement of solar energy from reflector assembly  105  for three different relative Z-axis positions:  FIG. 10A  shows impingement on both electricity-generating solar energy receiving surface  110  and nearly all of heat-generating solar energy receiving surface  114  when solar energy receiving surface  107  is at a distance of Z1 from the center of the reflector assembly  105 ;  FIG. 10B  shows impingement on both electricity-generating solar energy receiving surface  110  and part of heat-generating solar energy receiving surface  114  when solar energy receiving surface  107  is at a distance of Z2&lt;Z1 from the center of the reflector assembly  105 ; and  FIG. 10C  shows impingement on only electricity-generating solar energy receiving surface  110  when solar energy receiving surface  107  is at a distance of Z3&lt;Z2 from the center of the reflector assembly  105 . 
     Returning to  FIG. 6 , it is seen that preferably there is also provided an automatic transverse positioner  120  providing positioning along axes  121  in directions transverse to Z-axis  118  between the plurality of reflectors  106  and the electricity-generating solar energy receiving surface  110  and onto the heat-generating solar energy receiving surface  114 , thereby to enable precise focusing of solar energy onto surfaces  110  and  114  notwithstanding temporary or long term misalignments of the reflector assembly  105  and surfaces  110  and  114 , which may occur, for example, due to wind or thermal effects. Preferably, the automatic transverse positioner  120  receives inputs relating to voltage and current produced by the solar energy-to-electricity converter  108  and is operative to fine tune the location of the solar energy receiving surface  107  to optimize the power production of the system based on these inputs. 
       FIGS. 11A-11C  illustrate automatic positioning compensation provided by automatic transverse positioner  120 .  FIG. 11A  shows a typical preferred steady state orientation wherein the plurality of reflectors  106  precisely focus solar energy onto the electricity-generating solar energy receiving surface  110  and onto the heat-generating solar energy receiving surface  114 .  FIG. 11B  shows the effects of a distortion in the positioning of the plurality of reflectors  106 , due to wind or other environmental factors, which results in solar energy not being precisely focused onto the electricity-generating solar energy receiving surface  110  and onto the heat-generating solar energy receiving surface  114 .  FIG. 11C  shows the result of operation of automatic transverse positioner  120  in providing real time readjustment of the position of the electricity-generating solar energy receiving surface  110  and onto the heat-generating solar energy receiving surface  114  along axes  121  to compensate for the distortion, such that the plurality of reflectors  106  precisely focus solar energy onto the electricity-generating solar energy receiving surface  110  and onto the heat-generating solar energy receiving surface  114 . 
     Returning to  FIG. 6 , it is seen that additionally, there is preferably provided a dual-axis sun tracking mechanism, including a rotational tracker  122  and a positional tracker  123 , for positioning the solar energy converter assembly  102  such that the reflector assembly  105  optimally faces the sun as it moves in the sky during the day and during the year. 
     Returning to  FIG. 1A , it is seen that electricity produced by the solar energy-to-electricity converter  108  may be supplied via suitable transmission lines  130  via an inverter  132 , that converts the DC power to AC power, to electrical appliances (not shown) or via a conventional dual directional electric meter (not shown) to an electricity grid (not shown). Alternatively, the electricity produced may be supplied to a storage battery (not shown) without being converted from DC power to AC power. 
     The dual-axis sun tracking mechanism preferably receives, via inverter  132 , periodic inputs relating to voltage and current produced by solar energy-to-electricity converter  108 . The dual-axis sun tracking mechanism is preferably operative to compare the inputs from different time periods to fine tune the location of the reflector assembly  105  in order to optimize the power production of the solar electricity generation system  100  and to overcome slight misalignments or any other non-perfect focusing of the sunlight from reflector assembly  105  onto solar energy receiving surface  107 . 
     Preferably, water is circulated through the heat exchanger  112  by pipes  141  and  142  which are connected, respectively, to a water supply and a heated water storage tank  144 . This heated water can be used as domestic hot water and/or for other applications, such as air conditioning and/or heating. It is appreciated that liquids other than water may be circulated through heat exchanger  112 . 
     Reference is now made to  FIG. 1B , which shows a collection  150  of solar electricity generation systems  152  of the type described above arranged to provide electrical power and heated liquid to multiple dwellings or other facilities. The electrical outputs of solar electricity generation systems  152  may be combined as shown in  FIG. 1B . 
     Electricity produced by multiple solar energy-to-electricity converters  108  of systems  152  may be supplied via suitable transmission lines  153  to a common storage battery  156 , via multiple inverters  157  or a common inverter (not shown) to multiple dwellings  160  for powering electrical appliances (not shown) therein or via a common conventional dual directional electric meter (not shown) to electricity grid (not shown). 
     Preferably, water is circulated through the heat exchanger  112  by pipes  167  connected to a water supply and a heated water storage tank  168 . This heated water can be used as domestic hot water and/or for other applications, such as air conditioning and/or heating. 
     Reference is now made to  FIG. 1C , which shows a collection  170  of solar electricity generation systems  172  of the type described above mounted on a common dual-axis sun tracking mechanism  174  for positioning the plurality of reflectors  106  to optimally face the sun as it moves in the sky during the day and during the year. Solar electricity generation systems  172  are preferably operative to provide electrical power and heated liquid to multiple dwellings or other facilities. The electrical outputs of solar electricity generation systems  172  may be combined as shown in  FIG. 1C . 
     Electricity produced by multiple solar energy-to-electricity converters  108  of systems  172  may be supplied via suitable transmission lines  176  to a common storage battery  178 , via multiple inverters or a common inverter  180  to multiple dwellings  182  for powering electrical appliances (not shown) therein or via a common conventional dual directional electric meter (not shown) to electricity grid (not shown). 
     Preferably, water is circulated through the heat exchanger  112  by pipes  190  connected to a water supply and to a heated water storage tank  192 . This heated water can be used as domestic hot water and/or for other applications, such as air conditioning and/or heating. 
     Reference is now made to  FIGS. 2A &amp; 2B , which are simplified exploded view illustrations from two different perspectives of a preferred embodiment of a reflector assembly  200 , particularly suitable for use in the solar electricity generation systems constructed and operative in accordance with a preferred embodiment of the present invention; to  FIGS. 3A &amp; 3B , which are simplified assembled view illustrations corresponding to  FIGS. 2A &amp; 2B  respectively; to  FIG. 4 , which is a simplified pictorial and sectional illustration showing a preferred method of attachment of reflectors to the reflector portion of  FIGS. 2A-3B , and to  FIG. 5 , which is a simplified pictorial illustration of a preferred arrangement of mirrors in the solar electricity generation systems of the present invention. 
     As seen in  FIGS. 2A-5 , reflector assembly  200  preferably comprises a plurality, preferably four in number, of curved support elements  202 , each of which is configured to have a reflector support surface  204  configured as a portion of a paraboloid, most preferably a paraboloid having a focal length of either 1.6 or 2.0 meters. Support elements  202  are preferably injection molded of polypropylene and include glass fibers. Preferably, the reflector support surface  204  is formed with a multiplicity of differently shaped flat individual reflector support surfaces  206 , which define the precise optical positioning of the individual reflector elements. Preferably the surfaces  208  of the curved support elements  202  facing oppositely to reflector support surface  204 , are formed with transverse structural ribs  210 , preferably arranged in concentric circles about the center of reflector assembly  200  and about each of the outermost corners of elements  202 . 
     A multiplicity of flat reflector elements  212  are mounted onto reflector support surface  204 , each individual flat reflector element  212  being mounted onto a correspondingly shaped flat individual reflector support surface  206  formed on reflector support surface  204 . It is a particular feature of the present invention that the configuration, location and alignment of each individual flat reflector element  212  is selected such that the geometrical projection of the reflecting surface of each individual flat reflector element  212  is substantially coextensive with the electricity-generating solar energy receiving surface  107  ( FIG. 1A ). 
     In a preferred embodiment of the present invention, wherein the reflector support surface  204  has a focal length of 1.6 meters, a total of approximately 1600 individual reflector elements are provided and include approximately 400 different reflector element configurations. Preferably, the configuration and arrangement of individual reflector elements on each of support elements  202  is identical. The configuration and arrangement of individual reflector elements  212  on each of support elements  202  is generally symmetric along an imaginary diagonal extending outwardly from the geometrical center of the reflector assembly  200 . It is appreciated that all of the individual flat reflector elements  212  are preferably parallelograms and some of individual flat reflector elements  212 , particularly those near the geometrical center of the reflector assembly  200 , are squares. 
     As seen particularly in  FIG. 4 , flat reflector elements  212  are mounted onto reflector support surface  204 , along flat individual reflector support surfaces  206 . Flat individual reflector support surfaces  206  are preferably separated by upward protruding wall portions  220 , which provide for the proper alignment of reflector elements  212  along reflector support surfaces  206 . Reflector elements  212  are preferably attached to reflector support surfaces  206  using clips  222 , for ease of removal in the event replacement of a specific reflector element  212  is required. Reflector support surfaces  206  are preferably configured with slots  224  providing for the placement of clips  222  and ensuring proper alignment of reflector elements  212 . 
     It is appreciated that the provision of clips  222  and slots  224  allows for the precise alignment and attachment of reflector elements  212  to support surfaces  206 , typically formed of plastic, without requiring an adhesive material, which typically degrades over time. Clips  222  and slots  224  typically allow the accuracy of reflection of solar energy from reflector elements  212  to electricity-generating solar energy receiving surface  107  and heat-generating solar energy receiving surface  110  to be maintained within a range of several mili-radians. 
     Reference is now made to  FIG. 8 , which is a simplified exploded view illustration of solar energy receiving assembly  104 , constructed and operative in accordance with a preferred embodiment of the present invention and to  FIG. 9 , which is a simplified assembled view illustration of the solar energy receiving assembly  104  of  FIG. 8 . 
     As seen in  FIGS. 8 and 9 , solar energy receiving assembly  104  includes solar energy-to-electricity converter  108  having electricity-generating solar energy receiving surface  110 , including a plurality of photovoltaic cells  250 , preferably formed of a suitable semiconductor material, attached, preferably by soldering, to a heat sink portion  251 , preferably thermally and mechanically coupled to heat-generating solar energy receiving surface  114  which extends peripherally with respect thereto. Heat exchanger  112  preferably includes a water flow portion  252 , including multiple water channels for heat dissipation and transfer, and a water inflow/outflow portion  254  including water flow channels  256  in fluid communication with cold water inlet  141  and hot water outlet  142 . 
     In a preferred embodiment of the present invention, as shown in  FIG. 8 , each of photovoltaic cells  250  is individually encapsulated by a protective layer, preferably formed of glass or other suitable material. Additionally or alternatively, electricity-generating solar energy receiving surface  110  may be encapsulated in its entirety by a protective layer, preferably formed of glass or other suitable material. 
     It will be appreciated by persons skilled in the art that the present invention is not limited to the features specifically described and illustrated above. Rather the scope of the present invention extends to various combinations and subcombinations of such features as well as modifications and variations thereof which would occur to persons skilled in the art upon reading the foregoing description and which are not in the prior art.