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United States Patent m Adcock im 4,446,853 [45] May 8,1984 [54] SOLAR COLLECTOR PANEL [76] Inventor: Thomas P. Adcock, 300 Meadowbrook Dr., Huntsville, Ala. 35803 [21] Appl. No.: 967,044 [22] Filed: Dec. 6,1978 Related U.S. Application Data [62] Division of Ser. No. 804,022, Jun. 6, 1977, Pat No. 4,129,177. [51] Int.Cl.*..................................................F24J3/02 [52] U.S. Cl...................................... 126/450; 126/438; 126/440; 126/443 [58] Field of Search ............ . 126/442, 443, 450, 426, 126/438, 440 [56] References Cited U.S. PATENT DOCUMENTS 1,258,405 3,022,781 3,908,631 4,048,981 4,094,301 4,131,111 4,142,514 3/1918 Harrison .............................. 126/438 2/1962 Andrassy ............................. 126/426 9/1975 Rom..................................... 126/426 9/1977 Hobbs ................................. 126/423X 6/1978 Sorenson et al........................ 126/450X 12/1978 Hopper ................................ 126/450 3/1979 Newton................................ 126/450 4,146,012 3/1979 Elkins et al........................ 126/426 X Primary Examiner--Samuel Scott Assistant Examiner--Margaret A. Focarino Attorney, Agent, or Firm--John H. Raubitschek; Werten F. W. Bellamy; Harold W. Hilton [57] ABSTRACT An integrated, completely automatic solar heating and cooling system for buildings is disclosed. The system includes a first and a second interconnectable cooling/heating subsystem each of which includes a group of solar heat collecting panels, a heat storage reservoir, and a piping network for transferring the heat exchange media, preferrably water, therebetween. A third subsys tem transfers the media from one or both of the reser voirs to a heat exchanger which transfers heat to or from the building's heating and cooling distribution system. Cooling for the building is accomplished by using a fourth subsystem to chill the media in the first subsystem. In the cooling mode, the solar panels of the first sybsystem are covered and used as a heat ex changer, and the second subsystem, isolated from the first heating subsystem, is used to heat the building's hot water system and to provide building heat if required. 2 Claims, 9 Drawing Figures U.S. Patent May 8, 1984 Sheet 1 of 7 4,446,853 U.S. Patent May 8, 1984 Sheet 2 of 7 4,446,853 FIG. 4 U.S. Patent May 8, 1984 Sheet 3 of 7 4,446,853 U.S. Patent May 8, 1984 Sheet 4 of 7 4,446,853 U.S. Patent May 8, 1984 Sheet 5 of 7 4,446,853 FIG. 6 U.S. Patent May 8, 1984 Sheet 6 of 7 4,446,853 226 FIG. 8 208 FIG. 9 ^ T O VALVES 4 3 , 45 a 4 7 (OPTIONAL FOR ELECTRIC VALVES) (E 4,446,853 Sheet 7 of 7 U.S. Patent May 8, 1984 12 Analysis of both water and rock thermal storage SOLAR COLLECTOR PANEL systems coupled with other system component costs, efficiencies, space-limiting factors, etc., indicate that The invention described herein may be manufactured water is the simplest and least expensive means for the and used by or for the Government for governmental 5 collection, storage and transfer of solar energy. The purposes without payment of any royalty thereon. chief disadvantage of a water system is the potential This is a division of application Ser. No. 804,022, filed damage which could occur if the system should have a June 6, 1977, now U.S. Pat. No. 4,129,177, issued Dec. leak. , 12, 1978. A typical, conventional solar heating system is com 10 prised of a solar collector, one or more heat storage FIELD OF THE INVENTION areas which, for water, consist of large tanks and, for The present invention relates to a solar heating and air, usually consist of a rock filled enclosure, a heat cooling system for controlling the temperature within a exchanger which replaces the conventional furnace, building and for providing hot water for the building. and a piping system for distributing a primary coolant More particularly, the invention relates to the novel 15 between the solar collectors, the heat storage area, and arrangement of the components to provide two inde the heat exchanger. pendent, but interconnectable systems, one being used Most of the conventional solar heating systems use a for heating and one for cooling or both for heating. In primary coolant of water or air. The components are a more specific embodiment of the invention, the solar frequently fabricated from metal and this requires spe heating and cooling system includes a novel solar col 20 cial paints and coatings. To prevent freezing and scale lector and storage tank that are particularly well suited deposits in the water systems, the conventional systems for use in the system. require the use of antifreeze and chemical additives. When a conventional solar heating system is combined BACKGROUND OF THE INVENTION with a conventional cooling system, the cost of this Solar heating systems of various types are well known, but as a result of the fossil fuel crisis, such sys tems have recently attracted greater interest. Usable solar energy, like usable wind energy and tide energy, is only obtainable intermittently. However, the success of any energy source can be measured by the regularity and reliability with which it can supply the 25 30 system becomes prohibitively expensive and special skills and tools are required for installation because of component complexity, and the interconnecting piping systems. Furthermore, many of the conventional sys tems cannot be retrofitted into existing structures be cause of the weight and size requirements of the solar collectors and the storage tanks. There are many conventional solar heaters or collec needs of the user. In a building heating and cooling tors disclosed in the prior art. The following United system, this measure of success can be translated into States patents disclose typical conventional units: Mas the capability of supplying or removing thermal energy 35 ters U.S: Pat. No. 3,513,828; Hay U.S. Pat. No. from tiie living space without the use, or with a mini 3,563,305; Hay'U.S. Pat. No. 3,450,192; Andrassy U.S. mum use, of auxiliary and back up systems. Regularity Pat. No. 3,022,781; SkiffU.S. Pat. No. 1,074,219; Gough and reliability in the intermittent solar energy source is, et al U.S. Pat. No. 3,076,450; Schoenfelder U.S. Pat of course, obtained through the use of a thermal energy No. 3,951,128; Danner U.S. Pat. No. 1,473,018; Duncan storage system. The success of any solar energy system, 40 U.S. Pat. No. 3,089,480; Andrassy U.S. Pat. No. therefore, is largely dependent upon the energy storage 3,039,453; Abbot U.S. Pat. No. 1,801,710; Severy U.S. capacity of the system. Pat. No. 937,013; Stout et al U.S. Pat. No. 3,918,430; Selection of an optimum thermal energy storage sys and Crawford U.S. Pat. No. 3,859,980. tem for a building involves considerations of climate, Briefly considering some of the most relevant of the location, insulation, size, material costs, heating and 45 foregoing patents, the Masters patent discloses a solar cooling requirements, etc. The most widely used ther water heater utilizing a plastic bag having an upper mal energy storage systems for domestic heating and compartment filled with air and a plurality of lower cooling are water and rocks. Water has the highest heat compartments through which the water flows. The capacity per weight, volume and dollar value of any Andrassy U.S. Pat. No. 3,022,781 discloses a solar water conventional, commonly available material. Water can 50 heater having a water compartment comprised of a be easily stored and transmitted throughout the system flexible plastic top and bottom with a plurality of fluid from the solar collectors, to the storage areas and to the conduits interconnecting an upper and lower header, heat exchangers. On the other hand, thermal storage in the plastic top being transparent and the plastic bottom rocks is only about 30% to 40% as efficient per unit being black,, and a wooden frame for supporting the volume as thermal storage in water because of the dif 55 water compartment. The Stout et al patent discloses a ference in the specific heat or rocks. Consequently, solar heating panel having a rectangular frame made thermal storage in rocks requires a larger storage area. from rigid, foam plastic material, an upper plastic cover, Rock thermal storage systems require a closed-air circu a water compartment comprised of a reflective bottom lation loop between the solar collectors and the rock and a flexible top joined together so as to form a plural bins and an additional closed-loop system between the 60 ity of spaced apart, parallel water channels. The Skiff rock bins and the living space. Studies comparing sys patent discloses a solar heater having a channel shaped tem cost and thermal storage capacity show that the upper glass lens forming a top cover of the heater for minimum coverage operating costs in a water system focusing the solar rays. The aforementioned Hay pa are achieved when about 10 to 15 pounds (or more) of tents also disclose a solar heating system utilizing a water storage per square foot of collector area is used. 65 plurality of flexible water storage containers located in In a rock storage system, 1 cubic foot of rock is required the ceiling, floors and walls of a structure. per square foot of collector area (about 3 times more In general, conventional solar heating and cooling volume than water). systems, and their associated conventional components, 4,446,853 fail to provide an integrated, relatively inexpensive, collector panel is very light weight, yet is rigid enough easy to assemble, efficient system which can be con to withstand substantial punishment. structed from inexpensive and lightweight components. According to a preferred embodiment of the present SUMMARY OF THE INVENTION invention, the solar heating and cooling system includes a primary low pressure piping system for containing In accordance with the present invention, a total and pumping a primary media. The piping system in solar energy heating and cooling system is provided which overcomes the foregoing and other disadvan cludes a first and second piping network and a first and second pump therefor, and valve means for selectively tages and shortcomings of the prior art The solar en interconnecting the first and second piping networks. ergy heating and cooling system of the invention uti 10 The system further comprises a primary heat exchanger lizes conventional materials and constitutes a simple, in a heat exchange relationship with the building air inexpensive, heighly efficient system that can furnish up distribution system and the primary media transmitted to 80% or more of the total energy requirements for respectively through the first and second piping net heating, cooling, and domestic hot water for an average works. First and second low pressure media storage residential or commercial building. The component 15 reservoirs are connected to the first and second piping parts can be mass produced in a kit form for easy assem networks, respectively. Similarly, first and second solar bly and installation on site by an average handyman in heat collector means are thermally coupled, in heat either new structures or in presently existing structures exchange relationship, to the first and second piping without the need for special skills or tools. networks, respectively. Cooling of the primary media in The present system utilizes a closed loop flow of a 20 the first piping and storage system is achieved through primary heat exchange media, (water being used in a a cooling subsystem that chills a secondary media. The preferred embodiment) thereby preventing the entry of cooling subsystem in a preferred embodiment includes a contaminants into the media. The total system is main tained at low pressure throughout and employs a mini mum number of heat exchangers. A large media storage capacity can be obtained by utilizing unused areas such as under floors and under raised sundecks. Duplication of unnecessary components is eliminated on the one hand, while on the other hand, isolation of components, for example for repair, is possible, without interferring 25 30 rotary vane compressor unit for cooling the secondary coolant media (air), a high pressure piping system con nected to the compressor unit, a heat exchanger con nected to the high pressure piping network and a low pressure piping section connected to the compressor low pressure output. The cooling subsystem also in cludes a means for causing the secondary low pressure coolant media to flow through the low pressure piping system from the cooling unit to, and through, the solar with the operation of remaining portions of the system. collectors used as the heat exchanger. Complete automation of the system is possible and most Other features and advantages of the present inven of the operation of the system can be controlled from a tion will be discussed in, or apparent from, the descrip single control panel. Further, troubleshooting and re 35 tion of the preferred embodiment of the invention found pairing of the system is easy. The system is expandable, hereinbelow. and can be installed in stages with attendant reduction of initial cost. BRIEF DESCRIPTION OF THE DRAWINGS As stated in certain preferred embodiments of the FIG. 1 is a schematic drawing of a heating and cool present invention, water is used as a primary heat ex 40 ing system in accordance with the present invention; change media and the storage tanks and solar collectors FIG. 2 is a perspective view of a water storage bag are principally comprised of flexible, thermoplastic usable as a thermal energy reservoir in the disclosed sheets. Weight reduction, corrosion prevention and heating and cooling system; scale prevention can be obtained by using conventional FIG. 3 is an enlarged schematic flow diagram show plastic plumbing. The expansion problems caused by 43 ing the use of a solar collector as a cooling heat ex hot water are eliminated through the use of expandable changer to produce chilled water; storage tanks and solar collectors. In a preferred em FIG. 4 is a transverse cross-sectional view of a solar bodiment of the invention, a group of solar collectors is collector and reflective insulating cover used in the also used as heat exchangers for coolings the circulating cooling mode in accordance with the present invention; media, thereby eliminating the need for an additional 30 FIG. 5 is a plan view of the solar collector shown in heat exchanger. FIG. 4, with the reflective insulating cover removed; A solar collector panel according to a preferred em FIG. 6 is a top view of the solar collector absorber bodiment of the present invention is constructed en cell shown in FIGS. 4, 5 and 8 and particularly showing tirely out of thermoplastic materials and requires no the heat exchange media channels and manifolds; special heat absorbing paints or coatings. Presently 55 FIG. 7 is a top view of the solar collector inflatable available manufacturing techniques can be utilized for cover shown in FIGS. 4 and 5 and particularly showing mass production of the panels from low cost materials the air channels and manifolds; resulting in a very inexpensive component. Theremo- FIG. 8 is a perspective view, with parts removed, of plastic materials have a long life and the present design a comer of the solar collector; and permits easy repair or replacement of any individual 60 FIG. 9 is an electrical schematic diagram of the con component parts. The collector panel is resistant to trol circuitry for the heating and cooling system. scale buildup, freezing of the media (without the addi tion of antifreeze for water) and damage from sunlight, heat, hail and wind, and other impacting forces. The DESCRIPTION OF THE PREFERRED EMBODIMENT solar panel has a self-draining feature and can be 65 With reference to the figures, wherein like numerals mounted either flat, sloping in a vertical direction, or indicate like elements throughout the several views, a sloping in a horizontal direction. Because of its design heating and cooling system, and its components parts, and the use of thermoplastic materials, the present solar are illustrated in detail. As noted previously, the pres- 4,446,853 56 ently preferred embodiment of the invention uses water the top of hot water tank 62 through an outlet 64 to as the primary media to transfer heat between the vari supply the building's hot water needs. Make-up water ous components of the system. from the building's cold water supply is provided With reference to FIG. 1, the solar heating and cool through an inlet pipe 66 and a normally open, manually ing system in the present invention comprises a first 5 operated isolation valve 68 to the discharge side of group of solar collectors 20 connected to a first piping check valve 60, which prevents the direct addition of network 22 and a second group of solar collectors 24 cold water into hot water tank 62. The building's cold connected to a second piping network 26. First piping water pressure provides sufficient pressure in the build network 22 interconnects the first group of solar collec ing's hot water system. During periods of non-use, the tors 20 with a first thermal energy storage reservoir 28. 10 temperature is maintained in the hot water tank by the Similarly, second piping network 26 interconnects the aforedescribed circulation through second heat ex second group of solar collectors 24 with a second ther changer 34. Electric auxiliary heaters 70 can be installed mal energy storage energy reservoir 32. A cooling sub in the top of hot water tank 62 to add, if necessary, system 40 provides chilling of the water media and additional heat which will maintain the hot water at the includes, in the preferred embodiment, a secondary 15 desired temperature. An auxiliary pump can be located piping system 38 for transporting air as a secondary between the outlet ofhot water tank 62 and check valve coolant between a cooling unit 40 and the first group of 60, but should not be needed because of the thermal solar collectors 20 which can be used as a heat ex driving head and siphon effect in the hot water system. changer. Three interconnecting pipes, 42, 44, and 46, Both first piping network 22 and second piping net- together with corresponding, manually or electrically 20 work 26 are designed to use commercially available, operated valves, 43, 45, 47, permit the interconnection high temperature plastic piping and valves (CPVC) or isolation of first piping network 22 and second piping which are easily installed without the need for special network 26 between the solar collector supply, the solar tools. Numberous manually operated cut-off valves are collector discharge, and the thermal energy storage strategically located throughout the system to provide tanks 28 and 32, respectively. 25 isolation of various parts. Each of the water storage The first piping network 22 together with first group bags making up the storage reservoirs have isolation of solar collectors 20, first reservoir 28, and first heat valves 72 and, similarly, each of the solar panels making exchanger 30, provide the principal means for heating up the solar collectors 20 and 24 have individual inlet and cooling the building air conditioning system in and outlet isolation valves 74. In addition, both first and which the present invention is installed. As used in this 30 second piping networks 22 and 26 have a corresponding application, air conditioning means maintain the build electrically driven, centrifugal hot water pump, 76 and ing space at the desired temperature. Thus, the present 78 respectively, for circulating the water media through invention provides heat for the building's air handling the respective group of solar collectors at low-flow system during cold weather and provides cooling for rates of from 1 to 5 gallons per minute per collector the building's air handling system in hot weather. Heat 35 panel, the flow being adjusted by throttle valves 80 and exchanger 30 is located in the building's air handling 82 respectively and the pressure being measured by system which is disclosed as a forced central-air han pressure gauges 84 and 86 respectively located down dling and distribution system. Heat exchanger 30 com stream of throttle valves 80 and 82. The suction and prises a finned coil of piping 48 located on the suction discharge of a third pump 88 can be selectively con- side of the building's main air conditioning fan 50. Elec 40 trolled to be on either the first reservoir side, or the trical auxiliary heaters 52 can be located in the dis second reservoir side, of interconnecting valves 43 and charge of air conditioning fan 50 to supplement, if nec 47, respectively, by solenoid-operated, suction and dis essary, the heat added to the air conditioning system by charge, three-way valves 94 and 96. Naturally, if inter- the solar heating and cooling system or the present ' connecting valves 43 and 47 are open, pump 88 will take invention. The building air conditioning system also 45 suction from, and dischage to, both storage reservoirs includes air supply ducting 54 and air conditioning 28 and 32. return ducting 56. Make-up water for reservoirs 28 and 32 is obtained The secondary piping network 26 together with sec from a water make-up line 98 from the cold water inlet ond group of solar collectors 24, second reservoir 32, pipe 66 at a location upstream of isolation valve 68. and second heat exchanger 34 are principally used to 50 Make-up line 98 has a manually operated isolation valve provide the building's hot water and, when intercon 100 and a solenoid-operated isolation valve 102 which nected to the first piping network in a special mode permits automatic supply of make-up water to the sec described hereinbelow, provide space heating for the ond piping networks 26 and to the first piping network building when the first piping network is lined up in the 22 when valve 43 is open. Make-up water is first sent cooling mode of operation. Heat exchanger 34 com 55 through the solar collectors before being added to the prises, essentially, copper piping 58 configured in a reservoirs to limit unnecessary temperature variations serpentine pattern and mounted against the side of sec of the stored water media. Should the pressure in the ond reservoir 32. The low side of piping 58 is connected operating solar collectors approach dangerous levels, to the bottom end connection of the hot water tank for example by the water overheating in the solar col- through a check valve 60. The other end of copper 60 lectors, a low pressure relief valve 106 will automati piping 58 is connected to the normal cold water inlet of cally be opened, thereby preventing damage to the solar a standard hot water tank 62. Water will flow as a result collectors or to the reservoirs. Relief valve 106 is con of a thermal driving head from the bottom of hot water nected to the second solar collector outlet side of inter tank 62 where the water is the coldest and densest, to connecting valve 45 because, as explained below, sec- the low side of copper piping 58. Water will then flow 65 ond solar collectors 24 are always lined up to produce upwardly through the copper piping, pick up heat from heat. Pressure relief of all solar collectors and reservoirs reservoir 32 and becomes less dense, and, finally, flow is accomplished during winter months since valve 45 is into the top of hot water tank 62. Hot water is drawn off open and all collectors are lined up to produce heat. A 4,446,853 8 pressure gauge 108 can be used to monitor the pressure comprises a cooling unit for chilling a secondary media just upstream of relief valve 106. that is to be used to cool the primary media from reser The thermal energy storage reservoirs 28 and 32 are voir 28 in a further heat exchanger. In the preferred each comprised of a plurality of individual water stor embodiment, the first group of solar collectors 20 is age bags 120 as shown in FIG. 2. Each storage bag 120 used as the secondary heat exchanger, during summer is comprised of flexible, high temperature thermoplastic months and when so used, the sun is blocked out with a sheets 122, each sheet preferably having a minimum reflective insulated cover 152, installed over each of the thickness of 15 mils. The seams of sheets 122 can be either heat bonded or welded together using conven individual collector panels. In a presently preferred embodiment of the invention, cooling subsystems 40 tional beat welding techniques or can be bonded to 10 chills and circulates chilled air between he inflatable top gether with a solvent In any event, storage bag 120 cover 204 and the individual solar absorbers 206 of solar when filled with water must be able to withstand static collector 20, while water is pumped through the solar water pressure and residual steam pressure at an operat absorber 206 by pump 76. ing temperature of 180* F. during normal use and up to In the presently preferred embodiment of the inven 212* F. for intermittent short periods. Since storage 15 tion, cooling unit 40 is comprised of a rotary vaned air bags 120 are completely flexible without a rigid frame, compressor 154, a cooling fan 156, and a conventional they can be installed in existing installations without the heat exchanger 158. Air compressor 154 can be the removal of structural walls and floors. Storage bags 120 newly developed "ROVAC" Unit reported in the Au are normally sized so that when filled and expanded gust 1973 Popular Science Magazine at page 60 and in the with water the bag will conveniently fit within the 20 December 1970 Popular Science Magazine. The word building framing spaces. The flexibility of storage bags "ROVAC" is an acronym which stands for Rotary 120 also eliminates problems encountered from the ex Vane Air Cycle. The ROVAC compressor is basically a pansion of the water as it is heated. A flexible plastic vaned hub rotating within an eliptical housing. Air, pipe 124 is permanently attached at one end of storage taken in at ambient temperature and pressure, is com bag 120 by heat bonding or solvent bonding and is con- 25 pressed to about 30 psia, thereby being heated to ap nected to an internal extension 126 which extends to the proximately 250 F., and is discharged to a heat ex opposite end of storage bag 120. Pipe 124 preferably has changer which can be a basic "Modine" finned tube a three quarter inch minimum inner diameter and ex heat exchanger with a blower fan. The compressed air tends at least one foot out of storage bag 120. Extension is cooled to near ambient temperature in the heat ex tube 126 is preferably a one half inch diameter CPVC 30 changer and is returned to the opposite side of the com pipe that has been inserted through inlet pipe 124 during pressor where it is expanded, thereby returning a large the installation of storage bag 120. A flexible plastic portion of the energy of compression to the compressor pipe 128, which is similar to pipe 124, is located at the and resulting in cooling the air to 4 F. to 10 F. The same end as pipe 124 but terminates close to the upper result is a combination of air and ice crystals exiting end of storage bag 120, thereby preventing short cir 35 from the output port of the compressor. cuiting of the water flow path between the inlet and The chilled air exits from air compressor 154 with outlet pipes. Both inlet and outlet pipes 124 and 138 are sufficient pressure to flow through secondary piping preferably located at least two inches from either the systems 38 to the first group of collectors 20. The top or bottom of storage bag 120 and six inches from the chilled air flows across the clear top 250 of the absorber respective edges thereof. Located at approximately the 40 as the primary heat exchange media flows through center of the top of storage bag 120 and extending out channels 258 of the absorber thereby chilling the water. wardly approximately one foot therefrom is a flexible The air then exits through slotted vent holes in the plastic pipe 130. Pipe 130 provides for the return of collector frame at the opposite end of the individual water from the collector panels and pressure venting. solar panels. Connections to the system plumbing from pipe 124, pipe 45 A solar panel 20 in accordance with the present in 128 and pipe 130 can be made using simple plastic or vention is depicted in FIGS. 4 through 8, and is shown metal hose clamps. in FIG. 4 with cover 152 in place. Cover 152 comprises By combining a number of water storage bags 120, a group of flexible, rigid plastic lock-down brackets 160 the necessary volume of water storage can be obtained, that can extend the entire width of solar panel 20, a the volume of water storage being calculated in a con 50 sheet of thick aluminum film 162, and a block of rigid ventional manner as mentioned above. In one particular foam insulation 164 that is preferably at least one inch system, first thermal energy storage reservoir 28 was thick. comprised of six water storage bags 120 and the second Solar panel 20 comprises a frame 230 preferably thermal energy storage reservoir 32 was comprised of -molded from a rigid, thermo-plastic foam, an inflatable, two water storage bags 120. In a typical situation, indi 55 channeled top 204 mounted to the frame 230, a multi- vidual water storage bags 120 can be designed to fit channeled absorber cell 206 mounted to frame 230 specific space requirements or fabricated in standard spaced below top 204, upper and lower rigid insulation production sizes. Normally, the water storage bags 120 blocks 208 and 210 mounted inside frame 230 below comprising a particular reservoir will be connected absorber cell 206, and a plastic film bottom cover 212 through three manifolds, a solar collector supply mani 60 mounted to the bottom of frame 230 for preventing fold, a solar collector return manifold, and a heat ex entry of moisture into the interior of the assembled changer feed supply and return manifold. Naturally, collector. A thick sheet of aluminum foil 214 covers the should the actual location of any individual water stor upper surface of upper insulation block 208 to reflect age bag 120 be at a distance from the manifolds, further heat back into the water absorber. isolation valves at the location of the storage bag 120 65 With particular reference to FIGS. 4, 5 and 8, frame can be used. 230 is preferably injection or extrusion molded into With reference to FIG. 3, secondary cooling subsys standard lengths which can then be cut with 45 comers tem 40 is shown in greater detail. Cooling subsystem 40 into the desired length and fastened together with cor- 9 4,446,853 10 ner brackets (not shown) to form a hollow rectangular permits a build up of great temperatures inside solar frame. Each frame 230 has a plurality of five longitudi panel 20. nal grooves 218, 220,222, 224, and 226 extending.along In the cooling mode the inflatable top cover 204 can the length thereof. Each groove is substantially similar be replaced by a rigid plastic, reflective, insulating and has a circular cross section, as best seen in FIG. 5. 5 cover to block out the sun when the solar collector 20 Grooves 218, 220, and 222 are located in the upper is used as a heat exchanger during the summer months. portion on the inside surface of frame 230. Grooves 222, Absorber cell 206, similar to top 204, is comprised of 224, and 226 are respectively used to mount the edges of a top sheet 250 and a bottom sheet 252 that are heat absorber cell 206, bottom cover 212, and top 204 with welded together along the peripheries thereofand along conventional serrated or splined tubular plastic lock-in 10 a plurality of parallel means 254, thereby resulting in a strips 228. Typical diameters of lock-in strips 228 are fluid tight border 256 and a plurality of parrallel fluid from i inch to 3/16 inch. Grooves 218 and 220 can be channels 258. Seams 254 terminate at a point spaced used to mount rigid plastic or glass covers in lieu of from border 256 at each end of absorber cell 206, cover 206. thereby resulting in an inlet manifold 260 and an outlet The periphery of collector panel frame 230 is shaped 15 manifold 262. Top sheet 250 is clear thermoplastic mate to provide a large outer, centrally located notch or rial preferably comprised of a polyether base polyure cutout portion and a large inner, lower notch or cutout thane elastomer and has a preferred thickness of at least protion, both notches extending the entire length and six mils. Bottom sheet 252 is similar to top sheet 250, width of panel 230. Notches 267 provide an upper sur except that it is colored black. Borders 256 at each end face to permit attachment of panel cover lock down 20 of absorber cell 206 are tapered toward opposite sides strips 160 (as shown in FIG. 4) and a lower surface to thereby providing a tapered manifold for automatic permit engagement of a roof mounting, hold-down drainage of water cell 206 when the water pumps are bracket 234 (also shown in FIG. 4). Inner notch 268 is not operating. A flexible, thermoplastic hollow inlet used to hold insulation blocks 208 and 210 in place. tube 264 and a flexible thermoplastic hollow outlet tube A particular preferred embodiment of frame 230 uti 25 266 are mounted in a water tight seal between top and lizes a structural, theremo-plastic polyester foam such bottom sheets 250 and 252 at the tapered ends of border as "CELANEX" 3300 or 3310 encased by a solid skin 256 in fluid communication with inlet and outlet mani having a typical thickness of 0.03 to 0.08 inches. A folds 260 and 262, respectively. typical frame panel has a height of 3$ inches and overall When the suns rays strike absorber cell 206, the clear width of } inch. Such a panel has a high tensile strength, 30 top sheet 250 permits the rays, which are infrared, to a weather resistance of from 10 to 20 years, an ultravio penetrate through the media contained therein and let resistance of from 10 to 20 years, a useful tempera strike the black surface of bottom sheet 252 where maxi ture range for continuous use of from --40' F. to +285' mum heat absorption takes place. Reflected radiation F. (with short-term temperature excursions from --65 from bottom sheet 252, in the form of long wave radia F. up to 420' F.) a low moisture absorption, and excel 35 tion, passes back through the media and is trapped by lent dimensional stability, abrasion resistance, and sol top sheet 250 which maximizes collection of the sun's vent resistance. Although the frame can have any par heat energy. In addition, the cylindrical top and bottom ticular color, for outdoor continuous exposure it is ad part of channels 258 has a focusing effect on the infrared vantageous is frame 230 is colored black. and reflected radiation which further increases the The top cover 204 of solar panel 20 is shown in FIGS. 40 overall efficiency of absorber cell 206. 4, 5, and 7 and is comprised of upper and lower clear As mentioned above, located beneath absorber cell plastic sheets indicated at 236 and 238 of FIG. 5, which 206 are insulation blocks 208 and 210 covered by alumi are heat-welded together so as to form a plurality of num foil 214. Insulation blocks 208 and 210 are prefera spaced apart, parallel, hollow channels 240 in the inte bly comprised of one inch thick rigid foam insulation rior portion thereof and a wide circumferential border 45 material and one inch thick firm fiberglass material 242 for mounting to frame 230 to provide an airtight which meet local fire rating regulations. Aluminum foil seal. The seams between channels 240 preferably do not 214 can be either rested on top of upper insulation block extend completely to border 242 so that upper and 208 or bonded thereto, and further increases the effi lower manifolds 244 and 246 are provided. A hollow ciency of solar panel 20 by reflecting rear side heat loses plastic tube 248, FIG. 7, is heat welded between upper 50 back to absorber cell 206. The rigid insulation blocks and lower sheets 236 and 238 in fluid communication not only provide adequate insulation for solar panel 20, with lower manifold 246 and provides a means for in but further increase the rigidity of frame 230. flating top 204. The air channels 240 should preferably Because of the unique design, solar panel 20 can be have a minimum width of one inch and be separated by manufactured and shipped in individual components an eighth of an inch seam. As mentioned above, top 204 55 and easily assembled by the installer. After the individ is mounted to frame 230 in groove 226 along the edges ual frame panels 230 are cut to the desired length, they thereof at border 242. are bonded together with conventional solvent glue to After top 204 is installed on assembled collector form the frame assembly. Corner braces can then be frame 230 and is substantially inflated, channels 240 installed if desired. After upper and lower insulation expand and crate a tension between top 204 and frame 60 blocks 208 and 210 are cut to size and installed inside the 230, thereby providing rigidity and strength for solar frame assembly, absorber cell 206 is installed by wrap panel 20. When inflated, channels 240 have the affect of ping border 256 around a lock-in strip 228 and inserting a double cover and the rounded surfaces not only re the combination into channel 222. Top 204 is installed duce the incident angle between solar panel 20 and the by similarly wrapping border 242 around a lock in strip sun from sunrise to sunset, but also focus the suns rays 65 228 and inserting the combination into channel 226. as a result of the lens shape, which thus further increases Once collector panel 20 is set up, its operation is the overall efficiency of panel 20. In addition, the air completely automatic. The sun heats up the media flow inside channels 240 acts as an insulation barrier and ing through absorber cell 206 as follower. Short wave- 11 4,446,853 12 length radiation (0.3 to 3 micron wavelength) passes Improper conditions can also be indicated on a con through both clear plastic layers of top 204, which tend trol panel such as a low water media level which will to focus the light onto absorber cell 206. Short-wave energize solenoid operated isolation valve 102 to supply radiation then passes through the clear plastic layer of makeup water until the high water level limit switch is top sheet 250 of absorber cell 206 and is partially ab- 5 opened. Feed pump 88 provides either hot or chilled sorbed (as heat) by the media during the initial travel of water to the first heat exchanger 30 based on demand by the radiation through the media to the black bottom the building thermostat when switch S-5 is in the sheet 252 of absorber cell 206. The black surface col AUTO position. Fuses can be provided to protect the lects the heat of the short waves and retransmits heat control circuits. energy as long waves back through the media where 10 Switch S-6 selects the mode of operation and is pref more of the heat is absorbed. These long waves strike erably a three-pole, double-throw switch. During the the clear top sheet 250 and are reflected back through SUMMER mode of opeation, pumps 76 and 78 are the media to the black bottom sheet 252. This reflecting electrically isolated from one another. This switch also action continues (commonly referred to as the green applies power to normally open (NO) set of contacts on house effect, which in this case, is created by multiple 15 heat relay. The other side of the contacts of relay Ry-7 passes of the short and long waves within the transfer is connected to the solenoids of suction and discharge media) until the maximum heat is absorbed by the me three way valves 94 and 96. Thus, hot water can be dia. As can be seen from the above, the maximum drawn from second reservoir 32 during cold nights amount of heat is thereby transferred to the media dur when heat is required, while switch S-6 is in the SUM ing its travel from the inlet tube 264 to the outlet tube 266, which increases overall collector efficiency. The heat energy absorbed by the black bottom sheet 252 from the short waves is also transferred to the heat exchange media by conduction. Radiant heat emitted from the backside of bottom sheet 252 is deterred from entering the insulation material by aluminum foil 214. 20 MER position. The AUTO-READY relay Ry-6 is controlled by an external differential temperature sensor control unit which monitors the temperature difference between the solar collectors and the hot water stored in the reser voirs. When the temperature of the water in the collec tors rises above the temperature of the water stored in the reservoirs by a predetermined amount (normally Since aluminum has a low absorption and a high reflec from 10 to 15 F.), relay Ry-6 is energized and applies tance at all wavelengths, most of this heat energy is power through the selected (by switch S-7) high tem reflected back to the absorber. Thus, aluminum foil 214 perature limit switch to switch S-6. This permits pump helps to increase overall collector efficiency. 78 to be energized, provided switch S-l is in the AUTO Insulation blocks 208 and 210 further reduce heat position. Pump 76 will also be energized if switch S-2 is losses from the back of the solar panel. Edge losses are in the AUTO position and switch S-6 is in the WIN minimized by the foam core construction of frame 230 TER mode. When the collector temperature drops to and the plastic-to-plastic construction design techniques 35 within a predetermined differential temperature (ap used throughout the solar panel 20. proximately 5' F.) of the temperature of the water in the Outgassing exhibited by insulation (due to elevated thermal energy storage reservoirs, relay Ry-6 is deener temperatures) is virtually eliminated from entering the gized and the pumps are deenergized. area between top 204 and the absorber cell 206 by the Although the present invention has been described aforedescribed mounting methods used between frame 40 hereinabove in a presently preferred embodiment, mod 230 and absorber ceil 206. ifications within the scope and spirit of the invention FIG. 9 is illustrated in the electrical control circuits will be evident to one of ordinary skill in the art. Thus, for the system described hereinabove. A photo cell for example, although absorber cell 206 has been de switch PC-1 is mounted in group 1 collectors 20 to picted as having two headers and a plurality of parallel ensure that pump 76 will not be operated in the cooling 45 channels, it is apparent that a single serpentine channel mode during daylight hours if the cover 152 is not in can be used, if a smaller volume of hotter media is de stalled. When switch S-l is placed AUTO position, sired. It is also apparent that water or air can be used as operation of second pump 78 is possible only when the primary media or that water and a conventional auto-ready relay RY-6 is energized and the stored water chill water system can be used as the secondary coolant temperature is below the selected setting by switch S-7. 50 and cooling unit. The frame design allows use of rigid Alternatively, manual operation of second pump 78 can covers (glass or plastic) 269 to be used in lieu of top be accomplished by placing switch S-l in the manual cover 204 or absorbers such as flat plate metal or roll position to operate the pump or in the OFF position to bond aluminum can be used in lieu of absorber 206. manually turn off the pump. Control of first pump 76 is I claim: identical to that of second pump 78 when SUMMER/- 55 1. A solar collector panel comprising: WINTER SELECTOR switch S-6 is in the WINTER a. a frame; position. When switch S-6 is in the SUMMER position, b. a top transparent to solar radiation sealingly the operation of pump 76 when selector switch S-2 is in mounted to said frame, said top being lenticulated the AUTO position is determined by the satisfaction of and inflatable and comprised of molded thermo the following conditions. A thermostat T-l determines 60 plastic film; that there is a requirement for water chilling, photo cell c. an absorber cell mounted to said frame and spaced PC-1 indicates that it is either night or that cover 152 is below said top; in place, and the building theremostat calls for cooling d. a reflective member mounted in said frame and of the auto-ready relay RY-6 is de-energized. When spaced below said absorber cell; media chilling is required, pump 76 is energized and 65 e. an insulation member mounted in said frame and compressor 154 is energized if switch S-4 is in the spaced below said reflective member; AUTO position. The cooling operation will continue f. a bottom cover sealingly mounted to cover the until thermostat T-l is satisfied. bottom of said frame; and 4,446,853 13 g. mounting means for mounting said top, said ab 14 ity of vertically disposed, mutually spaced horizontal, sorber cell and said bottom cover at the respective continuous grooves adapted to receive splined strips peripheral edges thereof comprising corresponding lock-in means for engaging the respective periph and a first elongated, horizontal, continuous recess hav ing a shoulder portion adjacent the vertically disposed, eral edges and corresponding grooves in said frame 5 mutually spaced grooves, and, a second surface having for securely retaining said corresponding lock-in means. a second horizontal, continuous groove adapted to re ceive a splined strip and a second elongated, horizontal, 2. A rigid frame of thermal insulating material for continuous recess having first and second shoulder por surrounding and securing solar collector panel elements tions adapted to receive locking means in engagement in mutually spaced, parallel relation, said frame com 10 therewith, whereby said grooves in said frame, said prising, fluid inlet and outlet means connected to said elongated recesses and said locking means cooperate to frame and communicating with fluid-containing solar collector panel elements, a first surface having a plural- secure said frame and said collector panel elements. ***** 15 20 25 30 35 40 45 50 55 60 65