SOLAR THERMAL HEATING AND AIR CONDITIONING SYSTEM AND METHOD

Abstract: A solar thermal heating and cooling system which makes use of ambient, solar and ground energy sources in order to limit the amount of electrical energy or natural gas necessary to operate the system's compressor. The system includes an open fin, refrigerant solar collector (18) which has the ability to absorb or radiate thermal energy and a thermal ground unit (26) that uses the relatively constant ground temperature to buffer the system by acting as a heat source or sink of relatively constant temperature.

Description: SOLAR THERMAL HEATING AND AIR CONDITIONING SYSTEM AND METHOD Specification Background of the Invention The ever-increasing costs of electrical energy -and natural gas demands that the search for efficient cooling and heating systems continue. It has long been recognized that the utilization of natural sources of energy such as solar energy is at least part of the key to development of highly efficient cooling and heating systems. The utilization of underground storage has also been considered, particularly as a storage medium for energy collected from solar heat transfer. Field of the Invention The present invention relates to a solar and earth assisted heating and cooling system. The present system utilizes ambient energy sources to the maximum extent possible in order to limit the electrical energy necessary to operate the system. Summary of the Invention Solar is defined as a system wherein a solar component is a primary component and the system cannot function without the solar component; as defined in & Kreider, Principles of Solar Engineering, 1978 at page 9. A solar assisted system is a system wherein a solar collector is used as an add-on component which the system cannot function without; see Principles of Solar Engineering at p. 468. The present invention relates to a new and improved system for heating or cooling a home. It is an object of the present invention to provide a highly efficient solar heating or cooling system which makes use of ambient, solar and underground energy sources. The present system comprises a compressor and expansion devices as well as a solar collector and a thermal or ground unit. By including the solar collector and the ground unit in the heating and air conditioning system, ambient heat energy is used to limit the amount of outside energy necessary to operate the system. The design of the solar collector is such that it can either collect or reject heat for the system as necessary. Unlike the standard solar collector panels which use water or some form of heat transfer liquid to absorb the radiant heat, the solar collectors of this system utilize freon to absorb solar energy in an unglazed collector. The use of freon in an unglazed collector allows the unit to both absorb and radiate thermal energy. The use of freon in the solar collector allows the unit to operate more efficiently in absorbing or radiating thermal energy. The thermal or ground unit acts as a constant temperature heat source or sink. The ground unit consists of a cylindrical reservoir of water or other heat transfer fluid buried in the ground to a depth sufficient to provide a relatively constant temperature. The refrigerant of the system is circulated to or from the solar unit to a heat exchanger connected to the ground unit where the refrigerant is either heated or cooled to a relatively constant temperature. The combination of the utilization of refrigerant, solar collector panel and the thermal ground unit in conjunction with other features OMPI provide a highly efficient system. The coolant circulation system comprises a compressor, a pair of two position reversal valves to allow the system to be operated in both a heating and a cooling cycle, a series of expansion devices and heat exchangers which allow the system to make efficient use of the ambient solar energy collected by the solar collector and provided by the thermal ground unit. Brief Description of the Drawings Fig. 1 is a schematic view of the present system in its air cooling cycle. Fig. 2 is a schematic view.of the present system in its air heating cycle. Fig. 3 is an enlargement of area 3 in Fig. 1. Fig. 4 is a plan view along lines 4-4 of Fig. 3. Fig. 5 is a schematic view of alternate energy transfer means along lines 5-5 of Fig. 1. Description of the Preferred Embodiment Fig. 1 shows the flow of the coolant in the present system in the air cooling or conditioning cycle and Fig. 2 shows the flow of the coolant in the present system in the heating cycle. The following specific elements comprise the heating and air conditioning system: 10 compressor 11 discharge muffler 12 first water cooled heat exchanger 14 first reversal valve 16 second reversal valve 18 solar collector 20 thermal ground unit 22 heat exchanger for thermal ground unit 26 fluid reservoir 32 coolant reservoir 34 expansion device 36 coolant heat exchanger O P 38 capillary expansion device 40 expansion valve 42 heat exchanger coil 44 blower assembly 46 capillary expansion device Each of these components are interconnected as described herein by suitable piping which maintain the coolant at necessary pressure and temperature. The system will be described with reference to both Fig. 1 and Fig. 2, unless specific reference is otherwise made. The coolant is compressed in the compressor 10 which will increase coolant pressure and raise the coolant temperature. The coolant then flows to a discharge muffler 11 which protects the seals in the compressor, and then through a first water cooled heat exchanger 12 that supplies hot water for domestic use. From the first heat exchanger 12 the coolant flows through the first reversal valve 14. The first reversal valve 14 is a two position valve that alters the coolant flow pattern from a heating to a cooling cycle and thus provides means to control the flow of coolant and selecting the heating or cooling mode. In the cooling cycle (Fig. 1) the coolant flows from the first reversal valve 14 to the second reversal valve 16. The second reversal valve 16 is a two position reversal valve that cycles the coolant to the solar collector 18 before the thermal ground unit 20 in both the cooling and heating cycles. The solar collector 18 is an open finned tube design that has the ability to either absorb or radiate thermal energy. In the cooling cycle the solar collector radiates thermal energy to cool the hot compressed coolant. From the solar collector 18 the coolant flows to the thermal ground unit 20. The thermal ground unit comprises a heat exchanger 22, a pump 24 and a fluid reservoir 26. The fluid reservoir 26 is a cylinder buried in the ground 30 at a depth sufficient to provide an energy source at relatively constant temperature and of a size so as to be able to dissipate or supply thermal energy to the system at a rate sufficient to influence the system temperature. The pump 24 cycles the fluid 31 in the reservoir 26 from the heat exchanger 22 to -the bottom of reservoir 26 and from the top of the reservoir 26 to the heat " exchanger 22. As the fluid 31 circulates upward through the reservoir, thermal energy is either absorbed or dissipated to the relatively constant temperature surrounding earth 30. The reservoir fluid may be water or suitably treated water or other fluid. From the thermal ground unit 20 the coolant flows to a tip tank 32 which serves as a coolant reservoir. From the tip tank 32 the coolant flows through a first capillary expansion device 34 where it is cooled by expansion. The coolant then flows through a check valve 35 into a coolant to coolant heat exchanger 36 ' . The coolant absorbs heat in the heat exchanger 36 and then flows through a third capillary expansion device 38 and through an expansion valve 40. The cooling from the expansion of the coolant in the capillary expansion 38 and valve expansion 40 is transferred into the area to be cooled by typical forced air system generally distinguished as 41 which consists of a heat exchanger coil 42 and a blower assembly 44. . From the heat exchanger coil 42 the coolant flows to the coolant heat exchanger 36 where it is cooled prior to flowing to the compressor 10. In the cooling cycle, the heat of the compression is used to heat water for domestic use in heat exchanger 12. The hot compressed coolant is then cooled in the solar collector 18 by radiation of thermal energy and in the thermal ground unit by heat exchanger 22. The compressed coolant is then partially expanded in capillary expansion device 34 in order to provide some cooling to the compressor 10 inlet stream in the coolant to coolant heat exchanger 36. The coolant is then finally expanded in expansion devices 38 and 40 to provide cooling in the coil 42. OMPI In the heating cycle, reversal valves 14 and 16 alter the coolant flow pattern so as to provide heat to the home (Fig. 2). From the first reversal valve 14 hot compressed coolant flows to the coil 42 and blower unit 44 to provide heat for the house. From the coil 42 the coolant passes through check valve 43, bypassing expansion valve 40 and is expanded in the capillary expansion device 38. The coolant then flows to the coolant to coolant heat exchanger 36 to cool the compressor inlet stream. The coolant then is cooled by expansion in capillary expansion devices 46 and 34. From the capillary expansion devices 46 and 34, the coolant flows through the tip tank 32 and to the solar collector 18, where the super-cooled coolant is able to absorb ambient, solar energy. From the solar collector 18 the coolant flows to the thermal ground unit 20 where it absorbs more thermal energy. From the thermal ground unit 20 the coolant, flows to the coolant to coolant heat exchanger 36 and then to the compressor 10. In the heating cycle as well as the cooling cycle, the heat of compression is used to heat hot water for domestic use in heat exchanger 12. Hot compressed coolant is then used to supply heat to the house in the coil and blower assembly 42 and 34. The coolant is then super cooled in a series of expansion devices 34, 38 and 46 so as to be better able to absorb thermal energy from the solar collector 18 and the thermal ground unit 20. The system includes two filter-dryer units 48 and 50 which filter and dry the coolant to insure efficient operation of the system. The coil and blower assembly 41 that transfers- the heated or cooled air to the house in a common forced air temperature system can be replaced by a radiant temperature control means (Fig. 5) which, as is known in the prior art controls the temperature in the house by radiating or absorbing energy. An auxiliary heat exchanger may be added to the system of either Fig. 1 or Fig. 2 to heat a spa or pool. Such a heat exchanger is illustrated in the Fig. 2 system at 18a, such heat exchanger 18a extending into heat transfer connection with a spa or pool (not shown) . The solar unit 18 comprises a serpentine configuration of copper tube 52 with aluminum fins 56, of an approximate heart shape (Fig. 4) mounted thereon. The fins 56 are spaced along the tube by stamped collars 54 (Fig. 3) on fins 56. The shape of the fins 56 is substantially a rectangle with two adjacent corners cut away, leaving edges 56a and 56b converging to end 56c, and a truncated, notch cut between the two remaining corners leaving void 56d, and with a hole 56e in the center to fit over tube 52. Thus the fins 56 are of an approximate heart shape. In a typical residential application of the present system of three ton capacity operating in the cooling mode the following operational parameters have been observed. The compressor 10 increases the coolant temperature by approximately 30°C to an outlet ' temperature of between approximately 72° to 82°C. The high temperature coolant can be used to supply domestic hot water in a coolant to water heat exchanger 12. The solar collector is able to radiate heat thereby cooling the coolant from approximately 10° to 40°C in the cooling cycle of Fig. 1. The ability of the solar unit to radiate heat is dependant on weather conditions, however, because of the high temperature of the coolant, cooling by radiation is possible even on the hotest summer day. When the solar unit 18 efficiency is decreased for example by a hot summer day, the thermal ground unit 20 acts as a constant temperature buffer. . In a typical three ton residential system the thermal ground 20 unit is sized so as to have the ability to absorb or supply up to 36,000 BTUs per hour. In an area having an average ground temperature of 20°C this requires a four inch cylinder one-hundred fifty feet in the ground, or its equivalent. The freon to freon heat exchanger 36 cools the coolant stream to the compressor approximately 2 to 5°C in order to prevent overheating of the compressor and to allow more efficient compressor operation. The specific temperatures are given as examples only since applications in terms of capacity, ambient ground temperature, and solar radiation conditions will affect these described temperature differentials. The coolant utilized here is F eon-22, which is a commercially available coolant. It should be understood that other suitable heat transfer mediums or coolants can be used within the system described herein but it is believed that Freon-22 is the most efficient, inexpensive coolant. Although the invention is described as a heating and cooling system for a residential home, the invention is readily adaptable for use in a variety of applications without departing from the spirit and scope of the invention. For example, the solar collector and thermal unit could be used as a relatively constant temperature source or sink for an thermal process. It should be understood that the foregoing description and the drawings of the invention are not intended to be limiting, but are only exemplary of the inventive features which are defined in the claims. What is claimed is:

Claims: CLAIMS : 1. A solar system for heating or cooling an enclosed space with a circulating stream of a refrigerant which comprises: a. a compressor; b. a first water-cooled heat exchanger; c. a second solar heat exchanger; d. a third refrigerant-cooled heat exchanger; e. a fourth refrigerant to air heat exchanger " ; f. a " first refrigerant expansion means; g. ' - a second refrigerant expansion means; h. a third refrigerant expansion means; i. a fourth refrigerant expansion means; j. a subterranean thermal storage buffer; and k. control means for selectively cooling ^ said enclosed space by cycling said refrigerant from said compressor to said first heat exchanger, then to said second solar heat exchanger, then to said thermal storage buffer, then to said first expansion means, then to said third heat exchanger, then to said third expansion means, then to said fourth expansion means, then to said fourth heat exchanger, then to said third heat exchanger, then to said compressor, and said control means for selectively heating said enclosed space by cycling said refrigerant from said compressor to said first heat exchanger, then to said fourth heat exchanger, then to said fourth and third expansion means, then to said third heat exchanger; then to said second expansion means, then to said first expansion means, then to said second solar heat exchanger, then to said thermal storage buffer, then to said third heat exchanger, then to said compressor. 2. The solar heating and cooling system of claim 1, wherein said fourth heat exchanger comprises a coil and blower assembly to heat or cool said enclosed space. 3. The solar heating and cooling system of claim 1, wherein said fourth heat exchanger comprises means to radiate or absorb thermal energy in said enclosed space. 4. The solar heating and cooling system of claim 1, wherein said thermal storage buffer comprises: a. a relatively constant temperature reservoir of heat transfer liquid; b. a liquid to refrigerant heat exchanger connected to said reservoir to transfer thermal energy between said refrigerant and said reservoir liquid; and c. a pump connected between said reservoir and said heat exchanger to circulate said heat transfer liquid from said reservoir to said heat exchanger. 5. The solar thermal storage buffer of claim 4, wherein said heat transfer liquid is substantially water. 6. The solar heating and cooling system of claim 1, wherein said first, second and third expansion devices are capillary tube expansion devices, and said fourth expansion device is an expansion valve. 7. The solar heating and cooling system of claim 1, wherein said solar heat exchanger comprises fins mounted on tubing exposed to ambient conditions including sunlight. 8. The solar heat exchanger of claim 7, wherein the shape of said fins comprises a rectangle having opposing converging edges at one end and having a truncated notch between the two remaining corners of the other end. 9. The solar heating and cooling system of claim 1, wherein said control means comprises: a plurality of reversal valves which allow switching of said system from a heating to a cooling cycle. 10. The solar heating and cooling system of claim 1, wherein said first heat exchanger is adapted to be connected to a hot water supply for domestic use. 11. The solar heating or cooling system of claim 1, wherein said second solar heat exchanger comprises an exposed fin, roof mounted, finned tube heat exchanger. 12. The solar heating or cooling system of claim 1, wherein said thermal storage buffer comprises: a. a refrigerant to liquid heat exchanger; b. a cylindrical container of liquid buried to a depth sufficient to maintain such liquid at a relatively constant temperature; and c. pump means to circulate said liquid from said heat exchanger to the bottom of said cylindrical container and from the top of said cylindrical container to said heat exchanger. .13. The air conditioning system of claim 1, further including: auxiliary heat transfer means mounted with said second solar heat exchanger and adapted for connection to a spa or pool to heat same. 14. An air conditioning system for heating or cooling air for supply to an area, comprising: a circulation system for a coolant, and control means for circulating said coolant in either a heating or a cooling mode; compressor means positioned in said circulation system for compressing said coolant; predesignated area heat exchange means positioned in such area to be heated or cooled for removing heat from said coolant to heat air in said heating mode and for adding heat to said coolant to cool air for said area in said cooling mode; a subterranean thermal storage buffer means positioned in said circulating system for providing a heat transfer fluid sink of constant temperature to heat said coolant in said heating mode and for cooling said coolant in said cooling mode; a solar heat transfer exchanger positioned in said circulation system to circulate coolant from said solar heat transfer exchanger to said subterranean thermal storage buffer means. 15. The air conditioning system of claim 14 wherein said thermal storage buffer comprises: . a. coolant to heat transfer fluid heat exchanger; b. container means adapted to be positioned below ground to maintain said heat transfer fluid at a relatively constant temperature; c. circulation means between said heat exchanger and said container means which transfers said fluid from the said container to said heat exchanger and from said heat exchanger to the said container. 16. The air conditioning system of claim 14, wherein said control means comprises two position reversal valves to switch said coolant circulation system from a heating mode to a cooling mode. 17. The air conditioning system of claim 14, wherein said circulation system further comprises: a coolant to water heat exchanger to supply domestic hot water; a coolant to coolant heat exchanger to cool the inlet stream to said compressor; and a series of expansion means positioned between said coolant to coolant heat exchanger - and said predesignated area heat exchange means. 18. A method of heating or cooling an enclosed space with a circulating stream of refrigerant which comprises the sequential steps of: cooling said enclosed spaced by compressing said - refrigerant, cooling said refrigerant in a first heat exchanger, cooling said refrigerant in a second solar heat exchanger, cooling said refrigerant in a thermal storage . buffer, partially expanding said refrigerant in a first expansion means, heating said refrigerant in a third heat exchanger, expanding said refrigerant in a third expansion means, expanding said refrigerant in a fourth expansion means, adding heat to said refrigerant in a fourth heat exchanger in order to cool • circulating air for said enclosed space and cooling said refrigerant in said third heat exchanger prior to compressing said refrigerant again, and heating said enclosed space by compressing said - refrigerant, cooling said refrigerant in said fourth heat exchanger, cooling said refrigerant in a fourth heat exchanger to add heat to the .circulating air for said enclosed space; cooling said refrigerant in said third expansion means, heating said refrigerant in said third OMPI heat exchanger, cooling said refrigerant in said second expansion means, cooling said refrigerant in a first expansion means, heating said refrigerant in said solar heat exchanger, heating said refrigerant in said thermal storage buffer, cooling said refrigerant in said third heat exchanger prior to compressing said refrigerant again. 19. The method of heating or cooling an enclosed space of claim 18, wherein this step of heating said coolant in a thermal storage buffer comprises: a. providing a relatively constant temperature reservoir of heat transfer liquid; b. circulating said coolant through a liquid to coolant heat exchanger connected to said reservoir to transfer thermal energy between said refrigerant and said reservoir liquid. 20. The method of heating or cooling an enclosed space of claim 18, wherein said first, second and third expansion means are capillary tube expansion means, and said fourth expansion means is an expansion valve. 21. The method of heating or cooling an enclosed space of claim 18, wherein said solar collector/heat exchanger comprises, a series of fins mounted on tubing exposed to ambient conditions. 22. A system of natural thermal energy sources to raise or lower process stream temperatures which comprises: an open fin finned tube solar collector adapted to be positioned for exposure to ambient air and solar conditions; and a thermal storage buffer adapted to be positioned within the. ground sufficient depth to provide a liquid medium at relatively constant temperature. 23. The system of claim 22, wherein said solar collector comprises a series of approximately heart-shaped fins mounted on tubing exposed to ambient conditions. 24. The system of claim 22, wherein said thermal storage buffer comprises: a. a relatively constant temperature reservoir of heat transfer liquid; b. a liquid to process stream heat exchanger connected to said reservoir to transfer thermal energy between said process stream and said reservoir liquid; and c. . circulation means connected between said reservoir and said heat exchanger to circulate said heat transfer liquid from said reservoir to said heat exchanger. - tTRE _ OMPI WIP

Inventors: CARWAY EUGENE V III, CARWAY, EUGENE, V., III
Applicants: CARWAY EUGENE V III, CARWAY, EUGENE, V., III
Application year: 1984
Main classification: G05D23
IPC codes: F24D11, F24J2, G05D23