Abstract:
A new and improved heat powered heat pump system and method of making same is provided. More particularly, the present invention relates to a heat powered heat pump system which uses standard commonly available refrigerant fluids, supplements pressurizing the refrigerant fluid by use of an external available heat source, enables selective switching between heating or cooling modes, and utilizes a thermal four-chambered compressor having a double piston head that is partially powered by an external heat source. Since the heat powered heat pump system may be made in various sizes and configurations, it may be utilized to cool and heat the interior of vehicles using waste engine heat and an initializing battery powered heating element to provide for immediate heating and cooling. The heat powered heat pump system attains better efficiency than current systems employed for the same purpose because of its capability to use a heat source such as a solar collector, waste heat from a generator, vehicle engine or power plant, various types of fuel cells, and a gas-fired or electrical heating element to power the four-chambered thermal compressor.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a new and improved heat powered heat pump system and method of using it. More particularly, the present invention relates to a heat powered heat pump system which would utilize relatively low temperature heat energy, waste energy or direct electrical energy to implement the heat pump process for the purpose of selectively cooling or heating an interior space more efficiently. 
     2. Description of the Related Art 
     High energy costs and environmental concerns over the generation of pollution are requiring more energy efficient mechanisms for heating and cooling interior spaces utilizing renewable energy resources and, in some cases, waste heat from any number of sources. Such a mechanism must be easily adapted to a number of different energy sources without the need for expensive or customized adaptors. 
     The interior spaces which require heating and cooling are not limited to living and working environments, but also extend to space involved in transportation for humans as well as perishable commodities. The means of providing heating and cooling must be economical, efficient to manufacture and inexpensive to maintain in order to be readily accessible for any number of applications in everyday life. 
     The standard Carnot reversible heat pump cycle, as simplified by use of a throttling valve for expansion of the refrigerant fluid and a mechanical compressor for the compression of the vapor, has been in use for a wide variety of applications, and is well known. Essentially, in the cooling mode, such systems pass saturated liquid refrigerant through an expansion valve to a lower pressure, the temperature of the refrigerant falls, and the cooled refrigerant is then directed to an evaporator where heat is absorbed from the atmosphere, thereby cooling said atmosphere (or some other medium where cooling is desired). 
     This cycle is frequently reversible such that the same system is used as a heat pump. To provide heating of a space, energy is added to the system by a compressor and ambient air. Most of the prior art devices which accomplish this task are known to consume large amounts of energy (usually electrical energy), and are inefficient in both the cooling and heating modes. 
     However, the benefits of heat powered heat pump devices designed for use in the home or office are well known. Examples of different types and kinds of arrangements and techniques for utilizing heat powered heat pumps are disclosed in U.S. Pat. Nos. 4,918,837, 4,617,801, 4,537,037, RE 31,281 and 4,250,715. 
     In general, the standard vapor-compression cycle is the commonly used system to cool interior space. This cycle can be reversed to supply heat to interior space, and such a system that can cool and heat interior space is referred to as a “heat pump”. 
     This vapor-compression cycle utilizes a compressor unit to compress refrigerant vapor to perform the cooling/heating process. The compressor component is conventionally a rotary device that requires external rotary shaft power to perform its compression function. This rotary shaft power is commonly supplied by an electric motor or, in the case of vehicles, an internal combustion engine. 
     Heat pumps for heating and cooling interior spaces in vehicles are generally known in the prior art. Such a device is described in U.S. Pat. No. 4,918,937. The claimed device comprises a hybrid system which uses both a mechanical and a thermal compressor. The mechanical compressor initiates cooling of the passenger compartment and the engine driven compressor is started after the compartment is precooled. 
     This novel invention, while allowing for lower fuel consumption over conventional cooling mechanisms for automobiles, requires the use of both a mechanical and a thermal compressor. The mechanical compressor would require energy in order to function just as conventional cooling systems for automobiles with associated energy losses. In addition, the mechanism would be complex, bulky, expensive to manufacture and potentially very costly to maintain. 
     Furthermore, this inventive device provides for cooling of passenger compartments, so another entire unit would have to be provided for heating the passenger compartment, resulting in additional weight, bulk, equipment and further expense. Additionally, this invention is designed specifically for automobiles with no mention or suggestion of conversion to other applications or usages. 
     Therefore, it would be highly desirable to have a new and improved heat powered heat pump system and method for making same which would allow the expedited cooling or warming of an interior space, efficiently utilize available waste heat, a renewable energy source, or direct electrical energy at much greater efficiency to facilitate the heat pump process, have a multitude of potential applications, be economical to manufacture and maintain and be readily adapted to a variety of sizes and uses. 
     The device described in U.S. Pat. No. 4,617,801 addresses the problem of providing for both heating and cooling capacities in a single unit. This unique invention uses thermally powered dual reciprocating compressors and any number of closed heat transfer loops. The size and complexity of this invention would make it impractical for use in small confined areas such as the interior space of an automobile. Additionally, there is no mechanism to provide for the near instantaneous initiation of heating or cooling that has come to be expected in heating or cooling such low volume spaces. 
     Therefore, it would be highly desirable to have a new and improved device and method for making same for a heat powered heat pump which would allow immediate cooling or warming of an interior space, utilize waste heat, a renewable energy source or direct electrical energy at much greater efficiency to perform the heat pump process, have a multitude of potential applications, be economical to manufacture and maintain and be readily adapted to a variety of usages. 
     U.S. Pat. No. 4,537,037 also describes a device that addresses the problem of providing for both heating and cooling options in a single unit. However, the device is complex in structure, employing two or more compressors and three or more closed loops and three or more different refrigerants, as well as three or more evaporators. The device uses sequential displacement and necessarily utilizes a series of interconnected subsystems in order to accomplish the heating or cooling of a space within a structure. 
     Because of the complexity and consequential enormous size of the resulting device, the primary object of this invention is necessarily aimed at the cooling or heating of relatively large structures, for example buildings. The unit would not be practical for the use in a small volume space such as in a vehicle. 
     In addition, the invention does not provide for the immediate heating or cooling of a confined space that would be expected in automobiles. 
     Therefore, it would be highly desirable to have a new and improved device and method for making same for a heat powered heat pump which would allow immediate cooling or warming of an interior space, utilize waste heat, a renewable energy source or direct electrical energy at much greater efficiency to perform the heat pump process, have a multitude of potential applications, be economical to manufacture and maintain and be readily adapted to a variety of usages. 
     U.S. Pat. No. RE 31,281 describes a device that has a two heat exchangers, one of which communicates with a source of air outside a structure and one of which communicates with a source of air inside a structure. While the invention provides for both a heating and a cooling system, it is primarily designed to heat and cool structures rather than small confined spaces. 
     Additionally, the invention utilizes a natural gas fired vapor generator which is then used to power a steam turbine or turbo generator unit. This complex heat pump does not provide for utilization of renewable energy sources, direct electrical energy, or waste heat to facilitate or perform the heat pump process. 
     Therefore, it would be highly desirable to have a new and improved device and method for making same for a heat powered heat pump which would allow immediate cooling or warming of an interior space, utilize waste heat, a renewable energy source or direct electrical energy at much greater efficiency to perform the heat pump process, have a multitude of potential applications, be economical to manufacture and maintain and be readily adapted to a variety of usages. 
     Finally, U.S. Pat. No. 4,250,715 provides for a heat transfer system utilizing standard vapor/compression refrigeration cycle. This novel invention also provides for both heating and cooling of an interior space. However, the heat pump utilizes conventional power sources such as electric motors to provide energy to the compressors which then perform the vapor-compression process. If the heat from another source such as solar panels, waste heat or direct electrical energy were to be utilized to provide energy to a thermal compressor, there would be less demand on energy from non-renewable sources providing for a more efficient and economical method of heating and cooling an interior space. 
     Therefore, it would be highly desirable to have a new and improved device and method for making same for a heat powered heat pump which would allow immediate cooling or warming of an interior space, utilize waste heat, a renewable energy source or direct electrical energy at much greater efficiency to perform the heat pump process by utilizing a thermal compressor, be economical to manufacture and maintain and be readily adapted to a variety of usages. 
     SUMMARY OF THE INVENTION 
     Therefore, the principal object of the present invention is to provide a new and improved device and method for making same, for a heat powered heat pump that can utilize waste heat or heat generated by alternative means, to power a thermal compressor and to more efficiently heat or cool a space. The subject heat powered heat pump system can cool and can heat an interior space by employing a switching means to reversing the cycle. Moreover, the subject system may be readily adapted for either heating or cooling only by selectively eliminating specified components from said system. 
     It is a further object of the present invention to provide such a new and improved device and method for making same, for a heat powered heat pump with a four-chambered, double piston thermal powered compressor. The thermal compressor would eliminate the necessity of an additional external energy source, commonly direct electrical energy, for powering a purely mechanical compressor. This feature facilitates the use of waste heat, solar collectors or direct electrical energy at much greater efficiency to power the compressors, and provides for economical manufacture and maintenance of the entire unit as well. 
     It is a further object of the present invention to provide such a new and improved device and method for making same, for a heat powered heat pump, which could be made in such a manner that it might be used to heat or cool a small confined space such as the interior of an automobile. The device would be adaptable so as to be readily used in conjunction with a conventional internal combustion engine utilizing waste heat to power thermal compressors or with electric engines using direct electric heating elements at much greater efficiency to power thermal compressors. 
     It is yet a further object of the present invention to provide such a new and improved device and method for making same, for a heat powered heat pump, which would also allow for an both direct electric heating elements from batteries to initially power the thermal compressors. The device would then switch to waste engine heat when the temperature is sufficient to power the thermal compressors. This would allow for immediate heating or cooling in the interior space of buildings or automobiles which has become expected in modern heating and cooling systems, at much greater efficiency. 
     It is yet a further object of the present invention to provide such a new and improved device and method for making same, for a heat powered heat pump, which would be inexpensive to manufacture and maintain. The design of the device provides a simple, yet effective means by which to provide heating and cooling for interior spaces without excessively complex motorization or mechanization. Since the present invention lacks complex mechanisms and motorization and is considerably less expensive to manufacture, the initial cost to procure this device is relatively low, and repairs to the device are inexpensive and required much less frequently. 
     Briefly, the above and further objects of the present invention are realized by providing a new and improved heat powered heat pump system and method of making it. More particularly, the present invention relates to a heat powered heat pump system which uses standard commonly available refrigerant fluids, supplements pressurizing the refrigerant fluid by use of an external available heat source, enables selective switching between heating or cooling modes, and utilizes a thermal four-chambered compressor having a double piston head that is partially powered by an external heat source. Since the heat powered heat pump system may be made in various sizes and configurations, it may be utilized to cool and heat the interior of automobiles using waste engine heat and an initializing battery powered heating element to provide for immediate heating and cooling. The heat powered heat pump system attains better efficiency than current systems used for the same purpose because of its capability to use a heat source such as a solar collector, waste heat from a generator, vehicle engine or power plant, various types of fuel cells, and a gas-fired or electrical heating element to power the four-chambered thermal compressor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The above mentioned and other objects and features of this invention and the manner of attaining them will become apparent, and the invention itself will be best understood by reference to the following description of the embodiment of the invention in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a schematic representation of a conventional prior art heat pump device; 
     FIG. 2 is a schematic representation of the novel heat powered heat pump system constructed in accordance with the present invention; 
     FIG. 3 is a cross-sectional side elevational view of the compressor unit component of the heat powered heat pump system constructed in accordance with the present invention; 
     FIG. 4 is a schematic representation of a switching valve controller circuit for the heat pump system constructed in accordance with the present invention; 
     FIG. 5 is a schematic representation of a heat exchanger controller circuit for the heat pump system constructed in accordance with the present invention; 
     FIG. 6 is an enlarged partial schematic representation of the novel heat powered heat pump system constructed in accordance with the present invention further illustrating switching valve and piston assembly movement; 
     FIG. 7 is an enlarged partial schematic representation of the novel heat powered heat pump system constructed in accordance with the present invention further illustrating switching valve and piston assembly movement; and 
     FIG. 8 is an enlarged partial schematic representation of the novel heat powered heat pump system constructed in accordance with the present invention further illustrating switching valve and piston assembly movement. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings, and more particularly to FIG. 1 thereof, there is shown a typical prior art system for a conventional heat pump device. This conventional heat pump system requires that a common compressor unit be driven by direct electric motor energy input, or power transferred from a rotating shaft, as in a vehicle system. 
     FIG. 2 depicts the subject heat powered heat pump system. As shown, it is a device that can cool an interior space, and by reversing the operation cycle, can also be used to heat an interior space. If the device is used only for cooling or only for heating, certain components, such as a cooling/heating switch and a valve assembly can be altogether eliminated from the system. 
     Referring now to FIG. 2, there is shown a heat powered heat pump system  10  constructed in accordance with the present invention. This heat powered heat pump system  10  is readily scalable, as will be seen, making it applicable to cooling and heating uses in large spaces as well as smaller volumes, and can be readily carried on board vehicles with space limitations for such systems. 
     The heat powered heat pump system is comprised of three main components, a cooling/heating switch  12 , a switching valve  20  and a novel four chamber compressor unit  30 . Cooling/heating switch  12  can be set in a cooling position or a heating position. With cooling/heating switch  12  in the cooling position, the interaction of the components of the system will be described below. 
     To initiate functioning of the system  10 , a pump/electric motor unit  14  is receiving liquid refrigerant from valve  16 . The pump/electric motor unit  14  pressurizes and delivers liquid refrigerant to heat exchanger  18 . Note that pump/electric motor unit  14  can be any device that can pressurize liquid refrigerant. Heat exchanger  18  receives the pressurized liquid refrigerant and adds available heat from a power source Q S , discussed in greater detail below, which converts the liquid to a high pressure vapor. The high pressure vapor is supplied to switching valve  20  along high pressure vapor line  48 . 
     For the purposes of safety, and since high pressure liquid is traveling along line  47  to heat exchanger  18 , a relief/check valve assembly  60  is interposed between heat exchanger  18  and the pump  14 . 
     Switching valve  20  is illustrated here in FIG. 2, supplying the high pressure vapor to chamber A of four chamber compressor unit  30 . Also, switching valve  20  is exposing chamber D of compressor  30  to exhaust line  28 . Compressor unit  30  consists of a compressor cylinder housing  22 , and a double piston assembly  24 , connected by a piston rod  26 . The cylinder housing  22 , in which this double piston assembly operates, has a divider  32  at its midpoint. Therefore, four separate chambers are created within compressor unit  30 , and these compressor chambers are designated chambers A, B, C and D. If high pressure vapor is conducted, through switching valve  20 , into chamber A, and chamber D is exposed, through switching valve  20 , to exhaust line  28 , then the double piston assembly  24  will move in a downward motion. This downward motion of the piston assembly  24  will cause the volume of chamber B to decrease, having a resulting compression effect, and simultaneously the volume of chamber C to increase, having a resulting suction effect. 
     This compression of the vapor in chamber B causes compressed vapor to be delivered to valve  34 , which in turn allows vapor to be routed and delivered to cooling/heating switching valve  12 , through line  36 , and on to heat exchanger  40 . Heat exchanger  40 , a condenser, is exposed to the atmosphere and heat from the compression of the vapor, causes heat transfer to the atmosphere, which transforms the vapor back to a liquid state before returning to pump/electric motor unit  14  via valve assembly  16 . 
     Referring back to FIG. 2, and more particularly to compressor  30 , the downward motion of piston assembly  24  increases the volume of chamber C, which creates a suction, which effect through check valve  42  and cooling/heating valve  12  causes a low pressure on heat exchanger  50 . At this same point in time, heat exchanger  50  is receiving liquid refrigerant, from throttling valve  52 , located on valve assembly  16 , which is a direct result of the formation of fluid in heat exchanger  40 . This liquid refrigerant, in heat exchanger  50 , is exposed to the low pressure and changes state back to a vapor, with the addition of available heat. This heat transfer to heat exchanger  50 , is from the interior space, thus cooling the interior space. 
     The described process has covered the downward movement of the double piston assembly  24 , and at which time switching valve  20  is alternatively switched such that now high pressure vapor is delivered to chamber D of compressor unit  30 , and simultaneously chamber A is exposed to exhaust line  28  thru switching valve  20 . This action causes the piston assembly  24  to move in an upward motion, which causes chamber C to compress vapor and deliver vapor through valve  34 , to cooling/heating valve  12 , and then on to heat exchanger  40 . Also, the upward motion of the pistons causes chamber B of the compressor  30 , to increase in volume causing suction and drawing vapor through check valve  38  from cooling/heating valve  12  and thus, from heat exchanger  50 . This produces the same effect at the heat exchangers  40  and  50  as the downward motion of the piston assembly, heat being rejected at the condenser heat exchanger  40 , and at the same time, heat being absorbed at heat exchanger  50 , now the evaporator. 
     The switching time period on switching valve  20  is variable and can be specifically varied to determine the heat transfer rate of the system. In operation, when the system  10  is functioning with a short switching time period for switching valve  20 , this causes faster cycling rates of the piston assembly  24  of compressor unit  30 , and therefore, a higher heat transfer rate at the respective heat exchangers  40  and  50 . 
     As the system has been described, in the interior cooling mode, and if we denote heat or energy transfer as positive “+” when put into the system, and as negative “−” when energy is transferred out of the system, we can write an energy balance equation as follows:                  Q   1     +     Q   S     +     Q   50     -     Q   40       =   0         where           Q   1     =     pump                 input                 power                                           Q   S     =     energy                 from                 heat                 source               or                       Q   50     =     interior                 heat                 transfer                                           Q   40     =     atmosphere                 heat                 transfer                     Q   1     +     Q   S     +     Q   50       =     Q   40                                                          
     Therefore, all heat/power is rejected to the atmosphere when the heat powered heat pump system  10  is in the cooling mode. 
     If the system is used to supply heat to the interior space, switching valve  20  is switched to the heating position, which in effect switches (reverses) the functions of the heat exchanger  40  and heat exchanger  50 . Now, in this heating functioning mode, heat exchanger  40  has become an evaporator and heat exchanger  50  has become a condenser. The condenser function, to reject heat, is now in the interior space and will now heat the interior space. The heat exchanger functioning as an evaporator, here heat exchanger  40  is now located outside the interior space and has the ability to absorb heat from the atmosphere. 
     The energy balance equation now becomes:                  Q   1     +     Q   S     +     Q   40     -     Q   50       =   0         where           Q   1     =     pump                 input                 power                                           Q   S     =     energy                 from                 heat                 source               or                       Q   50     =     interior                 heat                 transfer                                           Q   40     =     atmosphere                 heat                 transfer                     Q   1     +     Q   S     +     Q   40       =     Q   50                                                          
     Therefore, during the heating mode of the system, Q 50  (interior heat transfer) is equal to the total energy input to the system  10 , including the large heat input Q 40 , from the atmosphere. When the system  10  is used to heat an electric car, Q 1  and Q S  are consumed from the battery, but we also get the available heat picked up from the atmosphere Q 40 . This will result in a decreased consumption of battery power for the same amount of heat to heat the cars interior, adding up to less energy required to operate the system  10 , and much greater efficiency overall. 
     Moreover, still referring to FIG. 2, and the main component, namely, the compressor unit  30 . The power supplied from switching valve  20  is conducted to the larger chambers A and D of the compressor. One could conduct the vapor power, from switching valve  20  to chambers B and C of the compressor unit  30 . In this alternate configuration, vapor is then directed to chambers A and D, and subsequently conducted to check valves  42  and  38 , and eventually on to valve  34 . 
     Efficiency of the overall system  10  is greatly enhanced by the available heat input to heat exchanger  18 . To illustrate this point, energy, in the form of heat is applied to heat exchanger  18  in many forms, here designated Q S . This available heat might be generated by direct electrical power from a power grid, photovoltaic cells, wind power generators, and fuel cell technology, including proton exchange membrane fuel cells, and fuel cell designed for electric car power plants, such as zinc pellet fuel cells. Alternatively, the heat passed on to the heat exchanger  18  may be derived from hot water sources. This hot water may have been generated using all of the above systems, or directly through the use of solar power hot water generation (direct exposure panels, etc.). All of these methods to provide generated heat and/or waste heat from mechanical heat creation (for example engine waste heat) are factors in the overall greater operating efficiency realized with the subject heat powered heat pump system  10 . 
     To outline the advantages and disadvantages of each method consider the following: 
     (I) Switching valve  20  powering chambers A and D: The required temperature of the main power source Q S  will be significantly lower than the temperature required in method (II) described below. But, the overall efficiency of the total system  10  is lower than in method (II) below. 
     (II) Switching valve  20  powering chambers B and C: The required temperature of the power source Q S  here is higher than in method (I) above, but the overall system  10  efficiency is higher than that of method (I) above. 
     Therefore, the temperature of the power (heat) source Q S  will determine the interconnection method and thereby configuration between switching valve  20  and the compressor unit  30 . 
     Referring now to FIG. 3, there is shown an enlarged cross-sectional illustration of the compressor unit  30 , in particular pointing out the presence and location of the important seals, sealing elements  62 ,  64 , and  66 . These sealing elements  62 ,  64 , and  66  represent the necessary sliding seals within compressor unit  30 . The sealing elements  62 ,  64 , and  66  can be constructed from metallic materials, alloys, or elastomer sealing material. The elastomer sealing material would be chosen for compatibility with refrigerant fluids and the anticipated system operating temperature extremes. Note that sealing elements  62  and  66  act as piston rings, being centrally located at the piston heads  44  and  46  respectfully. Sealing element  64 , located in compressor housing  22  divider  32 , acts to seal the piston rod  26 . Overall, the sealing elements  62 ,  64  and  66  act to insure that each compressor  30  chamber A, B, C and D do not come into fluid communication with one another. Therefore, these seals are vitally important to the operation of the compressor unit  30 . 
     Referring now to FIG. 4, and more particularly to the details of the controlling mechanism for switching valve  20 , there is shown the switching valve  20  wired to a controlling circuit  70 . Switching valve  20  is a conventional three-position, electrically actuated, spring centered, four-way fluid diverter valve. Switching valve  20  has three positions, namely, a straight diversion position  72 , a center “off” position  74 , and a crossed diversion position  76 . The center position  74  of switching valve  20  has the configuration of “blocked flow” on the fluid input and return ports of the valve  20 , and the “working ports” supplying the compressor unit  30  (not shown here) are in fluid communication with the selected chambers of the compressor. 
     The cycling and frequency of the cycling between positions  72 ,  74  and  76  of switching valve  20  is controlled by an electrical control circuit  70 . Electrical power, designated P, is switched and alternately supplied to outputs wires  82  and  84 . The cycling of the electrical signals traveling to switching valve  20  from the control circuit  70  via output wires  82  and  84  is regulated by a control signal, designated signal C, acting on control circuit  70 . 
     Signal C regulates the frequency at which power is applied to output wires  82  and  84 . The circuit controller  70  has a delay in timing, or “dead time,” after the signal to output wire  82  is removed and before the signal to output wire  84  is applied, and conversely, when a signal is removed from output wire  84  and before a signal is applied to output wire  82 . This “dead time” feature allows switching valve  20  to remain in the center position for a predetermined amount of time, the advantages of which are described in greater detail below. 
     The frequency of the cycling rate of switching valve  20  will also determine the cycling rate of compressor  30  (not shown), which will in turn determine the rate of heat transfer if heat exchangers  40  and  50 . When no heat transfer is required of heat exchangers  40  and  50 , power input P is removed from controller circuit  70 , which causes the cycling of switching valve  20  and compressor  30  to halt. 
     Referring now to FIG. 5, there is shown an alternative embodiment, including a power control system  80 , to further improve the overall efficiency of the heat powered heat pump system  10 , in particular by enabling the amount of power Q S  supplied to heat exchanger  18  to be controlled and limited depending upon the rejection temperature of the acting condenser unit within the system. 
     Recall that heat exchangers  40  and  50 , as shown in FIG. 1, can act as a condenser or an evaporator depending upon the position of switching valve  20 . Therefore, the temperature of the power Q S  supplied to heat exchanger  18  is proportional to the rejection temperature of the systems condenser heat exchanger at the time, whether it be heat exchanger  40  or heat exchanger  50 . 
     FIG. 5 here depicts a power control system  80  that monitors the rejection temperature of the “condenser” heat exchanger, designated X, and monitors the temperature, designated Y, of the high-pressure vapor leaving heat exchanger  18 . Depending upon the physical thermodynamic characteristics of the refrigerant fluid being used in the system, a circuit controller  78  maintains a differential relationship between temperature X and temperature Y by supplying a signal along output wire  86  to modulate the amount of power being supplied to heat exchanger  18 . Signals traveling along output  86  could energize a flow valve  88  when the system is being powered by hot fluid (such as solar powered hot water generation). Alternatively, signals traveling along output  86  could energize a power relay (not shown) which would be located directly in substitution of flow valve  88 , in the case where electrical power is being employed to power an electrical heating element to heat the refrigerant in heat exchanger  18 . 
     Referring now to FIGS. 6,  7  and  8 , there is shown in greater detail the three positions of switching valve  20 , namely the dynamics of the system during the cycling of switching valve  20  through each of the three positions of the switch. 
     Beginning with FIG. 6, switching valve  20  is receiving a signal from output wire  82  and consequently is in the straight open position  72 . In this position  72 , high pressure vapor is being supplied to compressor  30  chamber A and evacuating from chamber D along lines  54  and  28  respectively. This causes the internal double piston assembly  24  to move downwardly, thereby exhausting vapor out of chamber D and chamber B, while simultaneously receiving vapor into chamber C by the movement action of the piston heads. 
     FIG. 7 depicts the double piston assembly  24  as having reached its maximum downward stroke. At this point, the electric signal along output wire  82  has been discontinued, and removed from switching valve  20  by circuit controller  70 , thereby allowing switching valve  20  to move to its center position. Control circuit  70  could be sensing the maximum travel position of piston assembly  24 , by using a position sensor device (not shown), to facilitate the switching sequence of switching valve  20 . This allows the pressurized vapor in compressor  30  chamber A to communicate through switching valve  20  and move into chamber D and pressurize chamber D. This sequence of events improves the operating efficiency of the overall system  10  since the vapor pressure in chamber A is not completely exhausted to condenser  40  (not shown, see FIG. 1) through switching valve  20 . 
     Referring now to FIG. 8, there is shown the last cycle of piston movement in the heat powered heat pump system  10 . Here, after a pre-determined time, the “dead time,” circuit controller  70  applies an electrical current along output wire  84  to switching valve  20  which causes switching valve  20  to supply high pressure vapor to chamber D of compressor  30 . As a result, the piston assembly  24  moves in an upwardly fashion as depicted by the arrow of movement. When the piston assembly  24  reaches its maximum upward stroke, the cycle begins again, as described in FIG.  6 . 
     It should be understood, however, that even though these numerous characteristics and advantages of the invention have been set forth in the foregoing description, together with details of the structure and function of the invention, the disclosure is illustrative only, and changes may be made in detail, especially in matters of shape, size, chemistry and arrangement of parts within the principal of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.