The present embodiments relate to air conditioning systems and are more particularly directed to such systems that use heat energy transferred from a system to drive all, or part, of the refrigeration compression requirements.
By way of background, a type of conventional prior art air conditioning system is shown in FIG. 1 and generally at 10. System 10 typically include four primary elements, namely, an evaporator 12 (sometimes part of an air exchanger 12a), a compressor 14, a condenser 16, and a metering device 18. A line 20 is in fluid communication between these elements and carries a refrigerant, where the refrigerant changes phase based on its location along the line and the conditions at that location. Typically, the various elements of system 10 are in different physical locations relative to the building (or vehicle) to which they are providing cooling. For example, air exchanger 12a (and its evaporator) is usually located in a building space that is not typically accessed by occupants, such as in the attic of a house. As another example, compressor 14 and condenser 16 are typically outside of the building, for purposes of noise reduction and also so as to dispel heat from the system, as further described below.
The operation of system 10 in general as follows. Refrigerant flows through line 20, and for sake of example consider the direction of flow as clockwise as shown by an arrow in FIG. 1. For example, refrigerant in a relatively cool and liquid phase enters evaporator 12; at the same time, indoor air is inlet, in response to a circulation created by a fan 12b, into heat exchanger 12a so that the air passes over or by line 20 as that line communicates refrigerant through evaporator 12. In this manner, heat from the relatively warmer inlet air is transferred into the refrigerant (i.e., removed from the inlet air), so the outlet air is cooler than the inlet air—the relatively cooler outlet air may then be distributed to the home or other building by ducts or the like (not shown) to cool, so as to improve comfort in that building with which system 10 is associated. Note also that the addition of heat to the refrigerant via evaporator 12 causes the refrigerant to experience a phase change from a liquid to a vapor.
The vapor from evaporator 12 continues along line 20 to an inlet of compressor 14. Compressor 14, driven by a motor M that is typically electrically-sourced, compresses the vapor, thereby increasing both its pressure and temperature. A typical compressor may include some type of cylinder chamber to compress the vapor in this regard, where the motor M drives a mechanism, such as a shaft, to cause a piston within the cylinder to reciprocate and thereby compress the vapor. In any event, the compressed, higher temperature, higher pressure vapor is then output from an outlet of compressor 14.
The compressed, higher temperature, higher pressure vapor from compressor 14 is received from line 20 at an inlet 16, of condenser 16, which typically also has an associated fan 16a. Fan 16a circulates air across condenser 16, and that air along with the typical structure or coiling of the condenser removes heat from the vapor and thus causes it to condense, thereby causing the vapor that was inlet to experience a phase change to liquid, at a relatively high pressure. Note also therefore that warm air is discharged from the area of condenser 16 in response to fan 16a and the condensing effect of the vapor in line 20. As noted above, typically condenser 16 is located outside, so that this warm air discharge is away from the home and does not further burden or otherwise affect the home, system 10, or the home occupants. In any event, the high pressure liquid is then output from an outlet 16o of condenser 16.
The high pressure liquid from outlet 16o of condenser 16 continues along line 20 to an inlet of metering device 18, which typically includes some type of appropriately sized valve and or tube and is sometimes referred to as a backpressure or refrigeration valve. Metering device 18 thereby reduces the pressure of the liquid refrigerant, and as a result also reduces its temperature, while further limiting the flow rate into evaporator 12. Thus, the output of metering device 18 toward evaporator 12 is a relatively lower temperature, lower pressure liquid refrigerant that then enters evaporator 12, whereby the above process repeats so that such liquid refrigerant may carry heat away from the air introduced by inlet to air exchanger 12a. 
The above approach of system 10 has been prolific in homes and other structures for many decades and has proven quite beneficial to mankind, particularly in warmer environments. Various improvements have been made to the elements of system 10, with various goals in making such improvements. One very important aspect of system 10 has been and is the amount of energy used to drive the system. As society has advanced, energy consumption and use have been offered to have more and more significance not only to people, but also to the entire planet. Thus, there is a growing if not imperative need to improve efficiencies of system 10 or comparable air conditioning systems, and the preferred embodiments are directed to this endeavor, as further discussed below.