This Small Business Innovation Research Phase I project will improve the energy efficiency of both air conditioners and refrigerator units with equal or lower capital cost. Air conditioners operate on thermodynamic cycle to pump heat from a low temperature to a higher temperature where it is rejected o the environment. Heat is transferred from air at a high temperature (e.g., 77ÃF) cooling it to a lower temperature (e.g., 55ÃF). Even though the heat removal is non-isothermally, the evaporator of the conventional vapor compression cycle operates isothermally at a single, lower temperature (e.g., 45 Ã F) . Thermodynamics predict that if some of the heat were transferred to the refrigerant at a higher temperature, then the work of the cycle would be reduced. Non-Azeotropic Refrigerant Mixtures (NARMs) are being developed to transfer heat non-isothermally thereby reducing power, but NARMs have problems, particularly in small scale systems. TDA Research, Inc. (TDA) modified the conventional vapor compression air conditioner slightly to evaporate a single, non-ozone depleting refrigerant (HFC-134a) at two temperatures (45ÃF and 55ÃF). The new cycle operates with only one mechanical compressor with its inlet at the pressure of the higher temperature evaporator. The vapor leaving the 45ÃF evaporator is compressed to the higher pressure using fluid power normally wasted in a conventional cycle. They anticipate a 18% improvement in the Coefficient of Performance (COP) with a 20% increase in the cooling capacity of the same compressor In Phase I they will measure the performance of the fluid power recovery device and compare life cycle cost of their system to the conventional cycle.
