Air conditioning system with thermal energy storage and load leveling

Abstract

A vapor compression air conditioning (cooling and heating) system adapted for operation to reduce the consumption of electric power during peak periods of demand for power is characterized by four refrigerant circuits. A first circuit includes a compressor, a first heat exchanger and a second heat exchanger. A second circuit comprises the compressor, the first heat exchanger and a third heat exchanger. A third circuit comprises the third heat exchanger, a refrigerant pump and a thermal energy storage unit characterized by a tank having a thermal energy storage medium disposed therein. A fourth circuit includes the thermal energy storage unit, the refrigerant pump and a fourth heat exchanger. The first heat exchanger is an outdoor heat exchanger. The second and fourth heat exchangers are indoor heat exchangers in heat transfer relationship with the fluid (e.g., indoor supply air) to be cooled or heated. A first refrigerant, preferably a compressible phase change fluid, is circulated in the first and second circuits by the compressor. A second refrigerant, preferably an incompressible liquid, is circulated in the third and fourth circuits. The system is operable in plural cooling and heating modes to provide load leveling between vapor compression heating and cooling using the compressor and heating and cooling using the thermal energy storage unit, to achieve reduced power consumption during peak electrical power demand periods.