Patent ID: 7024877

Claim:
A water heating system comprising: a water storage vessel; a water circuit circulating water from at least one inlet in fluid communication with said storage vessel to at least one outlet in fluid communication with said storage vessel; a first heat exchanger and a second heat exchanger operably disposed in said water circuit, said first heat exchanger and said second heat exchanger arranged in parallel; a vapor compression system defining a refrigerant circuit for circulating a refrigerant, said vapor compression system including a first compressor mechanism and a second compressor mechanism, said first compressor mechanism compressing a refrigerant from a suction pressure to an intermediate pressure, said second compressor mechanism compressing the refrigerant from the intermediate pressure to a discharge pressure; said first heat exchanger being operably disposed in said refrigerant circuit between said first and second compressor mechanisms wherein intermediate pressure refrigerant heats water in said water circuit; an expansion device operably disposed in said refrigerant circuit, reducing the pressure of said refrigerant; an evaporator operably disposed in said refrigerant circuit between said expansion device and said first compressor mechanism; and wherein said second heat exchanger is operably disposed in said refrigerant circuit between said second compressor mechanism and said expansion device wherein discharge pressure refrigerant heats water in said fluid circuit.