Patent ID: 8047011

Claim:
A refrigeration system comprising: a refrigerant circuit including a compressor, a heat-source heat exchanger connected to a discharge side of the compressor at one end thereof, a liquid pipe connected to the other end of the heat-source heat exchanger through a heat-source expansion valve, a plurality of heat exchangers connected in parallel to the liquid pipe at one ends thereof, a plurality of expansion valves, each of which is provided on one end of the corresponding heat exchanger to adjust an amount of a refrigerant flowing to the corresponding heat exchanger, and a switching mechanism which switches a flow path of the refrigerant so that the other ends of the heat exchangers are connected to one of a suction side and a discharge side of the compressor, wherein the refrigeration circuit includes a high-pressure-side pressure difference detection unit which detects an index of pressure difference between a high pressure refrigerant on the discharge side of the compressor and a refrigerant in the liquid pipe in concurrent operation of performing a refrigeration cycle in which the heat-source heat exchanger functions as a condenser, and simultaneously, at least one of the plurality of heat exchangers functions as a condenser, and at least one of the plurality of heat exchangers functions as an evaporator, an expansion valve control unit which adjusts the degree of opening of the heat-source expansion valve in the concurrent operation so that a value detected by the high-pressure-side pressure difference detection unit becomes larger than a predetermined value, wherein the refrigerant circuit includes three or more heat exchangers connected in parallel to the liquid pipe, and a low-pressure-side pressure difference detection unit which detects an index of pressure difference between the refrigerant in the liquid pipe and a low pressure refrigerant on the suction side of the compressor, and the expansion valve control unit adjusts the degree of opening of the heat-source expansion valve so that a value detected by the high-pressure-side pressure difference detection unit becomes larger than a predetermined value, and a value detected by the low-pressure-side pressure difference detection unit becomes larger than a predetermined value, in the concurrent operation of performing a refrigeration cycle in which the heat-source heat exchanger functions as a condenser, and simultaneously, at least two of the plurality of heat exchangers function as evaporators, and at least one of the plurality of heat exchangers functions as a condenser.