Patent ID: 8997508
Filing Date: 2015-04-07
Classification: F25B,Y02B

Abstract:
1. A refrigerating apparatus in which a refrigerant circuit includes a compression means, a gas cooler, auxiliary reducing means, an intermediate heat exchanger, main reducing means and an evaporator, the refrigerating apparatus being configured to branch a refrigerant exiting from the gas cooler into two flows, pass a first refrigerant flow through a first flow path of the intermediate heat exchanger via the auxiliary reducing means, pass a second refrigerant flow through a second flow path of the intermediate heat exchanger and then through the evaporator via the main reducing means, perform heat exchange between the first refrigerant flow and the second refrigerant flow in the intermediate heat exchanger, suck the refrigerant exiting from the evaporator into a low pressure portion of the compression means and suck the first refrigerant flow exiting from the intermediate heat exchanger into a medium pressure portion of the compression means, to obtain a supercritical pressure on a high pressure side, the refrigerating apparatus comprising: control means for controlling the auxiliary reducing means, wherein the control means calculates a first control amount exerted in such a direction as to increase an open degree of the auxiliary reducing means in a case where a temperature DT of the refrigerant discharged from the compression means is higher than a predetermined value DT0, a second control amount exerted in such a direction as to increase the open degree of the auxiliary reducing means in a case where an over-compression judgment value MPO obtained from a pressure MP of a medium pressure region of the refrigerant circuit and a low pressure side pressure LP of the refrigerant circuit is lower than a high pressure side pressure HP of the refrigerant circuit, and a third control amount exerted in such a direction as to increase the open degree of the auxiliary reducing means in a case where a difference (GCT-LT) between a temperature GCT of the refrigerant discharged from the gas cooler and a temperature LT of the second refrigerant flow discharged from the intermediate heat exchanger is smaller than a predetermined value SP, and the control means adds up the first to third control amounts to determine an operation amount of the valve open degree of the auxiliary reducing means.