Patent ID: 9689730
Date: 2017-06-27
CPC Classifications: F25B,G01F

Claim:
1. A heat-source unit comprising: a compressor that compresses a refrigerant; a condenser that condenses the compressed refrigerant by means of a heat-source medium; an evaporator that evaporates the condensed refrigerant and also performs heat exchange between the refrigerant and a heat transfer medium; an expansion valve that allows liquid-phase refrigerant retained in the condenser to expand; and a heat transfer medium flow rate estimating device that estimates a flow rate of a heat transfer medium of a heat-source unit provided with a compressor that compresses a refrigerant, a condenser that condenses the compressed refrigerant by means of a heat-source medium, an evaporator that evaporates the condensed refrigerant and also performs heat exchange between this refrigerant and the heat transfer medium, and an expansion valve that allows liquid-phase refrigerant retained in the condenser to expand, the heat transfer medium flow rate estimating device comprising: a refrigerant-flow-rate calculating portion that calculates a heat quantity exchanged between the refrigerant and the heat transfer medium at the evaporator based on a planned value of the flow rate of the heat transfer medium and a measured value of the temperature of the heat transfer medium flowing in the evaporator, and that calculates the flow rate of the refrigerant flowing in the evaporator from the heat quantity; and a heat-transfer-medium-flow-rate back-calculating portion that back-calculates the flow rate of the refrigerant flowing in the evaporator based on the flow rate of the refrigerant calculated by the refrigerant-flow-rate calculating portion and a ratio between a set value of the differential pressure between the condenser and the evaporator and a measured value of the differential pressure, that back-calculates a heat quantity exchanged between the refrigerant and the heat transfer medium at the evaporator from the back-calculated flow rate of the refrigerant, and that back-calculates the flow rate of the heat transfer medium based on the back-calculated heat quantity and the measured value of the temperature of the heat transfer medium flowing in the evaporator, wherein updating processing for updating a planned value of the flow rate of the heat transfer medium is performed based on the flow rate of the heat transfer medium that is back-calculated by the heat-transfer-medium-flow-rate back-calculating portion; the flow rate of the refrigerant is calculated by the refrigerant-flow-rate calculating portion based on an updated planned value; and the degree-of-opening of the expansion valve is controlled in accordance with the calculated flow rate of the refrigerant.