Heat pump and method for calculating heating-medium flow rate of heat pump

Abstract

A heating-medium flow rate is obtained with sufficient accuracy even if an inexpensive flow rate sensor is used. Provided is a turbo-refrigerator including an evaporator that cools or heats a heating medium flowing from an external load, a condenser that exchanges heat with outside air or cooling water, a coolant circulation path through which a coolant is circulated between the evaporator and the condenser, and a turbo-compressor provided in the coolant circulation path, the turbo-refrigerator comprising a differential pressure sensor that measures the differential pressure between the inlet-side pressure and the outlet-side pressure of cold water in the evaporator, and a control panel storing a loss factor of the evaporator and calculating the flow rate of the cold water in the evaporator on the basis of the loss factor and the differential pressure output from the differential pressure sensor, wherein the control panel performs control using the calculated flow rate of the cold water and transmits the flow rate of the cold water to facility-side equipment.

1 . A heat pump including a first heat exchanger that cools or heats a heating medium flowing from an external load, a second heat exchanger that exchanges heat with outside air or cooling water, a coolant circulation path through which a coolant is circulated between the first heat exchanger and the second heat exchanger, and a turbo-compressor provided in the coolant circulation path, the heat pump comprising:
 a differential-pressure measuring part for measuring the differential pressure between the inlet-side pressure and the outlet-side pressure of the heating medium in the first heat exchanger; and   a control part storing a loss factor of the first heat exchanger, for calculating the flow rate of the heating medium in the first heat exchanger on the basis of the loss factor and the differential pressure output from the differential-pressure measuring part,   wherein the control part performs control using the flow rate of the heating medium and transmits the flow rate of the heating medium to facility-side equipment.   
     
     
         2 . The heat pump according to  claim 1 , wherein the control part obtains a correction term depending on the measurement delay time of the outlet-side pressure according to the amount of the heating medium held in the first heat exchanger and corrects the flow rate of the heating medium using the correction term. 
     
     
         3 . The heat pump according to  claim 1 , wherein the control part obtains the permissible quantity of heat exchanged in the first heat exchanger by substituting the current motive power consumption of the turbo-compressor and the quantity of heat exchanged in the second heat exchanger into a relational expression expressing the relationship among the motive power consumption of the turbo-compressor, the quantity of heat exchanged in the first heat exchanger, and the quantity of heat exchanged in the second heat exchanger and determines the permissible range of the flow rate of the heating medium in the first heat exchanger from the permissible quantity of heat exchanged in the first heat exchanger, wherein if the flow rate of the heating medium determined by calculation exceeds the flow rate range of the heating medium, the control part determines the flow rate of the heating medium on the basis of the flow rate range of the heating medium and transmits the value to the facility-side equipment. 
     
     
         4 . A method for calculating the heating-medium flow rate of a heat pump including a first heat exchanger that cools or heats a heating medium flowing from an external load, a second heat exchanger that exchanges heat with outside air or cooling water, a coolant circulation path through which a coolant is circulated between the first heat exchanger and the second heat exchanger, and a turbo-compressor provided in the coolant circulation path,
 wherein a differential-pressure measuring part for measuring the differential pressure between an inlet-side pressure and an outlet-side pressure are provided at an inlet and an outlet of the heating medium of the first heat exchanger, and   the flow rate of the heating medium in the first heat exchanger is calculated on the basis of the loss factor of the first heat exchanger and the differential pressure output from the differential-pressure measuring part.