Supply-water warming system

Abstract

A supply-water warming system includes a steam compression heat pump circuit, a heat recovery heat exchanger, a heat source fluid line in which heat source fluid flows in the heat recovery heat exchanger and the evaporator in this order, a water supply line in which supply water flows in the heat recovery heat exchanger and the condenser in this order, a refrigerant flow rate adjustment section controlled based on the superheat degree of gas refrigerant flowing into the compressor and configured to adjust a refrigerant flow rate, a supply water flow rate adjustment section controlled based on the tapping temperature of the supply water flowing out of the condenser and configured to adjust a supply water flow rate, and a control section configured to control the refrigerant flow rate adjustment section and the supply water flow rate adjustment section.

What is claimed is: 
     
         1 . A supply-water warming system comprising:
 a steam compression heat pump circuit configured such that a compressor, a condenser, an expansion valve, and an evaporator are connected in an annular shape through a refrigerant circulation line and configured to take out warmth in the condenser by drive of the compressor;   a heat recovery heat exchanger;   a heat source fluid line in which heat source fluid flows in the heat recovery heat exchanger and the evaporator in this order;   a water supply line in which supply water flows in the heat recovery heat exchanger and the condenser in this order;   a refrigerant flow rate adjustment section controlled based on a superheat degree of gas refrigerant flowing into the compressor and configured to adjust a refrigerant flow rate;   a supply water flow rate adjustment section controlled based on a tapping temperature of the supply water flowing out of the condenser and configured to adjust a supply water flow rate; and   a control section configured to control the refrigerant flow rate adjustment section and the supply water flow rate adjustment section.   
     
     
         2 . The supply-water warming system according to  claim 1 , wherein
 the heat source fluid line has a connection configuration in which after the heat source fluid and the supply water have exchanged heat in a counter flow in the heat recovery heat exchanger, the heat source fluid and liquid refrigerant exchange heat in a counter flow in the evaporator.   
     
     
         3 . The supply-water warming system according to  claim 1 , further comprising:
 a suction temperature sensor configured to sense a suction temperature of the gas refrigerant flowing into the compressor;   a steam pressure sensor configured to sense a steam pressure of the gas refrigerant flowing out of the evaporator; and   a tapping temperature sensor configured to sense a tapping temperature of the supply water flowing out of the condenser,   wherein the control section
 obtains an evaporation temperature of the liquid refrigerant from the pressure sensed by the steam pressure sensor, calculates the superheat degree of the gas refrigerant by subtracting the evaporation temperature from the temperature sensed by the suction temperature sensor, and controls the refrigerant flow rate adjustment section such that the calculated superheat degree reaches a target superheat degree, and 
 controls the supply water flow rate adjustment section such that the temperature sensed by the tapping temperature sensor reaches a target tapping temperature. 
   
     
     
         4 . The supply-water warming system according to  claim 3 , further comprising:
 a heat source temperature sensor configured to sense a temperature of the heat source fluid before the heat source fluid flows into the evaporator,   wherein the control section sets the target superheat degree according to the temperature sensed by the heat source temperature sensor.   
     
     
         5 . The supply-water warming system according to  claim 4 , wherein
 the control section increases the target superheat degree in a case where it is determined that fluctuation in the temperature sensed by the heat source temperature sensor is great.   
     
     
         6 . The supply-water warming system according to  claim 4 , wherein
 the control section decreases the target superheat degree in a case where it is determined that the temperature sensed by the heat source temperature sensor is stable.   
     
     
         7 . The supply-water warming system according to  claim 3 , further comprising:
 a supply water temperature sensor configured to sense a temperature of the supply water before the supply water flows into the condenser,   wherein the control section sets the target tapping temperature according to the temperature sensed by the supply water temperature sensor.   
     
     
         8 . The supply-water warming system according to  claim 3 , further comprising:
 a supply water temperature sensor configured to sense a temperature of the supply water before the supply water flows into the condenser,   wherein the target tapping temperature is settable to a value between an upper limit and a lower limit, and the lower limit is a value obtained by addition of a predetermined value to the temperature sensed by the supply water temperature sensor and increasing as the temperature sensed by the supply water temperature sensor increases.   
     
     
         9 . The supply-water warming system according to  claim 1 , further comprising:
 one or two bypass lines configured to cause the supply water to bypass the heat recovery heat exchanger and/or cause the heat source fluid to bypass the heat recovery heat exchanger; and   a preheating mode switching section configured to switch a preheating mode between a supply water preheating mode in which the supply water and the heat source fluid simultaneously flow in the heat recovery heat exchanger and a preheating stop mode in which at least one of the supply water or the heat source fluid flows in the one or two bypass lines.   
     
     
         10 . The supply-water warming system according to  claim 9 , further comprising:
 a pre-heat-exchanger-inflow supply water temperature sensor configured to sense a temperature of the supply water before the supply water flows into the heat recovery heat exchanger; and   a pre-heat-exchanger-inflow heat source temperature sensor configured to sense a temperature of the heat source fluid before the heat source fluid flows into the heat recovery heat exchanger,   wherein the control section
 compares a first sensed temperature obtained by the pre-heat-exchanger-inflow supply water temperature sensor and a second sensed temperature obtained by the pre-heat-exchanger-inflow heat source temperature sensor, 
 controls the preheating mode switching section to execute the supply water preheating mode in a case where the first sensed temperature falls below the second sensed temperature, and 
 controls the preheating mode switching section to execute the preheating stop mode in a case where the first sensed temperature exceeds the second sensed temperature. 
   
     
     
         11 . The supply-water warming system according to  claim 9 , wherein
 the control section includes
 a signal input unit configured to receive a preheating mode specifying signal for specifying a type which is the supply water preheating mode or the preheating stop mode, and 
 a preheating mode switching control unit configured to control, according to the preheating mode specifying signal input to the signal input unit, the preheating mode switching section to execute the supply water preheating mode or the preheating stop mode.