Hot water supply apparatus and hot water control method therefor

Abstract

A hot water supply apparatus according to an embodiment of the present disclosure includes a first heat exchanger that heats heating water and a second heat exchanger that generates hot water, a first temperature sensor that is installed on a first flow path through which the supply water supplied by the first heat exchanger flows to the second heat exchanger and measures a temperature of the supply water, a second temperature sensor that is installed on a second flow path through which return water of the supply water cooled after heat exchange with the second heat exchanger flows to the first heat exchanger and measures a temperature of the return water, and a controller that predicts the temperature of the supply water based on the temperature of the return water measured by the second temperature sensor and preforms hot water control based on the predicted temperature of the supply water.

What is claimed is: 
     
         1 . A hot water supply apparatus comprising a first heat exchanger configured to heat heating water using heat obtained by combusting a fuel by a burner and a second heat exchanger configured to generate hot water by exchanging heat between supply water supplied by the first heat exchanger and direct water, the hot water supply apparatus comprising:
 a first temperature sensor installed on a first flow path through which the supply water supplied by the first heat exchanger flows to the second heat exchanger and configured to measure a temperature of the supply water;   a second temperature sensor installed on a second flow path through which return water of the supply water cooled after heat exchange with the second heat exchanger flows to the first heat exchanger and configured to measure a temperature of the return water; and   a controller configured to predict the temperature of the supply water based on the temperature of the return water measured by the second temperature sensor and configured to preform hot water control based on the predicted temperature of the supply water.   
     
     
         2 . The hot water supply apparatus of  claim 1 , wherein the controller predicts the temperature of the supply water based on a combustion heat amount of the first heat exchanger, a circulation flow rate of water flowing along the first flow path and the second flow path, and the temperature of the return water, before a temperature reaction delay time until a change in the temperature of the return water is reflected on the temperature of the supply water. 
     
     
         3 . The hot water supply apparatus of  claim 2 , wherein the controller performs supply water temperature limiting control when the predicted temperature of the supply water is greater than a preset reference temperature. 
     
     
         4 . The hot water supply apparatus of  claim 3 , wherein the controller sets the reference temperature to the temperature of the supply water measured by the first temperature sensor when performing the supply water temperature limiting control and performs a combustion heat amount control operation based on the reference temperature. 
     
     
         5 . The hot water supply apparatus of  claim 1 , further comprising:
 a mixing valve installed on a bypass flow path connecting a third flow path through which the direct water flows into the second heat exchanger and a fourth flow path through which the hot water generated by the second heat exchanger is discharged and configured to adjust a flow rate of the direct water to adjust a temperature of the hot water discharged through the fourth flow path.   
     
     
         6 . The hot water supply apparatus of  claim 5 , wherein the controller performs a supply water temperature limiting control when the predicted temperature of the supply water is greater than a preset reference temperature and controls an opening rate of the mixing valve such that the temperature of the hot water is maintained at a target temperature while performing the supply water temperature limiting control. 
     
     
         7 . The hot water supply apparatus of  claim 6 , wherein, while performing the supply water temperature limiting control, the controller controls an outlet temperature of the second heat exchanger to a temperature higher than the temperature of the hot water adjusted by the mixing valve. 
     
     
         8 . The hot water supply apparatus of  claim 1 , wherein, while combustion is performed by the burner, in a stable state in which the temperature of the supply water and the temperature of the return water are maintained constant for a predetermined period of time, the controller calculates a correction value for a combustion heat amount of the first heat exchanger and a circulation flow rate of water flowing along the first flow path and the second flow path. 
     
     
         9 . The hot water supply apparatus of  claim 8 , wherein the controller calculates the correction value based on the temperature of the supply water, the temperature of the return water, the combustion heat amount of the first heat exchanger, and the circulation flow rate. 
     
     
         10 . The hot water supply apparatus of  claim 8 , wherein the controller predicts the temperature of the supply water based on a correction average value of the correction values calculated in each stable state. 
     
     
         11 . The hot water supply apparatus of  claim 10 , wherein the controller predicts the temperature of the supply water based on a value obtained by reflecting the correction average value on the combustion heat amount of the first heat exchanger and the circulation flow rate and the temperature of the return water. 
     
     
         12 . The hot water supply apparatus of  claim 10 , wherein the controller predicts the temperature of the supply water based on the correction average value when usage conditions of the hot water supply apparatus are changed or when next combustion is performed by the burner. 
     
     
         13 . The hot water supply apparatus of  claim 10 , wherein the controller predicts the temperature of the supply water based on the correction average value when an output of a predetermined heat amount or more is generated in the first heat exchanger. 
     
     
         14 . A hot water control method for a hot water supply apparatus comprising a first heat exchanger configured to heat heating water using heat obtained by combusting a fuel by a burner and a second heat exchanger configured to generate hot water by exchanging heat between supply water supplied by the first heat exchanger and direct water, the hot water control method comprising:
 measuring a temperature of return water of the supply water cooled after heat exchange with the second heat exchanger using a temperature sensor installed on a flow path through which the return water flows to the first heat exchanger;   predicting a temperature of the supply water based on the temperature of the return water measured by the temperature sensor; and   performing hot water control based on the predicted temperature of the supply water.   
     
     
         15 . The hot water control method of  claim 14 , wherein the predicting of the temperature of the supply water includes predicting the temperature of the supply water based on the combustion heat amount of the first heat exchanger, the circulation flow rate of the supply water flowing from the first heat exchanger to the second heat exchanger along a first flow path and the return water flowing from the second heat exchanger to the first heat exchanger along a second flow path, and the temperature of the return water, before a temperature reaction delay time until a change in the temperature of the return water is reflected on the temperature of the supply water. 
     
     
         16 . The hot water control method of  claim 15 , wherein the performing of the hot water control includes:
 performing supply water temperature limiting control when the predicted temperature of the supply water is greater than a preset reference temperature; and   setting the reference temperature to the temperature of the supply water measured by the temperature sensor installed on the first flow path when performing the supply water temperature limiting control and performing a combustion heat amount control operation based on the reference temperature.   
     
     
         17 . The hot water control method of  claim 16 , wherein the performing of the hot water control further includes:
 controlling an opening rate of a mixing valve installed on a bypass flow path connecting a third flow path through which the direct water flows into the second heat exchanger and a fourth flow path through which the hot water generated by the second heat exchanger is discharged such that the temperature of the hot water is maintained at a target temperature when performing the supply water temperature limiting control.   
     
     
         18 . The hot water control method of  claim 15 , wherein the predicting of the temperature of the supply water further includes:
 calculating a correction value for the combustion heat amount of the first heat exchanger and the circulation flow rate of the supply water flowing through the first flow path and the return water flowing through the second flow path in a stable state in which the temperature of the supply water and the temperature of the return water are maintained constant for a predetermined period of time while combustion is performed by the burner; and   predicting the temperature of the supply water based on a correction average value of the correction values calculated in each stable state.