Heating medium circulation apparatus

Abstract

A heating medium circulation apparatus promptly detects an overheating abnormality, or local overheating of a heating medium caused by insufficient circulation. The heating medium is pumped by a circulation pump in a predetermined direction in a closed-loop circuit connecting a heater that heats the heating medium and a heat dissipator that dissipates heat from the heating medium. An outgoing temperature of the heating medium flowing out of the heater is detected by a sensor. Upon the start of a heat dissipation-based operation using heat dissipation with the heat dissipator, the circulation pump is activated, and heating is started. In repeated heating control, heating is temporarily stopped when the outgoing temperature reaches a heating stop temperature, and is resumed when the outgoing temperature decreases to a heating resumption temperature. An overheating abnormality is detected when the number of times heating is stopped reaches a determination count within a predetermined determination time.

1 . A heating medium circulation apparatus for circulating a heating medium between a heater configured to heat the heating medium and a heat dissipator configured to dissipate heat from the heating medium, the apparatus comprising:
 a circulation circuit being a closed-loop circuit connecting the heater and the heat dissipator;   a circulation pump configured to pump the heating medium in the circulation circuit in a predetermined direction;   an outgoing temperature sensor configured to detect a temperature of the heating medium flowing out of the heater;   a heating controller configured to control heating in the heater; and   an overheating abnormality detector configured to detect an overheating abnormality, the overheating abnormality being local overheating of the heating medium caused by insufficient circulation of the heating medium in the circulation circuit,   wherein the circulation pump is activated in response to a start of a heat dissipation-based operation and remains active during the heat dissipation-based operation, and the heat dissipation-based operation is an operation using heat dissipation performed by the heat dissipator,   the heating controller starts the heating in the heater in response to the start of the heat dissipation-based operation, and the heating controller temporarily stops the heating when the temperature detected by the outgoing temperature sensor reaches a heating stop temperature, and resumes the heating when the temperature of the heating medium in the circulation circuit decreases to a heating resumption temperature, and   the overheating abnormality detector increments a stop count when the heating in the heater is stopped in response to the temperature detected by the outgoing temperature sensor reaching the heating stop temperature during the heat dissipation-based operation, the overheating abnormality detector detects the overheating abnormality when a detection condition is satisfied, and the detection condition is that the stop count reaches a determination count within a predetermined determination time.   
     
     
         2 . The heating medium circulation apparatus according to  claim 1 , wherein
 the overheating abnormality detector increments the stop count when the heating in the heater is stopped in response to the temperature detected by the outgoing temperature sensor reaching the heating stop temperature during the heat dissipation-based operation and when the temperature detected by the outgoing temperature sensor remains higher than an abnormality determination temperature for at least a specified time after the heating is stopped, and the abnormality determination temperature is higher than the heating stop temperature.   
     
     
         3 . The heating medium circulation apparatus according to  claim 1 , further comprising:
 a return temperature sensor configured to detect a temperature of the heating medium flowing into the heater,   wherein the detection condition that the stop count reaches the determination count within the determination time includes a further condition that the temperature detected by the return temperature sensor remains below a return reference temperature during a period from a return specific time point to a time at which the stop count reaches the determination count, the return specific time point is after the start of the heat dissipation-based operation, and the overheating abnormality detector detects the overheating abnormality when the detection condition including the further condition is satisfied.   
     
     
         4 . The heating medium circulation apparatus according to  claim 3 , wherein
 the return reference temperature is obtained by adding a return estimated increase to the temperature detected by the return temperature sensor at the return specific time point.   
     
     
         5 . The heating medium circulation apparatus according to  claim 1 , wherein
 the heat dissipator is a hot-water supply heat exchanger configured to heat, through heat exchange with the heating medium, water supplied from a water supply to produce hot water,   the heating medium circulation apparatus further comprises a hot-water supply temperature sensor configured to detect a temperature of the hot water supplied from the hot-water supply heat exchanger, and   the detection condition that the stop count reaches the determination count within the determination time includes a further condition that the temperature detected by the hot-water supply temperature sensor remains below a hot-water supply reference temperature during a period from a hot-water supply specific time point to a time at which the stop count reaches the determination count, the hot-water supply specific time point is after the start of the heat dissipation-based operation, and the overheating abnormality detector detects the overheating abnormality when the detection condition including the further condition is satisfied.   
     
     
         6 . The heating medium circulation apparatus according to  claim 5 , wherein
 the hot-water supply reference temperature is obtained by adding a hot-water supply estimated increase to the temperature detected by the hot-water supply temperature sensor at the hot-water supply specific time point.   
     
     
         7 . The heating medium circulation apparatus according to  claim 2 , further comprising:
 a return temperature sensor configured to detect a temperature of the heating medium flowing into the heater,   wherein the detection condition that the stop count reaches the determination count within the determination time includes a further condition that the temperature detected by the return temperature sensor remains below a return reference temperature during a period from a return specific time point to a time at which the stop count reaches the determination count, the return specific time point is after the start of the heat dissipation-based operation, and the overheating abnormality detector detects the overheating abnormality when the detection condition including the further condition is satisfied.   
     
     
         8 . The heating medium circulation apparatus according to  claim 7 , wherein
 the return reference temperature is obtained by adding a return estimated increase to the temperature detected by the return temperature sensor at the return specific time point.   
     
     
         9 . The heating medium circulation apparatus according to  claim 2 , wherein
 the heat dissipator is a hot-water supply heat exchanger configured to heat, through heat exchange with the heating medium, water supplied from a water supply to produce hot water,   the heating medium circulation apparatus further comprises a hot-water supply temperature sensor configured to detect a temperature of the hot water supplied from the hot-water supply heat exchanger, and   the detection condition that the stop count reaches the determination count within the determination time includes a further condition that the temperature detected by the hot-water supply temperature sensor remains below a hot-water supply reference temperature during a period from a hot-water supply specific time point to a time at which the stop count reaches the determination count, the hot-water supply specific time point is after the start of the heat dissipation-based operation, and the overheating abnormality detector detects the overheating abnormality when the detection condition including the further condition is satisfied.   
     
     
         10 . The heating medium circulation apparatus according to  claim 9 , wherein
 the hot-water supply reference temperature is obtained by adding a hot-water supply estimated increase to the temperature detected by the hot-water supply temperature sensor at the hot-water supply specific time point.