JP5764533B2 - Hot water heating system - Google Patents

Description

  The technology disclosed in the present specification relates to a hot water supply / heating system.

  Patent Document 1 discloses a heat pump including a pipe for circulating a refrigerant, a hot water storage tank for storing hot water, a heating circulation circuit for introducing water in the hot water storage tank and returning the introduced water to the hot water storage tank, and heat of the refrigerant. A heat pump type hot water heater including a water-refrigerant heat exchanger that heats water in a heating circuit by exchange and an outside air temperature detection sensor that detects outside air temperature is disclosed. When the outside air temperature detection sensor detects a predetermined freezing risk temperature, the heat pump water heater of Patent Document 1 performs a freeze prevention operation that activates the heat pump and circulates the water in the heating circuit. By this anti-freezing operation, hot water is circulated in the heating circuit, and freezing of the heating circuit is suppressed.

JP 2009-156495 A

  The heat pump exchanges heat between the outside air and the refrigerant, and absorbs heat from the outside air. For this reason, when the outside air temperature becomes low, the temperature difference between the refrigerant and the outside air temperature becomes small, and a situation may occur in which the heat pump cannot efficiently absorb heat from the outside air. In such a case, in the heat pump type water heater of Patent Document 1, the heat pump does not effectively operate as a heat source. For this reason, even if anti-freezing operation is performed, high-temperature hot water cannot be circulated in the heating circulation circuit, and the freezing of the heating circulation circuit may not be sufficiently suppressed.

  In the present specification, a hot water supply and heating system capable of appropriately suppressing freezing of pipes even when the outside air temperature is so low as to be unsuitable for operation of a heat pump is disclosed.

  The hot water supply and heating system disclosed in the present specification includes a heat pump, a tank, a tank water circulation path, a second heat medium circulation path, a heating device, a heater, a three-fluid heat exchanger, and an outside air temperature sensor. Prepare. The heat pump includes a first heat medium circulation path for circulating the first heat medium. The tank stores water to be supplied to the hot water use location. The tank water circuit introduces water in the tank and returns the introduced water to the tank. The second heat medium circulation path circulates the second heat medium. The heating device heats the second heat medium with heat generated by consuming the gas. The heater heats using the heat of the second heat medium. The three-fluid heat exchanger performs heat exchange between the first heat medium circuit and the tank water circuit and between the first heat medium circuit and the second heat medium circuit. The outside air temperature sensor measures the outside air temperature. When the outside air temperature measured by the outside air temperature sensor is lower than the first predetermined temperature, the heating device is operated without operating the heat pump, the second heat medium in the second heat medium circulation path is circulated, and the tank water circulation The first anti-freezing operation for circulating the water in the road is executed.

  Here, the first predetermined temperature is a temperature at which, for example, when the outside air temperature falls below that temperature, there is a high possibility that the heat pump cannot efficiently absorb heat from the outside air.

  As described above, the first predetermined temperature is a temperature at which, for example, when the outside air temperature falls below that temperature, there is a high possibility that the heat pump cannot absorb heat efficiently from the outside air. In the hot water supply and heating system, when the outside air temperature measured by the outside air temperature sensor is lower than the first predetermined temperature, the heating device is operated without operating the heat pump and the first antifreezing operation is executed. Accordingly, the second heat medium in the second heat medium circuit is heated by the heating device. In the three-fluid heat exchanger, heat is exchanged between the second heat medium in the second heat medium circuit and the first heat medium in the first heat medium circuit, and the first heat medium is heated by the heat of the second heat medium. The heat medium is heated. Furthermore, heat exchange is performed between the first heat medium in the first heat medium circuit and the water in the tank water circuit, and the water is heated by the heat of the first heat medium. Therefore, as a result of the first freeze prevention operation, the temperature of the second heat medium in the second heat medium circuit, the first heat medium in the first heat medium circuit, and the water in the tank water circuit increases. . As a result, when the outside air temperature measured by the outside air temperature sensor is lower than the first predetermined temperature, the tank water circulation path, the first heat medium circulation path, the second heat medium circulation path, etc. can be used without operating the heat pump. Freezing of piping can be suppressed. Therefore, the hot water supply and heating system can appropriately suppress the freezing of the pipes even when the outside air temperature becomes so low that it is not suitable for the operation of the heat pump.

The figure which shows typically operation | movement of the hot water supply heating system at the time of a thermal storage driving | operation and a hot water supply driving | operation. The figure which shows typically operation | movement of the hot-water supply heating system at the time of heating operation. The flowchart which shows a tank water circuit freezing prevention driving | operation. The flowchart which shows the water circulation path freezing prevention operation for heating. The table | surface which shows the setting value of the operation time with respect to the detection temperature TW of the thermistor 98, and supply temperature. The table | surface which shows the setting value of the interval time with respect to outside temperature T. FIG. The figure which shows typically operation | movement of the hot-water supply heating system at the time of a 1st freeze prevention driving | operation. The figure which shows typically operation | movement of the hot-water supply heating system at the time of a 2nd freeze prevention driving | operation.

  The main features of the embodiments described below are listed. The technical elements described below are independent technical elements and exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Absent.

(Feature 1) When the outside air temperature measured by the outside air temperature sensor is equal to or higher than the first predetermined temperature and lower than the second predetermined temperature, at least the heat pump of the heat pump and the heating device is operated, and the second heat It is preferable to execute the second anti-freezing operation in which the second heat medium in the medium circulation path is circulated and the water in the tank water circulation path is circulated.

  The second predetermined temperature is, for example, a temperature at which the water in the tank water circulation path may freeze if the outside air temperature falls below that temperature. The second predetermined temperature is higher than the first predetermined temperature.

  When the outside air temperature is equal to or higher than the first predetermined temperature and lower than the second predetermined temperature, the heat pump can efficiently absorb heat from the outside air. According to the above configuration, when the outside air temperature measured by the outside air temperature sensor is equal to or higher than the first predetermined temperature and lower than the second predetermined temperature (that is, the heat pump can efficiently absorb heat from the outside air). In the case of the outside air temperature), at least the heat pump is operated among the heat pump and the heating device, and the second antifreezing operation is executed. Since a heat pump can be used as a heat source, freezing of piping can be effectively suppressed. Moreover, energy efficiency is good compared with the case where only a heating device is used as a heat source. Therefore, the hot water supply / heating system can appropriately suppress the freezing of the piping.

(Example)
As shown in FIG. 1, the hot water supply and heating system 2 according to this embodiment includes a hot water supply system 104, a heat pump system 106, a heating system 108, an outside air temperature sensor 40, and a control device 100.

The heat pump system 106 includes a heat pump 50 and a three-fluid heat exchanger 58. The heat pump 50 includes a heat medium circulation path 52 for circulating a heat medium (for example, HFC refrigerant (R410A) or CO ₂ refrigerant), a heat exchanger (evaporator) 54, a fan 56, and a compressor 62. And an expansion valve 60. The heat medium circulation path 52 passes through the three-fluid heat exchanger 58. Further, the heat exchanger 54, the compressor 62, and the expansion valve 60 are installed in the heat medium circuit 52.

  The heat exchanger 54 heats the heat medium by exchanging heat between the outside air blown by the fan 56 and the heat medium in the heat medium circulation path 52. The compressor 62 compresses the heat medium in the heat medium circuit 52 and sends it out to the three-fluid heat exchanger 58 side. As a result, the heat medium in the heat medium circuit 52 circulates in the order of the heat exchanger 54, the compressor 62, the three-fluid heat exchanger 58, and the expansion valve 60.

  The high-temperature and high-pressure gaseous heat medium sent out from the compressor 62 is supplied to the heat medium circuit 52 of the three-fluid heat exchanger 58. The three-fluid heat exchanger 58 can exchange heat between the heat medium in the heat medium circuit 52 and water in the tank water circuit 20 described later. Furthermore, the three-fluid heat exchanger 58 can exchange heat between the heat medium in the heat medium circulation path 52 and water in a heat recovery path 88 described later. That is, the three-fluid heat exchanger 58 functions as a first heat exchanger that heats the water in the tank water circulation path 20 and a second heat exchanger that heats the water in the heat recovery path 88. As a result of heat exchange, the heat medium is deprived of heat and condensed. As a result, the heat medium becomes a high-pressure liquid state at a relatively low temperature.

  The expansion valve 60 is supplied with a liquid medium having a relatively low temperature and high pressure after passing through the three-fluid heat exchanger 58. The heat medium is depressurized by passing through the expansion valve 60, and becomes a low-temperature and low-pressure liquid state. The heat medium that has passed through the expansion valve 60 is supplied to the heat exchanger 54 as described above.

  The hot water supply system 104 includes a tank 10, a tank water circulation path 20, a tap water introduction path 24, a supply path 36, and a burner heating device 81.

  The tank 10 stores hot water heated by the heat pump 50. The tank 10 is a hermetically sealed type, and the outside is covered with a heat insulating material. Water is stored in the tank 10 until it is full. The thermistors 12, 14, 16 and 18 are attached to the tank 10 at substantially equal intervals in the height direction of the tank 10. Each thermistor 12, 14, 16, 18 measures the temperature of water at its mounting position.

  The tank water circulation path 20 has an upstream end connected to the lower part of the tank 10 and a downstream end connected to the upper part of the tank 10. A circulation pump 22 is interposed in the tank water circulation path 20. The circulation pump 22 sends the water in the tank water circulation path 20 from the upstream side to the downstream side. Further, as described above, the tank water circulation path 20 passes through the three-fluid heat exchanger 58. Therefore, when the heat pump 50 is operated, the water in the tank water circulation path 20 is heated by the three-fluid heat exchanger 58. Accordingly, when the circulation pump 22 and the heat pump 50 are operated, the water in the lower part of the tank 10 is sent to the three-fluid heat exchanger 58 and heated, and the heated water is returned to the upper part of the tank 10. The tank water circulation path 20 is a water path for storing heat in the tank 10.

  The upstream end of the tap water introduction path 24 is connected to a tap water supply source 32. The downstream side of the tap water introduction path 24 is branched into a first introduction path 24a and a second introduction path 24b. The downstream end of the first introduction path 24 a is connected to the lower part of the tank 10. The downstream end of the second introduction path 24 b is connected in the middle of the supply path 36. A check valve 26 is interposed in the first introduction path 24a. A check valve 28 and a flow rate adjustment valve 30 are interposed in the second introduction path 24b. The flow rate adjustment valve 30 adjusts the flow rate of tap water flowing in the second introduction path 24b.

  The upstream end of the supply path 36 is connected to the upper part of the tank 10. As described above, the second introduction path 24 b of the tap water introduction path 24 is connected in the middle of the supply path 36. A flow rate adjustment valve 34 is interposed in the supply path 36 upstream from the connection portion with the second introduction path 24b. The flow rate adjustment valve 34 adjusts the flow rate of water flowing in the supply path 36. A burner heating device 81 is interposed in the supply path 36 on the downstream side of the connection portion with the second introduction path 24b. The burner heating device 81 heats the water in the supply path 36. The downstream end of the supply path 36 is connected to a hot water tap 38.

  The heating system 108 includes a cistern 70, a heating water circulation path 71, a burner heating device 82, and a heater 76. The heating water circulation path 71 includes a heating forward path 72, a heating return path 84, a regulating valve 90, a heat recovery path 88, a bypass path 94, and a circulation path 96. The heating water circulation path 71 is a water path for circulating the water in the cistern 70. Water in the heating water circulation path 71 is heated by the burner heating device 82 and the three-fluid heat exchanger 58.

  The cistern 70 is a container having an open top and stores water therein. The downstream end of the circulation flow path 96 and the upstream end of the heating forward path 72 are connected to the cistern 70. Water flows from the circulation channel 96 into the cistern 70. Water in the cistern 70 is introduced into the heating forward path 72.

  The heating forward path 72 has an upstream end connected to the cistern 70 and a downstream end connected to an outlet of the heater 76. A circulation pump 74 is interposed in the heating forward path 72. The circulation pump 74 sends out the water in the heating forward path 72 to the downstream side. A burner heating device 82 is interposed in the heating forward path 72 upstream of the heater 76. The burner heating device 82 heats the water in the heating forward path 72. The operation of the burner heating device 82 is illustrated in FIG. The burner heating device 82 has a higher ability to heat water circulating in the heating water circulation path 71 than the heat pump 50. In other words, the burner heating device 82 has a higher heating amount per unit time than the heat pump 50. The water heated by the burner heating device 82 is supplied to the heater 76. Further, a thermistor 86 is interposed on the downstream side of the burner heating device 82 and on the upstream side of the heater 76 in the heating forward path 72. The thermistor 86 measures the temperature of the water in the heating forward path 72 after passing through the burner heating device 82.

  The heater 76 heats the living room using the heat of water supplied from the heating forward path 72. When the water supplied from the heating forward path 72 is used for heating, it is deprived of heat and becomes relatively low temperature water. The relatively low-temperature water after being used for heating is introduced into the heating return path 84.

  The heating return path 84 has an upstream end connected to the return port of the heater 76, and a downstream end connected to the upstream end of the bypass path 94 and the upstream end of the heat recovery path 88.

  The heat recovery path 88 has an upstream end connected to the upstream end of the bypass path 94 and the downstream end of the heating return path 84, and a downstream end connected to the downstream end of the bypass path 94 and the upstream end of the circulation flow path 96. The heat recovery path 88 passes through the three-fluid heat exchanger 58. Therefore, when the heat pump 50 is operated, the water in the heat recovery path 88 is heated by the three-fluid heat exchanger 58.

  The bypass path 94 has an upstream end connected to the downstream end of the heating return path 84 and the upstream end of the heat recovery path 88, and a downstream end connected to the downstream end of the heat recovery path 88 and the upstream end of the circulation path 96. That is, the bypass path 94 bypasses the upstream side and the downstream side of the three-fluid heat exchanger 58.

  The regulating valve 90 is attached to a connection portion between the downstream end of the heating return path 84, the upstream end of the heat recovery path 88, and the upstream end of the bypass path 94. The regulating valve 90 changes the opening degree, thereby allowing the flow rate of water passing through the heat recovery path 88 (flow rate of water passing through the three-fluid heat exchanger 58) and the flow rate of water passing through the bypass path 94. The ratio of can be changed. For example, a three-way valve is used as the adjustment valve 90.

  The circulation channel 96 has an upstream end connected to the downstream end of the heat recovery path 88 and the downstream end of the bypass path 94, and a downstream end connected to the cistern 70. A thermistor 98 is interposed in the circulation channel 96. The thermistor 98 measures the temperature of water in the circulation channel 96.

  The outside air temperature sensor 40 is provided near the tank 10 of the hot water supply system 104 and can measure the outside air temperature.

  The control device 100 is electrically connected to the hot water supply system 104, the heat pump system 106, the heating system 108, and the outside air temperature sensor 40, and controls the operation of each component.

(Operation of hot water heating system)
Next, the operation of the hot water supply / heating system 2 of the present embodiment will be described. The hot water supply and heating system 2 can execute a heat storage operation, a hot water supply operation, a heating operation, and a freeze prevention operation. Hereinafter, each operation will be described.

(Heat storage operation)
The heat storage operation is an operation in which water in the tank 10 is heated by heat generated by the heat pump 50. 1 indicate the flow of the heat medium of the heat pump 50 and the flow of water in the tank 10 during the heat storage operation. When execution of the heat storage operation is instructed by the control device 100, the heat pump 50 operates and the circulation pump 22 rotates. At this time, in the heat pump 50, the compressor 62 operates.

  When the heat pump 50 operates, the heat medium in the heat medium circuit 52 circulates in the order of the heat exchanger 54, the compressor 62, the three-fluid heat exchanger 58, and the expansion valve 60. In this case, the heat medium in the heat medium circuit 52 passing through the three-fluid heat exchanger 58 is in a high-temperature and high-pressure gas state. Further, when the circulation pump 22 rotates, the water in the tank 10 circulates in the tank water circulation path 20. That is, the water existing in the lower part of the tank 10 is introduced into the tank water circulation path 20 and is heated by the heat of the heat medium in the heat medium circulation path 52 when the introduced water passes through the three-fluid heat exchanger 58. The heated water is returned to the upper part of the tank 10. Thereby, hot water is stored in the tank 10. A high temperature water layer is formed in the upper part of the tank 10, and a low temperature water layer is formed in the lower part.

(Hot water operation)
The hot water supply operation is an operation for supplying water in the tank 10 to the hot water tap 38. The broken line arrows in FIG. 1 indicate the flow of water in the tank 10 during the hot water supply operation. The hot water supply operation can also be executed during the above heat storage operation. When the hot water tap 38 is opened, the control device 100 opens the flow rate adjustment valve 34. Then, tap water flows into the lower part of the tank 10 from the tap water introduction path 24 (first introduction path 24 a) due to the water pressure from the tap water supply source 32. At the same time, the hot water in the upper part of the tank 10 is supplied to the hot water tap 38 via the supply path 36.

  When the temperature of the water supplied from the tank 10 to the supply path 36 (that is, the detected temperature of the thermistor 12) is higher than the hot water supply set temperature, the control device 100 opens the flow rate adjustment valve 30 and the second introduction path 24b. Tap water is introduced into the supply path 36. Accordingly, the water supplied from the tank 10 and the tap water supplied from the second introduction path 24 b are mixed in the supply path 36. The control device 100 adjusts the opening degree of the flow rate adjusting valve 30 so that the temperature of the water supplied to the hot water tap 38 matches the hot water supply set temperature. On the other hand, the control device 100 operates the burner heating device 81 when the temperature of the water supplied from the tank 10 to the supply path 36 is lower than the hot water supply set temperature. Accordingly, the water passing through the supply path 36 is heated by the burner heating device 81. The control device 100 controls the output of the burner heating device 81 so that the temperature of the water supplied to the hot-water tap 38 matches the hot-water supply set temperature.

(Heating operation)
The heating operation is an operation in which the room 76 is heated by operating the heater 76. FIG. 2 shows an example of the operation of each component during heating operation. The solid arrows in FIG. 2 indicate the flow of the heat medium of the heat pump 50 and the flow of water in the heating water circulation path 71.

  When the execution of the heating operation is instructed by the user, the control device 100 operates the circulation pump 74. As a result, the water in the cistern 70 circulates so as to pass through the heating forward path 72, the heater 76, the heating return path 84, the heat recovery path 88, and the circulation path 96 in this order and return to the cistern 70. Immediately after the heating operation is started, the opening of the adjustment valve 90 is adjusted so that all of the water in the heating water circulation path 71 passes through the three-fluid heat exchanger 58.

  Further, the control device 100 operates the burner heating device 82 and the heat pump 50 simultaneously with the circulation pump 74. As a result, the water circulating in the path is heated by the burner heating device 82 when passing through the heating forward path 72, and in the three-fluid heat exchanger 58 when passing through the heat recovery path 88. Heated by the heat of the heat medium in the circulation path 52. As a result, water heated using both the burner heating device 82 and the heat pump 50 is supplied to the heater 76. Furthermore, the control device 100 operates the heater 76. The heater 76 heats the living room using the heat of the supplied water.

  After that, when the temperature of the water in the heating water circulation path 71 is increased and the heating efficiency of the water by the heat pump 50 is reduced, the control device 100 causes the water flowing in the heat recovery path 88 to flow as shown in FIG. The opening degree of the regulating valve 90 is adjusted so that a part thereof passes through the bypass passage 94 and is introduced into the circulation passage 96. Thereby, since the flow volume of the water heated with the heat pump 50 reduces, the temperature rise of the water in the water circulation path 71 for heating can be suppressed.

  Thereafter, by continuing the heating operation, when the temperature of the water in the heating water circulation path 71 is increased again and the heating efficiency of the water by the heat pump 50 is decreased again, the control device 100 stops the heat pump 50. . Thereby, the water in the heating water circulation path 71 is not heated by the heat pump 50.

  Thereafter, by continuing the heating operation, when the temperature of the water in the heating water circulation path 71 becomes sufficiently high (that is, when the heater 76 is in a raised state), the control device 100 can control the burner heating device. 82 is stopped. Heat of the water in the heating water circulation path 71 that is sufficiently heated is supplied to the heater 76.

  Thereafter, when the temperature of the water in the heating water circulation path 71 is lowered by continuing the heating operation, the control device 100 appropriately operates the heat pump 50 to heat the temperature of the water in the heating water circulation path 71. To do. Thereby, the stable heating operation can be performed using the heat pump 50 as a heat source.

  In addition, when the temperature detected by the outside air temperature sensor 40 (that is, the outside air temperature T) is low enough that the heat pump 50 cannot efficiently heat water at the start of the heating operation (for example, the outside air temperature is −10 ° C. If lower, the control device 100 can also perform the heating operation by operating only the burner heating device 82 as a heat source without operating the heat pump 50 as a heat source.

(Anti-freezing operation)
The freeze prevention operation is an operation for preventing the pipes such as the tank water circulation path 20, the heating water circulation path 71, and the heat medium circulation path 52 from being frozen and damaged in a situation where the outside air temperature is low. The control device 100 performs the tank water circulation path freeze prevention operation (see FIG. 3) for preventing the tank water circulation path 20 from being frozen and broken, and the heating water circulation path freeze prevention for preventing the heating water circulation path 71 from being frozen and broken. The operation (see FIG. 4) is performed simultaneously. 3 and 4 are flowcharts showing the tank water circulation path freeze prevention operation and the heating water circulation path freeze prevention operation, respectively. As a result of the control device 100 performing the tank water circulation path freeze prevention operation and the heating water circulation path freeze prevention operation, the hot water heating and heating system 2 as a whole performs the first freeze prevention operation (see FIG. 7) and the second freeze. One of the prevention operations (see FIG. 8) is executed. FIG. 7 shows the operation of each component during the first freeze prevention operation. FIG. 8 shows the operation of each component during the second freeze prevention operation.

  Hereinafter, the tank water circuit freezing prevention operation and the heating water circuit freezing prevention operation performed by the control device 100 will be described in order with reference to FIGS. 3 and 4.

(Tank water circuit freeze prevention operation)
First, with reference to FIG. 3, the tank water circuit freezing prevention operation which prevents the tank water circuit 20 from freezing will be described. In S10 and S12, the control device 100 determines that the outside air temperature T detected by the outside air temperature sensor 40 is lower than a predetermined threshold T1, and the temperature detected by the thermistor 21 (that is, the water temperature in the tank water circulation path 20). ) Becomes lower than a predetermined threshold value T2. The predetermined threshold T1 is an air temperature at which the water in the tank water circulation path may freeze if the outside air temperature T falls below that temperature. The predetermined threshold T1 is 5 ° C., for example. Further, the predetermined threshold T2 is a water temperature at which the water in the tank water circulation path 20 may freeze if the temperature detected by the thermistor 21 (that is, the temperature of the water in the tank water circulation path 20) falls below that temperature. . The predetermined threshold T2 is, for example, 10 ° C. When the outside air temperature T is lower than the threshold value T1 and the detected temperature of the thermistor 21 is lower than the threshold value T2 (YES in S10 and YES in S12), the control device 100 proceeds to S14.

  In S <b> 14, the control device 100 operates the circulation pump 22. Thereby, the water in the lower part of the tank 10 is introduced into the tank water circulation path 20, passes through the three-fluid heat exchanger 58, and is returned to the upper part of the tank 10.

  Next, in S16, the control device 100 monitors that the first circulation time has elapsed. The first circulation time is, for example, 4 minutes. When the first circulation time has elapsed, the control device 100 determines YES in S16, and proceeds to S18.

  In S18, the control device 100 stops the circulation pump 22. By operating the circulation pump 22 during the first circulation time, the temperature of the water in each part in the tank water circulation path 20 is made uniform.

  Next, in S20, the control device 100 determines whether or not the detected temperature of the thermistor 25 (that is, the temperature of the water in the tank water circuit 20 after passing through the three-fluid heat exchanger 58) is lower than a predetermined threshold T3. to decide. The predetermined threshold T3 is, for example, 13 ° C. For example, even when the detected temperature of the thermistor 21 (that is, the temperature of water in the tank water circulation path 20) is lower than a predetermined threshold T2 at the time when the tank water circulation path freeze prevention operation is started, May contain relatively hot water. In that case, when the circulation pump 22 is operated during the first circulation time in S14 to S18 described above, the relatively hot water in the tank 10 circulates in the tank water circulation path 20. As a result, the detected temperature of the thermistor 25 may be equal to or higher than the threshold T3 at S20. When the temperature detected by the thermistor 25 is equal to or higher than the threshold T3, there is little possibility that the water in the tank water circulation path 20 will freeze. Therefore, in this case, the control device 100 determines NO in S20, ends the tank water circulation path freeze prevention, returns to S10 and S12 again, and performs monitoring.

  On the other hand, if the detected temperature of the thermistor 25 is lower than the threshold value T3 at the time of S20, the water in the tank water circulation path 20 may be frozen. Therefore, in that case, the control device 100 determines YES in S20, and proceeds to S24.

  In S24, the control device 100 determines whether or not the outside air temperature T detected by the outside air temperature sensor 40 is equal to or greater than a predetermined threshold value T4. Here, the predetermined threshold T4 is a temperature at which there is a high possibility that the heat pump 50 cannot efficiently absorb heat from the outside air when the outside air temperature T falls below that temperature. The predetermined threshold T4 is, for example, −10 ° C. The predetermined threshold T4 is a temperature lower than the predetermined threshold T1. When the outside air temperature T is equal to or higher than the threshold T4, the control device 100 determines YES in S24, and proceeds to S26. On the other hand, when the outside air temperature is lower than the threshold value T4, the control device 100 determines NO in S24, and proceeds to S34.

  In S26, the control device 100 operates the circulation pump 22 and the heat pump 50. Thereby, the water in the lower part of the tank 10 is sent to the three-fluid heat exchanger 58 and heated, and the heated water is returned to the upper part of the tank 10. As a result, the temperature of the water in the tank water circulation path 20 rises. By operating the circulation pump 22 and the heat pump 50 in S26, a second freeze prevention operation (see FIG. 8) described later is realized.

  When the circulation pump 22 and the heat pump 50 are operated in S26, in S28 and S30, the control device 100 indicates that the outside air temperature T becomes equal to or higher than the predetermined threshold T1, or the detected temperature of the thermistor 21 is equal to or higher than the predetermined threshold T2. Watch for becoming. When the outside air temperature T is equal to or higher than the threshold T1, the control device 100 determines YES in S28, and proceeds to S32. Further, as a result of operating the circulation pump 22 and the heat pump 50, when the detected temperature of the thermistor 21 is equal to or higher than the threshold T2 (that is, when the temperature of water in the tank water circulation path 20 is equal to or higher than the threshold T2), the control device 100 Determines YES in S30 and proceeds to S32.

  In S32, the control device 100 stops the circulation pump 22 and the heat pump 50. When S32 ends, the control device 100 ends the tank water circulation path freeze prevention operation. In that case, the control apparatus 100 returns to S10 and S12 again and performs monitoring.

  On the other hand, in S34, since the outside air temperature is lower than the threshold value T4, the control device 100 operates only the circulation pump 22 without operating the heat pump 50. In this case, as will be described later, the water in the heating water circulation path 71 (heat recovery path 88) heats the heat medium in the heat medium circulation path 52. Further, the water in the tank water circulation path 20 is heated by the heat of the heat medium in the heated heat medium circulation path 52. As a result, the temperature of the water in the tank water circuit 20 gradually increases. By operating the circulation pump 22 in S34, the first anti-freezing operation (see FIG. 7) described later is realized.

  When the circulation pump 22 is operated in S34, in S36 and S38, the control device 100 causes the outside air temperature T to be equal to or higher than the predetermined threshold T1, or the detected temperature of the thermistor 21 is equal to or higher than the predetermined threshold T2. To monitor. When the outside air temperature T is equal to or higher than the threshold T1, the control device 100 determines YES in S36, and proceeds to S40. If the detected temperature of the thermistor 21 is equal to or higher than the threshold T2, the control device 100 determines YES in S38, and proceeds to S40.

  In S40, the control device 100 stops the circulation pump 22. When S40 ends, the control device 100 ends the tank water circulation path freeze prevention operation. In that case, the control apparatus 100 returns to S10 and S12 again and performs monitoring.

(Heating water circuit freezing prevention operation)
Next, with reference to FIG. 4, the heating water circulation path freezing prevention operation for preventing the heating water circulation path 71 from freezing will be described. In S50, the control device 100 monitors that the outside air temperature T detected by the outside air temperature sensor 40 is lower than a predetermined threshold value T1. When the outside air temperature T is lower than the threshold value T1, the control device 100 determines YES in S50, and proceeds to S52.

  In S <b> 52, the control device 100 operates the circulation pump 74. As a result, the water in the cistern 70 circulates so as to pass through the heating forward path 72, the heater 76, the heating return path 84, the heat recovery path 88, and the circulation flow path 96 in this order and return to the cistern 70 (FIG. 7, see FIG. In the heating water circuit freezing prevention operation, the opening of the adjustment valve 90 is adjusted so that all the water in the heating water circuit 71 passes through the three-fluid heat exchanger 58 (FIGS. 7 and 7). 8).

  Next, in S54, the control device 100 monitors whether the second circulation time has elapsed. The second circulation time is, for example, 4 minutes. When the second circulation time has elapsed, the control device 100 determines YES in S54, and proceeds to S56.

  In S56, the control device 100 stops the circulation pump 74. By operating the circulation pump 74 for the second circulation time, the temperature of the water in each part in the heating water circulation path 71 is made uniform.

  Next, in S58, the control device 100 determines the operation time and the supply temperature based on the detected temperature TW of the thermistor 98 (that is, the temperature of the water in the heating water circulation path 71 after being made uniform). Here, the operation time is a time for operating the circulation pump 74 and the burner heating device 82. The supply temperature is the temperature of water supplied to the three-fluid heat exchanger 58 (heat recovery path 88). That is, the supply temperature is the temperature of water in the heating forward path 72 after being heated by the burner heating device 82 (the temperature detected by the thermistor 86).

  Specifically, in S58, the control device 100 determines a preset operation time and supply temperature according to the detected temperature TW of the thermistor 98 (see FIG. 5). FIG. 5 is a table showing the set values of the operation time and supply time for each detected temperature TW of the thermistor 98. As shown in FIG. 5, for example, when the temperature TW is 20 ° C. or higher, the operation time is set to 2 minutes and the supply temperature is set to 55 ° C. Moreover, when temperature TW is 15 degreeC or more and less than 20 degreeC, operation time is set to 4 minutes and supply temperature is set to 60 degreeC. That is, in this embodiment, the lower the temperature TW, the longer the operation time and the higher the supply temperature. In S <b> 58, the control device 100 determines the operation time and the supply temperature according to FIG. 5 according to the detected temperature TW of the thermistor 98.

  Next, in S60, the control device 100 operates the circulation pump 74 and the burner heating device 82. At this time, the burner heating device 82 adjusts the heating amount so that the temperature of the water in the heating forward path 72 after heating becomes the supply temperature determined in S58. As a result, the water circulating in the heating water circulation path 71 is heated by the burner heating device 82. As a result, the temperature of the water in the heating water circuit 71 rises. By operating the circulation pump 74 and the burner heating device 82 in S60, a first anti-freezing operation (see FIG. 7) and a second anti-freezing operation (FIG. 8) described later are realized.

  When the circulation pump 74 and the burner heating device 82 are operated in S60, the control device 100 monitors that the operation time determined in S58 has elapsed in S64. When the operation time has elapsed, the control device 100 determines YES in S64, and proceeds to S66. In S66, the control device 100 stops the circulation pump 74 and the burner heating device 82.

  Next, in S <b> 68, the control device 100 determines the interval time according to the outside air temperature T detected by the outside air temperature sensor 40. The interval time is the time until the heating water circulation path freeze prevention operation is started next. Specifically, in S68, the control device 100 determines a preset interval time according to the outside air temperature T (see FIG. 6). FIG. 6 is a table showing the set values of the interval time for each outside air temperature T. As shown in FIG. 6, for example, when the outside air temperature T is 3 ° C. or higher, the interval time is set to 60 minutes. When the outside air temperature T is 1 ° C. or higher and lower than 3 ° C., the interval time is set to 50 minutes. That is, in this embodiment, the interval time is set to be shorter as the outside air temperature T is lower. In S68, the control device 100 determines an interval time according to FIG.

  Next, in S70, the control device 100 monitors whether the interval time determined in S68 has elapsed. When the interval time elapses, the control device 100 determines YES in S70 and ends the heating water circulation path freeze prevention operation. In that case, the control apparatus 100 returns to S50 and performs monitoring.

  The tank water circulation path freeze prevention operation and the heating water circulation path freeze prevention operation executed by the control device 100 have been described above. Next, as a result of the controller 100 performing the tank water circulation path freeze prevention operation and the heating water circulation path freeze prevention operation, the first freeze prevention operation (see FIG. 7) and the first operation realized in the entire hot water supply and heating system 2 are performed. The anti-freezing operation 2 (see FIG. 8) will be described.

(First freeze prevention operation)
As described above, when the outside air temperature T is lower than a predetermined threshold value T4 (for example, −10 ° C.), the heat pump 50 cannot efficiently absorb heat from the outside air and is not suitable for operation. In that case, the control device 100 determines NO in S24 of FIG. 3 and determines YES in S50 of FIG. As a result, as shown in FIG. 7, in the hot water supply / heating system 2, the first anti-freezing operation is realized.

  Specifically, the control device 100 operates only the circulation pump 22 without operating the heat pump 50 (S34 in FIG. 3). Thereby, the water in the tank water circulation path 20 circulates. Further, the control device 100 operates the circulation pump 74 and the burner heating device 82 (S60 in FIG. 4). Thus, the water in the heating water circulation path 71 circulates in the heating water circulation path 71 and is heated by the burner heating device 82. As a result, the temperature of the water in the heating water circuit 71 increases.

  As shown in FIG. 7, in the first freeze prevention operation, the heat pump 50 does not operate, but in the three-fluid heat exchanger 58, the water in the heating water circulation path 71 (heat recovery path 88) and the heat medium circulation path Heat exchange is performed with the heat medium in 52. That is, the heat medium in the heat medium circulation path 52 is heated by the heat of the water in the heat recovery path 88. Further, in the three-fluid heat exchanger 58, heat exchange is performed between the heat medium in the heat medium circuit 52 and the water in the tank water circuit 20. That is, the water in the tank water circuit 20 is heated by the heat of the heat medium in the heat medium circuit 52. Therefore, as a result of the first freeze prevention operation, the temperature of the water in the tank water circulation path 20 gradually increases. Accordingly, the temperatures of the water in the heating water circulation path 71, the heat medium in the heat medium circulation path 52, and the water in the tank water circulation path 20 are increased.

  Therefore, when the outside air temperature is lower than the predetermined threshold T4, it is possible to suppress freezing of piping such as the tank water circulation path 20, the heat medium circulation path 52, and the heating water circulation path 71 without operating the heat pump 50. it can. Therefore, the hot water supply and heating system 2 of the present embodiment can appropriately suppress the freezing of the pipes even when the outside air temperature becomes so low that it is not suitable for the operation of the heat pump 50.

(Second anti-freezing operation)
As described above, the outside temperature T is equal to or higher than a predetermined threshold T4 (for example, −10 ° C.), but when it is lower than the predetermined threshold T1 (for example, 5 ° C.), the heat pump 50 can efficiently absorb heat from the outside air. . In this case, control device 100 determines YES in S24 of FIG. 3 and determines YES in S50 of FIG. As a result, as shown in FIG. 8, in the hot water supply and heating system 2, the second freeze prevention operation is realized.

  Specifically, the control device 100 operates the heat pump 50 and the circulation pump 22 (S26 in FIG. 3). Thereby, the water in the tank water circulation path 20 circulates in the tank water circulation path 20 and is heated by the three-fluid heat exchanger 58. As a result, the temperature of the water in the tank water circulation path 20 rises. Further, the control device 100 operates the circulation pump 74 and the burner heating device 82 (S60 in FIG. 5). Thus, the water in the heating water circulation path 71 circulates in the heating water circulation path 71 and is heated by the burner heating device 82. As a result, the temperature of the water in the heating water circuit 71 increases.

  As described above, when the outside air temperature T is equal to or higher than the predetermined threshold value T4 and lower than the predetermined threshold value T1, the heat pump 50 can be used as a heat source in addition to the burner heating device 82, so that freezing of the piping is effectively suppressed. can do. Therefore, the hot water supply and heating system 2 of the present embodiment can appropriately suppress the freezing of the piping when the outside air temperature is a temperature at which the piping may be frozen and damaged.

  In the above, the structure and operation | movement of the hot-water supply heating system 2 of a present Example were demonstrated. As described above, the hot water supply / heating system 2 according to the present embodiment performs the first freezing when the outside air temperature is lower than the predetermined threshold T4 (that is, when the outside air temperature is low enough not to be suitable for the operation of the heat pump 50). By performing the prevention operation, freezing of the piping can be appropriately suppressed. Further, the hot water supply / heating system 2 of the present embodiment has a temperature when the outside air temperature T is equal to or higher than the predetermined threshold value T4 and lower than the predetermined threshold value T1 (that is, the outside air temperature is a temperature at which the piping may be frozen and damaged). In some cases, it is possible to appropriately suppress the freezing of the piping by performing the second anti-freezing operation.

  The heat medium circulation path 52 and the heating water circulation path 71 of the present embodiment are examples of a “first heat medium circulation path” and a “second heat medium circulation path”, respectively. The threshold T4 and the threshold T1 are examples of “first predetermined temperature” and “second predetermined temperature”, respectively.

  As mentioned above, although the Example of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. For example, the following modifications are included.

(Modification 1) In the above embodiment, the control device 100 performs burner heating when the outside air temperature T is equal to or higher than a predetermined threshold T4 (for example, −10 ° C.) but lower than the predetermined threshold T1 (for example, 5 ° C.). In addition to the device 82, the heat pump 50 is operated and used as a heat source (second anti-freezing operation). Without being limited thereto, the control device 100 uses only the heat pump 50 as a heat source when the outside air temperature T is equal to or higher than a predetermined threshold T4 (for example, −10 ° C.) but lower than the predetermined threshold T1 (for example, 5 ° C.). May be. In this case, there is an advantage that the energy efficiency is good compared with the case where the burner heating device 82 is used as a heat source.

2: Hot water supply / heating system 10: Tanks 12, 14, 16, 18: Thermistor 20: Tank water circulation path 22: Circulation pump 24: Tap water introduction path 24a: First introduction path 24b: Second introduction path 26: Check valve 28 : Check valve 30: Flow rate adjustment valve 32: Tap water supply source 34: Flow rate adjustment valve 36: Supply path 38: Hot water tap 50: Heat pump 52: Heat medium circulation path 54: Heat exchanger 56: Fan 58: Three-fluid heat Exchanger 60: Expansion valve 62: Compressor 70: Systurn 71: Heating water circulation path 72: Heating forward path 74: Circulation pump 76: Heating machine 81: Burner heating apparatus 82: Burner heating apparatus 84: Heating return path 86: Thermistor 88: Heat recovery path 90: Regulating valve 94: Bypass path 96: Circulation path 98: Thermistor 100: Controller 104: Hot water supply system 106: Heat pump system 108: Heating system

Claims (2)

A hot water and heating system,
A heat pump including a first heat medium circulation path for circulating the first heat medium;
A tank for storing water to be supplied to the hot water use point;
A tank water circulation path for introducing water in the tank and returning the introduced water to the tank;
A second heat medium circulation path for circulating the second heat medium;
A heating device that heats the second heat medium by heat generated by consuming the gas;
A heater for heating using the heat of the second heat medium;
A three-fluid heat exchanger that exchanges heat between the first heat medium circuit and the tank water circuit and between the first heat medium circuit and the second heat medium circuit;
An outside air temperature sensor for measuring outside air temperature,
When the outside air temperature measured by the outside air temperature sensor is lower than the first predetermined temperature,
The first freeze prevention operation is performed in which the heating device is operated without operating the heat pump, the second heat medium in the second heat medium circuit is circulated, and the water in the tank water circuit is circulated.
Hot water heating system. When the outside air temperature measured by the outside air temperature sensor is equal to or higher than the first predetermined temperature and lower than the second predetermined temperature,
Performing at least a heat pump of the heat pump and the heating device, circulating the second heat medium in the second heat medium circulation path, and circulating the water in the tank water circulation path;
The hot water supply and heating system according to claim 1.

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