JP6520821B2 - Hot water storage system - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply system.

  A hot water storage type hot water supply system equipped with a hot water storage tank is widely used. The hot water storage type hot water supply system performs, for example, a heat storage operation in which hot water heated by heating means such as a heat pump device is accumulated in a hot water storage tank. If the hot water supplying operation of supplying hot water from the hot water storage tank to the outside is performed during the heat storage operation, the temperature of the water sent to the heating means may fluctuate. If the temperature of the water sent to the heating means fluctuates, the temperature of the hot water flowing out of the heating means fluctuates with respect to the target temperature.

  In the conventional hot water storage type hot water supply system disclosed in Patent Document 1 below, when the hot water supply operation is detected during heat storage operation, the driving speed of the pump that sends water to the heating means is fixed at a constant speed.

JP, 2014-1880, A

  A water supply pipe for supplying water from a water source such as a water supply is connected to the lower portion of the hot water storage tank. When the hot water supplying operation of supplying hot water from the hot water storage tank to the outside is performed, the water flows from the water supply pipe to the lower part of the hot water storage tank. In the state where the hot water supply operation is not performed at the time of the heat storage operation, the water stored in the lower part of the hot water storage tank is sent to the heating means. When the hot water supply operation is started from that state, the following occurs. Water flows into the lower part of the hot water storage tank from the water supply piping. Mixed water of the water supplied from the water supply pipe and the water stored in the lower part of the hot water storage tank is sent to the heating means.

  For example, in summer, the temperature of water supplied from the water supply pipe may be higher than the water temperature in the lower part of the hot water storage tank. In that case, the temperature of the mixed water is higher than the water temperature in the lower part of the hot water storage tank. Therefore, when the hot water supplying operation is started during the heat storage operation, the temperature of the water flowing into the heating means rises. In such a case, if the driving speed of the pump is fixed at a constant speed as in the invention of Patent Document 1, the temperature of the hot water from the heating means becomes higher than the target temperature. It is not preferable that the temperature of the outlet water from the heating means becomes higher than the target temperature, because an overshoot or the like of the hot water supply temperature may be caused.

  The present invention has been made to solve the above-described problems, and provides a hot water storage type hot water supply system capable of reducing fluctuations in the outlet water temperature from the heating means even when a hot water supply operation is performed during heat storage operation. The purpose is to

  The storage-type hot water supply system according to the present invention includes a hot water storage tank, a water supply flow path for supplying water to the hot water storage tank, a hot water supply flow path through which hot water flowing out from the hot water storage tank passes, and A means for detecting a certain water supply temperature, a means for detecting whether or not a hot water supply operation to a hot water supply channel is in progress, a heating means for heating water, and an incoming water flow for guiding water discharged from a hot water storage tank to an inlet of the heating means A hot water flow path for guiding the hot water from the outlet of the heating means to the hot water storage tank, a circulating pump in the incoming or outgoing water flow path, and the incoming water temperature which is the temperature of water entering the inlet of the heating means The water supply temperature is higher than the water supply temperature and the water supply temperature when the hot water supplying operation to the hot water supply flow path is started during the heat storage operation which is an operation of accumulating the hot water heated by the means and the heating means in the hot water storage tank. When the difference between the and the incoming water temperature is large compared to the standard Are those with respect to the state before the start of the hot water supply operation, and means for executing the speed increasing control to accelerated rotational speed of the circulating pump, the.

  According to the storage type hot water supply system of the present invention, even when the hot water supply operation is performed during the heat storage operation, it is possible to reduce the fluctuation of the outlet hot water temperature from the heating means.

FIG. 1 is a diagram showing a hot water storage type hot water supply system of a first embodiment. It is a figure which shows the example in case heat pump water intake temperature becomes high. It is a figure which shows the example when a hot-water supply operation is started from the state shown in FIG. It is a figure which shows the example in the case where heat pump outlet hot water temperature exceeds target value, and rises. It is a figure which shows the example in the case of performing a thermal storage driving | operation without the hot-water supply operation | movement in the state of the water temperature of the lower part in a hot water storage tank 10 degreeC. It is a figure which shows the example when a hot-water supply operation is started from the state shown in FIG. 5 is a flowchart of a routine executed in the first embodiment. It is a figure which shows the storage type hot-water supply system of Embodiment 2. FIG.

  Hereinafter, embodiments will be described with reference to the drawings. Elements common to the respective drawings are denoted by the same reference numerals, and overlapping descriptions will be simplified or omitted. The present disclosure can include any combination of combinations that can be combined among the configurations described in the following embodiments.

Embodiment 1
FIG. 1 is a diagram showing a hot water storage type hot water supply system 1 according to a first embodiment. As shown in FIG. 1, the hot water storage type hot water supply system 1 of the first embodiment includes a hot water storage tank unit 20, a heat pump unit 60, and a control device 70.

  The hot water storage tank unit 20 and the heat pump unit 60 are connected to each other via a water inlet flow passage 41, a hot water discharge passage 42, and an electrical wiring (not shown). In the present embodiment, the hot water storage tank unit 20 incorporates a control device 70. The operation of various actuators provided in the hot water storage tank unit 20 and the heat pump unit 60, such as valves, pumps, compressors, and blowers, is controlled by a control device 70 electrically connected thereto. Hereinafter, each component of the hot water storage type hot water supply system 1 will be described.

  The heat pump unit 60 is an example of a heating unit that heats water. The heating means is not limited to the heat pump unit 60. The heating means may be a combustion type heating device that heats with the combustion heat of a fuel such as gas, kerosene, heavy oil or coal. The heating means may be a device for heating water by solar heat. The heating means may be a device for heating water by waste heat of another heat engine.

  The heat pump unit 60 includes a refrigerant circuit in which a compressor 61, a heating heat exchanger 62, an expansion valve 63, and an air heat exchanger 64 are annularly connected by a refrigerant circulation pipe 65. The heat pump unit 60 operates the refrigeration cycle, that is, the heat pump cycle by circulating the refrigerant of the refrigerant circuit. In the heating heat exchanger 62, the water is heated by exchanging heat between the high-temperature and high-pressure refrigerant compressed by the compressor 61 and the water. The heat pump cycle of the heat pump unit 60 may use carbon dioxide as the refrigerant and may operate at a pressure exceeding the critical pressure.

  In the hot water storage tank unit 20, in addition to the hot water storage tank 10, the circulation pump 21, the three-way valve 31, and the mixing valve 32, various parts and pipes to be described later are incorporated. The hot water storage tank 10 stores hot and cold water. Inside the hot water storage tank 10, a temperature stratification in which the temperature is high on the upper side and the temperature is low on the lower side is formed due to the difference in the density of water due to the temperature. A water supply channel 2 is in communication with the lower portion of the hot water storage tank 10. The upstream side of the water supply flow path 2 is connected to a water source such as a water supply. The water supplied from the water source flows into the lower part of the hot water storage tank 10 through the water supply flow path 2. The pressure reducing valve 4 and the water supply temperature sensor 13 are installed in the middle of the water supply flow path 2. The pressure reducing valve 4 reduces the water pressure of the water source and regulates the pressure to a predetermined pressure. The pressure adjusted by the pressure reducing valve 4 acts in the hot water storage tank 10. In the following description, the temperature of water supplied from the water supply flow path 2 is referred to as "water supply temperature". The water supply temperature sensor 13 detects the water supply temperature.

  A hot water supply channel 3 is in communication with the upper portion of the hot water storage tank 10. The downstream end of the hot water supply flow path 3 is connected to an a port which is a high temperature side inlet of the mixing valve 32. The downstream end of the water supply branch flow channel 6 branched from the branch portion 5 downstream of the pressure reducing valve 4 of the water supply flow channel 2 is connected to the b port which is the low temperature side inlet of the mixing valve 32. The upstream end of the hot water supply channel 7 is connected to the c port which is the outlet of the mixing valve 32. The downstream side of the hot water supply flow path 7 is connected to a hot water supply tap of an external hot water supply terminal (not shown). The hot water supply terminal may be, for example, a shower of a bathroom, a faucet of a sink, or a faucet of a washbasin. The mixing valve 32 is an example of mixing means.

  When the hot water supply tap is opened at the hot water supply terminal downstream of the hot water supply flow passage 7, the hot water flows in the hot water supply flow passage 7 by the water pressure acting from the water supply flow passage 2 to start the hot water supply operation. A hot water supply temperature sensor 54 and a hot water supply flow rate sensor 55 are installed in the hot water supply flow path 7. Hot water supply temperature sensor 54 detects the temperature of hot water passing through hot water supply flow path 7. Hot water supply flow rate sensor 55 detects the flow rate of hot water passing through hot water supply flow path 7.

  The hot water supply operation to the hot water supply flow paths 3 and 7 is as follows. The high temperature water, i.e., hot water flowing out of the upper portion of the hot water storage tank 10 flows into the mixing valve 32 through the hot water supply passage 3. The low temperature water supplied from the water source flows into the mixing valve 32 through the water supply flow path 2 and the water supply branch flow path 6. Hot water whose temperature is controlled by mixing high temperature water and low temperature water by the mixing valve 32 is supplied to the external hot water supply terminal through the hot water supply channel 7. The mixing valve 32 can adjust the mixing ratio of high temperature water and low temperature water. Control device 70 controls the operation of mixing valve 32 so that the hot water supply temperature detected by hot water supply temperature sensor 54 becomes equal to the target value, ie, the set temperature.

  The upstream portion of the water inlet channel 41 communicates with the lower portion of the hot water storage tank 10. The downstream end of the water inlet channel 41 is in communication with the water inlet of the heating heat exchanger 62 of the heat pump unit 60. An incoming water temperature sensor 67 is installed in the incoming water flow path 41. In the following description, the temperature of the water entering the water inlet of the heating heat exchanger 62 of the heat pump unit 60 will be referred to as "heat pump inlet temperature". The incoming water temperature sensor 67 detects the heat pump incoming water temperature.

  In the present embodiment, the water supply flow passage 2 and the water intake flow passage 41 are connected to the hot water storage tank 10 via the common tank lower flow passage 40. The first end 40 a of the lower tank flow passage 40 is connected to the lower portion of the hot water storage tank 10. The second end 40 b of the tank lower flow passage 40 communicates with both the downstream end of the water supply flow passage 2 and the upstream end of the inflow water flow passage 41. By such a configuration, the following effects can be obtained. Since the number of pipes connected to the lower portion of the hot water storage tank 10 can be reduced, the structure is simplified and the manufacturing cost can be reduced.

  The upstream end of the hot water discharge passage 42 communicates with the water outlet of the heating heat exchanger 62 of the heat pump unit 60. The three-way valve 31 is an example of flow path switching means provided with an a port that is a first outlet, a b port that is a second outlet, and a c port that is an inlet. The downstream end of the hot water discharge passage 42 is connected to the c port of the three-way valve 31. A tapping temperature sensor 66 is installed in the tapping channel 42. In the following description, the temperature of the hot water which came out of the outlet of the water of the heating heat exchanger 62 of the heat pump unit 60 is called "heat pump outlet hot water temperature." The outlet temperature sensor 66 detects the heat pump outlet temperature. The circulation pump 21 is connected in the middle of the water inlet channel 41. Instead of this configuration, the circulation pump 21 may be connected in the middle of the hot water discharge passage 42.

  The upstream end of the hot water discharge passage 44 is connected to the b port of the three-way valve 31. The downstream portion of the hot water discharge passage 44 is in communication with the upper portion of the hot water storage tank 10. The bypass flow channel 43 connects between the position in the middle of the tank lower flow channel 40 and the a port of the three-way valve 31.

  In the present embodiment, the hot water supply flow passage 3 and the hot water discharge flow passage 44 are connected to the hot water storage tank 10 via the common tank upper flow passage 45. The first end 45 a of the tank upper flow passage 45 is connected to the upper portion of the hot water storage tank 10. The second end 45 b of the tank upper flow passage 45 is in communication with both the upstream end of the hot water supply flow passage 3 and the downstream end of the hot water discharge passage 44. By such a configuration, the following effects can be obtained. Since the number of pipes connected to the upper portion of the hot water storage tank 10 can be reduced, the structure is simplified and the manufacturing cost can be reduced.

  The hot water storage type hot water supply system 1 can execute a heat storage operation. The heat storage operation is an operation in which hot water heated by the heat pump unit 60, that is, high temperature water, is accumulated in the hot water storage tank 10. At the time of heat storage operation, it becomes as follows. The circulation pump 21 and the heat pump unit 60 are operated. The water at the lower portion in the hot water storage tank 10 flows out to the tank lower flow passage 40, and is sent to the heat pump unit 60 through the incoming water flow passage 41. The high temperature water heated by the heat pump unit 60 flows into the upper portion in the hot water storage tank 10 via the hot water discharge passage 42, the three-way valve 31, the hot water discharge passage 44 and the tank upper flow passage 45. In the hot water storage tank 10, the layer of high temperature water gradually becomes thicker from the upper side to the lower side.

  On the surface of the hot water storage tank 10, a plurality of hot water storage temperature sensors 11, 12 are attached at different heights. By detecting the temperature distribution in the vertical direction of the hot and cold water in the hot water storage tank 10 by the hot water storage temperature sensors 11 and 12, it is possible to calculate the hot water storage amount and the heat storage amount in the hot water storage tank 10. Control device 70 may control start, stop, etc. of heat storage operation based on the amount of stored hot water or the amount of stored heat.

  The three-way valve 31 communicates the outlet flow passage 42 with the bypass passage 43 to block the outlet flow passage 44, and the outlet passage 42 communicates with the outlet flow passage 44 to block the bypass passage 43. It is possible to switch to the second flow path configuration. During the heat storage operation, the control device 70 controls the three-way valve 31 to be in the second flow path configuration. For example, immediately after the start of the heat pump unit 60, when the heat pump outlet temperature is low, the control device 70 controls the three-way valve 31 to be in the first flow path configuration. By doing so, it is possible to prevent the temperature of the upper part in the hot water storage tank 10 from decreasing.

  The circulation pump 21 incorporates a rotation sensor (not shown) for detecting the rotation speed of the circulation pump 21. The controller 70 can control the rotational speed of the circulation pump 21.

  The control device 70 has a function of performing feedback control of the heat pump outlet temperature so that the heat pump outlet temperature detected by the outlet temperature sensor 66 becomes equal to the target value during the heat storage operation. The target value of the heat pump outlet temperature may be, for example, a value within the range of 65 ° C to 90 ° C. By adjusting the rotational speed of the circulation pump 21, the heat pump outlet temperature can be adjusted. For example, when the rotational speed of the circulation pump 21 is reduced, the flow rate of water passing through the heat pump unit 60 decreases, and the heat pump outlet temperature rises. Conversely, when the rotational speed of the circulation pump 21 is increased, the flow rate of water passing through the heat pump unit 60 is increased, and the heat pump outlet temperature is decreased. The control device 70 can bring the heat pump outlet temperature close to the target value by adjusting the rotational speed of the circulation pump 21 based on the deviation between the heat pump outlet temperature and the target value thereof. Alternatively, the control device 70 may adjust the heating capacity [W] of the heat pump unit 60 based on the deviation between the heat pump outlet temperature and its target value. The controller 70 may adjust both the rotational speed of the circulation pump 21 and the heating capacity of the heat pump unit 60.

  The fluctuation of the heat pump outlet temperature when the hot water supply operation is performed during the heat storage operation will be described below. For example, at a timing close to the completion of the heat storage operation when the hot water is accumulated to the full in the hot water storage tank 10, the water temperature in the lower part of the hot water storage tank 10 may be, for example, about 50 ° C. In that case, the heat pump water intake temperature also becomes a temperature as high as the temperature of the lower portion of the hot water storage tank 10. FIG. 2 shows an example in the case where the heat pump inlet temperature becomes high. The example shown in FIG. 2 is as follows. Hot water supply operation is not performed. The water temperature in the lower part of the hot water storage tank 10 is 50.degree. The temperature of water flowing from the hot water storage tank 10 to the tank lower flow passage 40 and the water intake flow passage 41 is 50 ° C. Heat pump water temperature is 50 ° C. The heat pump outlet temperature is feedback controlled to be equal to the target value of 90.degree.

  FIG. 3 shows an example where the hot water supply operation is started from the state shown in FIG. As shown in FIG. 3, when the hot water supply operation is started, the mixed water of the water flowing out from the lower part of the hot water storage tank 10 to the tank lower flow passage 40 and the water supplied from the water supply flow passage 2 It is led to the heat pump unit 60 through 41. As a result, the heat pump water inlet temperature is lower than in the state before the start of the hot water supply operation, that is, the state in FIG. 2. The example shown in FIG. 3 is as follows. The feed water temperature from the feed water channel 2 is 10 ° C. The temperature of the water flowing out from the lower part of the hot water storage tank 10 to the tank lower flow passage 40 is 50.degree. Heat pump water temperature is 30 ° C. The heat pump outlet temperature is lowered from 90 ° C. to 70 ° C. as the heat pump inlet temperature is lowered from 50 ° C. to 30 ° C., as compared with the state of FIG.

  Assuming that the hot water supply operation and the feedback control of the heat pump outlet temperature by the controller 70 continue from the state shown in FIG. 3, the following occurs. In order to raise the heat pump outlet temperature which has dropped to 70 ° C., the rotational speed of the circulation pump 21 is controlled to be low. As a result, the heat pump outlet temperature returns from 70 ° C. to the target value of 90 ° C. Thereafter, when the hot water supply operation is stopped, the heat pump inlet temperature returns from 30 ° C. to 50 ° C. Such a rise in heat pump inlet temperature may cause the heat pump outlet temperature to rise above the target value (90 ° C. in this example). FIG. 4 shows an example where the heat pump outlet temperature rises above the target value in this way. In the state shown in FIG. 4, the heat pump outlet hot water temperature has risen to 100.degree.

  As shown in FIG. 4, the occurrence of an event that the heat pump outlet temperature becomes significantly higher than the target value is not preferable because of the following reasons. When the hot water supply operation is performed with the heat pump outlet temperature significantly higher than the target value, abnormal high temperature hot water flows from the outlet hot water passage 44 into the hot water supply passage 3 and the hot water supply temperature from the hot water supply passage 7 is the set temperature. There is a possibility of exceeding.

  In the present embodiment, in order to reliably suppress the abnormal rise in heat pump outlet temperature as described above, the following is performed. When the hot water supplying operation to the hot water supply flow paths 3 and 7 is started during the heat storage operation, the control device 70 is based on the difference between the heat pump inlet temperature and the feed water temperature as the feed water temperature is lower than the heat pump inlet temperature. If it is larger than the above, feedback control of the heat pump delivery temperature is stopped, and control to maintain the rotational speed of the circulation pump 21 at a constant speed (hereinafter, referred to as "constant speed control") is performed. Thereby, the following effects can be obtained. If feedback control of the heat pump outlet temperature is stopped in the state of FIG. 3 and the rotational speed of the circulation pump 21 is maintained at a constant speed, the heat pump outlet temperature is maintained at 70 ° C. For this reason, when the hot water supply operation is stopped and the heat pump water inlet temperature returns from 30 ° C. to 50 ° C., the heat pump outlet hot water temperature can be reliably suppressed from rising above 90 ° C.

  When the temperature of the water supplied from the water source to the water supply flow path 2 is 10 ° C., the water of 10 ° C. is accumulated in the lower part of the hot water storage tank 10. FIG. 5 shows an example of the case where the heat storage operation is performed without the hot water supply operation in the state where the water temperature of the lower part in the hot water storage tank 10 is 10 ° C. The example shown in FIG. 5 is as follows. The temperature of water flowing from the hot water storage tank 10 to the tank lower flow passage 40 and the water intake flow passage 41 is 10 ° C. Heat pump water temperature is 10 ° C. The heat pump outlet temperature is feedback controlled to be equal to the target value of 90.degree.

  In a state where water does not flow in the water supply flow path 2, the temperature of the water staying in the water supply flow path 2 may change due to the influence of the outside air temperature or the like. For example, when the outside air temperature is high, such as in summer, the temperature may rise due to the water staying in the water supply channel 2 receiving heat such as the outside air. In the following description, it is assumed by way of example that the temperature of water staying in the water supply flow path 2 rises from 10 ° C. to 30 ° C. by receiving heat such as the open air.

  FIG. 6 shows an example when the hot water supply operation is started from the state shown in FIG. As shown in FIG. 6, when the hot water supply operation is started, mixing of water at 10 ° C. flowing out from the lower part of the hot water storage tank 10 to the tank lower channel 40 and water at 30 ° C. supplied from the water supply channel 2 Water is led to the heat pump unit 60 through the water inlet channel 41. As a result, the heat pump water inlet temperature rises compared to the state before the start of the hot water supply operation, that is, the state of FIG. 5. Such a rise in heat pump inlet temperature may cause the heat pump outlet temperature to rise above the target value (90 ° C. in this example). FIG. 6 shows an example where the heat pump outlet temperature rises above the target value in this way. In the example shown in FIG. 6, the heat pump outlet temperature is raised from 90 ° C. to 100 ° C. as the heat pump water inlet temperature is raised from 10 ° C. to 20 ° C. in the state of FIG.

  As shown in FIG. 6, the occurrence of an event that the heat pump outlet temperature becomes significantly higher than the target value is not preferable for the same reason as the above-mentioned reason. Assuming that the control of fixing the rotational speed of the circulation pump 21 at a constant speed as in Patent Document 1 is performed when the hot water supply operation is started from the state of FIG. 5, the temperature is higher than the heat pump outlet temperature before the start of the hot water supply operation. Hot water of temperature flows out from the heat pump unit 60, and the state as shown in FIG. 6 continues.

  In the present embodiment, in order to reliably suppress the abnormal rise in heat pump outlet temperature as described above, the following is performed. When the hot water supply operation to the hot water supply flow paths 3 and 7 is started during the heat storage operation, the control device 70 is based on the difference between the water supply temperature and the heat pump inlet temperature when the water supply temperature is higher than the heat pump inlet temperature. When it is larger than the above, the control for stopping the feedback control of the heat pump delivery temperature and accelerating the rotational speed of the circulation pump 21 (hereinafter referred to as "acceleration control"). I do. Thereby, the following effects can be obtained. If the rotational speed of the circulation pump 21 is increased when the hot water supply operation is started from the state of FIG. 5, it is possible to avoid the heat pump outlet temperature from rising as shown in FIG.

  FIG. 7 is a flowchart of the routine executed in the first embodiment. In the present embodiment, control device 70 periodically and repeatedly executes the routine shown in the flowchart of FIG. 7 while the heat storage operation is being performed.

  In step S1 of FIG. 7, the control device 70 performs the heat storage operation by operating the heat pump unit 60 and the circulation pump 21. The process proceeds from step S1 to step S2. In step S2, the control device 70 determines whether or not the hot water supplying operation to the hot water supply flow paths 3 and 7 is being performed. In the present embodiment, whether or not the hot water supply operation is being performed can be detected by the hot water supply flow rate sensor 55. When the hot water supply operation to the hot water supply flow paths 3 and 7 is started, the control device 70 may store the value of the rotational speed of the circulation pump 21 at that time. When the hot water supply operation to the hot water supply flow paths 3 and 7 starts, the control device 70 may store the value of the heating capacity [W] of the heat pump unit 60 at that time.

  If the hot water supply operation is not being performed, the process proceeds from step S2 to step S10. In step S10, the control device 70 executes feedback control of the heat pump outlet hot water temperature. After step S10, the process returns to step S1.

  If the hot water supply operation is being performed, the process proceeds from step S2 to step S3. In step S3, the control device 70 determines the magnitude relationship between the heat pump inlet temperature Tin detected by the inlet temperature sensor 67 and the water supply temperature T0 detected by the water supply temperature sensor 13. If the water supply temperature T0 is higher than the heat pump inlet temperature Tin, the process proceeds from step S3 to step S4. In step S4, the controller 70 determines whether the difference between the feed water temperature T0 and the heat pump inlet temperature Tin is larger than the reference. In step S4, for example, the case where the difference between the feed water temperature T0 and the heat pump water inlet temperature Tin is 10 ° C. or more is considered to be larger than the reference, and the case less than 10 ° C. is not larger than the reference It may be regarded as a thing.

  If the difference between the water supply temperature T0 and the heat pump inlet temperature Tin is not larger than the reference, the process proceeds from step S4 to step S10. That is, in this case, the control device 70 does not execute the speed increase control of the circulation pump 21 but performs the feedback control of the heat pump outlet hot water temperature. If the difference between the water supply temperature T0 and the heat pump inlet temperature Tin is not large compared to the standard, it is considered that the fluctuation of the heat pump outlet temperature accompanying the start and stop of the hot water supply operation is small. There is no need to do it. In this case, the heat pump outlet temperature can be maintained at a value close to the target value by executing feedback control of the heat pump outlet temperature.

  If the difference between the water supply temperature T0 and the heat pump inlet temperature Tin is larger than the reference, the process proceeds from step S4 to step S5. In step S5, the control device 70 confirms whether or not the difference between the feed water temperature T0 and the heat pump inlet temperature Tin continues to be larger than the reference. In step S5, for example, when the difference between the water supply temperature T0 and the heat pump inlet temperature Tin is 10 ° C. or more lasts for 3 seconds or more, the difference between the water supply temperature T0 and the heat pump inlet temperature Tin is larger than the reference If the condition is considered to be sustained, otherwise the difference between the feed water temperature T0 and the heat pump inlet temperature Tin may be considered to be non-sustained.

  If the difference between the water supply temperature T0 and the heat pump inlet temperature Tin does not continue to be larger than the reference, the process proceeds from step S5 to step S10. That is, in this case, the control device 70 does not execute the speed increase control of the circulation pump 21 but performs the feedback control of the heat pump outlet hot water temperature.

  If the difference between the water supply temperature T0 and the heat pump inlet temperature Tin is larger than the reference, the process proceeds from step S5 to step S6. In step S6, the control device 70 executes acceleration control to increase the rotational speed of the circulation pump 21.

  In step S6, for example, the following may be performed. Control device 70 may control the rotational speed of circulation pump 21 such that the rotational speed of circulation pump 21 is higher than the rotational speed of circulation pump 21 at the start of the hot water supply operation. The controller 70 controls the rotational speed of the circulation pump 21 such that the rotational speed of the circulation pump 21 increases stepwise or continuously as the difference between the water supply temperature T0 at the start of the hot water supply operation and the heat pump inlet temperature Tin increases. May be controlled. For example, in the case of T0-Tin ≧ 10 ° C., the rotational speed of the circulation pump 21 is controlled so as to be 1000 rpm higher than the rotational speed of the circulation pump 21 at the start of the hot water supply operation, and T0-Tin ≧ 20 ° C. In this case, the rotational speed of the circulation pump 21 may be controlled to be 2000 rpm higher than the rotational speed of the circulation pump 21 at the start of the hot water supply operation. After step S6, the process returns to step S1.

  In the present embodiment, the following effects can be obtained by executing the speed increase control in step S6. Even when the hot water supply operation is performed during the heat storage operation, it is possible to reduce the fluctuation of the heat pump outlet temperature. For example, occurrence of an event as shown in FIG. 6 can be reliably suppressed. That is, occurrence of an event in which the heat pump outlet temperature becomes significantly higher than the target value can be reliably suppressed.

  Furthermore, in the present embodiment, before the control device 70 executes the acceleration control in step S6, the state in which the difference between the feed water temperature T0 and the heat pump input water temperature Tin is larger than the reference continues. The following effects can be obtained by confirming in. The lower portion in the hot water storage tank 10 may have an uneven water temperature. The heat pump water inlet temperature Tin may change momentarily because water of such a non-uniform temperature is sent from the hot water storage tank 10 to the heat pump unit 60. In that case, the difference between the water supply temperature T0 and the heat pump inlet temperature Tin may instantaneously become larger than the reference. If the difference between the feed water temperature T0 and the heat pump inlet temperature Tin returns to a state smaller than the reference after the difference between the feed water temperature T0 and the heat pump inlet temperature Tin instantaneously becomes larger than the reference, acceleration control is executed. The need is low. Such execution of unnecessary speed control can be reliably avoided.

  When the feed water temperature T0 is equal to or lower than the heat pump inlet temperature Tin in step S3, the process proceeds to step S7. In step S7, the controller 70 determines whether the difference between the heat pump inlet temperature Tin and the feed water temperature T0 is larger than the second reference. In step S7, for example, the case where the difference between the heat pump inlet temperature Tin and the feed water temperature T0 exceeds 5 ° C. is regarded as larger than the second reference, and the case where the difference is 5 ° C. or lower is compared to the second reference It may be regarded as not big.

  If the difference between the heat pump inlet temperature Tin and the water supply temperature T0 is not larger than the second reference, the process proceeds from step S7 to step S10. That is, in this case, the control device 70 does not execute the constant speed control of the circulation pump 21 but performs feedback control of the heat pump outlet hot water temperature. If the difference between the heat pump inlet temperature Tin and the water supply temperature T0 is not large compared to the second standard, it is considered that the fluctuation of the heat pump outlet temperature accompanying the start and stop of the hot water supply operation is small. There is no need to carry out control. In this case, the heat pump outlet temperature can be maintained at a value close to the target value by executing feedback control of the heat pump outlet temperature.

  If the difference between the heat pump inlet temperature Tin and the water supply temperature T0 is larger than the second reference, the process proceeds from step S7 to step S8. In step S8, the control device 70 checks whether the difference between the heat pump inlet temperature Tin and the feed water temperature T0 is larger than the second reference. In step S8, for example, when the difference between the heat pump inlet temperature Tin and the feed water temperature T0 continues for more than 3 seconds, the difference between the heat pump inlet temperature Tin and the feed water temperature T0 is higher than the second reference. It may be considered that the large state is sustained, and otherwise the difference between the heat pump inlet temperature Tin and the feed water temperature T0 is not sustained compared to the second standard.

  If the difference between the heat pump inlet temperature Tin and the water supply temperature T0 does not continue to be larger than the second reference, the process proceeds from step S8 to step S10. That is, in this case, the control device 70 does not execute the constant speed control of the circulation pump 21 but performs feedback control of the heat pump outlet hot water temperature.

  If the difference between the heat pump inlet temperature Tin and the water supply temperature T0 is larger than the second reference, the process proceeds from step S8 to step S9. In step S9, the control device 70 executes constant speed control to maintain the rotational speed of the circulation pump 21 at a constant speed. In step S9, the control device 70 may control the rotational speed of the circulation pump 21 to be fixed at a speed equal to the rotational speed of the circulation pump 21 at the start of the hot water supply operation. After step S9, the process returns to step S1.

  In the present embodiment, the following effects can be obtained by executing the constant speed control in step S9. Even when the hot water supply operation is performed during the heat storage operation, it is possible to reduce the fluctuation of the heat pump outlet temperature. For example, occurrence of an event as shown in FIG. 4 can be reliably suppressed. That is, occurrence of an event in which the heat pump outlet temperature becomes significantly higher than the target value can be reliably suppressed.

  Furthermore, in the present embodiment, the control device 70 maintains that the difference between the heat pump inlet temperature Tin and the feed water temperature T0 is larger than the second reference before executing the acceleration control in step S9. By confirming at step S8, the following effects can be obtained. The lower portion in the hot water storage tank 10 may have an uneven water temperature. The heat pump water inlet temperature Tin may change momentarily because water of such a non-uniform temperature is sent from the hot water storage tank 10 to the heat pump unit 60. In that case, the difference between the heat pump inlet temperature Tin and the feed water temperature T0 may instantaneously become larger than the second reference. If the difference between the heat pump inlet temperature Tin and the feed water temperature T0 returns to a state smaller than the second reference after the difference between the heat pump inlet temperature Tin and the feed water temperature T0 instantaneously becomes larger than the second reference, constant speed The need to implement control is low. It is possible to reliably avoid the execution of constant speed control which is less necessary.

  During the execution of the acceleration control or the constant speed control, the amount of heat obtained from the heat pump unit 60 may be lower than before the start of the acceleration control or the constant speed control. When the acceleration control or the constant speed control ends and the control returns to the feedback control, the control device 70 determines that the heating capacity [W] of the heat pump unit 60 is higher than the heating capacity immediately before the start of the acceleration control or the constant speed control. The heat pump unit 60 and the circulation pump 21 may be controlled to be higher. By doing so, it is possible to recover the amount of heat lost during execution of the acceleration control or constant speed control. The control device 70 can control the heating capacity of the heat pump unit 60 by changing at least one of the operating frequency of the compressor 61 and the opening degree of the expansion valve 63.

  During the execution of the speed increase control or the constant speed control, the heat pump outlet temperature may be lower than before the start of the speed increase control or the constant speed control. When the heat pump outlet temperature decreases, the temperature of the hot water flowing from the hot water supply passage 3 into the mixing valve 32 decreases. Therefore, the temperature of the hot water flowing from the hot water supply flow passage 3 to the mixing valve 32 may decrease after the acceleration control or the constant speed control is started, and the hot water supply temperature to the hot water supply flow passage 7 may decrease. is there. If such a decrease in the hot water supply temperature is detected by the hot water supply temperature sensor 54, the control device 70 controls the mixing valve 32 to raise the hot water supply temperature, but at that time, the hot water supply temperature may overshoot. . As described above, there is a possibility that the hot water supply temperature to the hot water supply flow path 7 may fluctuate after the acceleration control or the constant speed control is started. In order to reduce such fluctuation of the hot water supply temperature, the controller 70 increases the mixing ratio of water from the water supply branch channel 6 in the mixing valve 32 when acceleration control or constant speed control is started. The mixing valve 32 may be controlled to be lower than the mixing ratio at the start of the speed control or the constant speed control (for example, the moment when the speed increase control or the constant speed control is started). According to the control, the following effects can be obtained. The mixing ratio of water in the mixing valve 32 can be reduced by feedforward before the decrease in the temperature of the hot water supply passage 7 is detected by the hot water supply temperature sensor 54. It can be reliably suppressed that a drop occurs. Therefore, the fluctuation of the hot water supply temperature to the hot water supply passage 7 can be reliably reduced.

  In the first embodiment, the configuration in which the water supply flow passage 2 and the water intake flow passage 41 are connected to the hot water storage tank 10 via the common tank lower flow passage 40, and the hot water supply flow passage 3 and the hot water discharge flow passage 44 are common. The structure connected to the hot water storage tank 10 via the tank upper flow path 45 was described. The present invention is not limited to these configurations. That is, the water supply flow path 2 and the incoming water flow path 41 may be separately connected to the hot water storage tank 10, and the hot water supply flow path 3 and the hot water discharge flow path 44 may be separately connected to the hot water storage tank 10. Even in such a configuration, a phenomenon similar to the fluctuation of the heat pump outlet temperature described with reference to FIGS. 2 to 6 may occur. Therefore, even in such a configuration, an effect similar to the above-described effect can be obtained.

Second Embodiment
Next, Embodiment 2 will be described with reference to FIG. 8, but differences from the above-described Embodiment 1 will be mainly described, and description of the same or corresponding parts will be simplified or omitted. FIG. 8 is a diagram showing a hot water storage type hot water supply system 1 according to a second embodiment. As shown in FIG. 8, in addition to the apparatus with which the hot water storage type hot-water supply system 1 of this Embodiment 2 is equipped, the following apparatuses are further provided.

  The downstream side of the pouring channel 46 is in communication with a bath (not shown) in the bathroom. The pouring mixing valve 33 includes an a port which is a high temperature side inlet, a b port which is a low temperature side inlet, and a c port which is an outlet. The upstream end of the pouring passage 46 is connected to the c port of the pouring mixing valve 33. The downstream side of the hot water supply flow path 3 is branched into two hands, and is connected to the a port of the mixing valve 32 and the a port of the hot water mixing valve 33, respectively. The downstream side of the water supply branch flow channel 6 is branched into two hands, and is connected to the b port of the mixing valve 32 and the b port of the hot-water mixing valve 33, respectively. In the middle of the pouring passage 46, a pouring solenoid valve 34, a pouring temperature sensor 56, and a pouring flow rate sensor 57 are installed. The filling solenoid valve 34 opens and closes the filling passage 46.

  When the hot water is supplied to the bathtub, the control device 70 controls as follows. Open the filling solenoid valve 34. The operation of the pouring mixing valve 33 is controlled so that the pouring temperature detected by the pouring temperature sensor 56 becomes equal to the target value, that is, the set temperature. When the integrated pouring amount obtained by integrating the detection flow rates of the pouring flow rate sensor 57 reaches a target value, the pouring solenoid valve 34 may be closed to finish the pouring.

  In the second embodiment, control device 70 can predict the timing at which the filling operation is completed, that is, the timing at which the hot water supplying operation to filling channel 46 is completed. For example, the timing at which the integrated pouring amount reaches the target value may be predicted.

  In the second embodiment, when the hot water supply operation to the hot water supply channel 46 is started without the hot water supply operation to the hot water supply channels 3 and 7 being started during the heat storage operation, the following is performed. . If the hot water supply operation to the pouring passage 46 is started during the heat storage operation, the control device 70 does not execute the speed increase control and the constant speed control of the circulation pump 21 and continues the feedback control of the heat pump outlet temperature as it is Do. The controller 70 stores the rotational speed of the circulation pump 21 and the operating state of the heat pump unit 60 when the hot water supplying operation to the pouring channel 46 is started. Here, the operating state of the heat pump unit 60 means, for example, the operating frequency of the compressor 61 and the opening degree of the expansion valve 63. When the hot water supply operation to the pouring passage 46 is started, the heat pump water temperature changes, whereby the heat pump water temperature changes. The feedback control acts to return the changed heat pump outlet temperature to the target value, so that the rotational speed of the circulation pump 21 and the operating state of the heat pump unit 60 change. When the hot water supply operation to the pouring channel 46 is started, the control device 70 starts the rotational speed of the circulation pump 21 and the operating state of the heat pump unit 60 immediately before the timing when the hot water supplying operation to the pouring channel 46 ends. The rotational speed of the circulation pump 21 and the operation state of the heat pump unit 60 are controlled to return. By doing as described above, it is possible to suppress the fluctuation of the heat pump outlet temperature caused by the termination of the hot water supplying operation to the pouring passage 46.

  The control apparatus 70 with which the hot water storage type hot water supply system 1 of Embodiment 1 and 2 is provided may be comprised as follows. Each function of the control device may be realized by a processing circuit. The processing circuitry of the controller may comprise at least one processor and at least one memory. When the processing circuit includes at least one processor and at least one memory, each function of the control device may be realized by software, firmware, or a combination of software and firmware. Software and / or firmware may be described as a program. At least one of the software and the firmware may be stored in at least one memory. At least one processor may implement each function of the control device by reading and executing a program stored in at least one memory. At least one memory may include non-volatile or volatile semiconductor memory, magnetic disk, and the like.

  The processing circuitry of the controller may comprise at least one dedicated hardware. When the processing circuit comprises at least one dedicated hardware, the processing circuit may, for example, be a single circuit, a complex circuit, a programmed processor, a parallel programmed processor, an application specific integrated circuit (ASIC), an FPGA (field- It may be a programmable gate array) or a combination thereof. The function of each part of the control device may be realized by the processing circuit. In addition, the functions of the respective units of the control device may be realized collectively by the processing circuit. For each function of the control device, a part may be realized by dedicated hardware, and another part may be realized by software or firmware. The processing circuit may implement each function of the control device by hardware, software, firmware, or a combination thereof.

  The configuration is not limited to a configuration in which the operation is controlled by a single control device, and a configuration in which a plurality of control devices cooperate to control the operation may be employed.

DESCRIPTION OF SYMBOLS 1 hot water storage type hot water supply system, 2 water supply flow path, 3 hot water supply flow path, 4 pressure reduction valve, 5 branching part, 6 water supply branch flow path, 7 hot water supply flow path, 10 hot water storage tank, 11, 12 hot water storage temperature sensor, 13 water supply temperature sensor , 20 hot water storage tank unit, 21 circulation pump, 31 three-way valve, 32 mixing valve, 33 hot water mixing valve, 34 hot water solenoid valve, 40 tank lower flow path, 40a first end, 40b second end, 41 incoming water flow path , 42 hot water flow path, 43 bypass flow path, 44 hot water discharge flow path, 45 tank upper flow path, 45a first end, 45b second end, 46 hot water flow path, 54 hot water supply temperature sensor, 55 hot water flow sensor, 56 hot water Tension temperature sensor, 57 water flow rate sensor, 60 heat pump unit, 61 compressor, 62 heating heat exchanger, 63 bloat Valve, 64 air heat exchanger, 65 refrigerant circulation pipe, 66 hot water temperature sensor, 67 incoming water temperature sensor, 70 control device

Claims (13)

With a hot water storage tank,
A water supply channel for supplying water to the hot water storage tank;
A hot water supply passage through which the hot water flowing out of the hot water storage tank passes;
A means for detecting a feed water temperature which is a temperature of water supplied from the water supply flow path;
A means for detecting whether a hot water supply operation to the hot water supply channel is in progress;
Heating means for heating water;
A water inlet flow path for guiding water discharged from the hot water storage tank to the inlet of the heating means;
A hot water discharge channel for guiding the hot water from the outlet of the heating means to the hot water storage tank;
A circulation pump in the inflow passage or the outflow passage;
A means for detecting an incoming water temperature which is a temperature of water entering the inlet of the heating means;
When the hot water supply operation to the hot water supply flow path is started during the heat storage operation which is the operation of accumulating the hot water heated by the heating means in the hot water storage tank, the water supply temperature is higher than the water intake temperature, And, when the difference between the feed water temperature and the incoming water temperature is larger than a reference, acceleration control is performed to accelerate the rotational speed of the circulation pump with respect to the state before the start of the hot water supply operation. Means,
Storage type hot water supply system equipped with.   The hot water storage type hot water supply system according to claim 1, wherein the acceleration control is executed when a state where a difference between the water supply temperature and the inflow temperature is larger than the reference continues. A means for detecting a hot water temperature which is a temperature of hot water which has come out of the outlet of the heating means;
When the hot water supply operation to the hot water supply flow path is started during the heat storage operation, the water supply temperature is higher than the water intake temperature, and the difference between the water supply temperature and the water intake temperature is compared with the reference Means for feedback controlling the hot water temperature when the
The hot water storage type hot water supply system according to claim 1 or 2, comprising   The device according to any one of claims 1 to 3, further comprising means for making the heating capacity of the heating means higher than the heating capacity before the start of the acceleration control when the acceleration control is finished. Hot water storage type hot water supply system. Mixing means for mixing water with hot water passing through the hot water supply passage;
A means for lowering the mixing ratio of water in the mixing means as compared to the mixing ratio at the start of the acceleration control, when the acceleration control is started;
The hot-water storage type hot water supply system according to any one of claims 1 to 4, comprising:   When the hot water supply operation to the hot water supply flow path is started during the heat storage operation, the water supply temperature is lower than the water intake temperature, and the difference between the water intake temperature and the water supply temperature is the second reference The hot water storage type hot water supply system according to any one of claims 1 to 5, further comprising means for performing constant speed control to maintain the rotational speed of the circulation pump at a constant speed if the comparison is larger.   7. The hot water storage type hot water supply system according to claim 6, wherein the constant speed control is executed when a state in which a difference between the inflow water temperature and the water supply temperature is larger than the second reference continues. A means for detecting a hot water temperature which is a temperature of hot water which has come out of the outlet of the heating means;
When the hot water supply operation to the hot water supply flow path is started during the heat storage operation, the water supply temperature is lower than the water intake temperature, and the difference between the water intake temperature and the water supply temperature is the second standard Means for feedback controlling the temperature of the hot water when the temperature is not larger than
The hot water storage type hot water supply system according to claim 6 or 7, comprising:   The device according to any one of claims 6 to 8, further comprising means for making the heating capacity of the heating means higher than the heating capacity before the start of the constant speed control when the constant speed control is finished. Hot water storage type hot water supply system. Mixing means for mixing water with hot water passing through the hot water supply passage;
A means for lowering the mixing ratio of water in the mixing means as compared to the mixing ratio at the start of the constant speed control when the constant speed control is started;
The hot water storage type hot water supply system according to any one of claims 6 to 9, comprising: A means for detecting a hot water temperature which is a temperature of hot water which has come out of the outlet of the heating means;
A means for supplying water to a hot water flow passage communicating with the bath;
A means for feedback controlling the temperature of the hot water when the hot water supply operation to the hot water flow passage is started without the hot water supply operation to the hot water supply flow passage being started during the heat storage operation;
The hot water storage type hot water supply system according to any one of claims 1 to 10, comprising:   When the hot water supply operation to the hot water flow passage is started after the hot water supply operation to the hot water flow passage is started without the hot water supply operation to the hot water supply flow passage being started during the heat storage operation, The rotation speed of the circulation pump and the operating state of the heating means are provided with means for returning the rotational speed of the circulation pump and the operating state of the heating means before the hot water supplying operation to the pouring channel starts. The hot water storage type hot water supply system described in.   Means for making the rotational speed of the circulating pump to increase stepwise or continuously as the difference between the feed water temperature and the incoming water temperature becomes larger at the time of the acceleration control is provided. The hot water storage type hot water supply system according to any one of the above.

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