Storage-type heat source system

Abstract

To provide a hot water storage type heat source system capable of preventing a heat pump device from executing unnecessary defrosting operation, and preventing frosting to an evaporator of the heat pump device from advancing early when operating the heat pump device by a large heating capacity.SOLUTION: A control device 70 of a heat source system 1 with a hot water storage tank 11 is configured to: when there is a request to perform high-power heating operation immediately after the end of high-efficiency heating operation of a heat pump device 30, cause the heat pump device 30 to perform defrosting operation after the end of the high-efficiency heating operation, regardless of the determination result of whether or not a condition for starting the defrosting operation is satisfied; and when there is no such a request, cause the heat pump device 30 to perform the defrosting operation when the condition for starting the defrosting operation is satisfied.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a hot water storage type heat source system equipped with a hot water storage tank. [Background technology]

[0002] In a hot water storage type heat source system that supplies hot water from a hot water storage tank that stores heated hot water, a system equipped with a heat pump device as a heat source for heating the hot water in the hot water storage tank has been known for some time (see, for example, Patent Documents 1 and 2).

[0003] In the hot water storage type heat source system described in Patent Document 1, after the heat pump device heats (boils) the hot water in the hot water storage tank, a technology is described in which the heat pump device performs a defrosting operation to prevent frost from forming on the evaporator (the evaporator that exchanges heat between the refrigerant and the outside air) of the outdoor unit of the heat pump device.

[0004] Patent document 2 also describes a technology in which the hot water in a hot water storage tank is heated by operating a heat pump device at a first capacity with good energy efficiency (hereinafter, this operation may be referred to as high-efficiency heating operation) a predetermined time before the expected start of hot water supply or bath filling, and then, when filling the water tank, when a large amount of hot water in the hot water storage tank is used, the heat pump device is operated at a second capacity that is higher than the first capacity in high-efficiency heating operation (hereinafter, this operation may be referred to as high-output heating operation), thereby boiling the hot water in the hot water storage tank early. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2015-21643 A [Patent Document 2] JP 2017-156062 A Summary of the Invention [Problem to be solved by the invention]

[0006] During the heating operation in which the heat pump device heats the hot water in the hot water storage tank, a cooled refrigerant is supplied to the evaporator of the heat pump device, and frost is likely to form on the evaporator during cold seasons such as winter. In particular, if the high-power heating operation is performed immediately after the high-efficiency heating operation of the heat pump device, frost is likely to form early during the high-power heating operation. When the frost forms, it becomes difficult for the evaporator of the heat pump device to properly exchange heat (transfer heat) from the outside air to the refrigerant.

[0007] Therefore, when a heating operation of a heat pump device is performed, regardless of whether the heating operation is a high-efficiency heating operation or a high-output heating operation, it is considered to perform a defrosting operation after the heating operation of the heat pump device is completed, as shown in Patent Document 1.

[0008] However, in this case, the following inconvenience occurs. That is, depending on the environmental conditions, there are many cases where frost formation on the evaporator of the heat pump device has not progressed much when the heating operation of the heat pump device is terminated. Therefore, if a defrosting operation is always performed after the heating operation of the heat pump device is terminated, it is likely to result in wasteful energy consumption.

[0009] In addition, when a high-power heating operation is performed continuously immediately after a high-efficiency heating operation of a heat pump device, defrosting is likely to progress in the early stage of the high-power heating operation because the high-efficiency heating operation is performed before the high-power heating operation starts. This tends to lengthen the period during which the high-power heating operation cannot be performed at its original output. As a result, it tends to be impossible to heat the hot water in the hot water storage tank early.

[0010] The present invention has been made in consideration of the above background, and aims to provide a hot water storage type heat source system that can suppress the execution of unnecessary defrosting operations of a heat pump device and can suppress the early progression of frost formation on the evaporator of the heat pump device when the heat pump device is operated with a large heating capacity. [Means for solving the problem]

[0011] In order to achieve the above object, the hot water storage type heat source system of the present invention is provided with a heat pump device capable of performing a heating operation for heating hot water in a hot water storage tank with a first heating capacity and a second heating capacity that is higher than the first heating capacity, and the heat pump device is configured to perform a defrosting operation for defrosting an evaporator mounted in the heat pump device so as to perform heat exchange with outside air, in addition to the heating operation, a control device that determines whether or not to cause the heat pump device to perform a defrosting operation after the heating operation of the heat pump device at the first heating capacity is completed, and controls the operation of the heat pump device in accordance with the determination; The control device is configured to have a function of determining whether or not to cause the heat pump device to perform a defrosting operation by judging whether or not a predetermined condition for starting the defrosting operation is satisfied after the end of the heating operation of the heat pump device at the first heating capacity, when there is no request to execute the heating operation of the heat pump device at the second heating capacity immediately after the end of the heating operation of the heat pump device at the first heating capacity, and a function of causing the heat pump device to perform a defrosting operation after the end of the heating operation of the heat pump device at the first heating capacity and before starting the heating operation of the heat pump device at the second heating capacity, regardless of the judgment result of whether or not the predetermined condition is satisfied (first invention).

[0012] According to the first aspect of the present invention, if there is no request to execute a heating operation of the heat pump device at the second heating capacity immediately after the end of the heating operation of the heat pump device at the first heating capacity, the heat pump device is made to execute a defrosting operation only when a predetermined condition for starting a defrosting operation is satisfied after the end of the heating operation of the heat pump device at the first heating capacity, and the heat pump device is not made to execute a defrosting operation when the predetermined condition is not satisfied. Therefore, it is possible to prevent an unnecessary defrosting operation from being executed after the end of the heating operation of the heat pump device at the first heating capacity.

[0013] In addition, when there is a request to execute a heating operation of the heat pump device at the second heating capacity immediately after the end of the heating operation of the heat pump device at the first heating capacity, it is possible to cause the heat pump device to execute a defrosting operation after the end of the heating operation of the heat pump device at the first heating capacity and before the start of the heating operation of the heat pump device at the second heating capacity, regardless of the result of the determination of whether the predetermined condition is satisfied. This makes it possible to start the heating operation of the heat pump device at the second heating capacity from a state in which frost has been removed from the evaporator. As a result, it is possible to prevent frost from progressing prematurely on the evaporator during the heating operation of the heat pump device at the second heating capacity, which is higher than the first heating capacity.

[0014] Therefore, according to the first aspect of the present invention, it is possible to prevent unnecessary defrosting operation of the heat pump device, and it is also possible to prevent frost from forming on the evaporator of the heat pump device from progressing too quickly when the heat pump device is operated with a large heating capacity.

[0015] In the above first invention, it is preferable that the control device is configured to have a function of, when a request occurs to perform heating operation of the heat pump device at the second heating capacity while the heat pump device is performing heating operation at the first heating capacity, stopping the heating operation of the heat pump device at the first heating capacity, performing the defrosting operation, and then performing heating operation of the heat pump device at the second heating capacity (second invention).

[0016] According to this, even if a request to execute a heating operation of the heat pump device at a second heating capacity occurs during the execution of a heating operation of the heat pump device at a first heating capacity, it is possible to start the heating operation of the heat pump device at the second heating capacity from a state in which frost has been removed from the evaporator, and thus it is possible to prevent frost from progressing prematurely on the evaporator during the execution of a heating operation of the heat pump device at a second heating capacity higher than the first heating capacity.

[0017] In the above first or second invention, an embodiment can be adopted in which the request to perform heating operation of the heat pump device at the second heating capacity immediately after completion of heating operation of the heat pump device at the first heating capacity is a request determined in advance by a learning process based on the past operating history of the hot water storage type heat source system (third invention).

[0018] This makes it possible to cause the heat pump device to perform a defrosting operation in advance in a situation where there is a high probability that a request will actually occur to perform heating operation of the heat pump device at the second heating capacity immediately after the heating operation of the heat pump device at the first heating capacity is completed.

[0019] In the above first to third inventions, when there is a request to execute the heating operation of the heat pump device at the second heating capacity immediately after the end of the heating operation of the heat pump device at the first heating capacity, the control device can be configured to cause the heat pump device to execute the defrosting operation under the necessary condition that the time interval from the end of the heating operation of the heat pump device at the first heating capacity to the requested timing to start executing the heating operation of the heat pump device at the second heating capacity is less than a predetermined time, or that the detected value of the outside air temperature is less than a predetermined temperature (fourth invention).

[0020] According to this, even if there is a request to execute a heating operation of the heat pump device at the second heating capacity immediately after the end of the heating operation of the heat pump device at the first heating capacity, it is possible to prevent the heat pump device from executing a defrosting operation in a situation where it is predictable that frost has disappeared or has not occurred on the evaporator at the timing when the heating operation of the heat pump device at the second heating capacity is started (a situation where the time interval is longer than a predetermined time and the detected value of the outside air temperature is higher than a predetermined temperature). Therefore, it is possible to prevent unnecessary defrosting operations from being executed.

[0021] In addition, in the above second invention, when a request occurs to perform heating operation of the heat pump device at the second heating capacity while heating operation of the heat pump device at the first heating capacity is being performed, the control device can be configured to cause the heat pump device to perform the defrosting operation after stopping the heating operation of the heat pump device at the first heating capacity, with the necessary condition that the detected value of the outside air temperature is equal to or lower than a predetermined temperature (fifth invention).

[0022] According to this, even if a request to execute a heating operation of the heat pump device at the second heating capacity occurs during the execution of a heating operation of the heat pump device at the first heating capacity, in a situation where the outdoor air temperature is higher than a predetermined temperature and it can be assumed that no frost has formed on the evaporator, it is possible to promptly start the execution of the heating operation of the heat pump device at the second heating capacity without causing the heat pump device to execute a defrosting operation. Therefore, it is possible to prevent unnecessary execution of a defrosting operation. The fifth invention can also be combined with the third or fourth invention. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a hot water storage type heat source system according to an embodiment of the present invention. [Diagram 2] 4 is a timing chart for explaining the operation of the hot water storage type heat source system of the embodiment. [Diagram 3]4 is a flowchart showing the processing of a control device of the hot water storage type heat source system of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] An embodiment of the present invention will be described below with reference to Figures 1 to 3. With reference to Figure 1, a hot water storage type heat source system 1 (hereinafter simply referred to as heat source system 1) of this embodiment is, for example, a hot water supply system, and includes a hot water storage unit 10 including a hot water storage tank 11 that stores heated hot water (hot water supply water), a heat pump device 30 as a heat source device that heats the hot water in the hot water storage tank 11, an auxiliary heat source device 50 as an auxiliary heat source device that heats the hot water (hot water supply water) supplied from the hot water storage tank 11 as necessary, and a control device 70 having a function of controlling the operation of the heat source system 1.

[0025] A water supply path 12 for supplying hot water to the hot water storage tank 11, a hot water supply path 13 for supplying heated hot water from the hot water storage tank 11 to an external hot water supply target location, and a circulation path 23 for circulating the hot water between the hot water storage tank 11 and a condenser 32 (described later) of the heat pump device 30 are connected to the hot water storage tank 11 of the hot water storage unit 10. The hot water storage unit 10 is also provided with a bypass path 14 for flowing hot water from the water supply path 12 to the hot water supply path 13 without passing through the hot water storage tank 11.

[0026] The upstream side of the water supply passage 12 is connected to a piping (water pipe or the like) of a water supply source (not shown) outside the hot water storage unit 10, and the downstream end is connected to the lower part of the hot water storage tank 11. A pressure reducing valve 15 for preventing the internal pressure of the hot water storage tank 11 from becoming excessive, and a check valve 16 for preventing backflow of the hot water supply are attached to the water supply passage 12. A bypass passage 14 is branched off from a midway point of the water supply passage 12, for example, a midway point between the pressure reducing valve 15 and the check valve 16.

[0027] The upstream end of the hot water supply passage 13 is connected to the top of the hot water storage tank 11, and a bypass passage 14 is joined to the downstream part of the upstream end via a mixing valve 17. The mixing valve 17 is constituted by an electrically operated three-way valve or the like, and is capable of mixing hot water flowing into the mixing valve 17 from the hot water storage tank 11 via the hot water supply passage 13 on the upstream side and hot water flowing into the mixing valve 17 from the bypass passage 14, and flowing the mixed water into the hot water supply passage 13 on the downstream side, and is capable of variably controlling the mixing ratio of the hot water flowing in from each of the hot water storage tank 11 and the bypass passage 14.

[0028] By controlling the operation of the mixing valve 17, the above-mentioned mixing ratio can be controlled, and therefore the temperature of the hot water flowing from the mixing valve 17 to the hot water supply passage 13 downstream can be adjusted.

[0029] The hot water supply passage 13 downstream of the mixing valve 17 is branched into two passages: a first branch hot water supply passage 13a that passes hot water supplied from the upstream side (mixing valve 17 side) downstream via the auxiliary heat source unit 50, and a second branch hot water supply passage 13b that passes hot water downstream without passing through the auxiliary heat source unit 50. The first branch hot water supply passage 13a extends from the hot water storage unit 10 to the auxiliary heat source unit 50, passes through a heat exchanger 51 (described later) in the auxiliary heat source unit 50, and is arranged so that the water returns to the hot water storage unit 10 from the heat exchanger 51.

[0030] The second branch hot water supply passage 13b is arranged in the hot water storage unit 10 so as to branch off from the upstream hot water supply passage 13 in parallel with the first branch hot water supply passage 13a and merge with the downstream end of the first branch hot water supply passage 13a. The hot water supply passage 13 downstream of the merger between the downstream ends of the first branch hot water supply passage 13a and the second branch hot water supply passage 13b is connected, outside the hot water storage unit 10, via a pipe (not shown) to a hot water tap (faucet, shower, etc.) arranged at a hot water supply location such as a kitchen, bathroom, or washroom.

[0031] In the hot water storage unit 10, check valves 18 and 19 for preventing backflow of hot water are respectively attached to the hot water supply passage 13 upstream of the mixing valve 17 and the bypass passage 14. In addition, an opening / closing valve 20 (e.g., a solenoid valve) capable of opening and closing the second branch hot water supply passage 13b is attached.

[0032] The circulation path 23 has an outward flow path 23a through which hot water flows from the hot water storage tank 11 to the heat pump device 30, and a return flow path 23b through which hot water returns from the heat pump device 30 to the hot water storage tank 11, and an upstream end of the outward flow path 23a is connected to a lower part of the hot water storage tank 11. The outward flow path 23a extends from the hot water storage unit 10 to the heat pump device 30, and a downstream end of the outward flow path 23a is connected to a condenser 32 in the heat pump device 30.

[0033] The return flow path 23b has an upstream end connected to the condenser 32 so as to communicate with the outward flow path 23a via the condenser 32. The return flow path 23b extends from the heat pump device 30 to the hot water storage unit 10, and has a downstream end connected to the upper part of the hot water storage tank 11 in the hot water storage unit 10.

[0034] The heat pump device 30, like known devices, includes a compressor 31, a condenser 32, an expansion valve 33, an evaporator 34, and a refrigerant flow path 35 that circulates a refrigerant. The refrigerant flow path 35 is configured to return the refrigerant pressurized by the compressor 31 to the compressor 31 via the condenser 32, the expansion valve 33, and the evaporator 34 in this order.

[0035] In this case, the condenser 32 is configured to function as a heat exchanger that performs heat exchange (heat transfer from the refrigerant to the hot water) between the hot water supplied from the forward flow path 23a of the circulation path 23 and the refrigerant supplied from the compressor 31 in the refrigerant flow path 35.

[0036] The evaporator 34 is disposed opposite an electric blower fan 36 mounted on the heat pump device 30, and is configured to function as a heat exchanger that performs heat exchange (heat transfer from the outside air to the refrigerant) between outside air supplied by the rotational operation of the blower fan 36 and the refrigerant supplied from the expansion valve 33 in the refrigerant flow path 35. Hereinafter, the evaporator 34 will be referred to as the air heat exchanger 34.

[0037] The heat pump device 30 is further equipped with an electric pump 38 as a power source for circulating the hot water in the circulation path 23. The pump 38 is attached to one of the outward flow path 23a and the return flow path 23b, for example, the outward flow path 23a. The heat pump device 30 is also equipped with a temperature sensor 39 for detecting the outside air temperature.

[0038] In the heat pump device 30 configured as described above, while operating the pump 38 and the blower fan 36, the operation of the compressor 31 and the expansion valve 33 is controlled so that the refrigerant is compressed (pressurized) by the compressor 31 and expanded (depressurized) by the expansion valve 33, thereby performing a heating operation in which the hot water circulating in the circulation path 23 is heated by the condenser 32 (and thus the hot water in the hot water storage tank 11 is heated).

[0039] In this case, in this embodiment, the heat pump device 30 can execute a heating operation at a first heating capacity that can operate the heat pump device 30 with high energy efficiency (hereinafter referred to as high-efficiency heating operation), and a heating operation at a second heating capacity in which the output (amount of heat) from the heat pump device 30 to the hot water supply is higher than the first heating capacity (hereinafter referred to as high-output heating operation). Note that the energy efficiency of the heat pump device 30 means the ratio of the output energy (thermal energy given to the hot water supply by the condenser 32) per unit time of the heat pump device 30 to the energy consumption (power consumption) per unit time of the heat pump device 30.

[0040] The heat pump device 30 is also capable of performing a defrosting operation to remove frost on the air heat exchanger 34. In this embodiment, the defrosting operation is an operation in which the compressor 31 is operated while the expansion valve 33 is controlled to be fully open and the operation of the pump 38 and the blower fan 36 is stopped. By this defrosting operation, the refrigerant pressurized and heated by the compressor 31 is supplied to the air heat exchanger 34 via the condenser 32 and the expansion valve 33, thereby warming the air heat exchanger 34. As a result, the air heat exchanger 34 is defrosted.

[0041] The defrosting operation of the heat pump device 30 can also be performed in a manner different from that described above. For example, the refrigerant flow path may be configured so that during the defrosting operation, the refrigerant pressurized and heated by the compressor 31 passes through the condenser 32, and then bypasses the expansion valve 33 and is supplied to the air heat exchanger 34. Also, for example, the refrigerant flow path may be configured so that during the defrosting operation, the refrigerant pressurized and heated by the compressor 31 passes through the air heat exchanger 34, the expansion valve 33, and the condenser 32 in this order, inversely to the heating operation, and is returned to the compressor 31.

[0042] In this embodiment, the auxiliary heat source unit 50 is a combustion type heat source unit, and includes a heat exchanger 51 connected to the first branch hot water supply passage 13a, and a burner 52 that heats the heat exchanger 51 with combustion heat. In this case, the supply of fuel and the supply of combustion air to the burner 52 are performed by a fuel supply device and a combustion fan (blower), respectively, not shown. The fuel for the burner 52 may be either gas fuel or liquid fuel.

[0043] The auxiliary heat source unit 50 is equipped with a bypass passage 53 that allows hot water to flow from the first branch hot water supply passage 13a upstream of the heat exchanger 51 to the first branch hot water supply passage 13a downstream without passing through the heat exchanger 51. The upstream end of the bypass passage 53 branches off from the first branch hot water supply passage 13a upstream of the heat exchanger 51 via a distribution valve 54, and the downstream end merges with the first branch hot water supply passage 13a downstream of the heat exchanger 51. The distribution valve 54 is constituted by an electric three-way valve or the like, and can distribute the hot water supplied from the first branch hot water supply passage 13a upstream to the heat exchanger 51 and the bypass passage 53, and can variably control the distribution ratio.

[0044] In addition, a water volume servo valve 55 is installed in the first branch hot water supply path 13a in the auxiliary heat source unit 50, upstream of the distribution valve 54, which can variably control the flow rate of hot water flowing through the first branch hot water supply path 13a.

[0045] A filling water flow path 56 branches off from the first branch hot water supply path 13a downstream of the heat exchanger 51 at a midway point downstream of the junction with the bypass path 53. The filling water flow path 56 is led out from the auxiliary heat source unit 50 and connected to a bathtub BT in the bathroom. A filling water valve 57 (e.g., a solenoid valve) that can open and close the filling water flow path 56 is attached to the filling water flow path 56.

[0046] In the auxiliary heat source unit 50 configured as described above, when hot water is supplied from the hot water storage tank 11 to the hot water supply target location downstream of the hot water supply path 13, the hot water supply flowing through the first branch hot water supply path 13a can be heated by performing a combustion operation of the burner 52. Therefore, even if the temperature of the hot water supply water that can be supplied from the hot water storage tank 11 is lower than the target hot water supply temperature (the target temperature of the hot water supply water to be supplied to the hot water supply target location) when the hot water storage tank 11 is out of hot water (a state in which the remaining amount of hot water at or above a predetermined temperature in the hot water storage tank 11 has dropped below a predetermined amount), the temperature of the hot water supply water (hot water supply temperature) supplied to the hot water supply target location downstream of the hot water supply path 13 can be raised to the target hot water supply temperature.

[0047] Furthermore, by opening the hot water filling valve 57, hot water can be filled into the bathtub BT from the hot water storage tank 11 via the mixing valve 17, the first branch hot water supply path 13a, and the hot water filling path 56. Even in this case, by operating the burner 52 for combustion when the hot water storage tank 11 is out of hot water, the temperature of the hot water supplied to the bathtub BT can be raised to the target hot water filling temperature even if the temperature of the hot water that can be supplied from the hot water storage tank 11 is lower than the target hot water filling temperature (the target temperature of the hot water to be supplied to the bathtub BT).

[0048] The control device 70 is configured with one or more electronic circuit units including, for example, a processor such as a microcomputer, a memory, an interface circuit, etc. For example, the control device 70 may be configured as an assembly of multiple electronic circuit units that are separately mounted on each of the hot water storage unit 10, the heat pump device 30, and the auxiliary heat source device 50 and can communicate with each other. However, the control device 70 may be of a single configuration.

[0049] The control device 70 can communicate by wire or wirelessly with a remote control 75 that allows the user to operate the heat source system 1. The remote control 75 includes an operation unit 75a including a plurality of operation switches, and a display unit 75b that displays various information related to the operation of the heat source system 1. By operating the operation unit 75a of the remote control 75, it is possible to perform operations such as turning on / off the hot water supply operation that supplies hot water to the target hot water supply locations, issuing an instruction to execute a hot water filling operation that fills the bathtub BT, and setting the target hot water supply temperature, the target hot water filling temperature, and the target amount of hot water filling (or the target water level of the bathtub BT).

[0050] The control device 70 can control the operation of each of the controlled devices, namely, the hot water storage unit 10, the heat pump device 30, and the auxiliary heat source device 50, by using functions realized by the implemented hardware configuration and program (software configuration). In this case, the controlled devices of the hot water storage unit 10 include the mixing valve 17 and the on-off valve 20 of the second branch hot water supply path 13b, and the controlled devices of the heat pump device 30 include the compressor 31, the expansion valve 33, the blower fan 36, and the pump 38.

[0051] The controlled devices of the auxiliary heat source unit 50 include the burner 52, the distribution valve 54, the water volume servo valve 55, and the water filling valve 57 of the water filling flow path 56. More specifically, the operation of the burner 52 is controlled through the operation of a fuel supply device, a combustion fan (blower), and an ignition device, which are not shown.

[0052] Next, the operation of the heat source system 1 of this embodiment will be described. First, the hot water supply operation and hot water filling operation in the heat source system 1 will be described. The hot water supply operation is performed as follows. That is, when the hot water tap of the hot water supply location is opened to start the flow of water in the hot water supply path 13 (flow of water at a predetermined flow rate or more), the control device 70 executes a control process related to the hot water supply operation. In this case, the control device 70 detects the start of the flow of water in the hot water supply path 13 via a flow sensor (not shown) provided in the hot water supply path 13 or the water supply path 12.

[0053] In the control process for hot water supply operation, when the hot water storage tank 11 is not out of hot water, the control device 70 controls the operation of the mixing valve 17 so that the temperature of the hot water supply water (hot water supply temperature) flowing from the mixing valve 17 to the hot water supply target location matches or nearly matches the target hot water supply temperature set by the user via the remote control 75, while controlling the opening and closing valve 20 of the second branch hot water supply path 13b to be open.

[0054] In addition, when the hot water storage tank 11 runs out of hot water, the control device 70 starts the combustion operation of the burner 52 of the auxiliary heat source unit 50 while controlling the opening / closing valve 20 of the second branch hot water supply line 13b to be closed, and controls the combustion amount of the burner 52 and the distribution valve 54 so that the temperature of the hot water supply water (hot water supply temperature) flowing from the first branch hot water supply line 13a to the hot water supply location matches or nearly matches the target hot water supply temperature.

[0055] By executing the control process of the hot water supply operation as described above, hot water at a temperature that is equal to or nearly equal to the target hot water temperature is supplied to the hot water supply target location. The hot water supply operation is terminated when the hot water tap of the hot water supply target location is closed and the water flow rate in the hot water supply path 13 or the water supply path 12 falls below a predetermined value.

[0056] Next, the water filling operation is performed as follows. That is, the control device 70 starts the water filling operation in response to the user's operation of the remote control 75 (operation to instruct the user to perform the water filling operation) or in response to a timer preset in the remote control 75. In the control process of this water filling operation, the control device 70 controls the opening / closing valve 20 of the second branch hot water supply path 13b to be closed, and controls the water filling valve 57 of the water filling flow path 56 to be open. This starts the supply of hot water from the hot water storage tank 11 to the bathtub BT. Then, when the hot water storage tank 11 is not out of hot water, the control device 70 controls the operation of the mixing valve 17 so that the temperature of the hot water flowing from the mixing valve 17 to the bathtub BT matches or nearly matches the target water filling temperature set by the user on the remote control 75.

[0057] In addition, when the hot water storage tank 11 runs out of hot water, the control device 70 starts the combustion operation of the burner 52 of the auxiliary heat source unit 50, and controls the combustion amount of the burner 52 and the distribution valve 54 so that the temperature of the hot water flowing from the first branch hot water supply path 13a to the bathtub BT matches or nearly matches the target water filling temperature.

[0058] By executing the control process for the bath filling operation as described above, hot water at a temperature that matches or nearly matches the target bath filling temperature is supplied to the bathtub BT, and the bathtub BT is filled with water. The bath filling operation ends when the cumulative amount of hot water supplied to the bathtub BT (or the water level of the bathtub BT) reaches the target bath filling amount (or target water level) set by the user via remote control 75.

[0059] Next, a description will be given of the boiling process of the hot water (water for hot water supply) in the hot water storage tank 11 by the heating operation of the heat pump device 30, and the defrosting operation of the heat pump device 30. In this embodiment, the control device 70 has a function of scheduling the execution timing of the boiling process for boiling the hot water in the hot water storage tank 11, based on the past history of the hot water supply operation and the water filling operation of the heat source system 1. The boiling process is a process in which the hot water in the hot water storage tank 11 is heated while being circulated between the condenser 32 of the heat pump device 30 and the hot water storage tank 11 via the circulation path 23 until the temperature of almost the entire hot water in the hot water storage tank 11 is raised to a predetermined temperature or higher by the heating operation of the heat pump device 30.

[0060] The predetermined temperature may be set according to, for example, a target hot water supply temperature or a target bath filling temperature set by the user via remote control 75. For example, the predetermined temperature may be set to a temperature that is a predetermined value higher than the higher of the target hot water supply temperature and the target bath filling temperature. However, the predetermined temperature may be a constant temperature that has been set in advance.

[0061] In the above scheduling, for example, at a predetermined update timing each day (e.g., 2 a.m.), the control device 70 predicts the start time S1 of the first hot water supply operation, the end time G1 of the last hot water supply operation, and the start time B1 of the hot water filling operation of the day (the day until the next update timing) by a learning process based on the past history (e.g., history for the past week) of the hot water supply operation and the hot water filling operation of the heat source system 1. Hereinafter, the predicted start time S1 of the hot water supply operation, the end time G1 of the hot water supply operation, and the start time B1 of the hot water filling operation are referred to as the predicted hot water supply start time G1, the predicted hot water supply end time G1, and the predicted hot water filling start time B1, respectively.

[0062] Then, the control device 70 determines time S0, a predetermined time α before the predicted hot water supply start time S1, as the start time of the boiling process before the start of the first hot water supply operation of the day (hereinafter referred to as pre-hot water supply boiling start time S0). The predetermined time α is set so that boiling of hot water in the hot water storage tank 11 can be completed before the predicted hot water supply start time S1 by the high-efficiency heating operation of the heat pump device 30 within the predetermined time α, even if the hot water storage tank 11 is out of hot water or close to it at the pre-hot water supply boiling start time S0.

[0063] Furthermore, the control device 70 determines the time B0, a predetermined time β before the predicted bath filling start time B1, as the start time for the boiling process before the start of the bath filling operation on that day (hereinafter referred to as the pre-filling boiling start time B0). The predetermined time β is set so that, even if the hot water storage tank 11 is out of hot water or close to it at the pre-filling boiling start time B0, the boiling of hot water in the hot water storage tank 11 can be completed by the predicted bath filling start time B1 through the high-efficiency heating operation of the heat pump device 30 within the predetermined time β.

[0064] The control device 70 also determines the time G0, a predetermined time γ before the predicted hot water supply end time G1, as the start time of the period during which the heat pump device 30 is maintained in an operation stopped state (hereinafter, referred to as the HP operation end time G0). The predetermined time γ is set so that the hot water supply operation during the period from the HP operation end time G0 to the predicted hot water supply end time G1 can be performed using the hot water remaining in the hot water storage tank 11.

[0065] The above-mentioned predetermined times α, β, and γ may be constant times determined in advance, or may be variably set to reflect environmental conditions such as the outside air temperature and the temperature of water supplied to the hot water tank 11.

[0066] The lower graphs in Figures 2A and 2B show the predicted hot water supply start time S1, the predicted bath filling start time B1, and the predicted hot water supply end time G1, as well as the corresponding pre-water supply heating start time S0, pre-water filling start time B0, and HP operation end time G0, which are determined as described above. This example is for the case where S1=6:00, B1=20:00, and G1=0:00.

[0067] After determining the pre-hot water heating start time S0, pre-filling water heating start time B0, and HP operation end time G0 as described above, the control device 70 successively monitors whether the current time has reached each of the times S0, B0, and G0. When the current time reaches the pre-hot water heating start time S0 and when the current time reaches the pre-filling water heating start time B0, the control device 70 starts the heating process using the high-efficiency heating operation of the heat pump device 30. When the current time reaches the HP operation end time G0, the control device 70 stops the operation of the heat pump device 30 (HP operation) thereafter until the pre-hot water heating start time S0 of the next day.

[0068] Here, the high-efficiency heating operation of the heat pump device 30 in the heating process from the pre-hot water supply heating start time S0 ends before the hot water supply start predicted time S1, as shown in Fig. 2A or 2B. Note that in the example shown in Fig. 2A or 2B, the heating process by the high-efficiency heating operation starts when the hot water in the hot water storage tank 11 is in a cooled state, so the high-efficiency heating operation ends just before the hot water supply start predicted time S1.

[0069] 2A or 2B, the high-efficiency heating operation of the heat pump unit 30 in the heating process starting from the pre-filling heating start time B0 ends before the predicted bath filling start time B1. In the example shown in Fig. 2A, hot water supply operation is performed from 6:00 and from 11:00 before the pre-filling heating start time B0, so the hot water storage tank 11 is, for example, close to running out of hot water. For this reason, the heating process is completed just before the predicted bath filling start time B1 (for example, 19:50), and the high-efficiency heating operation ends.

[0070] 2B, during the time period from the predicted hot water supply start time S1 to the start time B0 of pre-filling heating, the amount of hot water used in the hot water supply operation is small, for example during the daytime, due to the absence of users, and so there is a large amount of hot water remaining at or above the specified temperature in the hot water storage tank 11. For this reason, the heating process is completed in a relatively short time from the start time B0 of pre-filling heating, and the high-efficiency heating operation ends earlier than the predicted time B1 of filling the water.

[0071] Furthermore, when starting the water filling operation, the control device 70 starts the water heating process using the high-output heating operation in parallel with the control process for the water filling operation. For example, as shown in Fig. 2A or 2B, when the water filling operation starts at approximately the same time as the predicted water filling start time B1, the high-output heating operation of the heat pump unit 30 is started. Note that, if the water filling operation is started while the heat pump unit 30 is performing a defrosting operation, the control device 70 starts the water heating process using the high-output heating operation after the defrosting operation is completed.

[0072] Here, although a large amount of hot water is supplied from the hot water storage tank 11 to the bathtub BT during the bathtub filling operation, the hot water in the hot water storage tank 11 is boiled up by the high-power heating operation of the heat pump device 30, so it is possible to prevent the hot water storage tank 11 from running out of hot water while the bathtub BT is being filled with hot water. Furthermore, it is possible to prevent the combustion operation of the burner 52 of the auxiliary heat source unit 50 from being performed as much as possible. Note that in the example shown in Figure 2A or 2B, after the bathtub filling operation ends, the boiling process is completed and the high-power heating operation is ended.

[0073] In addition, when the boiling process by the high-efficiency heating operation of the heat pump unit 30 is completed, the control device 70 determines whether or not to perform defrosting operation of the heat pump unit 30, as shown in the flowchart of Figure 3, and controls the defrosting operation of the heat pump unit 30 in accordance with the decision.

[0074] Specifically, when the heating process by the high-efficiency heating operation of the heat pump unit 30 ends, the control device 70 judges in STEP 1 whether the high-efficiency heating operation is the high-efficiency heating operation that started from the start time B0 of the pre-heating. If the result of this judgment is negative, the control device 70 next judges in STEP 2 whether a defrosting start condition, which is a predetermined condition for starting the defrosting operation, is satisfied. In this case, for example, when the outside air temperature detected by the temperature sensor 39 and the temperature of the refrigerant detected by a temperature sensor (not shown) in the refrigerant flow path 35 (for example, the temperature on the inlet side or outlet side of the air heat exchanger 34) satisfy a predetermined condition, it can be considered that frost has formed on the air heat exchanger 34, and in this case, the judgment result in STEP 2 becomes positive (the defrosting start condition is satisfied).

[0075] The defrost start condition is not limited to the condition based on the outside air temperature or the refrigerant temperature as described above, and other conditions may be adopted as long as they are correlated with frost formation on the air heat exchanger 34. For example, when frost formation on the air heat exchanger 34 progresses to a certain extent, the air volume of the blower fan 36 decreases and the current supplied to the electric motor that drives the blower fan 36 decreases, so that the defrost start condition may be established when the current supplied to the electric motor decreases by a predetermined amount or more.

[0076] Then, if the determination result in STEP 2 is positive (if the defrosting start condition is satisfied), in STEP 3, the control device 70 starts the above-mentioned defrosting operation of the heat pump device 30. The defrosting operation is terminated, for example, when the elapsed time from the start of the defrosting operation reaches a predetermined time. If the determination result in STEP 2 is negative, the control device 70 does not cause the heat pump device 30 to execute the defrosting operation, and terminates the processing of the flowchart in FIG. 3.

[0077] 2A or 2B, the determination result in STEP 1 becomes negative at the end of the high-efficiency heating operation that started at pre-hot water heating start time S0. In this case, if the defrost start condition is satisfied at the end of the high-efficiency heating operation, the defrost operation of the heat pump unit 30 is started immediately after the end of the high-efficiency heating operation. Note that in FIG. 2A or 2B, the defrost start condition in STEP 2 is not satisfied at the end of the high-efficiency heating operation, so the defrost operation is not performed.

[0078] If the determination result in STEP 1 is positive, i.e., if the high-efficiency heating operation that has ended in the heat pump unit 30 is the high-efficiency heating operation that started at the start time B0 of pre-filling water heating, the control device 70 executes the determination processing in STEPs 4 and 5, and if either of the determination results is positive, starts the defrosting operation of the heat pump unit 30 in STEP 3. If the determination results in both STEPs 4 and 5 are negative, the control device 70 ends the processing of the flowchart in FIG. 3 without causing the heat pump unit 30 to execute the defrosting operation.

[0079] In STEP 4, the control device 70 determines whether the time interval from the end of the high-efficiency heating operation of the heat pump device 30 to the predicted bath filling start time B1 is equal to or less than a predetermined time ta (e.g., 20 minutes) (whether the predicted bath filling start time B1 is the time immediately after the end of the high-efficiency heating operation). In STEP 5, the control device 70 determines whether the current outside air temperature detected by the temperature sensor 39 (the outside air temperature at the end of the high-efficiency heating operation) is equal to or less than a predetermined temperature Ta (e.g., 5°C).

[0080] Therefore, when the judgment result of STEP 1 is positive, the control device 70 starts the defrosting operation of the heat pump device 30 regardless of the defrosting start conditions when the time interval from the end of the high-efficiency heating operation of the heat pump device 30 to the predicted water filling start time B1 is less than or equal to the predetermined time ta (20 minutes) (in other words, when it is predicted that the water filling operation will start immediately after the end of the high-efficiency heating operation), or when the outside air temperature at the end of the high-efficiency heating operation is less than or equal to the predetermined temperature Ta (5°C).

[0081] For example, in Fig. 2A, the high-efficiency heating operation that started at the pre-filling heating start time B0 ends at a time (e.g., 19:50) just before the expected bath filling start time B1 (20:00). Therefore, the condition that the time interval between the end of the high-efficiency heating operation (19:50) and the expected bath filling start time B1 (20:00) is less than the specified time ta (20 minutes) is met. In this case, as shown in Fig. 2A, the defrosting operation of the heat pump unit 30 is immediately started and ends at a time close to the expected bath filling start time B1 (20:00).

[0082] Therefore, if the water filling operation is started near the predicted water filling start time B1 (20:00), the defrosting operation defrosts the air heat exchanger 34 of the heat pump unit 30, and then high-power heating operation of the heat pump unit 30 is started.

[0083] Additionally, there may be cases where a water filling operation is started while a defrosting operation is being performed, which may result in a request to perform a high-power heating operation of the heat pump unit 30. In such a case, the control device 70 starts the high-power heating operation of the heat pump unit 30 after the defrosting operation is completed.

[0084] In addition, there are cases where a hot water filling operation is started (and a request to execute a high-power heating operation is generated) during the execution of the high-efficiency heating operation of the heat pump device 30, which is started from the pre-hot water supply heating start time S0 or the pre-hot water filling heating start time B0. In such a case, in this embodiment, the control device 70 immediately stops the high-efficiency heating operation of the heat pump device 30, and if the outdoor air temperature (the outdoor air temperature detected by the temperature sensor 39) at the time of the stop is equal to or lower than the predetermined temperature Ta (5°C), starts the defrosting operation of the heat pump device 30, and starts the high-power heating operation after the defrosting operation is completed. In addition, if the outdoor air temperature at the time of the stop of the high-efficiency heating operation of the heat pump device 30 is higher than the predetermined temperature Ta (5°C), the control device 70 starts the high-power heating operation without causing the heat pump device 30 to execute the defrosting operation.

[0085] Furthermore, when the judgment result of STEP 1 is positive, if the time interval from the end of the high-efficiency heating operation of the heat pump unit 30 to the predicted water filling start time B1 is longer than the specified time ta (20 minutes) and the outside air temperature at the end of the high-efficiency heating operation is higher than the specified temperature Ta (5°C), the control unit 70 will not start the defrosting operation of the heat pump unit 30, since it can be assumed that the frost on the air heat exchanger 34 of the heat pump unit 30 has disappeared by the predicted water filling start time B1.

[0086] For example, in the example shown in Fig. 2B, the high-efficiency heating operation that started at pre-filling boiling start time B0 ended much earlier than the estimated bath filling start time B1 (20:00), so the condition that the time interval from the end of the high-efficiency heating operation to the estimated bath filling start time B1 (20:00) is less than the specified time ta (20 minutes) is not met. In this case, if the outside air temperature at the end of the high-efficiency heating operation is higher than the specified temperature Ta (5°C), as shown in Fig. 2B, the defrosting operation is not performed after the high-efficiency heating operation of the heat pump unit 30 ends.

[0087] According to the embodiment described above, when the high-efficiency heating operation of the heat pump unit 30, which starts at the pre-filling heating start time B0, is completed, the defrosting operation of the heat pump unit 30 is performed except when the time interval from the end of the high-efficiency heating operation of the heat pump unit 30 to the predicted water filling start time B1 is longer than a predetermined time ta (20 minutes) and the outside air temperature is higher than a predetermined temperature Ta (5°C) is met.

[0088] In addition, when the water filling operation is started (and thus a request to perform high-output heating operation occurs) during the high-efficiency heating operation of the heat pump unit 30, which starts from the start time S0 of the pre-water heating operation or the start time B0 of the pre-water heating operation, the defrosting operation of the heat pump unit 30 is performed except when the condition that the outside air temperature is higher than a predetermined temperature Ta (5°C) is met.

[0089] Therefore, during high-efficiency heating operation performed before the start of high-power heating operation of the heat pump unit 30 during water filling operation, even if frost has progressed to a certain extent on the air heat exchanger 34, the high-power heating operation can be started in a state where the frost has disappeared from the air heat exchanger 34.

[0090] Here, during high-power heating operation of the heat pump unit 30, the temperature of the refrigerant supplied to the air heat exchanger 34 from the expansion valve 33 side becomes lower than during high-efficiency heating operation, so frost is likely to form on the air heat exchanger 34. However, in this embodiment, the high-power heating operation of the heat pump unit 30 during bath filling operation can be started in a state where frost has been removed from the air heat exchanger 34, so it is possible to prevent as much as possible the occurrence of a situation in which it is necessary to perform a defrosting operation during high-power heating operation.

[0091] As a result, high-power heating operation of the heat pump unit 30 can be continuously performed while the water filling operation is being performed, and ultimately, the occurrence of a situation in which combustion operation of the burner 52 of the auxiliary heat source unit 50 is required can be minimized.

[0092] In addition, if the time interval from the end of the high-efficiency heating operation of the heat pump unit 30, which starts at the pre-filling boiling start time B0, to the predicted bath filling start time B1 is longer than a specified time ta (20 minutes) and the outside air temperature is higher than a specified temperature Ta (5°C), that is, if it can be assumed that the frost on the air heat exchanger 34 has disappeared by the predicted bath filling start time B1, then defrosting operation will not be performed.

[0093] Furthermore, even if a water filling operation is started while the heat pump unit 30 is performing a high-efficiency heating operation, if the outside air temperature is higher than a predetermined temperature Ta (5°C), that is, if it can be assumed that no frost has formed on the air heat exchanger 34, then after the high-efficiency heating operation of the heat pump unit 30 is stopped, a high-power heating operation is performed without a defrosting operation being performed.

[0094] Furthermore, at the end of the high-efficiency operation of the heat pump unit 30, which starts from the pre-hot water heating start time S0, the defrosting operation is started only if the defrosting start condition is satisfied. This appropriately prevents unnecessary defrosting operations from being performed, and reduces the power consumption of the heat pump unit 30.

[0095] The present invention is not limited to the above-described embodiment, and other embodiments may be adopted. For example, at the end of the high-efficiency heating operation of the heat pump unit 30, which starts at the pre-filling heating start time B0, the defrosting operation may always be performed regardless of the time interval until the expected water filling start time B1 or the outside air temperature. Also, if the water filling operation is started during the high-efficiency heating operation, the defrosting operation may be immediately started regardless of the outside air temperature, and then the heat pump unit 30 may be caused to perform the high-output heating operation.

[0096] In the above embodiment, a combustion-type auxiliary heat source unit equipped with a burner 52 is exemplified as the auxiliary heat source unit 50, but the auxiliary heat source unit 50 may be an electric heating-type auxiliary heat source unit. The hot water storage type heat source system of the present invention may be a heat source system that does not include an auxiliary heat source unit. The hot water storage type heat source system of the present invention is not limited to a hot water supply function, and may be a system having a hot water heating terminal.

[0097] In addition, in the above embodiment, the predicted water filling start time B1 related to the pre-filling heating start time B0 was determined by a learning process based on the past operating history of the heat source system 1, but in cases where the user pre-reserves the start time of the water filling operation by operating the remote control 75, the pre-filling heating start time B0 may be determined according to that reserved time. [Explanation of symbols]

[0098] 1...hot water storage type heat source system, 11...hot water storage tank, 30...heat pump device, 34...evaporator, 37...outdoor unit, 70...control device.

Claims

1. A hot water storage type heat source system, a heat pump device capable of performing a first heating operation for heating hot water in a hot water storage tank with a first heating capacity, a second heating operation for heating hot water in the hot water storage tank with a second heating capacity that is a heating capacity higher than the first heating capacity, and a defrosting operation for defrosting an evaporator mounted so as to be able to exchange heat with outside air; A control device that determines whether or not to cause the heat pump device to perform the defrosting operation after the first heating operation is completed, and controls the operation of the heat pump device in accordance with the determination, The control device controls the heat pump device so as to execute the first heating operation before a hot water supply operation and a hot water filling operation, and to execute the second heating operation during the hot water filling operation; The control device is configured to have the following functions: (i) a function to determine whether or not to cause the heat pump device to perform a defrosting operation by judging whether or not a specified condition for starting the defrosting operation is met after the end of the first heating operation, when there is no request to perform the second heating operation immediately after the end of the first heating operation before the water filling operation; and (ii) a function to cause the heat pump device to perform the defrosting operation after the end of the first heating operation and before the start of the second heating operation, regardless of the result of the judgment of whether or not the specified condition is met, when there is a request to perform the second heating operation immediately after the end of the first heating operation before the water filling operation.

2. In the hot water storage type heat source system according to claim 1, A hot water storage type heat source system characterized in that the control device is configured to have the function of stopping the first heating operation, executing the defrosting operation, and then executing the second heating operation when a request to execute the second heating operation occurs while the first heating operation is being executed.

3. In the hot water storage type heat source system according to claim 1 or 2, A hot water storage type heat source system, characterized in that the request to perform the second heating operation immediately after the end of the first heating operation is a request that is predetermined by a learning process based on the past operating history of the hot water storage type heat source system.

4. In the hot water storage type heat source system according to any one of claims 1 to 3, The control device is configured to, when there is a request to perform the second heating operation immediately after the end of the first heating operation, cause the heat pump device to perform the defrosting operation, with the necessary condition that the time interval from the end of the first heating operation to the requested timing for starting execution of the second heating operation is less than a predetermined time, or the detected value of the outside air temperature is less than a predetermined temperature.A hot water storage type heat source system characterized in that it is configured to

5. In the hot water storage type heat source system according to claim 2, A hot water storage type heat source system characterized in that, when a request to perform the second heating operation occurs while the first heating operation is being performed, the control device is configured to cause the heat pump device to perform the defrosting operation after the first heating operation is stopped, with the necessary condition that the detected outside air temperature is below a predetermined temperature.

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