JP7310690B2 - Storage hot water heater - Google Patents

Description

The present disclosure relates to a hot water storage type hot water supply apparatus.

Patent Literature 1 describes a hot water storage type hot water supply apparatus having a heat exchanger for reheating that heats bathtub water flowing on the secondary side with heat source water. This hot water storage type water heater uses heat for reheating between the circuit that takes water from the top of the hot water storage tank and supplies it to the heat exchanger and the circuit that directs the water heated by the heat pump unit to the heat exchanger. It is configured to be able to switch the supply circuit of the heat source water to the exchanger.

JP 2008-032327 A

In a configuration in which high-temperature water heated by a heat pump unit is used as heat source water for a heat exchanger for reheating, as in Patent Document 1, the reheating performance depends on the heating performance of the heat pump unit. Therefore, when a high reheating capacity is required, for example, when the temperature of the bath water is low, reheating takes a long time, and there is a possibility that the user's convenience is reduced.

In addition, in the case of a configuration that does not have a circuit that supplies the water heated by the heat pump unit directly to the heat exchanger for reheating, that is, the heat source water that can be supplied to the heat exchanger for reheating is the hot water storage tank. In a hot water storage type hot water supply apparatus that uses only high-temperature water from the upper portion, it is necessary to raise the temperature of the hot water storage tank in advance in preparation for a user's request for reheating. In this case, hot water is generally stored in the hot water storage tank by the boiling operation at midnight. However, in this case, the amount of heat released from the boiling operation until the hot water in the hot water storage tank is used for reheating increases, resulting in a large energy loss. In addition, there is variation in whether or not users use reheating. If the user does not reheat the water the next day, the high-temperature boiling in the middle of the night in preparation for the reheating will be wasted, and there is a risk that energy loss will increase.

In order to solve the above-described problems, the present disclosure ensures high reheating ability without increasing the heating ability of the heating means in the reheating operation using high-temperature water heated by the heating means. To provide a hot water storage type hot water supply device improved so as to suppress wasteful energy consumption due to high temperature boiling in preparation for reheating.

The hot water storage type hot water supply apparatus according to the present disclosure is configured such that the heating means for heating water and the water heated by the heating means is supplied from the upper side, forming a temperature stratification in which the upper side has a high temperature and the lower side has a low temperature. A hot water storage tank that stores water by means of a heating means, a reheating heat exchanger that heats the medium to be heated using the water heated by the heating means as heat source water, and a reheating operation that heats the medium to be heated by the reheating heat exchanger . a boiling operation in which the water taken out from the hot water storage tank is heated by the heating means and returned to the hot water storage tank; and water taken out from the first water intake port of the hot water storage tank. and a mixing valve for mixing water taken out from a second water intake on the upper side of the first water intake of the hot water storage tank and sending the mixed water to the inlet side of the heating means. The mixing valve is configured to be able to change the mixing ratio of the water from the first water intake and the water from the second water intake, and the control device adjusts the mixing ratio to 100 when performing the boiling operation. Control the mixing valve so that it becomes 0, control the operation of the boiling operation so that the water taken out from the first water intake and heated by the heating means returns to the hot water storage tank, and execute the reheating operation In this case, the mixing valve is controlled so that the mixing ratio becomes a preset mixing ratio, and the water taken out from the first water intake and the second water intake and heated by the heating means is reheated. Controls the operation of the reheating operation so that it is fed directly to the exchanger.

According to the present disclosure, it is possible to increase the water temperature after heating by the heating means without increasing the heating capacity of the heating means, and to ensure high reheating capacity. In addition, since the heating means can quickly heat the water, the amount of heat to be stored in the hot water storage tank in preparation for the reheating operation can be reduced. Therefore, it is possible to reduce the energy consumption due to the boiling operation in the middle of the night, and it is possible to suppress the energy loss due to the heat radiation from the boiling operation until the reheating operation is performed.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram schematically showing the configuration of a hot water storage type hot water supply apparatus according to Embodiment 1 of the present disclosure; FIG. 4 is a diagram showing temperature changes on the primary side and the secondary side inside the reheating heat exchanger of the hot water storage type hot water supply apparatus according to Embodiment 1 of the present disclosure. FIG. 10 is a flow chart showing a control operation executed by a controller for a hot water storage type hot water supply apparatus according to Embodiment 2 of the present disclosure; FIG. FIG. 10 is a flow chart showing a control operation executed by a controller for a hot water storage type hot water supply apparatus according to Embodiment 2 of the present disclosure; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings. In addition, the same code|symbol is attached|subjected to the element which is common in each figure, and the overlapping description is abbreviate|omitted. In the present disclosure, the term “water” or “hot water” may include liquid water of any temperature, from low-temperature water to high-temperature hot water. Further, in the present disclosure, the amount of heat that hot water has may be treated as the amount of hot water converted to hot water at a predetermined temperature. That is, in the present disclosure, the description of "amount of hot water" may substantially mean an amount of heat.

Embodiment 1.
FIG. 1 is a diagram schematically showing the configuration of a hot water storage type hot water supply apparatus according to Embodiment 1 of the present disclosure. Based on FIG. 1, the configuration and the like of the hot water storage type hot water supply apparatus according to the present disclosure will be described. A hot water storage type hot water supply apparatus 100 of FIG. 1 includes a heat pump unit 1, a tank unit 2, and a remote controller 15. The heat pump unit 1 and the tank unit 2 are connected via pipes 23b and 23c, which will be described later, and electrical wiring (not shown).

In the heat pump unit 1, a water-refrigerant heat exchanger 4 as a radiator, a compressor (not shown), an expansion valve, and an air heat exchanger as an evaporator are mounted. These are annularly connected by piping to form a refrigeration cycle circuit (refrigerant circuit). The water-refrigerant heat exchanger 4 is a plate-type or double-tube heat exchanger, and performs heat exchange between the inflowing refrigerant and water. Through heat exchange in the water-refrigerant heat exchanger 4, the refrigerant releases heat and the water absorbs heat to be heated.

In the tank unit 2, a hot water storage tank 7 for storing hot water, a pump 8a, a pump 8b, a reheating heat exchanger 9, a three-way valve 10, and mixing valves 30a, 30b, 30c are mounted, which will be described later. connected by wiring. Each of the pumps 8a and 8b has an inverter circuit, and can change the flow rate according to the driving rotation speed.

A water inlet port 7a and a water outlet port 7b, which is the first water intake port, are formed in the lower portion (that is, the bottom surface) of the hot water storage tank 7, and a hot water inlet port is formed in the upper portion (that is, the ceiling surface) of the hot water storage tank 7. 7c and a hot water inlet port 7d are formed, and a hot water outlet port 7e, which is a second water intake port, is formed in a portion of the side surface of the hot water storage tank 7 near the ceiling surface. A water supply pipe 21a for supplying water from a water source is connected to the water inlet 7a, and low-temperature water such as tap water is supplied from the water source. Further, high-temperature water heated by the heat pump unit 1 flows into the hot water storage tank 7 from the hot water introduction outlet 7c by the boiling operation described later. As a result, temperature stratification is formed inside the hot water storage tank 7 due to the difference in water density depending on the temperature, with the upper side having a higher temperature and the lower side having a lower temperature.

The boiling circuit A is a circuit for circulating hot water between the heat pump unit 1 and the tank unit 2 . The boiling circuit A is composed of a hot water storage tank 7, pipes 23a to 23d, a water-refrigerant heat exchanger 4, a three-way valve 10, a mixing valve 30c, and a pump 8a. Specifically, one end of the pipe 23a is connected to the water outlet 7b at the bottom of the hot water storage tank 7, and the other end of the pipe 23a is connected to the mixing valve 30c. The outflow port of the mixing valve 30c is connected to the inlet of the water-refrigerant heat exchanger 4 via a pipe 23b. A pump 8a is installed in the middle of the pipe 23b. The pump 8 a sends water toward the inlet of the water-refrigerant heat exchanger 4 . The outlet of the water-refrigerant heat exchanger 4 is connected to the three-way valve 10 via a pipe 23c. The three-way valve 10 is connected to a hot water introduction outlet 7c at the top of the hot water storage tank 7 via a pipe 23d.

The reheating circuit B is a circuit that allows hot water heated by the heat pump unit 1 to flow into the primary side of the reheating heat exchanger 9 as heat source water. The reheating circuit B is composed of pipes 23a to 23c, pipes 23e to 23g, a three-way valve 10, a reheating heat exchanger 9, and a pump 8a. Specifically, one end of a pipe 23e is formed in a hot water outlet 7e formed on the side surface of the hot water storage tank 7, and the other end of the pipe 23e is connected to a mixing valve 30c. The mixing valve 30c mixes the water from the pipe 23a and the water from the pipe 23e at a set mixing ratio. The mixing ratio of the mixing valve 30c can be changed. The three-way valve 10 and the inlet of the reheating heat exchanger 9 are connected by a pipe 23f, and the outlet of the reheating heat exchanger 9 and the hot water introduction outlet 7d at the top of the hot water storage tank 7 are connected by a pipe 23g. there is

The return port of the water flowing out of the reheating heat exchanger 9 to the hot water storage tank 7, that is, the connecting portion of the pipe 23g to the hot water storage tank 7 is not limited to the hot water introduction outlet 7d at the top of the hot water storage tank 7. It may be formed in the middle or lower part of 7 . Alternatively, a configuration may be adopted in which a plurality of return ports, pipes connected thereto, and switching valves are arranged, and the return ports are switched according to conditions.

The three-way valve 10 can switch the path between a state in which the pipe 23c and the pipe 23d are communicated and a state in which the pipe 23c and the pipe 23f are communicated. That is, by switching the three-way valve 10, the boiling circuit A and the reheating circuit B can be switched.

The bathtub water circulation circuit C is a circuit for circulating the bathtub water in the bathtub 11 to the reheating heat exchanger 9 to reheat (that is, keep warm or heat) the bathtub water in the bathtub 11 . The bathtub water circulation circuit C is provided with a pump 8b. When the pump 8b is driven, bathtub water is circulated in the bathtub water circulation circuit C. As shown in FIG. That is, the bathtub water taken out of the bathtub 11 is returned to the bathtub 11 through the pump 8b and the reheating heat exchanger 9.

A hot water inlet 7d at the top of the hot water storage tank 7 is connected to a hot water supply channel for supplying hot water from the hot water storage tank 7 according to various hot water supply applications. The hot water supply flow path includes hot water outlet pipes 20a to 20c, mixing valves 30a and 30b, water supply pipes 21b and 21c, a mixing cock 32, and a bath electromagnetic valve 31a. Specifically, one end of the hot water discharge pipe 20a is connected to the middle of the pipe 23g connected to the hot water introduction outlet 7d of the hot water storage tank 7, and the other end of the hot water discharge pipe 20a branches into two, mixing valves 30a and 30b. connected to each inlet. The mixing valves 30a and 30b adjust the flow ratio between the high temperature water supplied from the hot water supply pipe 20a and the low temperature water supplied from the water supply pipe 21b.

The outlet of the mixing valve 30a and the mixing tap 32 are connected by a hot water discharge pipe 20b. The mixing faucet 32 is connected to a faucet (not shown) such as a shower or a faucet used by the user. A water supply pipe 21c branched from the water supply pipe 21a is connected to the mixing valve 32, and is configured to supply water from a water source. One end of the hot water outlet pipe 20c is connected to the mixing valve 30b, and the other end is connected downstream of the reheating heat exchanger 9 of the bathtub water circulation circuit C. As shown in FIG. A bath solenoid valve 31a is installed in the hot water outlet pipe 20c.

The remote control device 15 is for operating operation commands and changes in set values. For example, the set temperature for hot water supply can be set by the user operating the remote control device 15 . Although not shown, the remote control device 15 includes a display section for displaying information such as the state of the storage-type hot water supply apparatus 100, an operation section such as switches operated by the user, a speaker, a microphone, and the like.

A measurement control device 14 a is arranged in the heat pump unit 1 , and a measurement control device 14 b is arranged in the tank unit 2 . Each of the measurement controllers 14a and 14b comprises, for example, a microcomputer having at least one memory and at least one processor. The measurement control device 14a controls the operation of the actuators of the heat pump unit 1, such as the compressor, the expansion valve, and the amount of air blown by the fan of the air heat exchanger. The measurement control device 14b controls the operation of the actuators provided in the tank unit 2, such as the operation, stop, and driving rotation speed of the pumps 8a and 8b, the opening of the three-way valve 10, and the mixing ratio of the mixing valves 30a to 30c. do.

The measurement control device 14a and the measurement control device 14b are connected so as to be able to communicate with each other, and control the hot water storage type hot water supply device 100 in cooperation. Therefore, in the following description, the measurement control device 14a and the measurement control device 14b are collectively referred to simply as the control device 14 for simplification of description. Note that the storage-type hot water supply apparatus 100 does not have two control devices, the measurement control device 14a and the measurement control device 14b. good too.

Control device 14 is configured to be able to communicate with remote control device 15 . Control device 14 transmits information about the operation of storage-type hot water supply apparatus 100 to remote control device 15 and causes remote control device 15 to display the information, thereby notifying the user of the operation information. Further, when the user operates the remote control device 15 to issue a command relating to the operation of the storage-type hot water supply apparatus 100 and change various setting values, the control device 14 receives the user's operating command and information relating to the setting values from the remote control device 15 . do. Further, control device 14 receives data on the results of measurement by various sensors such as a pressure sensor and a temperature sensor arranged in hot water storage type hot water supply apparatus 100 .

The sensors provided in the hot water storage type hot water supply apparatus 100 include an inlet temperature sensor 13a installed in the inlet side pipe 23b of the heat pump unit 1, an outlet temperature sensor 13b installed in the outlet side pipe 23c, and a hot water introduction outlet of the pipe 23d. Temperature sensor 13c installed near 7c, temperature sensor 13d installed near the inlet of reheating heat exchanger 9 on pipe 23f, 13m installed near the exit of reheating heat exchanger 9 on pipe 23g, bathtub water circulation A temperature sensor 13n installed near the inlet of the reheating heat exchanger 9 of the circuit C and a temperature sensor 13k installed near the exit of the reheating heat exchanger 9 of the bathtub water circulation circuit C are included. Each temperature sensor detects the temperature of hot water in the pipe at each installation position and transmits the detection data to the control device 14 .

Further, stored hot water temperature sensors 13e to 13j are attached to the hot water storage tank 7 from the upper part to the lower part at different heights. The stored hot water temperature sensors 13e to 13j detect the water temperature at their installation heights. A signal indicating the result of detection by the stored hot water temperature sensors 13e to 13j is transmitted to the control device . The control device 14 thereby grasps the heat storage amount and the remaining hot water amount in the hot water storage tank 7 .

The control device 14 controls each actuator of the hot water storage type hot water supply device 100 according to the operation command and setting values sent from the remote control device 15 and the detection data sent from various sensors. 100 driving motions. Specifically, the control device 14 performs a heating operation for storing high-temperature water in the hot water storage tank 7, a hot water discharge operation for discharging the high-temperature water in the hot water storage tank 7 to the hot water supply load, and a bathtub water in the bathtub 11. Controls the operation of the reheating operation for heating. These driving operations will be described below.

When starting the boiling operation, the control device 14 switches the three-way valve 10 so that the above-described boiling circuit A is established. Also, the mixing ratio of the mixing valve 30c is controlled so that the flow rate of high temperature water from the pipe 23e is zero and the flow rate of low temperature water from the pipe 23a is 100%. In this state, the controller 14 drives the pump 8a. Low-temperature water taken out from the lower part of the hot water storage tank 7 is sent to the water-refrigerant heat exchanger 4 via the pipe 23a, the mixing valve 30c, the pump 8a, and the pipe 23b. The sent low-temperature water is heated by heat exchange with the refrigerant in the water-refrigerant heat exchanger 4 to become high-temperature water. The high-temperature water flowing out of the water-refrigerant heat exchanger 4 is returned to the hot water storage tank 7 from the hot water introduction outlet 7c at the top of the hot water storage tank 7 via the pipe 23c, the three-way valve 10 and the pipe 23d.

A target value of the stored hot water temperature in the boiling operation (hereinafter also referred to as a “target stored hot water value”) can be set by the user using the remote control device 15 . The control device 14 adjusts the temperature of hot water at the outlet of the water-refrigerant heat exchanger 4 (hereinafter also referred to as "boiling water temperature"), which is detected by the temperature sensor 13c, for example, to a set hot water storage target value. It controls the flow rate of water sent to the heat exchanger 4 . The water flow rate is controlled by controlling the rotation speed of the pump 8a. Specifically, for example, when the boiling water temperature is lower than the hot water storage target value, the rotation speed of the pump 8a is reduced so that the flow rate of water conveyed to the water-refrigerant heat exchanger 4 is reduced. Conversely, when the boiling water temperature is higher than the stored hot water target value, the rotation speed of the pump 8a is increased so that the flow rate of water to be conveyed increases.

Due to the boiling operation, high-temperature water stays in the upper part and low-temperature water stays in the lower part in the hot water storage tank 7 to form temperature stratification, and a temperature boundary layer is generated between the high-temperature water and the low-temperature water. As the boiling operation progresses, the proportion of low-temperature water decreases and the proportion of high-temperature water increases, so the temperature boundary layer moves to the lower portion of the hot water storage tank 7 . The control device 14 ends the boiling operation when the temperature at the inlet of the water-refrigerant heat exchanger 4 detected by the inlet temperature sensor 13a (hereinafter also referred to as "inlet water temperature") reaches the hot water storage target value.

During the boiling operation, in the heat pump unit 1, the measurement control device 14a operates the water-refrigerant heat exchanger 4 according to the detection values of the water-refrigerant heat exchanger inlet temperature sensor 13a and outlet temperature sensor 13b and the hot water storage target value. to control the heating capacity of the

In the hot water discharge operation, high temperature water in the upper part of the hot water storage tank 7 is taken out from the hot water discharge pipe 20a. At this time, low-temperature water such as tap water flows into the hot water storage tank 7 from the water supply pipe 21a. As a result, the amount of water stored in the hot water storage tank 7 is always kept constant. When the hot water operation is performed, the temperature boundary layer formed between the low temperature water and the high temperature water in the hot water storage tank 7 moves to the upper portion of the hot water storage tank 7 according to the hot water amount.

In the hot water supply operation, the flow rate of the hot water supplied from the hot water supply pipe 20a and the flow rate of the low temperature water supplied from the water supply pipe 21b are adjusted by the mixing valve 30a or 30b, whereby the temperature of the hot water is adjusted to the set temperature. Temperature controlled. The temperature-controlled hot water is supplied to the mixing tap 32 or the bathtub 11, which is the terminal on the hot water supply side. It should be noted that hot water is discharged to the mixing tap 32 according to the usage of the faucet by the user. When the user operates the remote control device 15 to issue a hot water filling command, the control device 14 opens the bath electromagnetic valve 31a. As a result, hot water filling to the bathtub 11 is started.

When the reheating operation is performed, the control device 14 switches to the reheating circuit B by switching the three-way valve 10 so that the pipes 23c and 23f are in communication. In this state, the controller 14 drives the pump 8a. As a result, the low temperature water taken out from the lower part of the hot water storage tank 7 flows into the mixing valve 30c through the pipe 23a, and the high temperature water taken out from the upper part of the hot water storage tank 7 flows into the mixing valve 30c through the pipe 23e. do.

In the mixing valve 30c, the low-temperature water from the pipe 23a and the high-temperature water from the pipe 23b are mixed at a set mixing ratio. The mixing ratio of the high-temperature water and the low-temperature water in the mixing valve 30c can be arbitrarily set, and in the present embodiment, it is assumed to be fixed at the set mixing ratio. The mixing ratio may be controlled by a control device, for example, according to the incoming water temperature or the like. However, the mixing ratio is set within a range in which the temperature of water flowing into the heat pump unit 1 (inlet water temperature) is lower than the upper limit of the allowable incoming water temperature. As an example, the upper limit of the allowable incoming water temperature is 50°C.

Medium-temperature water mixed by the mixing valve 30c is introduced into the water-refrigerant heat exchanger 4 through the pipe 23b and heated by the water-refrigerant heat exchanger 4 to become high-temperature water. The high-temperature water flowing out from the water-refrigerant heat exchanger 4 is introduced into the reheating heat exchanger 9 through the pipe 23c, the three-way valve 10, and the pipe 23f, and then returned to the upper part of the hot water storage tank 7 through the pipe 23g. .

Further, the control device 14 drives the pump 8b to circulate the bathtub water in the bathtub water circulation circuit C. As shown in FIG. The bathtub water is heated by heat exchange when passing through the reheating heat exchanger 9 , is heated, and is returned to the bathtub 11 .

As described above, in the present embodiment, during the reheating operation, the upper high-temperature water and the lower low-temperature water in the hot water storage tank 7 can be mixed and introduced into the heat pump unit 1 . This effect will be explained. FIG. 2 is a diagram showing temperature changes on the primary side and the secondary side inside the reheating heat exchanger 9. As shown in FIG. In FIG. 2 , the vertical axis represents the temperature, and the horizontal axis represents the position in the flow direction on the primary side in the reheating heat exchanger 9 . 2, the inlet on the primary side of the reheating heat exchanger 9 corresponds to the left side of the horizontal axis in FIG. 2, and the inlet on the secondary side corresponds to the right side of the horizontal axis in FIG. 2, 13D, 13M, 13N, and 13K indicate temperatures detected by temperature sensors 13d, 13m, 13n, and 13k provided near the reheating heat exchanger 9 in FIG. The graph on the left side of FIG. 2 shows the case where the mixing ratio of the low-temperature water in the mixing valve 30c is 100%, that is, only the low-temperature water taken out from the lower part of the hot water storage tank 7 is allowed to flow into the heat pump unit 1. indicates the case. The graph on the right side shows the case where low-temperature water and high-temperature water are mixed and flowed into the heat pump unit 1 as middle-temperature water.

As shown in FIG. 2, the temperature (13D) of the hot water flowing into the primary side of the reheating heat exchanger 9 is higher when medium-temperature water is introduced than when only low-temperature water is introduced. ing. As a result, when the medium-temperature water is introduced, the temperature of the bathtub water of 13N introduced to the secondary side is sufficiently increased to 13K and is discharged from the reheating heat exchanger 9 . That is, by increasing the inlet water temperature of the heat pump unit 1 using the high-temperature water in the upper part of the hot water storage tank 7, the outlet water temperature of the reheating heat exchanger 9 (13D ) can be heated. As a result, the heat exchange temperature difference with the bathtub water increases, so the amount of heat exchange (that is, reheating capacity) increases, and the temperature 13K of the bathtub water returning to the bathtub 11 can be increased. Therefore, the time required for reheating can be shortened, and the user's request for reheating can be promptly met.

The amount of heat exchanged in the reheating heat exchanger 9 (that is, the reheating capacity) is proportional to "flow rate x inlet/outlet water temperature difference". Therefore, if the temperature of the inlet temperature 13D on the primary side rises and the outlet temperature 13K on the secondary side rises accordingly, the reheating capacity will increase by the amount of change in the water temperature difference between the inlet and outlet on the secondary side (13K-13N). can be said to have risen. For example, if the temperature of the bathtub water of 30° C. is conventionally raised to 50° C., the temperature of the bathtub water of 30° C. can be raised to 70° C. , It can be said that the reheating capacity is doubled compared to the conventional one.

As described above, storage-type hot water supply apparatus 100 according to the present embodiment enables reheating operation with high reheating capacity in response to a user's reheating request without changing the heating capacity of the heat pump unit. As a result, compared to the conventional reheating method using high-temperature water in the hot water storage tank 7, the amount of heat to be stored in the hot water storage tank 7 in advance can be reduced. Therefore, it is possible to reduce the energy loss due to heat radiation during the period from hot water storage in the late-night heating operation to actual use for reheating. Also, even if the user's life pattern is irregular, the amount of wasted energy can be reduced.

Embodiment 2.
A hot water storage type hot water supply apparatus 100 according to the present embodiment has the same configuration as the hot water storage type hot water supply apparatus 100 according to the first embodiment. The hot water storage type hot water supply apparatus 100 of the present embodiment is the same as the hot water storage type hot water supply apparatus 100 of the first embodiment except that the boiling water temperature during the reheating operation is controlled to be the reference boiling water temperature.

As described above, during the reheating operation, the inlet water temperature can be increased to increase the boiling water temperature, and a high reheating capacity can be obtained. However, in general, the heat pump unit 1 is set with an upper limit of the boiling water temperature by the water-refrigerant heat exchanger 4 and an upper limit of the inlet water temperature due to the characteristics of the equipment, and the operation of the heat pump unit 1 is below these upper limits. must be done in Considering the energy efficiency of the heat pump unit 1, it is desirable to limit the inlet water temperature during the reheating operation to a certain level or less. Therefore, in consideration of these, in the present embodiment, the boiling water temperature is controlled to a preset reference boiling water temperature (that is, "reference outlet temperature").

FIG. 3 is a flow chart showing a control operation for controlling the boiling water temperature of the heat pump unit 1. As shown in FIG. The control in FIG. 3 is repeatedly executed at regular control intervals during the reheating operation. In step S1 of FIG. 3, the controller 14 acquires the boiling water temperature Twd, which is the temperature on the outlet side of the heat pump unit 1, and the inlet water temperature Twi of the heat pump unit. Here, the boiling water temperature Twd can be obtained by the temperature sensor 13b, and the inlet water temperature Twi can be obtained by the temperature sensor 13a.

Next, in step S2, it is determined whether or not the boiling water temperature Twd is higher than the reference boiling water temperature Twdset. When it is determined that the boiling water temperature Twd is higher than the reference boiling water temperature Twdset, the process proceeds to step S3.

In step S3, the mixing ratio is adjusted by adjusting the opening degree of the mixing valve 30c so as to increase the amount of low-temperature water. As a result, the inlet water temperature Twi is lowered, and as a result, the boiling water temperature Twd can be lowered.

On the other hand, if it is determined in step S2 that the boiling water temperature Twd is equal to or lower than the boiling water temperature set value Twdset, then the process proceeds to step S4. In step S4, it is determined whether or not the inlet water temperature Twi is lower than the inlet water temperature upper limit value Twimax.

When it is determined in step S4 that the inlet water temperature Twi is lower than the inlet water temperature upper limit value Twimax, the process proceeds to step S5. In step S5, the mixing ratio is adjusted by adjusting the opening of the mixing valve 30c so as to increase the amount of hot water. As a result, the inlet water temperature Twi can be increased. As a result, the boiling water temperature Twd can be increased.

If it is determined in step S4 that the inlet water temperature Twi is equal to or higher than the inlet water temperature upper limit value Twimax, the current process ends without increasing the inlet water temperature Twi. As a result, it is possible to avoid damage to the equipment caused by excessively high temperature water entering the heat pump unit 1 .

As described above, in storage-type hot water supply apparatus 100 according to Embodiment 2, the boiling water temperature is controlled by controlling the boiling water temperature to the reference boiling water temperature. As a result, the outlet water temperature of the heat pump unit 1 can be kept at the target reference boiling water temperature, and the reheating capacity can be stably increased while the inlet water temperature is kept within the upper limit value of the inlet water temperature.

Embodiment 3.
The hot water storage type hot water supply apparatus 100 of the third embodiment has the same configuration as the hot water storage type hot water supply apparatus 100 of the first and second embodiments. The hot water storage type hot water supply apparatus 100 of the third embodiment is the same as the hot water storage type hot water supply apparatus 100 of the first or second embodiment except that the inlet water temperature of the heat pump unit 1 is controlled to the reference inlet water temperature.

FIG. 4 is a flow chart showing a control operation executed by a controller for a hot water storage type hot water supply apparatus according to Embodiment 3. FIG. The flowchart of FIG. 4 is the same as the flowchart of FIG. 3 except that the process of step S2 is replaced with the process of step S12, and the process of step S4 is replaced with the process of step S14. The control in FIG. 4 is repeatedly executed at constant control intervals during execution of the reheating operation.

Specifically, in step S12 of FIG. 4, it is determined whether or not the inlet water temperature Twi is higher than the reference inlet water temperature Twiset. When it is determined that the inlet water temperature Twi is higher than the reference inlet water temperature Twiset, the process proceeds to step S3 to lower the inlet water temperature.

On the other hand, when it is determined that the inlet water temperature Twi is equal to or lower than the reference inlet water temperature Twiset, the process proceeds to step S14. In step S14, it is determined whether or not the boiling water temperature Twd is lower than the boiling water temperature upper limit value Twdmax. When it is determined that the boiling water temperature is lower than the boiling water temperature upper limit value Twdmax, the process proceeds to step S5 to increase the inlet water temperature to raise the boiling water temperature.

Further, when it is determined in step S14 that the boiling water temperature Twd is equal to or higher than the boiling water temperature upper limit value Twdmax, the boiling water temperature is not increased and the current process ends. As a result, it is possible to prevent the equipment from being damaged due to an excessive rise in boiling water temperature.

As described above, according to the present embodiment, the inlet water temperature of the heat pump unit 1 can be controlled to the reference inlet water temperature. When the inlet water temperature of the heat pump unit 1 rises, the power consumption of the heat pump unit 1 tends to rise and the energy efficiency decreases. According to the control of the present embodiment, by maintaining the inlet water temperature at the reference inlet water temperature, it is possible to ensure a high reheating capability to the extent possible while suppressing a decrease in energy efficiency.

The control for keeping the boiling water temperature Twd of the heat pump unit 1 constant and the inlet water temperature Twi in the third embodiment described in the second embodiment can be combined. Further, an operation for increasing the heating capacity of the heat pump unit 1 may be combined with either or a combination of the controls of the second and third embodiments. Specifically, for example, the inlet water temperature Twi is controlled in a range lower than the inlet water temperature upper limit value Twimax, and when the boiling water temperature does not reach the reference boiling water temperature, the frequency of the compressor of the heat pump unit 1 is controlled to increase the heating capacity. to raise As a result, a high reheating capacity can be ensured and rapid reheating can be performed. Note that the heating capacity of the heat pump unit 1 can be increased by, for example, increasing the operating frequency of the compressor.

Embodiment 4.
A hot water storage type hot water supply apparatus 100 of the fourth embodiment has the same configuration as the hot water storage type hot water supply apparatuses of the first to third embodiments. In the hot water storage type hot water supply apparatus 100 of Embodiment 4, a first mode in which reheating is performed with the high temperature water heated by the heat pump unit 1 and a second mode in which reheating is performed only with the high temperature water stored in the upper part of the hot water storage tank 7 are performed. The reheating operation can be performed in either of two modes. When the reheating operation is performed in the first mode, the method described in the first to third embodiments is performed.

On the other hand, the second mode is executed by fixing the mixing ratio of the mixing valve 30c to 100% on the pipe 23e side (that is, on the high temperature water side) during the reheating operation. As a result, the high-temperature water in the upper part of the hot water storage tank 7 is taken out, and passes through the pipe 23e, the mixing valve 30c, the pipe 23b, the water-refrigerant heat exchanger 4, the pipe 23c, the three-way valve 10, the pipe 23f, and the reheating heat exchanger 9. sent to In this case, the compressor operation of the heat pump unit 1 is stopped, and the water-refrigerant heat exchanger 4 simply becomes a part of the flow path through which hot water flows.

The first mode and the second mode are determined, for example, according to the amount of hot water remaining in the hot water storage tank 7 when the reheating request is made. That is, when the amount of remaining hot water at the time when the reheating request is made is larger than the reference amount, the control device 14 selects the second mode and sets the mixing ratio of the mixing valve 30c to 100% on the high-temperature water side. fixed to On the other hand, when the remaining hot water amount is equal to or less than the reference amount, the first mode is selected and the reheating operation is performed by the method described in the first to third embodiments. The reference amount used in this control is predetermined and stored in the control device 14 at a value near the lower limit of the range of the amount of stored hot water that can be judged to be sufficient for reheating.

As described above, according to the control of the present embodiment, when a sufficient amount of high-temperature water for reheating is stored in the hot water storage tank 7, reheating is performed only with the hot water stored in the hot water storage tank 7. It can be carried out. As a result, the heat pump unit 1 can be operated less often, and power consumption can be reduced.

In addition, the high-temperature water supply route in the second mode according to the present embodiment is not limited to the route described above. For example, a pump is installed in the pipes 23d, 23f, or 23g connecting the reheating heat exchanger 9 and the upper part of the hot water storage tank 7, and the reheating heat exchange is performed directly from the upper part of the hot water storage tank 7 via the pipes 23d and 23f. A configuration in which hot water is supplied to the vessel 9 may be employed. In addition, a bypass pipe and a pump that connect the upper part of the hot water storage tank 7 and the reheating heat exchanger 9 are newly installed, and the high temperature water in the upper part of the hot water storage tank 7 is transferred from the bypass pipe to the reheating heat exchanger 9. It is good also as a structure which supplies directly.

100 storage hot water heater 1 heat pump unit 2 tank unit 4 water-refrigerant heat exchanger 7 hot water storage tank 7a water inlet 7b water outlet 7c hot water inlet 7d hot water inlet 8a, 8b pump 9 reheating heat exchanger 10 three-way valve 11 bathtub 13a inlet temperature sensor 13b outlet temperature sensor 13c, 13d, 13k, 13n temperature sensor 13e to 13j stored hot water temperature sensor 14 control device 14a measurement control device 14b measurement control device, 15 remote control device, 20a to 20c hot water outlet pipe, 21a to 21c water supply pipe, 23a to 23g pipe, 30a to 30c mixing valve, 31a bath solenoid valve, 32 mixing cock

Claims (6)

a heating means for heating water;
a hot water storage tank configured to supply water heated by the heating means from the upper side, and storing water by forming a temperature stratification with a high temperature on the upper side and a low temperature on the lower side;
a reheating heat exchanger for heating a medium to be heated using the water heated by the heating means as heat source water;
Controls a reheating operation in which the medium to be heated is heated by the reheating heat exchanger, and a boiling operation in which the water taken out from the hot water storage tank is heated by the heating means and returned to the hot water storage tank. a controller configured to
The water taken out from the first water intake of the hot water storage tank and the water taken out from the second water intake on the upper side of the first water intake of the hot water storage tank are mixed, and the heating means is heated. A mixing valve that delivers to the inlet side;
with
The mixing valve is configured to change the mixing ratio of the water from the first water intake and the water from the second water intake,
The control device is
When executing the boiling operation,
The mixing valve is controlled so that the mixing ratio is 100:0, and the boiling operation is performed so that the water taken out from the first water intake port and heated by the heating means returns to the hot water storage tank. controls the behavior of
When executing the reheating operation,
The mixing valve is controlled so that the mixing ratio becomes a preset mixing ratio, and the water taken out from the first water intake and the second water intake and heated by the heating means is heated by the heating means. A hot water storage type hot water supply apparatus characterized by controlling the operation of the reheating operation so that the hot water is directly supplied to the reheating heat exchanger . 2. The hot water storage type hot water supply apparatus according to claim 1 , wherein the controller controls the mixture ratio so that the temperature of the water flowing into the heating means becomes a reference inlet water temperature. 3. The hot water storage type hot water supply apparatus according to claim 1, wherein the controller controls the mixing ratio of the mixing valve so that the temperature of the water flowing out of the heating means becomes a reference outlet temperature. The heating means is composed of a refrigeration cycle circuit that circulates refrigerant through a compressor, an expansion valve, an evaporator, and a water-refrigerant heat exchanger, and heat exchange with the refrigerant in the water-refrigerant heat exchanger. heat the water by
The control device is
controlling the mixing valve with the upper limit value of the allowable range of the temperature of the water flowing into the inlet of the heating means as the target value of the temperature of the water flowing into the heating means;
controlling the operating frequency of the compressor so that the temperature of the water flowing out of the outlet of the heating means reaches the reference outlet temperature;
The hot water storage type hot water supply apparatus according to claim 3 , characterized in that it is configured as follows. When the control device executes the reheating operation,
Instead of the first mode in which the water heated by the heating means is directly supplied from the heating means to the reheating heat exchanger,
The mixing valve is controlled so that the mixing ratio is 100:0 , and only the water taken out from the second water intake is supplied to the reheating heat exchanger without being heated by the heating means. 5. The hot water storage type hot water supply apparatus according to any one of claims 1 to 4 , wherein the operation of the reheating operation can be controlled in the second mode. 6. The hot water storage type hot water supply apparatus according to claim 5 , wherein the control device is configured to select the second mode when the amount of heat of the water in the hot water storage tank is greater than a reference amount. .

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