JP6819815B2 - Hot water storage type water heater - Google Patents

Description

The present invention relates to a hot water storage type water heater.

Patent Document 1 discloses a hot water storage type water heater. The hot water storage type water heater collects the hot water until the temperature of the hot water remaining inside the heat source machine becomes lower than the temperature of the lower part of the hot water storage tank.

Japanese Patent Application Laid-Open No. 2008-249247

However, in the hot water storage type water heater described in Patent Document 1, when the recovery of the hot water remaining inside the heat source machine is completed, the residual heat cannot be recovered and is dissipated to the atmosphere. Therefore, the efficiency of recovering heat is reduced.

The present invention has been made to solve the above-mentioned problems. An object of the present invention is to provide a hot water storage type water heater capable of efficiently recovering the heat inside the heat source machine.

The hot water storage type water supply device according to the present invention includes a hot water storage tank for storing hot water, a heat source machine having a heat pump cycle in which a water refrigerant heat exchanger, a compressor, an air heat exchanger, and an expansion valve are connected by a refrigerant circuit. A water circuit that connects the upper and lower parts of the hot water storage tank and the heat source machine, a bypass circuit that branches in the middle of the water circuit and connects the heat source machine and the lower part of the hot water storage tank, a circulation pump that circulates hot water in the water circuit, and a heat source. After the boiling operation to store the hot water heated by the machine in the hot water storage tank is completed and the compressor is stopped, the heat source pump is continued to operate, and the heat inside the heat source machine is returned to the lower part of the hot water storage tank through the bypass circuit. Control to execute the reheat recovery operation to return the heat inside the heat source machine to the lower part of the hot water storage tank through the bypass circuit when the operation is performed and the preset start condition is satisfied after the heat recovery operation is completed. With a part.

According to the present invention, the heat inside the heat source machine can be efficiently recovered.

It is a block diagram of the hot water storage type water heater in Embodiment 1. FIG. It is a block diagram of the hot water storage type water heater in Embodiment 1. FIG.

A mode for carrying out the present invention will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are designated by the same reference numerals. The duplicate description of the relevant part will be simplified or omitted as appropriate.

Embodiment 1.
1 and 2 are configuration diagrams of a hot water storage type water heater according to the first embodiment. The HP unit 1 uses a heat pump cycle as a heat source machine. Specifically, in the HP unit 1, the air heat exchanger 2, the compressor 3, the primary side of the water refrigerant heat exchanger 4, and the expansion valve 5 are cyclically connected via a refrigerant pipe 6 as a refrigerant circuit. Will be done. The inlet side of the secondary side of the water refrigerant heat exchanger 4 is connected to the outlet side of the HP going pipe 7 as a part of the water circuit. The secondary side outlet side of the water refrigerant heat exchanger 4 is connected to the inlet side of the HP return pipe 8 as a part of the water circuit. In the HP unit 1, the hot water temperature thermistor 9 is provided on the secondary side of the water refrigerant heat exchanger 4 as a hot water temperature detecting device.

The air heat exchanger 2 is provided so that heat can be exchanged between the refrigerant in the refrigerant pipe 6 and the atmosphere. The compressor 3 is provided so that the temperature of the refrigerant can be raised by compressing the refrigerant. The water refrigerant heat exchanger 4 is provided so that heat can be exchanged between the refrigerant flowing on the primary side and the low temperature water flowing on the secondary side. In the water refrigerant heat exchanger 4, heat may be exchanged between the refrigerant flowing to the primary side and the low temperature water directly supplied from a water source such as tap water. The expansion valve 5 is provided so that the temperature of the refrigerant can be lowered by expanding the refrigerant. The hot water temperature thermistor 9 is provided so as to be able to detect the temperature of the hot water after heat exchange.

In the tank unit 10, the lower portion of the hot water storage tank 11 is provided so that low-temperature water can flow in. The upper part of the hot water storage tank 11 is provided so that hot water can flow in. The upper part and the lower part of the hot water storage tank 11 are provided so as to be able to store hot water having a temperature difference. The lower part of the hot water storage tank 11 is connected to the inlet side of the HP going pipe 7. The hot water storage temperature sensor 12 and the hot water storage temperature sensor 13 are attached to the surface of the hot water storage tank 11 at different heights. For example, the hot water storage temperature sensor 13 is provided as a lower temperature detecting device at a position where the volume from the lowermost part of the hot water storage tank 11 is 40 L.

The inlet side of the first water supply pipe 14a is connected to a water source such as water supply. The first water supply pipe 14a is provided so that water can be supplied from a water source such as a water supply. The inlet side of the second water supply pipe 14b is connected to the outlet side of the first water supply pipe 14a. The inlet side of the third water supply pipe 14c is connected to the outlet side of the first water supply pipe 14a. The outlet side of the third water supply pipe 14c is connected to the lower part of the hot water storage tank 11. The third water supply pipe 14c is provided so that the water supplied from the first water supply pipe 14a can flow into the inside of the hot water storage tank 11.

The pressure reducing valve 15 is provided on the outlet side of the first water supply pipe 14a. The pressure reducing valve 15 is provided so that the pressure of the water supplied from the first water supply pipe 14a can be adjusted.

The three-way valve 16 includes an a port, a b port, and a c port. The three-way valve 16 is provided so as to be able to switch between the flow path connecting the a port and the b port and the flow path connecting the a port and the c port. The a port is connected to the outlet side of the HP return pipe 8. The a port is provided so that hot water can flow in from the HP return pipe 8. The b port is provided so that hot water can flow out. The c port is provided so that hot water can flow out.

The first bypass pipe 17 is provided as a bypass circuit that branches in the middle of the water circuit. The entry side of the first bypass pipe 17 is connected to the b port of the three-way valve 16. The outlet side of the first bypass pipe 17 is connected to the lower part of the hot water storage tank 11. For example, the outlet side of the first bypass pipe 17 is provided at a position where the volume from the bottom of the hot water storage tank 11 is 20 L. The hot water supply pipe 18 is provided as a part of the water circuit. The inlet side of the hot water supply pipe 18 is connected to the c port of the three-way valve 16. The outlet side of the hot water supply pipe 18 is connected to the upper part of the hot water storage tank 11. The inlet side of the hot water supply pipe 19 is connected to the upper part of the hot water storage tank 11. The hot water supply pipe 19 is provided so that the hot water stored inside the hot water storage tank 11 can be supplied to the outside of the hot water storage type water heater.

The hot water supply mixing valve 20 is connected to the outlet side of the second water supply pipe 14b. The hot water supply mixing valve 20 is connected to the outlet side of the hot water supply pipe 19. The hot water supply mixing valve 20 is provided so as to be able to generate hot water at a set temperature by adjusting the flow rate ratio of the high temperature hot water supplied from the hot water supply pipe 19 and the low temperature water supplied from the second water supply pipe 14b. Be done.

The inlet side of the first hot water supply pipe 21 is connected to the hot water supply mixing valve 20. The first hot water supply pipe 21 is provided as a hot water supply circuit so that hot water supplied from the hot water supply mixing valve 20 can be supplied to a faucet such as a shower or a curan (not shown). The hot water supply flow rate sensor 22 is provided in the middle of the first hot water supply pipe 21. The hot water supply flow rate sensor 22 is provided so as to be able to detect the flow rate of hot water passing through the first hot water supply pipe 21.

The heat source pump 23 is provided in the middle of the HP going pipe 7 as a circulation pump. The heat source pump 23 is provided so that hot water can be circulated through various pipes of the tank unit 10.

The control unit 24 is electrically connected to various devices of the HP unit 1 and the tank unit 10. The control unit 24 is provided so as to be able to control the operation of these devices.

For example, the control unit 24 detects the temperature distribution of hot water inside the hot water storage tank 11 based on the detection results of the hot water storage temperature sensor 12 and the hot water storage temperature sensor 13. The control unit 24 grasps the amount of remaining hot water inside the hot water storage tank 11 based on the detection result of the temperature distribution of the hot water inside the hot water storage tank 11. The control unit 24 controls the start and stop of the boiling operation of storing the hot water heated by the HP unit 1 inside the hot water storage tank 11 based on the amount of hot water remaining inside the hot water storage tank 11.

The remote control device 25 is provided so as to be able to communicate with the control unit 24. The remote control device 25 is provided so as to be able to receive an operation operation command from the outside, for example, an operation corresponding to a change in a set temperature.

When the boiling operation is completed, the control unit 24 stops the compressor 3. After that, the control unit 24 carries out a heat recovery operation. Specifically, the control unit 24 continues to drive the heat source pump 23, and returns the hot water to a position lower than the position of the hot water storage temperature sensor 13 in the hot water storage tank 11 through the first bypass pipe 17. As a result, the heat remaining in the compressor 3, the water refrigerant heat exchanger 4, and the like is recovered.

At this time, as shown in FIG. 1, when the temperature of the hot water inside the HP return pipe 8 and the temperature of the lower part of the hot water storage tank 11 become the same temperature, the control unit 24 temporarily stops the heat recovery operation. For example, when the temperature of the hot water inside the HP return pipe 8 and the temperature of the lower part of the hot water storage tank 11 reach 30 ° C., the control unit 24 temporarily stops the heat recovery operation.

After that, the temperature of the hot water remaining in the compressor 3, the water refrigerant heat exchanger 4, and the like gradually decreases. For example, the temperature of the hot water remaining in the water-refrigerant heat exchanger 4 and the like drops to 25 ° C. When hot water is supplied in this state, water flows into the lower part of the hot water storage tank 11. Therefore, as shown in FIG. 2, the temperature of the lower part of the hot water storage tank 11 drops. For example, the temperature of the lower part of the hot water storage tank 11 drops to 9 ° C. As a result, the temperature of the lower part of the hot water storage tank 11 becomes lower than the temperature of the hot water remaining in the compressor 3, the water refrigerant heat exchanger 4, and the like.

Therefore, the control unit 24 executes the reheat recovery operation when the preset start condition is satisfied. For example, when the detection temperature of the hot water temperature thermistor 9 becomes higher than the detection temperature of the hot water storage temperature sensor 13, the reheat recovery operation is performed. Specifically, the control unit 24 drives the heat source pump 23 again and returns the hot water to a position lower than the position of the hot water storage temperature sensor 13 in the hot water storage tank 11 through the first bypass pipe 17. Similar to the first heat recovery operation, when the temperature of the hot water inside the HP return pipe 8 and the temperature of the lower part of the hot water storage tank 11 become the same temperature, the control unit 24 stops the reheat recovery operation.

According to the first embodiment described above, the control unit 24 performs the reheat recovery operation when the preset start conditions are satisfied. For example, when the temperature detected by the hot water temperature thermistor 9 becomes higher than the temperature detected by the hot water storage temperature sensor 13, the reheat recovery operation is performed. Therefore, the heat inside the HP unit 1 can be efficiently recovered.

The temperature detected by the hot water temperature thermistor 9 is the temperature detected by the hot water storage temperature sensor 13 or the outside air temperature detected by an outside air temperature detection device (not shown) plus a preset adjustment temperature α. When it becomes, the reheat recovery operation may be started as a condition. At this time, if the temperature detected by the hot water temperature thermistor 9 or the outside air temperature is the temperature obtained by adding the preset adjustment temperature α to the temperature detected by the hot water storage temperature sensor 13, the control unit 24 reheats. Do not carry out recovery operation. Also in this case, the heat inside the HP unit 1 can be efficiently recovered.

Further, the first bypass pipe 17 is connected to the lower part of the hot water storage tank 11 below the hot water storage temperature sensor 13. Therefore, the heat inside the HP unit 1 can be efficiently recovered.

The start condition of the reheat recovery operation may be when the integrated value of the flow rate detected by the hot water supply flow rate sensor 22 after the completion of the boiling operation reaches a preset value. For example, the amount of hot water in the hot water storage tank 11 is 30 L so that the integrated value of the flow rate detected by the hot water supply flow rate sensor 22 is larger than the value of the volume corresponding to the area from the bottom of the hot water storage tank 11 to the outlet side of the first bypass pipe 17. When it decreases, it may be a condition for starting the reheat recovery operation. Also in this case, the heat inside the HP unit 1 can be efficiently recovered.

Further, the start condition of the reheat recovery operation may be when the integrated value of the amount of heat calculated based on the flow rate of hot water detected by the hot water supply flow rate sensor 22 after the completion of the boiling operation reaches a preset value. For example, when the hot water storage temperature is 80 ° C. and the water temperature is 9 ° C., the start condition of the reheat recovery operation is when the integrated value of the calorific value reaches 9 MJ, which is the calorific value when the hot water amount of the hot water storage tank 11 is reduced by 30 L. May be. Also in this case, the heat inside the HP unit 1 can be efficiently recovered.

Further, it is not necessary to carry out the reheat recovery operation when the temperature detected by the hot water temperature thermistor 9 is preset or when the preset time elapses after the completion of boiling. For example, if one hour has passed after the completion of boiling, the reheat recovery operation may not be performed. In this case, it is possible to prevent the reheat recovery operation from being unnecessarily carried out.

Further, if the temperature of the hot water inside the HP return pipe 8 and the temperature of the lower part of the hot water storage tank 11 do not reach the same temperature and the maximum recovery time elapses, the heat recovery operation or the reheat recovery operation may be stopped. .. For example, when the circulation flow rate is 5 L / min and 8 minutes, which is the time required for recovering to 40 L, which is the height of the hot water storage temperature sensor 13, has elapsed, the heat recovery operation or the reheat recovery operation may be stopped. In this case, it is possible to prevent the heat recovery operation or the reheat recovery operation from being unnecessarily continued.

The heat recovery heat amount may be calculated based on the temperature detected by the hot water temperature thermistor 9, the temperature detected by the hot water storage temperature sensor 13, and the heat recoverable hot water amount at the lower part of the hot water storage tank 11. The heat recovery efficiency may be calculated by dividing the heat recovery heat amount by the power consumption amount of the heat source pump 23 consumed in the heat recovery operation. For example, (temperature detected by the hot water temperature thermistor 9-temperature detected by the hot water storage temperature sensor 13) x 40 L x specific heat of water / (predetermined power consumption of the heat source pump 23 0.03 kW x 40 L / circulation flow rate 5 L / min) may be the heat recovery efficiency. If the heat recovery efficiency does not exceed a preset efficiency, it is not necessary to carry out the heat recovery operation or the reheat recovery operation. For example, if the heat recovery efficiency does not exceed 3.0, which is the rated efficiency of the HP unit 1, the heat recovery operation or the reheat recovery operation may not be performed. In this case, it is possible to prevent the heat recovery operation or the reheat recovery operation from being carried out in an inefficient state.

Further, if the outside air temperature does not exceed a preset temperature, it is not necessary to carry out the heat recovery operation or the reheat recovery operation. For example, when the outside air temperature does not exceed 0 ° C., it is not necessary to carry out the heat recovery operation or the reheat recovery operation. In this case, freezing of each pipe can be prevented by maintaining the remaining heat.

Further, the rotation speed of the heat source pump 23 during the heat recovery operation or the reheat recovery operation may be set to be lower than the rotation speed during the boiling operation. In this case, the stirring of the lower part of the hot water storage tank 11 can be suppressed.

As described above, the hot water storage type water heater according to the present invention can be used in a system for efficiently recovering the heat inside the heat source machine.

1 HP unit, 2 Air heat exchanger, 3 Compressor, 4 Water refrigerant heat exchanger, 5 Expansion valve, 6 Coolant piping, 7 HP outbound piping, 8 HP return piping, 9 Hot water temperature thermista, 10 Tank unit, 11 Hot water storage Tank, 12 Hot water storage temperature sensor, 13 Hot water storage temperature sensor, 14a 1st water supply pipe, 14b 2nd water supply pipe, 14c 3rd water supply pipe, 15 Pressure reducing valve, 16 Three-way valve, 17 1st bypass pipe, 18 Hot water supply pipe, 19 Hot water supply piping, 20 Hot water supply mixing valve, 21 1st hot water supply piping, 22 Hot water supply flow sensor, 23 Heat source pump, 24 Control unit, 25 Remote control device

Claims (9)

A hot water storage tank that stores hot water and
A heat source machine equipped with a heat pump cycle in which a water refrigerant heat exchanger, a compressor, an air heat exchanger, and an expansion valve are connected by a refrigerant circuit.
A water circuit that connects the upper and lower parts of the hot water storage tank to the heat source machine,
A bypass circuit that branches in the middle of the water circuit and connects the heat source machine and the lower part of the hot water storage tank,
A circulation pump that circulates hot water in the water circuit,
After the boiling operation of storing the hot water heated by the heat source machine in the hot water storage tank is completed and the compressor is stopped, the circulation pump is continued to be driven, and the heat inside the heat source machine is transferred through the bypass circuit. A heat recovery operation for returning to the lower part of the hot water storage tank is carried out, and after the heat recovery operation is completed, when a preset start condition is satisfied, the heat inside the heat source machine is transferred to the hot water storage tank through the bypass circuit. A control unit that performs a reheat recovery operation to return to the bottom,
Hot water storage type water heater equipped with. A lower temperature detection device provided at the lower part of the hot water storage tank and detecting the temperature of the lower part of the hot water storage tank,
A hot water temperature detection device provided in the heat source machine and detecting the temperature of the hot water outlet side of the water refrigerant heat exchanger, and
With
The control unit claims that the start condition is when the temperature detected by the hot water temperature detection device becomes a temperature obtained by adding a preset adjustment temperature to the temperature detected by the lower temperature detection device. Item 1. The hot water storage type water heater according to item 1. The hot water storage type water heater according to claim 2, wherein the bypass circuit is connected to the lower part of the hot water storage tank below the lower temperature detection device. A hot water supply circuit that supplies hot water from the hot water storage tank to the outside,
A flow rate sensor that detects the flow rate of hot water passing through the hot water supply circuit, and
With
The control unit has an integrated value of the amount of heat calculated when the integrated value of the flow rate of hot water detected by the flow rate sensor reaches a preset value after the completion of the boiling operation or based on the flow rate of the hot water. The hot water storage type water heater according to claim 1, wherein the start condition is when the value reaches a preset value. When the temperature detected by the hot water temperature detection device is equal to or lower than the preset temperature or when the preset time elapses after the completion of the boiling operation, the control unit restarts even if the start condition is met. The hot water storage type water heater according to claim 2 or 3, wherein the heat recovery operation is not performed. The hot water storage type water heater according to any one of claims 1 to 5, wherein the control unit stops the heat recovery operation or the reheat recovery operation when a preset maximum recovery time has elapsed. The control unit calculates the amount of heat recovered based on the temperature detected by the hot water temperature detecting device, the temperature detected by the lower temperature detecting device, and the amount of heat recoverable hot water in the lower part of the hot water storage tank, and calculates the heat recovery heat amount. The heat recovery efficiency is calculated by dividing the amount of heat recovered by the amount of power consumed by the circulation pump consumed in the heat recovery operation, and if the heat recovery efficiency does not exceed the preset efficiency, even if the start condition is met, The hot water storage type water heater according to claim 2 or 3, wherein the heat recovery operation or the reheat recovery operation is not performed. If the outside air temperature does not exceed a preset temperature, the control unit does not perform the heat recovery operation or the reheat recovery operation even under the start condition. Any one of claims 1 to 7. The hot water storage type water supply machine described in item 1. Any of claims 1 to 8, wherein the control unit sets the rotation speed of the circulation pump during the heat recovery operation or the reheat recovery operation to be lower than the rotation speed during the boiling operation. The hot water storage type water supply machine described in item 1.

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