WO2019186683A1

WO2019186683A1 - Storage-type water heater

Info

Publication number: WO2019186683A1
Application number: PCT/JP2018/012347
Authority: WO
Inventors: 直紀柴崎
Original assignee: 三菱電機株式会社
Priority date: 2018-03-27
Filing date: 2018-03-27
Publication date: 2019-10-03
Also published as: JPWO2019186683A1; JP6819815B2

Abstract

Provided is a storage-type water heater with which heat inside a heat source device can be recovered efficiently. This storage-type water heater comprises: a hot water storage tank for storing hot water; a heat source device equipped with a heat pump cycle wherein a water-refrigerant heat exchanger, a compressor, an air heat exchanger, and an expansion valve are connected in a refrigerant circuit; a water circuit connecting an upper part and a lower part of the hot water storage tank and the heat source device; a bypass circuit branching from partway along the water circuit and connecting the heat source device to the lower part of the hot water storage tank; a circulation pump for circulating hot water in the water circuit; and a control unit for carrying out a heat recovery operation wherein, after a boiling operation wherein hot water heated by the heat source device is stored in the hot water storage tank is completed and the compressor is stopped, driving of a heat source pump is continued and heat inside the heat source device is returned to the lower part of the hot water storage tank through the bypass circuit, and a secondary heat recovery operation wherein, when the heat recovery operation has been completed and a preset start condition has been satisfied, the heat inside the heat source device is returned to the lower part of the hot water storage tank through the bypass circuit.

Description

Hot water storage water heater

This 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 hot water heater collects the hot water until the temperature of the hot water remaining in the heat source machine becomes lower than the temperature at the lower part of the hot water storage tank.

Japanese Unexamined Patent Publication 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 in the heat source device is completed, the residual heat cannot be recovered and is radiated to the atmosphere. For this reason, the efficiency which collect | recovers heat falls.

This 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 that can efficiently recover the heat inside the heat source machine.

A hot water storage type water heater according to the present invention includes a hot water storage tank for storing hot water, a heat source machine including 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 tank and the heat source unit, a bypass circuit that branches in the middle of the water circuit and connects the heat source unit and the lower part of the hot water 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 stops, the heat source pump continues to be driven, and the heat inside the heat source machine is returned to the lower part of the hot water storage tank through the bypass circuit After the operation is completed and the heat recovery operation is completed, a reheat recovery operation is performed to return the heat inside the heat source unit to the lower part of the hot water storage tank through the bypass circuit when a preset start condition is satisfied. A control unit that, with a.

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

1 is a configuration diagram of a hot water storage type water heater in Embodiment 1. FIG. 1 is a configuration diagram of a hot water storage type water heater in Embodiment 1. FIG.

DETAILED DESCRIPTION Embodiments for carrying out the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the part which is the same or it corresponds in each figure. The overlapping explanation of the part is appropriately simplified or omitted.

Embodiment 1 FIG.
FIG. 1 and FIG. 2 are block diagrams of a hot water storage type water heater in 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 annularly connected via a refrigerant pipe 6 serving as a refrigerant circuit. Is done. The inlet side of the secondary side of the water-refrigerant heat exchanger 4 is connected to the outlet side of the HP outgoing pipe 7 as a part of the water circuit. The outlet side of the secondary 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 tapping temperature thermistor 9 is provided on the outlet side of the secondary side of the water refrigerant heat exchanger 4 as a tapping temperature detector.

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 as to increase the temperature of the refrigerant 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 on the primary side and low-temperature water directly supplied from a water source such as 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 detect the temperature of the hot water after heat exchange.

In the tank unit 10, the lower part 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 high temperature water can flow in. The upper part and the lower part of the hot water storage tank 11 are provided so that hot water having a temperature difference can be stored. The lower part of the hot water storage tank 11 is connected to the inlet side of the HP outgoing 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 detection device at a position where the volume from the lowermost portion of the hot water storage tank 11 is 40L.

The inlet side of the first water supply pipe 14a is connected to a water source such as a water supply. The 1st water supply piping 14a is provided so that supply of water can be received from water sources, 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 14 c is connected to the lower part of the hot water storage tank 11. The third water supply pipe 14 c is provided so that the water supplied from the first water supply pipe 14 a can flow into 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 1st water supply piping 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 that the flow path connecting the a port and the b port and the flow path connecting the a port and the c port can be switched. 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 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 inlet 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 lowermost part 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 hot water stored in the hot water storage tank 11 can be supplied to the outside of the hot water storage type hot water supply machine.

The hot water 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 having a set temperature by adjusting the flow rate ratio between the hot water supplied from the hot water supply pipe 19 and the low temperature water supplied from the second water supply pipe 14b. It is done.

The inlet side of the first hot water supply pipe 21 is connected to the hot water mixing valve 20. The first hot water supply pipe 21 is provided as a hot water supply circuit so as to be able to supply hot water supplied from the hot water supply mixing valve 20 to a faucet such as a shower or a currant (not shown). The hot water supply flow sensor 22 is provided in the middle of the first hot water supply pipe 21. The hot water flow rate sensor 22 is provided so as 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 outgoing 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 the HP unit 1 and various devices of the tank unit 10. The control part 24 is provided so that operation | movement of these apparatuses can be controlled.

For example, the control unit 24 detects the temperature distribution of the hot water in 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 for storing the hot water heated by the HP unit 1 in the hot water storage tank 11 based on the remaining hot water amount in 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 accept an operation operation command from the outside, for example, an operation corresponding to a change in the set temperature.

When the boiling operation is completed, the control unit 24 stops the compressor 3. Thereafter, the control unit 24 performs a heat recovery operation. Specifically, the control unit 24 continues to drive the heat source pump 23 and returns 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 portion 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 portion of the hot water storage tank 11 reach 30 ° C., the control unit 24 temporarily stops the heat recovery operation.

Thereafter, 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 hot water remaining in the water-refrigerant heat exchanger 4 or the like decreases to 25 ° C. In this state, when hot water is supplied, water flows into the lower part of the hot water storage tank 11. For this reason, as FIG. 2 shows, the temperature of the lower part of the hot water storage tank 11 falls. For example, the temperature of the lower part of the hot water storage tank 11 is lowered 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 performs the reheat recovery operation when a preset start condition is satisfied. For example, the reheat recovery operation is performed 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. Specifically, the control unit 24 drives the heat source pump 23 again to return 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 a preset start condition is satisfied. For example, the reheat recovery operation is performed 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. For this reason, the heat inside the HP unit 1 can be efficiently recovered.

Note that the temperature detected by the hot water temperature thermistor 9 is a temperature obtained by adding a preset adjustment temperature α to the temperature detected by the hot water storage temperature sensor 13 or the outside air temperature detected by an outside air temperature detector (not shown). It is good also as a start condition of the reheat recovery operation. At this time, if the temperature detected by the hot water temperature thermistor 9 or the outside air temperature is a temperature obtained by adding a preset adjustment temperature α to the temperature detected by the hot water storage temperature sensor 13, the control unit 24 reheats. Do not perform recovery operation. Also in this case, the heat inside the HP unit 1 can be efficiently recovered.

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. For this reason, the heat inside the HP unit 1 can be efficiently recovered.

It should be noted that the reheat recovery operation start condition may be set when the integrated value of the flow rate detected by the hot water supply flow rate sensor 22 after the boiling operation is completed 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 sensor 22 is larger than the volume value corresponding to the bottom of the hot water storage tank 11 and the outlet side of the first bypass pipe 17. It is good also as a start condition of a reheat recovery driving | operation when it reduces. Also in this case, the heat inside the HP unit 1 can be efficiently recovered.

Also, the reheat recovery operation start condition may be set 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 boiling operation is completed reaches a preset value. For example, when the hot water storage temperature is 80 ° C. and the water temperature is 9 ° C., the reheat recovery operation start condition is when the integrated value of heat reaches 9 MJ, which is the heat amount when the amount of hot water in the hot water storage tank 11 is reduced by 30 L It is good. Also in this case, the heat inside the HP unit 1 can be efficiently recovered.

Further, when the temperature detected by the tapping temperature thermistor 9 is set in advance or when a preset time has elapsed after the completion of boiling, the reheat recovery operation may not be performed. For example, when 1 hour has passed since 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 performed unnecessarily.

Further, when the maximum recovery time has elapsed without 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 being the same, the heat recovery operation or the reheat recovery operation may be stopped. . For example, the heat recovery operation or the reheat recovery operation may be stopped when 8 minutes, which is a time required for recovering up to 40 L, which is the height of the hot water storage temperature sensor 13, when the circulation flow rate is 5 L / min. In this case, it is possible to prevent the heat recovery operation or the reheat recovery operation from being continued unnecessarily.

The heat recovery heat quantity 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 amount of hot recoverable hot water in 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 of the heat source pump 23 that is consumed in the heat recovery operation. For example, (temperature detected by hot water temperature thermistor 9−temperature detected by hot water storage temperature sensor 13) × 40 L × specific heat of water / (predetermined power consumption of heat source pump 23 × 3 kW × 40 L / circulation flow rate 5 L / min) may be the heat recovery efficiency. When the heat recovery efficiency does not exceed a preset efficiency, the heat recovery operation or the reheat recovery operation may not be performed. For example, when the heat recovery efficiency does not exceed 3.0 of 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 performed in an inefficient state.

In addition, when the outside air temperature does not exceed a preset temperature, the heat recovery operation or the reheat recovery operation may not be performed. For example, when the outside air temperature does not exceed 0 ° C., the heat recovery operation or the reheat recovery operation may not be performed. 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 a lower rotation speed 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 that efficiently recovers the heat inside the heat source unit.

1 HP unit, 2 air heat exchanger, 3 compressor, 4 water refrigerant heat exchanger, 5 expansion valve, 6 refrigerant piping, 7 HP forward piping, 8 HP return piping, 9 hot water temperature thermistor, 10 tank unit, 11 hot water storage Tank, 12 hot water storage temperature sensor, 13 hot water storage temperature sensor, 14a first water supply piping, 14b second water supply piping, 14c third water supply piping, 15 pressure reducing valve, 16 three-way valve, 17 first bypass piping, 18 hot water supply piping, 19 Hot water supply pipe, 20 hot water supply mixing valve, 21 first hot water supply pipe, 22 hot water flow sensor, 23 heat source pump, 24 control unit, 25 remote control device

Claims

A hot water storage tank for storing hot water,
A heat source machine comprising 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 connecting the upper and lower parts of the hot water storage tank and the heat source unit;
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 for circulating hot water in the water circuit;
After the boiling operation for storing the hot water heated by the heat source device in the hot water storage tank is completed and the compressor is stopped, the driving of the circulation pump is continued, and the heat inside the heat source device is transmitted through the bypass circuit. When the heat recovery operation is performed to return to the lower part of the hot water storage tank and the preset start condition is satisfied after the heat recovery operation is completed, the heat inside the heat source unit is transferred to the hot water storage tank through the bypass circuit. A control unit for performing the reheat recovery operation to return to the lower part;
Hot water storage water heater equipped with.
A lower temperature detecting device that is provided at a lower portion of the hot water storage tank and detects a temperature of the lower portion of the hot water storage tank;
A hot water temperature detection device that is provided in the heat source device and detects the temperature of the hot water outlet of the water-refrigerant heat exchanger;
With
The said control part makes it a said start condition when the temperature detected by the said tapping temperature detection apparatus turns into the temperature which added preset adjustment temperature with respect to the temperature detected by the said lower temperature detection apparatus. Item 2. A hot-water storage water heater according to item 1.
The hot water storage type water heater according to claim 2, wherein the bypass circuit is connected to a lower part of the hot water storage tank below the lower temperature detecting device.
A hot water supply circuit for supplying hot water from the hot water storage tank to the outside;
A flow rate sensor for detecting a flow rate of hot water passing through the hot water supply circuit;
With
The controller is configured such that when the integrated value of the flow rate of hot water detected by the flow sensor after the completion of the boiling operation reaches a preset value or based on the flow rate of the hot water, The hot water storage type hot water supply device according to claim 1, wherein the start condition is when the value reaches a preset value.
When the temperature detected by the tapping temperature detection device is equal to or lower than a preset temperature or when a preset time has elapsed after the completion of the boiling operation, the control unit re-starts even if the start condition is met. The hot water storage type hot water supply device 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 a heat recovery heat amount based on a temperature detected by the tapping temperature detection device, a temperature detected by the lower temperature detection device, and a heat recoverable hot water amount at a lower portion of the hot water storage tank, and the heat Calculate the heat recovery efficiency by dividing the recovered heat amount by the power consumption of the circulation pump that is consumed in the heat recovery operation, and if the heat recovery efficiency does not exceed the preset efficiency, 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.
8. The controller according to claim 1, wherein the controller does not perform the heat recovery operation or the reheat recovery operation even if the start condition is satisfied when the outside air temperature does not exceed a preset temperature. The hot water storage type water heater according to item 1.
The said control part makes any rotation speed of the said circulation pump at the time of the said heat recovery operation or the said reheat recovery operation into a rotation speed lower than the rotation speed at the said boiling operation. The hot water storage type water heater according to claim 1.