JP5097054B2 - Heat pump water heater - Google Patents

Description

  The present invention relates to a heat pump type hot water heater that performs a heating operation in which hot water in a hot water storage tank is heated to a desired temperature by a heat pump type heating means.

  Conventionally, this type of heat pump type water heater has a configuration as shown in FIG. 101 is a hot water storage tank unit having a hot water storage tank 102 for storing hot water, 103 is a heat pump unit as a heat pump heating means for heating the hot water in the hot water storage tank 102, and 104 is water as a heating heat exchanger of the heat pump unit 103. A refrigerant heat exchanger 105 is a heat-pump circuit, which connects the lower part of the hot water storage tank 102 and the water refrigerant heat exchanger 104 to supply the hot water in the hot water storage tank 102 to the water refrigerant heat exchanger 104, and a water refrigerant. The heat exchanger 104 and the upper part of the hot water storage tank 102 are connected to each other, and a return pipe 107 for returning the hot water heated by the water refrigerant heat exchanger 104 to the upper part of the hot water storage tank 102 is provided. It is a circulation pump that circulates hot water through the heat pump unit 103.

  Reference numeral 109 denotes a bypass pipe branched from the middle of the return pipe 107. One end of the bypass pipe 109 is connected to the middle of the return pipe 107 via the bypass switching valve 110, and the other end is connected to the lower part of the hot water storage tank 102. Yes. The bypass switching valve 110 switches the flow of hot water passing through the return pipe 107 to the bypass pipe 109 side so as to return to the lower part of the hot water storage tank 102 and switches to the upper side of the hot water storage tank 102 so as to return to the upper part of the hot water storage tank 102. Can be set to Reference numeral 111 denotes a heat exchange inlet temperature sensor that detects the temperature of hot water flowing into the water-refrigerant heat exchanger 104, and 112 denotes a hot water storage temperature sensor that is arranged in a plurality in the vertical direction of the side surface of the hot water storage tank 102.

  Reference numeral 113 denotes a hot water storage control unit that has a microcomputer that controls the driving of each actuator in response to inputs from various sensors. The hot water storage control unit 113 heats hot water in the hot water storage tank 102 by the heat pump unit 103. Then, the boiling operation for controlling to a desired temperature is controlled. At the beginning of the boiling operation, the circulation pump 108 is driven with the bypass switching valve 110 switched to the bypass pipe 109 side, and the heat pump The unit 103 was operated, and hot water having a low temperature that was not sufficiently heated at the beginning of the boiling operation was returned to the lower part of the hot water storage tank 102. (For example, refer to Patent Document 1.)

Further, in the one described in Patent Document 1, generally, the detected temperature detected by the heat exchange inlet temperature sensor 111 or the hot water storage temperature sensor provided below the hot water storage tank 102 in the hot water storage temperature sensor 112. Based on the detected temperature of 112, the boiling operation was terminated.
JP 2003-279136 A

  By the way, this conventional heat pump type hot water heater is often installed outdoors, and the forward pipe 106 and the return pipe 107 between both the hot water storage tank unit 101 and the heat pump unit 103 are exposed to the outside air. When the direct sunlight hits the forward pipe 106 and the return pipe 107 at a high outside air temperature, the hot water staying in the forward pipe 106 and the return pipe 107 is heated, and the water stored in the lower part of the hot water storage tank 102 is heated. When the boiling operation is started in this state, the temperature of the hot water detected by the heat exchange inlet temperature sensor 111 becomes a temperature that satisfies the condition for terminating the boiling operation depending on the case. In this case, there is a problem that the boiling operation is stopped immediately after the boiling operation is started.

  In order to solve the above-mentioned problems, the present invention is particularly configured as claimed in claim 1 and includes a hot water storage tank for storing hot water, heat pump heating means for heating the hot water in the hot water storage tank, a lower portion of the hot water storage tank, A forward pipe connecting the heating heat exchanger housed in the heat pump heating means, a circulation pump provided in the middle of the outgoing pipe for circulating hot water, and hot water heated by the heating heat exchanger in the hot water storage tank A return pipe returning to the upper part, a bypass pipe branched from the return pipe and connected to the lower part of the hot water storage tank, and a flow path switching means for switching the flow of hot water flowing through the return pipe to the upper side of the hot water storage tank or the bypass pipe side And a heat exchange inlet temperature detecting means for detecting the temperature of the hot water flowing into the heating heat exchanger, and an outside air temperature detecting means for detecting the outside air temperature. In a heat pump water heater that operates a heat pump heating means to perform a boiling operation for boiling hot water in a hot water storage tank to a desired temperature, and terminates the boiling operation based on a temperature detected by the heat exchange inlet temperature detection means When the start of the boiling operation is instructed and the outside air temperature detected by the outside air temperature detecting means is equal to or higher than a predetermined temperature, the circulation pump is switched in the state where the flow path switching means is switched to the bypass pipe side. Was driven for a predetermined time, and then the boiling operation was started.

  According to this invention, when the start of the boiling operation is instructed, if the outside air temperature detected by the outside air temperature detecting means is equal to or higher than the predetermined temperature, the flow path switching means is switched to the bypass pipe side and the circulation is performed. By driving the pump for a predetermined time and then starting the boiling operation, before the boiling operation, the hot water staying in the return pipe and return pipe and circulating hot water heated by sunlight and the lower part of the hot water tank are circulated. The temperature of the hot water in the forward and return pipes is almost the same as the temperature of the cold hot water in the lower part of the hot water storage tank, and the temperature of the hot water flowing into the heating heat exchanger is lowered. Can prevent the problem of stopping as soon as the boiling operation is started, and the temperature of the hot water flowing into the heating heat exchanger is stable with little fluctuations. But The can smooth, it is capable of performing boiling for stable operation.

Next, a heat pump type water heater according to an embodiment of the present invention will be described with reference to FIG.
1 is a hot water storage tank unit having a hot water storage tank 2 for storing hot water, 3 is a heat pump unit as a heat pump heating means for heating the hot water in the hot water storage tank 2, and 4 is a heat exchange unit housed in the heat pump unit 3. A water-refrigerant heat exchanger 5 is a heat-pump circuit, which connects the lower part of the hot water tank 2 and the water-refrigerant heat exchanger 4 and supplies the hot water in the hot water tank 2 to the water-refrigerant heat exchanger 4. And a return pipe 7 that connects the water refrigerant heat exchanger 4 and the upper part of the hot water storage tank 2 and returns hot water heated by the water refrigerant heat exchanger 4 to the upper part of the hot water storage tank 2. Reference numeral 8 denotes a circulation pump provided in the forward pipe 6 for circulating hot water in the hot water storage tank 2 to the heat pump unit 3.

  Reference numeral 9 denotes a bypass pipe branched from the middle of the return pipe 7. One end of the bypass pipe 9 is connected to the middle of the return pipe 7 via a bypass switching valve 10 as flow path switching means, and the other end is connected to the hot water storage tank 2. Connected to the bottom of the. Here, the return pipe 7 connecting the upper part of the hot water storage tank 2 and the water refrigerant heat exchanger 4 includes the return pipe 7 a connecting the water refrigerant heat exchanger 4 and the bypass switching valve 10, the bypass switching valve 10 and the hot water storage tank 2. The bypass switching valve 10 is composed of, for example, an electric three-way valve, and the flow of hot water flowing through the return pipe 7 is switched to the bypass pipe 9 side, that is, A state in which the return pipe 7a communicates with the bypass pipe 9 connected to the lower part of the hot water tank 2, and a state in which the hot water flowing through the return pipe 7 is switched to the upper side of the hot water tank 2 so as to return to the upper part of the hot water tank 2. That is, it is possible to set the return pipe 7a and the return pipe 7b to communicate with each other.

  11 is connected to the lower end of the hot water storage tank 2 to supply water to the hot water storage tank 2, 12 is connected to the upper end of the hot water storage tank 2 to discharge hot water stored in hot water, and 13 is the water supply pipe. A water supply bypass pipe branched from 11, 14 is a hot water mixing valve for mixing hot water from the hot water discharge pipe 12 and water from the water supply bypass pipe 13 to supply hot water at a set temperature, and 15 is provided in a kitchen or a washroom, etc. When the hot water tap 15 is opened, the water supplied from the water supply pipe 11 flows into the hot water storage tank 2 and low temperature water is stored from the lower part of the hot water storage tank 2.

  The heat pump unit 3 is composed of the water refrigerant heat exchanger 4 as a condenser, a compressor 16 with a variable rotation speed, an electronic expansion valve 17 and an air heat exchanger 18 as a forced air-cooled evaporator. 19, an outdoor fan 20 that blows air to the air heat exchanger 18, and a heat pump control unit 21 that controls the heat pump unit 3. In the heat pump circuit 19, carbon dioxide is used as a refrigerant and a supercritical heat pump is used. It constitutes a cycle.

  A plurality of hot water storage temperature sensors 22 as hot water storage temperature detecting means arranged in the vertical direction of the side surface of the hot water storage tank 2. In this embodiment, five hot water storage temperature sensors 22 are arranged, and temperature information detected by the hot water storage temperature sensors 22 is detected. Thus, the amount of heat remaining in the hot water storage tank 2 is detected, and the vertical temperature distribution in the hot water storage tank 2 is detected. Reference numeral 23 denotes a heat entrance temperature sensor serving as a heat entrance temperature detecting means that is provided in the forward pipe 6 and detects the temperature of hot water flowing into the water / refrigerant heat exchanger 4. In addition, at the time of a heating operation for boiling hot water in the hot water storage tank 2 to a desired temperature, the temperature detected by the hot water storage temperature sensor 22 arranged at the lowermost part of the hot water storage tank 2 among the hot water storage temperature sensors 22 or the heat exchange inlet. The boiling operation is terminated based on the temperature detected by the temperature sensor 23.

  Reference numeral 24 denotes a heat exchange outlet temperature sensor serving as a heat exchange outlet temperature detecting means for detecting the temperature of the hot water heated by the water / refrigerant heat exchanger 4. Reference numeral 25 denotes an upwind side of the air heat exchanger 18. It is an outside air temperature sensor as an outside air temperature detection means which detects the temperature of the outside air provided in the.

  A hot water storage control unit 26 includes a microcomputer that receives inputs from various sensors in the hot water storage tank unit 1 and controls driving of each actuator. The hot water storage control unit 26 includes a hot water supply remote controller (not shown). Is connected wirelessly or by wire so that the user can set an arbitrary hot water supply set temperature, and is connected to the heat-pump controller 21 so as to be communicable by wire to start and stop the boiling temperature and the boiling operation. Is sent to the heat pump control unit 21 to control the boiling operation of boiling hot water in the hot water storage tank 2.

Next, a heating operation for boiling hot water in the hot water storage tank 2 to a desired temperature in the operation of the embodiment shown in FIG. 1 will be described with reference to the flowchart of FIG.
The hot water storage control unit 26 is heated on the basis of the temperature detected by the hot water temperature sensor 22 in the daytime time period to compensate for the amount of hot water or heat that is insufficient due to the use of hot water during the daytime when the power rate is low. Instruct the start of lifting operation. When the start of the heating operation is instructed, first, it is determined whether or not the temperature detected by the outside air temperature sensor 25 is a predetermined temperature, for example, 35 ° C. or more (step S1), and the temperature detected by the outside air temperature sensor 25 is determined. When it is determined that the temperature is 35 ° C. or higher, the driving of the circulation pump 8 is started (step S2). At this time, the bypass switching valve 10 is switched to the bypass pipe 9 side, and hot water taken out from the lower part of the hot water storage tank 2 circulates through the forward pipe 6, the water / refrigerant heat exchanger 4, the return pipe 7 a, and the bypass pipe 9. Then, it returns to the lower part of the hot water storage tank 2 again.

  Then, it is determined whether or not a predetermined time, for example, 2 minutes has elapsed since the circulation pump 8 was driven in step S2 (step S3). If it is determined that the predetermined time has elapsed, the compressor 16 of the heat pump unit 3 is determined. Then, the operation of the electronic expansion valve 17 and the outdoor fan 20 is started (step S4), the boiling operation is started, the hot water supplied from the lower part of the hot water storage tank 2 is heated, and the temperature detected by the heat exchange temperature sensor 24 Is set to a desired boiling temperature.

  When the boiling water operation is started and the hot water temperature detected by the heat exchange outlet temperature sensor 24 reaches a predetermined temperature, the bypass switching valve 10 is set to the upper side of the hot water storage tank 2, that is, the return pipe 7a and the return pipe 7b. The hot water extracted from the lower part of the hot water storage tank 2 is heated by the water / refrigerant heat exchanger 4 and returned to the upper part of the hot water storage tank 2 via the return pipe 7a and the return pipe 7b. Hot water is stored in the upper part, and when the hot water temperature detected by the heat exchange outlet temperature sensor 24 reaches a predetermined temperature, the bypass switching valve 10 is moved from the bypass pipe 9 to the upper part of the hot water tank 2. By switching, the low-temperature water that is not sufficiently heated immediately after starting the boiling operation is returned to the lower part of the hot water tank 2 and is not returned to the upper part of the hot water tank 2. Is intended does not lower the temperature of the hot water in the upper in the hot water tank 2.

  In step S4, the heat pump unit 3 is activated to start boiling operation, and the detected temperature of the heat exchange inlet temperature sensor 23 or the hot water storage temperature sensor disposed at the lowermost part of the hot water storage tank 2 in the hot water storage temperature sensor 22 is used. Based on the detected temperature of the hot water storage tank 22, it is determined whether or not the boiling of the hot water in the hot water storage tank 2 has been completed (step S 5), and the detected temperature of the heat exchange inlet temperature sensor 23 or hot water stored in the hot water storage temperature sensor 22 is determined. When the temperature detected by the hot water storage temperature sensor 22 arranged at the lowermost part of the tank 2 reaches, for example, 50 ° C., it is determined that the boiling has been completed, and the drive of the circulation pump 8 is stopped and the operation of the heat pump unit 3 is stopped. The bypass switching valve 10 is switched from the upper side of the hot water storage tank 2 to the bypass pipe 9 side to end the boiling operation. Sometimes, by switching the bypass switching valve 10 from the upper side of the hot water tank 2 to the bypass pipe 9 side, convection of hot water from the lower side of the hot water tank 2 to the upper side of the hot water tank 2 via the heat pump circulation circuit 5 can be prevented. The temperature of the high temperature water in the upper part of the tank 2 is not lowered.

  If it is determined in step S1 that the outside air temperature detected by the outside air temperature sensor 25 is lower than a predetermined temperature, for example, 35 ° C., the circulating pump 8 is driven and the heat pump unit 3 is activated to start a boiling operation ( Step S6) shifts to the processing of step S5.

  In the above-described boiling operation, when the start of the boiling operation is instructed, it is determined that the temperature detected by the outside air temperature sensor 25 is a predetermined outside temperature, that is, a high outside air temperature of 35 ° C. or higher (the step) In S1 (YES), with the bypass switching valve 10 switched to the bypass pipe 9 side, the circulation pump 8 is driven for a predetermined time (steps S2 and S3), and then the heat pump unit 3 is operated ( In step S4), by starting the boiling operation, for example, the hot water staying in the forward pipe 6 and the return pipe 7 is heated by high-temperature outdoor air or sunlight during the day at a high outdoor temperature such as summer. Even before the heating operation, the circulating pump 8 is driven to circulate hot water remaining in the forward pipe 6 and the return pipe 7 and return to the lower part of the hot water storage tank 2, and the forward pipe 6 and the return pipe 7. Since the temperature of the hot water in the hot water tank 2 is made substantially the same as the temperature of the hot water in the lower part of the hot water storage tank 2 and the temperature of the hot water flowing into the water-refrigerant heat exchanger 4 is lowered, Therefore, it is possible to prevent the trouble of stopping immediately, and the temperature of the hot water flowing into the water-refrigerant heat exchanger 4 is stable with little fluctuation, so that the start-up of the boiling operation can be made smooth. It is possible to perform a stable boiling operation.

  In the present embodiment, the present invention is applied to both the heating operation in the midnight time zone and the boiling operation in the daytime time zone, but it is particularly suitable for the heating operation in the daytime time zone.

The schematic block diagram of one Embodiment of this invention. The flowchart which shows the action | operation of the boiling operation of the same embodiment. The schematic block diagram of a prior art example.

Explanation of symbols

2 Hot water storage tank 3 Heat pump heating means (heat pump unit)
4 Heating heat exchanger (water refrigerant heat exchanger)
6 Outward pipe 7 Return pipe 8 Circulation pump 9 Bypass pipe 10 Channel switching means (bypass switching valve)
23 Heat exchange inlet temperature detection means 25 Outside air temperature detection means

Claims (1)

  A hot water storage tank for storing hot water, a heat pump heating means for heating the hot water in the hot water storage tank, a forward pipe connecting a lower portion of the hot water storage tank and a heating heat exchanger housed in the heat pump heating means, A circulating pump provided in the middle of the forward pipe for circulating hot water, a return pipe for returning hot water heated by the heating heat exchanger to the upper part of the hot water storage tank, a branch from the return pipe and connected to the lower part of the hot water storage tank. A bypass pipe, flow path switching means for switching the flow of hot water flowing through the return pipe to the hot water tank upper side or the bypass pipe side, and a heat entrance temperature for detecting the temperature of the hot water flowing into the heating heat exchanger An outside air temperature detecting means for detecting the outside air temperature, driving the circulation pump and operating the heat pump heating means to bring the hot water in the hot water storage tank to a desired temperature. In a heat pump type water heater that performs a boiling operation and ends the boiling operation based on a temperature detected by the heat exchange inlet temperature detection means, when the start of the boiling operation is instructed, the outside air temperature detection When the outside air temperature detected by the means is equal to or higher than a predetermined temperature, the circulation pump is driven for a predetermined time while the flow path switching means is switched to the bypass pipe side, and then the boiling operation is started. A heat pump type water heater characterized by that.

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