JP2005249264A - Hot-water storage type hot-water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a power consumption in operation at low ambient temperatures. <P>SOLUTION: In this hot-water storage type hot-water supply device comprising a defrosting operation means for eliminating a frost produced in an evaporator in hot-water storage operation at low ambient temperatures, a drain port 23 is formed at the lower part of the evaporator 14, a freeze prevention heat exchanger 24 is installed between the drain port 23 and the evaporator 14, the freeze prevention heat exchanger 24 is connected to a hot water output tube 10 through an opening/closing valve 26 and a drain heat exchange input tube 25, and the freeze prevention heat exchanger 24 and a water input tube 9 between the hot-water storage tank and a circulation pump 16 are connected to each other through a heat exchange output tube 27. The device also comprises a freeze prevention means controlling the opening/closing valve 26 according to the defrosting operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hot water storage type hot water supply apparatus such as a heat pump water heater.

Conventionally, in this type, for example, the applicant previously filed, a hot water storage tank for connecting hot water and hot water stored in a hot water tank connected to a water inlet pipe and a hot water outlet, and heating means for heating hot water in the hot water storage tank, A circulation circuit that connects the hot water storage tank and the heating means so that hot water can be circulated; and a circulation pump that is provided in the circulation circuit and circulates the hot water. The hot water in the hot water storage tank is driven by the circulation pump. In the one that is circulated to the heating means through the circulation circuit and heated and then returned to the hot water storage tank, a temperature sensor is provided in the circulation circuit, and the displacement pump of the positive displacement pump is provided according to the output of the temperature sensor. Since the capacity is controlled, the circulation flow rate is not affected by pressure loss from the upper limit to the lower limit of the flow control range of the circulation pump, and the circulation flow rate can be controlled stably. There is a hot water storage type hot water supply device that makes it easy to control the heating means when heating hot water, can stably generate hot water, and can store hot water using the capacity of the hot water storage tank to the maximum. there were. (For example, see Patent Document 1)
Further, in this type of hot water storage type hot water supply apparatus, when the amount of frost generated in the evaporator during hot water storage operation at a low outside air temperature becomes large, the capacity of the heat exchanger is reduced, so that heat exchange is performed periodically. A defrosting operation for heating and melting the frost attached to the vessel is necessary, but the water generated in this defrosting operation is drained from a drain outlet provided below the evaporator. However, due to the low outside air temperature, once the melted water reaches the drain outlet, it begins to freeze again, and the drain outlet is blocked, so that it cannot be drained. In order to prevent this phenomenon, an electric heater has been provided between the evaporator and the drain outlet.
JP 2003-294316 A

  However, since this conventional device uses electric power for preventing freezing directly by an electric heater of about 100 w, the power consumption increases at a low outside temperature, which causes a significant decrease in energy consumption efficiency (COP).

  This invention pays attention to this point, and in order to solve the above-mentioned drawbacks, it comprises a hot water storage tank unit having a hot water storage tank in which hot water is stored by connecting a water inlet pipe and a hot water outlet pipe, a compressor, an expansion valve, an evaporator, etc. Heating means for heating hot water in a hot water storage tank, a circulation circuit for connecting the hot water storage tank and the heating means so that hot water can circulate, and a circulation pump provided in the middle of the circulation circuit for circulating hot water, Hot water in the hot water storage tank is circulated and heated to the heating means through the circulation circuit by driving the circulation pump, and returned to the hot water storage tank to store hot water, and during the hot water storage operation at a low outside temperature, the evaporation is performed. Provided with a defrosting operation means for removing frost generated in the evaporator, a drain outlet is provided below the evaporator, and an anti-freezing heat exchanger is provided between the drain outlet and the evaporator. Heat exchange And a drain heat exchange pipe, and a water inlet pipe between the hot water storage tank and the circulation pump is connected to a freeze prevention heat exchanger by a drain heat exchange pipe, and the drain heat exchange pipe or drain The heat exchanging pipe is provided with an on-off valve, and is provided with anti-freezing means for controlling the on-off valve in accordance with the defrosting operation.

  According to this invention, the electric heater for preventing freezing of drain water can be changed to an anti-freezing heat exchanger, so that the power consumption at the low outside temperature can be kept low, and the decrease in COP at the low outside temperature can be minimized. It can be done.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  In this hot water storage type hot water supply apparatus, hot water is boiled and stored in the midnight hours when the unit price of contracted power by time zone is low, and the hot water stored in the hot water is used for hot water supply. 1 is a hot water storage tank 2 for storing hot water. 3 is a heat pump unit as a heating means for heating hot water in the hot water storage tank, 4 is a hot water tap provided in a kitchen or a washroom, etc. 5 is a remote control for remotely operating the hot water storage type hot water supply device , 6 is a bathtub.

  The hot water storage tank 2 of the hot water storage tank unit 1 has a hot water supply pipe 7 connected to the upper end, a water supply pipe 8 connected to the lower end, a water inlet pipe 9 constituting a heat pump circulation circuit in the lower part, and a heat pump circulation circuit in the upper part. The hot water in the hot water storage tank 2 taken out from the incoming water pipe 9 by the heat pump unit 3 is boiled up and returned to the hot water storage tank 2 from the hot water storage pipe 2 to be stored in the hot water storage tank 8. As a result, hot water in the hot water storage tank 2 is pushed up, and hot water in the upper part of the hot water storage tank 2 is supplied from the hot water supply pipe 7.

The heat pump unit 3 includes a compressor 11 having a variable number of revolutions, a refrigerant-water heat exchanger 12 as a condenser, an expansion valve 13, a forced air-cooled evaporator 14, and a hot water storage tank 2. A circulating pump 16 that circulates the hot water to the refrigerant-water heat exchanger 12 through the water inlet pipe 9 and the hot water outlet pipe 10, and a heat pump control unit 17 that controls the driving thereof. Is one in which carbon dioxide is used as a refrigerant to constitute a supercritical heat pump cycle. Since carbon dioxide is used as the refrigerant, it is possible to boil low temperature water to a high temperature of about 90 ° C. without an electric heater.
The power source of the compressor 11 or the heat pump unit 3 is provided with a current sensor 18 that always detects the current value d1 of the compressor 11 or the heat pump unit 3 as a whole.

Reference numeral 19 denotes an incoming water temperature sensor attached to the inlet pipe 9 or the inlet of the refrigerant-water heat exchanger 12, and detects the water temperature before being heated by the refrigerant-water heat exchanger 12 by a thermistor sensor or the like.
A hot water temperature sensor 20 is attached to the outlet pipe 10 or the outlet of the refrigerant-water heat exchanger 12, and detects the hot water temperature heated by the refrigerant-water heat exchanger 12 by a thermistor sensor or the like.

  Here, the refrigerant-water heat exchanger 12 employs a counter flow system in which the refrigerant and hot water in the hot water storage tank 2 that is heated water are opposed to each other. In the supercritical heat pump cycle, the refrigerant is exchanged during heat exchange. The water to be heated can be efficiently heated to a high temperature because it is condensed in the supercritical state, and according to the temperature difference t between the refrigerant-water heat exchanger 12 inlet temperature b and the refrigerant outlet temperature a. In addition to controlling the rotational speed of the expansion valve 13 or the compressor 11 and providing the COP control means 21 for controlling the flow rate c of the circulation pump 16, the water to be heated is heated with a very good COP. Is possible.

In order to prevent the ability of the evaporator 14 from being significantly reduced during operation at a low outside temperature where frost is generated in the evaporator 14, the heat pump control unit 17 is periodically operated by opening the expansion valve 13 or the like. The defrosting control means 22 which performs a defrosting operation is provided.
Reference numeral 23 denotes a drain outlet provided below the evaporator 14, and a freeze prevention heat exchanger 24 is provided in a drain path between the drain outlet 23 and the evaporator 14.

  This anti-freezing heat exchanger 24 prevents the freezing of the drainage path including the drain outlet 23 by allowing warm water to flow inside. A drain heat inlet pipe 25 which is one of the pipes is connected via an on-off valve 26. By connecting the drain heat exchange pipe 27, which is the other pipe, to the hot water pipe 10 and the inlet pipe 9 on the upstream side of the circulation pump 16, the opening / closing valve 26 can be opened during operation of the circulation pump 16. Accordingly, hot water flows from the hot water outlet pipe 10 to the on-off valve 26, the freeze prevention heat exchanger 24, and the water inlet pipe 9, and the freeze prevention heat exchanger 24 is heated by the hot water to prevent freezing of the drain outlet 23 and the like. .

  The on-off valve 26 is operated for 10 minutes after completion of the defrosting operation, and is controlled for a certain period of time after the completion of the defrosting operation, such as control such as changing according to the state of the heat pump unit 3 and the temperature. It can also be made to.

  Next, 28 is a heat exchanger made of stainless steel for heating the hot and cold water in the bathtub 6, and is arranged at the upper part in the hot water storage tank 2. A bath circulation circuit 32 comprising a bath return pipe 31 provided with a bath circulation pump 30 is connected so that hot water in the bathtub 6 can be circulated, and the hot water in the bathtub 6 is heated by the high-temperature water in the hot water storage tank 2 to keep warm. Or it is something that is chased.

  33 is a bath return temperature sensor that detects the temperature of the bath water flowing into the heat exchanger 28 through the bath return pipe 31, and 34 is a bath that flows out of the heat exchanger 28 and flows into the bath 6 through the bath return pipe 29. A temperature sensor that detects the temperature of water.

  Next, 35 is a hot water mixing valve composed of an electric mixing valve that mixes hot water from the hot water supply pipe 7 and low temperature water from the water supply bypass pipe 36 branched from the water supply pipe 8. The mixing ratio is controlled such that the hot water temperature detected by the provided hot water temperature sensor 37 becomes the hot water supply set temperature set by the user using the remote controller 5.

  38 is a hot water pipe branched from the hot water supply pipe 7 and communicated with the bath return pipe 31. A bath flow counter 40 that counts the amount of hot water filling and a check valve 41 that prevents the bath water from flowing back to the hot water supply pipe 7 are provided.

  Next, a plurality of hot water storage temperature sensors 42 are arranged in the vertical direction of the hot water storage tank 2. In this embodiment, five hot water storage temperature sensors are arranged and are called 42a, 42b, 42c, 42d, 42e from the top. The amount of heat remaining in the hot water storage tank 2 is detected based on the temperature information detected by the temperature sensor 42, and the vertical temperature distribution in the hot water storage tank 2 is detected.

  A hot water supply control unit 43 includes a microcomputer that receives the input of each sensor in the hot water storage tank unit 1 and controls driving of each actuator, and constitutes a control unit. The remote controller 5 is connected to the hot water supply control unit 43 by wireless or wired so that the user can set an arbitrary hot water set temperature and bath set temperature.

  The hot water supply control unit 43 receives outputs of the plurality of hot water storage temperature sensors 42a to 42e, and determines whether there is sufficient residual heat in the hot water storage tank 2 based on the detected temperatures. 44 is provided.

  The remote controller 5 is provided with a hot water supply temperature setting switch 45 for setting the hot water supply set temperature and a bath temperature setting switch 46 for setting the bath set temperature. A bath automatic switch 47 that fills the hot water amount set by a hot water amount setting switch (not shown) and keeps it warm for a predetermined time, a reheating switch 48 that repels bathtub water, and hot water in the hot water storage tank 2 A reheating switch 49 for increasing a certain amount even in the daytime period is provided. The remote controller 5 is provided with a dot matrix display section 50, a speaker 51 for outputting a buzzer sound and voice guidance, and a remote control control section 52 for controlling them.

  Further, in a partial area of the display unit 50, a hot water storage amount display unit 53 that visually displays the remaining hot water amount in the hot water storage tank 2 is provided, and is calculated by the residual heat amount determination unit 44. In accordance with the amount of remaining hot water, the number of lighting of the bar display indicating the remaining hot water is changed in a figure imitating the hot water storage tank 2.

In addition, 54 is an overpressure relief valve for releasing the overpressure of the hot water storage tank 2, 55 is a pressure reducing valve for reducing the pressure of the water supply, 56 is a hot water supply flow rate counter for counting the amount of hot water to be supplied, and 57 is a temperature of the water supply. It is a feed water temperature sensor.
Reference numeral 58 denotes an outside air temperature sensor provided on the windward side of the evaporator 14, which is composed of a thermistor sensor or the like and detects the outside air temperature.

  The COP control means 21 includes a current value d1 of the heat pump unit 3 as a heating means, a temperature difference t between the value a of the hot water temperature sensor 20 and the value b of the incoming water temperature sensor 19, and the flow rate c of the circulation pump 16 to t × The number of revolutions of the compressor 11 and the opening degree of the expansion valve 13 are controlled so as to calculate a rough COP by calculating c / d1 and maintain the predetermined value x.

  Next, the operation of the first embodiment will be described. When the hot water storage temperature sensor 42 detects that the necessary amount of heat does not remain in the hot water storage tank 2 in the midnight power time zone, the hot water supply control unit 43 issues a boiling start command to the heat pump control unit 17. Upon receiving the command, the heat pump control unit 17 starts driving the compressor 11 and then starts to drive the circulation pump 16, and cool water of about 5 to 20 ° C. taken out from the water inlet pipe 9 connected to the lower part of the hot water storage tank 2. Heated to a high temperature of about 65 to 90 ° C. with the heat exchanger 12, returned to the hot water storage tank 2 from the hot water discharge pipe 10 connected to the upper part of the hot water storage tank 2, and sequentially stacked from the upper part of the hot water storage tank 2 to store the hot water. To go. When the hot water storage temperature sensor 42 and the hot water temperature sensor 20 detect that the necessary amount of heat has been stored, the hot water supply control unit 43 issues a boiling stop command to the heat pump control unit 17, and the heat pump control unit 17 turns on the compressor 11. At the same time, the circulation pump 16 is stopped and the boiling operation is finished.

  When the outside air temperature is low, frost is gradually generated in the evaporator 14 during this hot water storage operation, and the heat exchange efficiency of the evaporator 14 is reduced by covering the evaporator 14, so that the evaporation valve 13 is opened to evaporate. The defrosting operation which removes frost by heating the vessel 14 temporarily is necessary, and the drain water generated in the defrosting operation is frozen again to prevent the drainage path such as the drain pan and the drain outlet 23 from being blocked. In order to prevent the freezing by passing high temperature water led from the hot water pipe 10 to the antifreezing heat exchanger 24 provided below the evaporator 14, the water after heat exchange is returned to the water inlet pipe 9. is there.

  The operation of the freeze prevention means will be described in detail. If the opening / closing valve 26 is opened after the defrosting operation for a predetermined time by the defrosting control means 22 is completed, the drain heat inlet pipe 25 is discharged from the hot water discharge pipe 10 by the operation of the circulation pump 16. The anti-freezing heat exchanger 24 is heated by flowing warm water in the order of the anti-freezing heat exchanger 24, the drain heat exchanging pipe 27, and the water inlet pipe 9, and after a predetermined time (about approximately) 10 minutes later), the on-off valve 26 is closed to end the water flow to the anti-freezing heat exchanger 24, and this operation is repeated every time after the defrosting operation is completed, thereby preventing the drainage passage and the drain outlet 23 from freezing. Is.

  Next, the hot water supply operation will be described. When the hot water tap 4 is opened, the water supplied from the water supply pipe 8 flows into the hot water storage tank 2. Then, the hot water stored in the hot water storage tank 2 flows into the hot water supply mixing valve 35 through the hot water supply pipe 7 and is mixed with the low temperature water from the hot water supply bypass pipe 36, and the hot water control section 43 determines the mixing ratio of the hot water supply mixing valve 35. The adjusted hot water of the hot water supply set temperature is supplied from the hot water tap 4. Then, the hot water supply is completed by closing the hot water tap 4.

  Next, the hot water filling operation to the bathtub 6 will be described. When the automatic bath switch 47 of the remote controller 5 is operated, the hot water supply control unit 43 opens the hot water filling valve 39. Then, the hot water adjusted to the set temperature by the hot water supply mixing valve 35 is filled from the hot water filling pipe 38 to the bathtub 6 through the hot water return pipe 31, and a bath flow rate counter 40 provided in the middle of the hot water filling pipe 38 has a predetermined value. When the amount of hot water filling is counted, the hot water supply control unit 43 closes the hot water filling valve 39 and ends the hot water filling operation.

It should be noted that the present invention is not limited to the first embodiment described above, and in this embodiment, the predetermined time is after the defrosting operation, but the on-off valve 26 may be opened before the defrosting operation is completed. Alternatively, the on-off valve 26 can be opened after the defrosting operation has finished for a certain period of time to perform the antifreezing operation for a predetermined time.
In the first embodiment, the open / close valve 26 is provided in the drain heat exchange pipe 25. However, even if the open / close valve 26 is provided in the drain heat exchange pipe 27, the same effect can be obtained.

The schematic block diagram of the hot water storage type hot-water supply apparatus of the Example of this invention. The principal part block diagram of the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank unit 2 Hot water storage tank 3 Heat pump unit 14 Evaporator 16 Circulation pump 24 Freezing prevention heat exchanger 25 Drain heat inlet pipe 26 On-off valve 27 Drain heat outlet pipe

Claims (1)

  A hot water storage tank unit having a hot water storage tank in which hot water is stored with a water intake pipe and a hot water discharge pipe connected, a heating means for heating the hot water in the hot water storage tank, comprising a compressor, an expansion valve, an evaporator, and the like, and the hot water storage tank A circulating circuit that connects hot water to the heating means so that the hot water can circulate, and a circulation pump that circulates the hot water in the circulation circuit, and the circulating circuit drives the hot water in the hot water storage tank by driving the circulation pump. Circulates to the heating means through the heating means, stores the hot water by returning it to the hot water storage tank, and has a defrosting operation means for removing frost generated in the evaporator during hot water storage operation at a low outside temperature In this case, a drain outlet is provided below the evaporator, and an anti-freezing heat exchanger is provided between the drain outlet and the evaporator, and the anti-freezing heat exchanger and the outlet pipe are connected by a drain heat inlet pipe. Then both An inlet pipe between the hot water storage tank and the circulation pump is connected to an anti-freezing heat exchanger by a drain heat exchange pipe, and the drain heat exchange pipe or the drain heat exchange pipe includes an on-off valve, and the defrosting operation A hot water storage type hot water supply apparatus comprising anti-freezing means for controlling the on-off valve according to the conditions.

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