JP4354389B2 - Hot water storage water heater - Google Patents

Description

  The present invention relates to a hot water storage type hot water supply apparatus that supplies hot water using hot water taken out from an intermediate portion of a hot water storage tank.

Conventionally, in this type of water, boiling the hot water is performed by returning the medium-temperature water, which has been used in a heat source such as heating, to a lower temperature, and returning it to the middle part of the hot water storage tank. The COP at the time of raising was improved. (For example, refer to Patent Document 1.)
Japanese Patent Application No. 2003-88638

  By the way, in this conventional one, after the intermediate temperature water taken out from the intermediate hot water pipe is mixed with hot water by an intermediate mixing valve to make warm water slightly higher than the hot water set temperature, it is mixed with low temperature water by a hot water mixing valve to adjust the set temperature. Since it is supplied as hot water, two temperature sensors are required: an intermediate mixing temperature sensor that detects the temperature of the mixed water at the intermediate mixing valve, and a hot water temperature sensor that detects the temperature of the mixed water at the hot water mixing valve. The hot water stored in the hot water is used to make the hot water higher than the set hot water temperature, which is wasteful and uneconomical. It had a problem to say.

This invention pays attention to this point and solves the above-mentioned drawbacks. In particular, the construction thereof includes a hot water storage tank for storing hot water, a heating means for heating the hot water in the hot water storage tank, and a hot water connected to the upper part of the hot water storage tank. A water supply pipe connected to the lower part of the hot water storage tank, a water supply bypass pipe branched from the water supply pipe, an intermediate hot water pipe connected to the intermediate part of the hot water storage tank, and a hot water pipe provided in the hot water supply pipe An intermediate mixing valve for mixing hot water flowing through the hot water from the intermediate outlet pipe, a hot water mixing valve for mixing hot water from the intermediate mixing valve and hot water from the water supply bypass pipe, and setting a hot water supply set temperature When the hot water temperature taken out from the intermediate hot water discharge pipe is higher than the hot water supply set temperature, the intermediate mixing valve is fully opened on the intermediate hot water discharge pipe side and provided in the hot water supply pipe. Hot water temperature When only the hot water mixing valve is driven and controlled so that the detected temperature of the sensor becomes the hot water set temperature, hot water is supplied, and when the hot water temperature taken out from the intermediate hot water pipe is lower than the hot water set temperature, the hot water mixing is performed. The valve is in the fully open state on the intermediate mixing valve side, and hot water is supplied by controlling only the intermediate mixing valve so that the detected temperature of the hot water temperature sensor provided in the hot water supply pipe becomes the hot water set temperature .

  According to the present invention, the temperature sensor is only one of the hot water temperature sensor and can be inexpensive, and when the intermediate hot water is higher than the hot water set temperature, the intermediate mixing valve is operated with the intermediate hot water outlet side fully open. First, hot water is adjusted to the hot water set temperature with the hot water mixing valve, and hot water is adjusted to the hot water set temperature by adding high-temperature water with the intermediate mixing valve when the medium temperature water is lower than the hot water set temperature, and hot water is passed through the hot water mixing valve. Therefore, either one of the mixing valves will always be used, high-temperature water and low-temperature water are not supplied at the same time, the use of high-temperature water can be suppressed as much as possible, and the amount of medium-temperature water used can be increased. It can be cut and the COP (energy consumption efficiency) can be improved.

  Next, an embodiment of the present invention will be described with reference to FIGS. In the figure, hatched hatched lines in the hot water storage tank indicate low temperature water, double hatched lines indicate medium hot water, triple hatched lines indicate hot water, and thick lines indicate hot water flow.

  This hot water storage type hot water supply device boils and stores hot water in the midnight hours when the unit price of contracted power by time is low, and uses the hot water stored 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 the hot water in the hot water storage tank, 4 is a hot water tap provided in a kitchen or a washroom, and 5 is provided in the vicinity of the hot water tap 4 A hot water supply remote controller 6 is a heating terminal such as a floor heating panel using the hot water in the hot water storage tank 1 as a heat source.

  The hot water storage tank 2 of the hot water storage tank unit 1 has a hot water discharge pipe 7 connected to the upper end, a water supply pipe 8 connected to the lower end, a heat pump forward pipe 9 constituting a heat pump circulation circuit in the lower part, and a heat pump circulation circuit in the upper part. The heat pump return pipe 10 is connected, the hot water in the hot water storage tank 2 taken out from the heat pump forward pipe 9 is boiled by the heat pump unit 3 and returned to the hot water storage tank 2 from the heat pump return pipe 10 to be stored in the hot water supply pipe. The hot water in the hot water storage tank 2 is pushed up by the water supply from 8, and the hot water in the upper part of the hot water storage tank 2 is pushed out from the hot water discharge pipe 7 to supply hot water.

  The heat pump unit 3 includes a compressor 11, a refrigerant-water heat exchanger 12 as a condenser, an electronic expansion valve 13, a forced air-cooled evaporator 14, and hot water in the hot water storage tank 2. The heat pump circuit 15 includes a heat pump circulation pump 16 that circulates to the refrigerant-water heat exchanger 12 through the heat pump forward pipe 9 and the heat pump return 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.

  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. Since it is condensed in the supercritical state, the heated water can be efficiently heated to a high temperature so that the temperature difference between the refrigerant-water heat exchanger 12 inlet temperature and the refrigerant outlet temperature is constant. By controlling the electronic expansion valve 13 or the compressor 11, the COP (energy consumption efficiency) is very high when the inlet temperature of the refrigerant-water heat exchanger 12 of the water to be heated is a low temperature of about 5 to 20 ° C. It is possible to heat the water to be heated in a good state.

  Reference numeral 18 denotes a heat exchanger for heating the hot water of the heating terminal 6, and on the primary side thereof, a hot water outlet pipe 19 connected to the upper part of the hot water storage tank 2 and an intermediate hot water return pipe 20 connected to the lower part of the hot water storage tank 2. Are connected to each other to constitute a heat exchange circuit 21, and hot water taken out from the hot water storage tank 2 is circulated to the heat exchanger 18 by the operation of the heat exchange circulation pump 22 provided in the middle hot water return pipe 20. The medium temperature water whose temperature has been lowered by the replacement is returned to the hot water storage tank 2 again.

  On the secondary side of the heat exchanger 18, a heating circulation circuit 25 composed of a heating forward pipe 23 and a heating return pipe 24 is connected to be able to circulate the circulating water of the heating terminal 6, and is provided in the middle of the heating return pipe 24. By the operation of the heating circulation pump 26, the circulating water of the heating terminal 6 is circulated to the heat exchanger 18 and heated by the high temperature water on the primary side.

  Next, 27 is an intermediate hot water pipe connected to an intermediate position higher than the intermediate hot water return pipe 20 of the hot water storage tank 2 and lower than the hot water pipe 7, and the heat exchanger 18 exchanges heat with the secondary side to lower the temperature. The hot water stored in the intermediate position of the hot water storage tank 2 such as medium hot water is discharged from the hot water storage tank 2.

  28 is an intermediate mixing valve constituted by an electric mixing valve provided in the middle of the hot water discharge pipe 7 and downstream of the intermediate hot water supply pipe 27, and 29 is a water supply bypass branched from the hot water from the intermediate mixing valve 28 and the water supply pipe 8. The hot water mixing valve is composed of an electric mixing valve that mixes low-temperature water from the pipe 30, and both the intermediate mixing valve 28 and the hot water mixing valve 29 are hot water temperature sensors 32 including a thermistor provided in the downstream hot water pipe 31. The intermediate mixing valve 28 controls the mixing ratio of medium-temperature water and high-temperature water so that the detected hot-water temperature becomes the hot-water supply set temperature set by the user using the hot-water supply remote controller 5, and the hot-water supply mixing valve 29 controls medium-temperature water and low-temperature. It controls the mixing ratio of water.

  A plurality of hot water storage temperature sensors 33 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 33 a, 33 b, 33 c, 33 d, 33 e from the top. Is used to detect how much heat is left in the hot water storage tank 2 and to detect the temperature distribution in the vertical direction in the hot water storage tank 2.

  The hot water supply remote controller 5 is provided with a hot water supply temperature setting switch 34 for setting a hot water supply set temperature, and constitutes a hot water supply temperature setting means.

  Reference numeral 35 denotes a hot water supply control unit having a microcomputer that receives the input of each sensor in the hot water storage tank unit 1 and controls the drive of each actuator. The hot water remote controller 5 is connected to the hot water controller 35 by radio or wire so that the user can set an arbitrary hot water set temperature and bath set temperature.

  The hot water supply control unit 35 sets the temperature detected by the hot water storage temperature sensor 33d provided at a height immediately below the intermediate hot water discharge pipe 27 as a hot water temperature to be taken out, and compares this hot water temperature with the hot water supply set temperature, When the hot water temperature is higher than the hot water supply set temperature, the intermediate mixing valve 28 is not mixed with high-temperature water, and the intermediate mixing valve 28 is communicated with the hot water supply mixing valve 29 in the fully opened state on the intermediate hot water outlet pipe 27 side. Feed-forward control is performed so that the opening of the hot water mixing valve 29 for mixing water is mixed with the hot water set temperature based on the hot water temperature and the feed water temperature detected by the feed water temperature sensor 36 provided in the middle of the feed water pipe 8. The opening degree of the hot water supply mixing valve 29 is feedback-controlled so that the temperature detected by the temperature sensor 32 becomes the hot water supply set temperature, and when the hot water temperature is lower than the hot water supply set temperature, The hot water mixing valve 29 is fully open on the side of the intermediate mixing valve 28 to communicate with the hot water supply pipe 31, and the degree of opening of the intermediate mixing valve 28 for mixing the high temperature water is determined based on the hot water temperature and the hot water storage temperature sensor. Based on the high temperature water temperature detected by 33a, feedforward control is performed so as to mix with the hot water supply set temperature, and at the same time, the opening degree of the intermediate mixing valve 28 is feedback controlled so that the temperature detected by the hot water temperature sensor 32 becomes the hot water supply set temperature. To do.

Next, the operation of this embodiment will be described.
First, the boiling operation shown in FIG. 2 will be described. When the hot water storage temperature sensor 33 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 35 performs heat pump control. A boiling start command is issued to the unit 17. Upon receiving the command, the heat pump control unit 17 starts driving the heat pump after starting the compressor 11, and cools the low temperature water of about 5 to 20 ° C. taken out from the heat pump forward pipe 9 connected to the lower part of the hot water storage tank 2 as a refrigerant. -Heated to a high temperature of about 70 to 90 ° C by the water heat exchanger 12, returned to the hot water storage tank 2 from the heat pump return 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 Store hot water. When the hot water storage temperature sensor 33 detects that the necessary amount of heat has been stored, the hot water supply control unit 35 issues a boiling stop command to the heat pump control unit 17, and the heat pump control unit 17 stops the compressor 11 and heat pump circulation. The pump 16 is also stopped to end the boiling operation.

  Next, the hot water supply operation shown in FIG. 3 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, high-temperature water is pushed out to the intermediate mixing valve 28 via the intermediate tap pipe 27. In the hot water storage tank 2, high temperature water is stored in the upper part and low temperature water is stored in the lower part. However, a specific gravity difference is generated due to the temperature difference, and a high temperature water having a low specific gravity is formed on the upper part by forming a temperature boundary layer. Since low-temperature water with a high specific gravity is located at the lower part, they do not mix with each other.

  Here, the hot water supply control unit 35 mixes the hot water from the intermediate hot water outlet pipe 27 and the hot water from the hot water outlet pipe 7 so as to reach a temperature higher than the preset hot water temperature set by the hot water remote controller 5 at the intermediate mixing valve 28. The intermediate mixing valve 28 is adjusted to an appropriate ratio. Here, since the hot water flowing in from the intermediate hot water pipe 27 is hot and higher than the hot water supply set temperature, the hot water pipe 7 side of the intermediate mixing valve 28 is closed.

  Then, the hot water flowing out from the intermediate mixing valve 28 flows into the hot water supply mixing valve 29 and is mixed with the low temperature water from the water supply bypass pipe 30, and the hot water supply control unit 35 adjusts the mixing ratio of the hot water supply mixing valve 29 to achieve the hot water supply set temperature. Hot water is supplied from the hot water tap 4. Then, the hot water supply is completed by closing the hot water tap 4.

  Next, the heating operation shown in FIG. 4 will be described. When a heating operation instruction is input, the hot water supply control unit 35 drives the heat exchange circulation pump 22 and the heating circulation pump 26 to supply the high-temperature water taken out from the high-temperature water discharge pipe 19. Heating operation is performed by flowing into the heat exchanger 18 and exchanging heat with the circulating water on the secondary side. Then, the intermediate temperature water whose temperature has decreased due to the heat exchange returns to the lower part of the hot water storage tank 2 via the intermediate temperature water return pipe 20, and the intermediate temperature water is stored so as to push up the boundary surface between the high temperature water and the intermediate temperature water in such a manner that it is replaced with the high temperature water. Is. In the hot water storage tank 2, high temperature water is stored in the upper part, medium temperature water is stored in the middle part, and low temperature water is stored in the lower part. If the temperature difference is about 20 ° C, a specific gravity difference occurs and a temperature boundary layer is formed. Since the high-temperature water having a low specific gravity is located at the upper part, the intermediate intermediate water is located at the intermediate part, and the low-temperature water having a high specific gravity is located at the lower part, they are not mixed with each other.

  On the secondary side, the circulating water heated by the heat exchanger 18 returns to the heating terminal 6 to perform heating. And when the instruction | indication of a heating stop is input, the hot-water supply control part 35 stops the drive of the heat exchange circulation pump 22 and the heating circulation pump 26, and complete | finishes heating operation.

  As described above, when the heating operation is performed, a large amount of medium-temperature water whose temperature has been lowered by heat exchange is stored in the hot water storage tank 2. This medium temperature water cannot be used as a heat source for heating and is also inefficient in boiling by the heat pump circuit 15. Therefore, it is required to use this medium temperature water preferentially for hot water supply.

  Therefore, a hot water supply operation after the medium temperature water is stored in the hot water storage tank 2 will be described. As shown in FIG. 5, when the hot water tap 4 is opened, the hot water from the water supply pipe 8 flows into the hot water storage tank 2 and at the same time, the intermediate hot water is pushed out from the intermediate hot water pipe 27. When this temperature is detected by the sensor 33d and this temperature is higher than the hot water supply set temperature, the hot water mixing is performed with the intermediate mixing valve 28 in the fully opened state on the side of the intermediate hot water outlet 27 so that the intermediate mixing valve 28 does not mix with hot water. The opening degree of the hot water supply mixing valve 29 that communicates with the valve 29 and mixes low temperature water is determined based on the medium hot water temperature and the feed water temperature detected by the feed water temperature sensor 36, and then the temperature detected by the hot water temperature sensor 32. Is mixed with low-temperature water and medium-temperature water by the hot-water supply mixing valve 29 so that the hot-water supply set temperature is reached.

  On the other hand, when the temperature of the intermediate hot water pushed out from the intermediate hot water discharge pipe 27 is equal to or lower than the hot water supply set temperature, the hot water supply mixing valve 29 is fully opened on the intermediate mixing valve 28 side so as not to mix with the low temperature water by the hot water supply mixing valve 29. The opening of the intermediate mixing valve 28 that communicates with the hot water supply pipe 31 and mixes high temperature water is determined based on the medium hot water temperature and the high temperature water temperature detected by the hot water storage temperature sensor 33a, and then detected by the hot water temperature sensor 32. Hot water and intermediate temperature water by the intermediate mixing valve 28 are mixed so that the temperature to be set becomes the hot water supply set temperature, and hot water supply at the hot water supply set temperature is performed.

  The temperature sensor is only one of the hot water temperature sensors, and it can be inexpensive, and when the medium hot water is higher than the hot water set temperature, the intermediate mixing valve does not operate because the intermediate hot water outlet side is fully open. Hot water is adjusted to the hot water supply set temperature, and when the hot water is below the hot water set temperature, hot water is added to the hot water set temperature with the intermediate mixing valve to adjust the hot water supply set temperature, and hot water is passed through the hot water supply mixing valve. As the mixing valve is used, high-temperature water and low-temperature water are not supplied at the same time, the use of high-temperature water can be suppressed as much as possible, and the amount of medium-temperature water used can be increased and used up. The COP (energy consumption efficiency) can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of one Embodiment which shows the hot water storage type hot-water supply apparatus of this invention. The schematic block diagram explaining the action | operation of the boiling operation of the same embodiment. The schematic block diagram explaining the action | operation of the hot water supply driving | operation of the same embodiment. The schematic block diagram explaining the action | operation of the heating operation of the same embodiment. The figure explaining the action | operation of the hot water supply operation in case the middle temperature water higher than the hot water supply preset temperature exists in the hot water storage tank of the same embodiment. The figure explaining the action | operation of the hot-water supply driving | running | working when intermediate temperature water below hot-water supply preset temperature exists in the hot water storage tank of the same embodiment.

Explanation of symbols

2 Hot water storage tank 3 Heat pump unit (heating means)
7 Hot water supply pipe 8 Water supply pipe 27 Intermediate hot water supply pipe 28 Intermediate mixing valve 30 Hot water supply mixing valve 31 Water supply bypass pipe 34 Hot water storage temperature sensor 35 Hot water supply temperature setting switch (hot water supply temperature setting means)
36 Hot water supply control unit (control means)

Claims (1)

A hot water storage tank for storing hot water, heating means for heating the hot water in the hot water storage tank, a hot water pipe connected to the upper part of the hot water storage tank, a water supply pipe connected to the lower part of the hot water storage tank, and a branch from the water supply pipe An intermediate mixing valve that mixes the hot water flowing through the hot water pipe provided in the hot water pipe and the hot water from the intermediate hot water pipe, and an intermediate hot water pipe connected to the intermediate portion of the hot water storage tank. A hot water supply mixing valve for mixing hot water from the intermediate mixing valve and hot water from the water supply bypass pipe, and hot water supply temperature setting means for setting a hot water supply set temperature are taken out from the intermediate hot water discharge pipe. hot water temperature is higher than the hot water set temperature, the intermediate mixing valve with intermediate tapping pipe side fully open state, driving the detected temperature of the hot water supply temperature sensor provided in the hot water supply pipe is only the hot water supply mixing valve so that the hot water set temperature When the temperature of hot water to be controlled is controlled and the hot water temperature taken out from the intermediate hot water pipe is equal to or lower than the hot water set temperature, the hot water mixing valve is fully opened and the hot water temperature sensor provided in the hot water pipe is provided. The hot water storage type hot water supply apparatus is characterized in that only the intermediate mixing valve is driven and controlled so that the detected temperature becomes the hot water supply set temperature .

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