JP2011141076A - Heat pump type hot water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that water of intermediate temperature which is not boiled up by a heat pump type heating means, is increased day by day. <P>SOLUTION: This heat pump type hot water supply device includes a switching means 30 for switching returning of hot water/water heated by the heat pump type heating means 21 to an upper part of a hot water storage tank 1 through a boiling-up pipe 29, and returning of the same to an intermediate part of the hot water storage tank 1 through an intermediate return pipe 28, and a control means 39 for switching the switching means 30 to an intermediate return pipe 28 side in starting a boiling-up operation, to return the hot water boiled up by the heat pump type heating means 21 to the intermediate part of the hot water storage tank 1 from the intermediate return pipe 28 so that the hot water at an upper part with respect to the intermediate return pipe 28 in the hot water storage tank 1, is heated, then switching the switching means 30 to an upper part side of the hot water storage tank 1, of the boiling-up pipe 29 to return the hot water boiled up by the heat pump type heating means 21 to the upper part of the hot water storage tank 1. Thus the water of intermediate temperature can be reduced by heating the water of intermediate temperature by the water of high temperature from the intermediate return pipe 28 in starting the boiling-up. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a heat pump hot water storage type hot water supply apparatus that boils hot water in a hot water storage tank with a heat pump heating means.

  Conventionally, in this kind of heat pump hot water storage type hot water supply apparatus, as shown in Patent Document 1, water taken out from the lower part of the hot water storage tank is heated to the target temperature by the heat pump heating means and returned from the upper part of the hot water storage tank. There is something like that. When hot water is supplied, hot water boiled from the upper or middle part of the hot water storage tank is supplied by water supplied from the lower part of the hot water storage tank, and hot water is supplied to the hot water tank. Water, and intermediate temperature water is located in the boundary layer between them.

  And in this conventional one, when boiling with the heat pump heating means in the midnight time zone where the unit price of electricity is low, only the low-temperature water at the bottom of the hot water tank is boiled, leaving the medium temperature water in the hot water tank. The heating operation of the heat pump heating means was prevented from deteriorating by terminating the boiling operation.

JP 2005-49054 A

  However, in this conventional apparatus, when an indirect heat exchanger for flow heating or the like is disposed in the hot water storage tank and the heat in the hot water storage tank is used for flow heating or the like, the hot water storage tank as shown in FIG. A large amount of medium-temperature water of about 50 ° C. is generated between the upper end of the indirect heat exchanger and the cold water layer. And when it is the midnight time zone, as shown in FIG. 5 (B), only the cold water layer is boiled, and all the generated medium warm water is left and heated at midnight. As shown in FIG. 5 (C), medium temperature water is newly generated by heat exchange with the indirect heat exchanger, and the temperature of the previous day's medium temperature water is further lowered, and the amount of medium temperature water increases every day. Will end up.

  Thus, if the amount of intermediate temperature water increases, the amount of heat storage in the hot water storage tank is reduced, the possibility of running out of hot water increases, and the temperature of the remaining intermediate temperature water can be raised. Even if the temperature is lowered, the heating efficiency of the heat pump heating means is deteriorated, and the power consumption is increased.

  Therefore, in order to solve the above problems, the present invention provides a hot water storage tank for storing hot water, a water supply pipe for supplying water to the lower part of the hot water storage tank, a hot water discharge pipe for discharging hot water from the upper part of the hot water storage tank, and the lower part of the hot water storage tank. A water intake pipe connected to the water supply pipe, a heat pump heating means for heating and boiling hot water taken out from the water intake pipe, a water heating pipe for returning the hot water heated by the heat pump heating means to the upper part of the hot water storage tank, and An intermediate return pipe branched from the boiling pipe and connected to an intermediate part of the hot water storage tank, and provided at a branch part of the boiling pipe and the intermediate return pipe, the hot water boiled by the heat pump heating means is A switching means for switching between returning to the upper part of the hot water storage tank via the boiling pipe or returning to the intermediate part of the hot water tank via the intermediate return pipe; Sometimes, the switching means is switched to the intermediate return pipe side, the hot water boiled by the heat pump heating means is returned from the intermediate return pipe to the intermediate portion of the hot water storage tank, and more than the intermediate return pipe in the hot water storage tank. Control means for switching the switching means to the upper side of the hot water storage tank of the boiling pipe after raising the temperature of the hot water in the upper part, and returning the hot water heated by the heat pump heating means to the upper part of the hot water storage tank And provided.

  The control means switches the switching means to the intermediate return pipe side at the start of the boiling operation when intermediate temperature water in a predetermined temperature range exists above the intermediate return pipe in the hot water storage tank. The hot water boiled by the heat pump heating means is returned from the intermediate return pipe to the intermediate portion of the hot water storage tank, and the hot water above the intermediate return pipe in the hot water storage tank has a temperature higher than the predetermined temperature range. On the other hand, when there is no medium temperature water in a predetermined temperature range above the intermediate return pipe in the hot water storage tank at the start of the boiling operation, the switching means is connected to the hot water storage tank of the hot water pipe. The hot water boiled by the heat pump heating means is returned to the upper part of the hot water storage tank.

  In addition, an internal heat exchanger for exchanging heat with an external fluid is provided above the intermediate return pipe in the hot water storage tank.

  Further, an external heat exchanger for exchanging heat between the hot water in the hot water storage tank and an external fluid, and hot water taken out from the upper part of the hot water storage tank are circulated to the external heat exchanger, and a lower part or an intermediate part of the hot water storage tank And an external circuit for returning to the ground.

  The heat pump heating means is a supercritical heat pump cycle that uses carbon dioxide refrigerant as a refrigerant and becomes supercritical on the high-pressure side.

  As described above, according to the present invention, the amount of medium-temperature water is reduced by raising the temperature of the medium-temperature water having poor boiling efficiency at the time of re-boiling remaining in the hot water storage tank without directly boiling it with the heat pump heating means. As a result, it is possible to suppress a decrease in the heat storage capacity of the hot water storage tank and reduce the possibility of running out of hot water, and incur deterioration of the heating efficiency of the heat pump heating means due to re-boiling of the medium temperature water. Therefore, it is possible to reduce the amount of power used and improve the efficiency of the device.

The schematic block diagram of one Embodiment of this invention. The flowchart for demonstrating the action | operation of the same embodiment. It is a figure for demonstrating the hot water storage state of the same embodiment, (A) is before the start of boiling operation, (B) is the end of intermediate boiling, (C) is the end of boiling operation, (D) Indicates the hot water storage state before the start of the next day's boiling operation. The schematic block diagram of another embodiment of this invention. It is a figure for demonstrating the hot water storage state of the conventional heat pump type hot-water supply apparatus, (A) is before the start of boiling operation, (B) is the end of boiling operation, (C) is the start of boiling operation of the next day. Shows the previous hot water storage status.

Next, an embodiment of the present invention will be described with reference to the drawings.
1 is a stainless steel hot water storage tank for storing hot water, 2 is a water supply pipe for supplying city water to the bottom of the hot water storage tank 1, 3 is a hot water discharge pipe for discharging hot water from the top of the hot water storage tank 1, 4 is a water supply bypass branched from the water supply pipe 2 A hot water mixing valve that mixes hot water from the hot water discharge pipe 3 and water from the hot water supply bypass pipe 4 so as to reach a hot water supply set temperature, 6 is a hot water supply pipe through which hot water mixed by the hot water mixing valve 5 flows, 7 is a hot-water tap for supplying hot water from the hot-water supply pipe 6, 8 is a hot-water supply temperature sensor for detecting the hot-water supply temperature provided in the middle of the hot-water supply pipe 6, and 9 is a hot-water supply flow rate sensor for detecting the amount of hot water provided in the middle of the hot-water supply pipe 6. A pressure reducing valve 10 is provided in the water supply pipe 2 to reduce the supply pressure of city water to a constant pressure, and 11 is an overpressure relief valve for releasing the overpressure in the hot water storage tank 1.

  Reference numeral 12 denotes a bathtub, 13 is an internal heat exchanger provided in the upper part of the hot water storage tank 1 for heating the bathtub water as an external fluid by the heat of the hot water in the hot water storage tank 1, and 14 is the bathtub 12 and the internal heat exchanger 13. Is connected to the flow circulation circuit 14, and 15 is a flow circulation pump for circulating the bath water provided in the flow circulation circuit 14, and 16 is a hot water branched from the hot water supply pipe 6 and connected to the flow circulation circuit 14. A tension pipe 17 is provided in the middle of the hot water filling pipe 16 and opens and closes the hot water filling pipe 16, and 18 is provided in the middle of the flow circulation circuit 14, and the temperature of the bathtub water flowing from the bathtub 12 to the internal heat exchanger 13 is determined. It is a flow temperature sensor to detect. Here, the internal heat exchanger 13 has a configuration in which a stainless steel tube is spirally wound.

  Reference numeral 19 denotes an intermediate hot water pipe for discharging the hot water from the intermediate portion of the hot water storage tank 1 below the internal heat exchanger 13 to join the hot water discharge pipe 3, and 20 is provided at the junction of the intermediate hot water discharge pipe 19 and the hot water discharge pipe 3. This is an intermediate switching valve for mixing either one or both of hot water from the upper part of the tank 1 and hot water from the intermediate part of the hot water storage tank 1 and flowing it into the hot water side of the hot water supply mixing valve 5.

  21 is a heat pump type heating means as a heating means, a compressor 22 for compressing the refrigerant, a refrigerant water heat exchanger 23 for exchanging heat between the refrigerant and water, a decompressor 24 for reducing the pressure of the refrigerant, and a liquid refrigerant The evaporator 25 evaporates the refrigerant, and the refrigerant absorbed by the evaporator 25 is compressed by the compressor 22 to heat the water via the refrigerant water heat exchanger 23. A carbon dioxide refrigerant is used as the refrigerant in the heat pump type heating means 21, and the water can be heated to a high temperature of 90 ° C. when the high pressure side becomes a supercritical state.

  A heating circulation circuit 26 connects the lower part of the hot water storage tank 1, the water side of the refrigerant water heat exchanger 23, and the upper part of the hot water storage tank 1 so that hot water can circulate, and 27 a heating circulation pump provided in the middle of the heating circulation circuit 26. , 28 is an intermediate return pipe that branches off in the middle of the boiling pipe 29 downstream of the refrigerant water heat exchanger 23 of the heating circuit 26 and connects the intermediate portion of the hot water storage tank 1, and 30 is the refrigerant water heat exchanger 23. It is a switching means comprising a three-way valve that switches whether heated hot water is returned to the upper part of the hot water storage tank 1 via the boiling pipe 29 or returned to the intermediate part of the hot water storage tank 1 via the intermediate return pipe 28. Here, the intermediate return pipe 28 is connected to the side surface of the hot water storage tank 1 below the upper end of the indirect heat exchanger 13 of the hot water storage tank 1, and is preferably connected to the vicinity of the lower end of the indirect heat exchanger 13.

  31 is a water temperature sensor that detects the temperature of water flowing into the refrigerant water heat exchanger 23, 32 is a boiling temperature sensor that detects the temperature of hot water heated by the refrigerant water heat exchanger 23, and 33 is a hot water storage tank 1. A plurality of hot water storage temperature sensors provided in the vertical direction of the side surface are used to detect the temperature of hot water in the hot water storage tank 1, and are referred to as 33a, 33b, 33c, 33d, 33e, and 33f from the top. Of these hot water storage temperature sensors 33a to 33f, 33b is provided at a position near the middle portion of the internal heat exchanger 13 and above the intermediate return pipe 28 to detect the hot water storage temperature, and 33c is the internal heat exchanger 13's. It is provided at a position for detecting the hot water storage temperature below the lower end and below the intermediate return pipe 28.

  Reference numeral 34 denotes a remote controller for setting and operating a display unit 35 for displaying various information related to the hot water supply device (hot water supply set temperature, flow set temperature, remaining hot water amount, operating state of the hot water supply device, etc.), and hot water set temperature and flow set temperature. Temperature setting switch 36, a hot water switch 37 for instructing the bathtub 12 to fill a certain amount of water, and a reheating switch 38 for instructing reheating of the bath water.

  Reference numeral 39 is a hot water supply temperature sensor 8, a hot water supply flow rate sensor 9, a flow temperature sensor 18, an incoming water temperature sensor 31, a boiling temperature sensor 32, and hot water storage temperature sensors 33 a-f. 17 is a control means that controls the operation of the compressor 22, the decompressor 24, the heating circulation pump 27, and the switching means 30 and is communicably connected to the remote controller 34. The control means 39 stores a program for controlling the operation of the hot water supply device in advance, and has a calculation, comparison, storage function, and clock function.

  Next, the hot water supply operation will be described. When the hot water tap 7 is opened, city water flows into the bottom of the hot water storage tank 1 from the water supply pipe 2 and from the top of the hot water storage tank 1 through the hot water discharge pipe 3 or the intermediate hot water discharge pipe 19. The hot water is discharged, and the control means 39 adjusts the opening of the hot water mixing valve 5 so that the hot water temperature detected by the hot water temperature sensor 8 becomes the hot water set temperature set by the temperature setting switch 36 of the remote controller 34. Hot water at a preset hot water supply temperature is supplied from the plug 7 and the hot water supply tap 7 is closed, thereby completing the hot water supply operation.

  At this time, if the hot water temperature in the intermediate portion of the hot water storage tank 1 is higher than the hot water supply set temperature, the intermediate switching valve 20 is switched to open the intermediate hot water discharge pipe 19 side and close the hot water discharge pipe 3 side. The hot water in the section is discharged in preference to the hot water in the upper part of the hot water storage tank 1. Further, when the hot water temperature in the intermediate portion of the hot water storage tank 1 is lower than the hot water supply set temperature, the intermediate switching valve 20 is switched to open the hot water discharge pipe 3 side and close the intermediate hot water discharge pipe 19 side. Is surely done.

  During this hot water supply, the water flowing into the bottom of the hot water storage tank 1 is sufficiently decelerated in the hot water storage tank 1 having a sufficiently large cross-sectional area compared to the cross-sectional area of the water supply pipe 2, and hardly disturbs the hot water layer. A layer of water is formed from below. A temperature boundary layer L is formed in which the hot water at the upper part of the hot water storage tank 1 and the low temperature water at the lower part of the hot water storage tank 1 are in contact. As the amount of hot water supply increases, the hot water layer at the upper part of the hot water tank 1 decreases, the water layer at the lower part of the hot water tank 1 increases, and the temperature boundary layer L rises. The temperature boundary layer L does not mix due to the difference in specific gravity based on the respective temperatures if there is a predetermined temperature difference. The thickness of the temperature boundary layer L increases due to heat conduction over time, and the temperature gradient gradually increases. Will become loose.

  Next, the hot water filling operation will be described. When the hot water filling switch 37 of the remote control 34 is operated, the control means 39 opens the hot water filling on / off valve 17 and the hot water supply temperature detected by the hot water supply temperature sensor 8 is the temperature setting of the remote control 34. When the opening of the hot water supply mixing valve 5 is adjusted so that the flow setting temperature set by the switch 36 is reached, hot water of an appropriate temperature is filled, and when the hot water supply flow rate sensor 9 adds up the desired hot water filling flow rate, the hot water opening / closing valve 17 is filled. To close the hot water filling operation.

  And the heat retention operation | movement which keeps the temperature of bathtub water at a flow setting temperature for the predetermined fixed time after completion | finish of hot-water filling operation | movement is performed. The heat retaining operation will be described. The control means 39 drives the flow circulation pump 15 at predetermined intervals, circulates the bath water through the flow circulation circuit 14, and detects the temperature of the bath water with the flow temperature sensor 18. When the temperature of the bath water is lower than the flow setting temperature, the flow circulation pump is continuously driven to absorb the heat of the hot water in the hot water storage tank 1 from the internal heat exchanger 13 to heat the bath water. When the temperature detected by the flow temperature sensor 18 detects the flow set temperature, the operation of the flow circulation pump 15 is terminated, and the same operation is repeated when the interval time elapses again. Then, when the predetermined time is finished, the heat retaining operation is finished.

  Further, a description will be given of a chasing operation when the chasing switch 38 of the remote controller 34 is operated. The control means 39 is configured so that the temperature of the bath water is chased to the set flow temperature + a constant temperature (for example, 2 ° C.). The circulation pump 15 is driven, the bathtub water is circulated to the internal heat exchanger 13, and the bathtub water is heated by absorbing the heat of the hot water in the hot water storage tank 1 from the internal heat exchanger 13. When the temperature detected by the flow temperature sensor 18 detects the flow set temperature + the constant temperature, the flow circulation pump 15 is driven to end the chasing operation.

  Next, the boiling operation will be described with reference to FIGS. 1 to 3. When the unit price of the electric power is in a midnight time zone, which is a cheap predetermined time zone (step S <b> 1), the control means 39 performs (A) in FIG. 3. When the hot water storage temperature sensor 33b above the connection position of the intermediate return pipe 28 detects a predetermined temperature range (for example, 35 to 60 ° C.), the connection position of the intermediate return pipe 28 of the hot water storage tank 1 is as follows. In step S2, it is determined that medium-temperature water is present on the top, and the switching means 30 is switched to the intermediate return pipe 28 side (step S3), and the compressor 22 and the decompressor 24 are driven to control the heat pump heating means. 21 and the heating circulation pump 27 are driven, and the boiling operation is started so that the temperature detected by the boiling temperature sensor 32 becomes the boiling target temperature (step S4).

  As described above, the hot water returned from the intermediate portion of the hot water storage tank 1 into the hot water storage tank 1 is the intermediate hot water remaining in the hot water storage tank 1 as the remaining hot water and located at a position higher than the intermediate return pipe 28. Raise the temperature. At this time, since the low-temperature water at the lower part of the hot water storage tank 1 is supplied to the heat pump heating means 21, the heating efficiency of the heat pump heating means 21 can be kept good.

  Then, after starting the boiling operation, the hot water in the upper part of the intermediate return pipe 28 is heated as shown in FIG. 3B, and the hot water storage temperature sensor 33b above the connection position of the intermediate return pipe 28 is set to a predetermined value. Is detected in step S5, the switching means 30 is switched to the upper side of the hot water storage tank 1 (step S6), and the heat pump type heating means 21 raises the boiling target. The boiling operation is continued by returning the hot water heated to the temperature from the upper part of the hot water storage tank 1 into the hot water storage tank 1.

  Next, as shown in FIG. 3C, the hot water storage temperature sensor 33f at the bottom of the hot water storage tank 1 detects an upper limit temperature (for example, 50 ° C.) that can be heated by the heat pump heating means 21, or the midnight time zone. When the end time is reached, it is determined that boiling of the hot water in the hot water storage tank 1 has been completed (Yes in step S7), the compressor 22 and the decompressor 24 are stopped and the heat pump heating means 21 is stopped. The heating circulation pump 27 is also stopped and the boiling operation is finished (step S8).

  In this way, the medium-temperature water having low boiling efficiency at the time of re-boiling remaining in the hot water storage tank 1 is heated without being directly boiled by the heat pump heating means 21, so that the medium-temperature water at the end of the boiling operation is heated. The amount can be reduced, and at the start time of the next midnight time zone, the amount of intermediate temperature water can be reduced as shown in FIG. Without remaining, it is possible to prevent the amount of medium-temperature water from increasing every day.

  On the other hand, in step S2, when the hot water storage temperature sensor 33b above the connection position of the intermediate return pipe 28 detects a temperature higher or lower than a predetermined temperature range (here, for example, 35 to 60 ° C.), No in step S2, the switching means 30 is switched to the upper side of the hot water storage tank 1 (step S9), the compressor 22 and the decompressor 24 are driven and controlled, and the heat pump heating means 21 and the heating circulation pump 27 are driven. The boiling operation is started so that the temperature detected by the boiling temperature sensor 32 becomes the boiling target temperature (step S10).

  As described above, when the intermediate temperature water does not remain above the intermediate return pipe 28 in the hot water storage tank 1, the low temperature water taken out from the lower portion of the hot water storage tank 1 is boiled by the heat pump heating means 21, and the hot water storage tank 1. When the normal boiling operation for returning to the hot water storage tank 1 from above is performed and the boiling is completed (Yes in step S7), the compressor 22 and the decompressor 24 are stopped and the heat pump heating means 21 is stopped. At the same time, the heating circulation pump 27 is stopped and the boiling operation is finished (step S8).

  Thus, the amount of medium-temperature water can be reduced by raising the temperature of the medium-temperature water having low boiling efficiency at the time of re-boiling remaining in the hot water storage tank 1 without directly boiling it with the heat pump heating means 21. While it is possible to suppress a decrease in the heat storage capacity of the hot water storage tank 1 and to reduce the possibility of running out of hot water, the heating efficiency in the heat pump heating means 21 due to re-boiling of the medium-temperature water is not incurred, It is possible to reduce the amount of power used and improve the efficiency of the device.

  The present invention is not limited to the above-described embodiment. For example, as shown in FIG. 5, an external heat exchanger 40 for heating an external fluid is used instead of the internal heat exchanger. An external circulation circuit 41 that is provided outside and circulates hot water taken out from the upper part of the hot water storage tank 1 to the external heat exchanger 40 to heat the external fluid and returns the hot water whose temperature has decreased to the lower part or intermediate part of the hot water storage tank 1 is provided. The configuration may be different.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Water supply pipe 3 Hot water discharge pipe 13 Internal heat exchanger 21 Heat pump type heating means 28 Intermediate return pipe 29 Heating pipe 30 Switching means 33 Hot water storage temperature sensor 39 Control means 40 External heat exchanger 41 External circulation circuit

Claims (5)

  A hot water storage tank for storing hot water, a water supply pipe for supplying water to the lower part of the hot water storage tank, a hot water discharge pipe for discharging hot water from the upper part of the hot water storage tank, a water intake pipe connected to the lower part of the hot water storage tank, and the water intake pipe Heat pump type heating means for heating and boiling the extracted hot water, a boiling pipe for returning the hot water heated by the heat pump type heating means to the upper part of the hot water storage tank, and an intermediate portion of the hot water storage tank branched from the heating pipe The hot water heated by the heat pump type heating means is provided at the upper part of the hot water storage tank via the hot water pipe. Switching means for switching between returning to the intermediate portion of the hot water storage tank via the intermediate return pipe and the switching means to the intermediate return pipe side when starting the boiling operation The hot water boiled by the heat pump heating means is returned from the intermediate return pipe to the intermediate portion of the hot water storage tank, and the temperature of the hot water above the intermediate return pipe in the hot water storage tank is raised. And a control means for switching the means to the upper side of the hot water storage tank of the heating pipe and returning the hot water heated by the heat pump heating means to the upper part of the hot water storage tank. Water heater   The control means switches the switching means to the intermediate return pipe side when medium temperature water in a predetermined temperature range is present above the intermediate return pipe in the hot water storage tank at the start of the boiling operation. The hot water boiled by the heat pump heating means is returned from the intermediate return pipe to the intermediate portion of the hot water storage tank, and the hot water above the intermediate return pipe in the hot water storage tank is raised to a temperature higher than the predetermined temperature range. On the other hand, when there is no medium temperature water in a predetermined temperature range above the intermediate return pipe in the hot water storage tank at the start of the boiling operation, the switching means is placed above the hot water storage tank in the boiling pipe. 2. The heat pump type hot water supply apparatus according to claim 1, wherein the hot water boiled by the heat pump type heating means is returned to the upper part of the hot water storage tank.   The heat pump type hot water supply apparatus according to claim 1 or 2, further comprising an internal heat exchanger for exchanging heat with an external fluid above the intermediate return pipe in the hot water storage tank.   An external heat exchanger for exchanging heat between hot water in the hot water storage tank and an external fluid, and hot water taken out from the upper part of the hot water storage tank are circulated to the external heat exchanger and returned to the lower part or intermediate part of the hot water storage tank. The heat pump type hot water supply apparatus according to claim 1 or 2, further comprising an external circulation circuit.   The heat pump type hot water supply device according to any one of claims 1 to 4, wherein the heat pump type heating means uses a carbon dioxide refrigerant as a refrigerant and is a supercritical heat pump cycle that becomes supercritical on a high pressure side. .

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