JP2016031199A - Hot water supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water supply system including a heat pump and capable of stably supplying hot water while keeping a high COP state even when an outside air temperature changes.SOLUTION: A hot water supply system includes a water supply pipe 5 connected to a lower portion of a sealed hot water storage tank 1 and connected to a heat pump 3, a heating pipe 13 for heating water of low temperature taken out from the lower portion of the sealed hot water storage tank and returning the same to an upper portion, a high-temperature water pipe 15 connected to the upper portion of the sealed hot water storage tank at one end, and connected to a three-way valve 30 at the other end, an intermediate-temperature water pipe 9 connected to a vertical intermediate portion of the sealed hot water storage tank at one end, and connected to the three-way valve at the other end, a hot water supply pipe 17 connected to the three-way valve at one end, and connected to a hot water supply destination at the other end, and a water supply branch pipe 11 branched from the water supply pipe at one end, and connected to the intermediate temperature water pipe at the other end. The hot water supply pipe includes a control device 40 provided with a hot water supply temperature sensor T4, and adjusting a flow rate of high temperature water flowing in the high-temperature water pipe and a flow rate of water of the intermediate-temperature water pipe by controlling an opening of the three-way valve according to a detection value of the hot water supply temperature sensor so that a temperature of supply hot water is kept at a set temperature.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hot water supply system including a sealed hot water storage tank.

  As a conventional hot water supply system, there has been proposed a hot water supply system in which water is heated by a heat pump, and the heated hot water is stored in a sealed hot water storage tank and used for hot water supply (see Patent Document 1). In this hot water supply system, when the temperature of the hot water stored in the upper layer of the hot water tank exceeds the set temperature of the hot water supply destination, the hot water and the water of the water supply source are set to the set temperature via the three-way valve. Mix and supply to hot water supply. In addition, if the temperature of the medium-temperature water stored in the intermediate layer in the vertical direction of the hot water tank is lower than the set temperature, the medium-temperature water is heated with a heat exchanger and returned to the hot-water tank to increase the temperature of the medium-temperature water. Used for hot water supply.

  On the other hand, the present applicants have proposed a hot water supply system in which high temperature water heated by a heat pump using CO2 as a refrigerant is stored in a sealed hot water storage tank and used for hot water supply. A heat pump using CO2 as a refrigerant can store high-temperature water of about 90 ° C. in a sealed hot water tank in an operation of heating with a large temperature difference from the feed water temperature, and has high efficiency (COP).

JP 2007-292456 A

  In the hot water supply system described in Patent Document 1, a three-way valve provided on the upstream side of a hot water supply pipe extending to a hot water supply destination by joining a pipe through which high temperature water flows and a pipe through which intermediate temperature water flows is a hot water supply pipe. It is a direction switching valve for switching to the side or the heat exchanger side. For this reason, the hot water supply system described in Patent Document 1 supplies hot water in a hot water storage layer or heated intermediate hot water to a hot water supply destination. For this reason, in the hot water supply system described in Patent Document 1, it is not possible to mix the hot water and medium hot water taken out from the hot water storage layer so as to reach the set temperature and supply the hot water to the hot water supply destination.

  On the other hand, in a hot water supply system including a heat pump using CO2 as a refrigerant, when the outside air temperature changes in winter, summer, etc., the temperature of the hot water may decrease due to heat radiation from the hot water stored in the hot water tank. In particular, in winter, the temperature drop of hot water becomes larger. Therefore, it becomes necessary to reheat the hot water stored in the hot water tank with the heat pump, and the efficiency of the heat pump is reduced.

  In view of the circumstances described above, at least one embodiment of the present invention provides a hot water supply system that can stably supply hot water while maintaining a high COP even when the temperature of the outside air changes in a hot water supply system including a heat pump. The purpose is to do.

A hot water supply system according to at least one embodiment of the present invention includes:
A hot water supply system that heats water with a heat pump, stores the heated hot water in a sealed hot water storage tank and uses it for hot water supply,
A water supply pipe capable of supplying water from a water supply source to the lower part of the sealed hot water storage tank using a water supply pressure and connected to the heat pump;
A heating pipe that heats the low-temperature water taken out from the lower part of the sealed hot water tank by the heat pump and returns it to the upper part of the sealed hot water tank;
One end is connected to the upper part of the sealed hot water storage tank, and the other end is connected to a three-way valve whose opening is adjustable,
Medium hot water piping with one end connected to the middle in the vertical direction of the sealed hot water storage tank and the other end connected to the three-way valve;
A hot water supply pipe having one end connected to the three-way valve and the other end connected to the hot water supply destination;
A water supply branch pipe having one end branched from the water supply pipe and the other end connected to the medium temperature water pipe;
The hot water pipe is provided with a hot water temperature sensor for detecting the temperature of hot water flowing through the hot water pipe,
The hot water flowing through the hot water pipe by controlling the opening of the three-way valve according to the detection value detected by the hot water temperature sensor so that the temperature of the hot water supplied to the hot water supply destination becomes a set temperature. And a control device for adjusting the flow rate of water flowing through the intermediate temperature water pipe.

  According to the hot water supply system, the control device controls the opening of the three-way valve according to the detection value detected by the hot water temperature sensor so that the temperature of the hot water supplied to the hot water supply destination becomes the set temperature. Adjust the flow rate of high-temperature water flowing through the high-temperature water piping and the flow rate of water flowing through the medium-temperature water piping. For this reason, when supplying hot water to the hot water supply destination, the mixed hot water is supplied by adjusting the flow rates of the high-temperature water and medium-temperature water stored in the sealed hot water storage tank, and then stored in the sealed hot water storage tank with a heat pump. The frequency of reheating hot water to supply hot water can be suppressed, and high-temperature water can be effectively used. Therefore, it is possible to realize a hot water supply system that can stably supply hot water while maintaining the COP at a high level even when the temperature of the outside air changes (decreases).

In some embodiments,
The intermediate temperature water pipe is provided with a first on-off valve that blocks or allows the flow of the intermediate temperature water flowing through the intermediate temperature water pipe.
The water supply branch pipe is provided with a second on-off valve that blocks and allows the flow of water flowing through the water supply branch pipe,
Provided,
An intermediate warm water temperature sensor for detecting the temperature of the intermediate warm water stored in the middle temperature layer in the vertical middle part of the sealed hot water storage tank is provided,
The control device opens the first on-off valve and closes the second on-off valve when the detected value of the intermediate temperature water temperature sensor is lower than a set temperature, and the high temperature water flowing through the high temperature water pipe The medium temperature water flowing through the medium temperature water pipe is supplied to the three-way valve.

  In this case, when the detected value of the medium hot water temperature sensor is smaller than the predetermined temperature, the control device opens the first on-off valve and closes the second on-off valve, and hot water and medium hot water flowing through the high-temperature water pipe. The opening degree of the three-way valve is controlled so that the mixed water of the medium temperature water flowing through the pipe reaches the set temperature. For this reason, the flow rate of the high-temperature water flowing through the high-temperature water pipe and the flow rate of the medium-temperature water flowing through the medium-temperature water pipe are controlled by the three-way valve, and the mixed water at the set temperature can be supplied to the hot water supply destination. For this reason, even if the temperature of the outside air decreases and the temperature of the medium temperature water becomes lower than the predetermined temperature, the high temperature water is effectively used, so that the set temperature can be mixed without reheating the hot water by the heat pump. You can get water. Therefore, even if the temperature of the outside air changes, stable hot water supply can be performed while maintaining the COP of the heat pump at a high level.

In some embodiments,
The control device closes the first on-off valve and opens the second on-off valve when the detected value of the intermediate temperature water temperature sensor exceeds a set temperature, and opens the high-temperature water flowing through the high-temperature water pipe. And water flowing through the water supply branch pipe is supplied to the three-way valve.

  In this case, when the detected value of the intermediate temperature water temperature sensor exceeds a predetermined temperature, the control device closes the first on-off valve and opens the second on-off valve, and supplies high-temperature water and water supply flowing through the high-temperature water pipe. The opening degree of the three-way valve is controlled so that the mixed water of water flowing through the branch pipe reaches the set temperature. Therefore, the flow rates of the high-temperature water flowing through the high-temperature water pipe and the water flowing through the water supply branch pipe are controlled by the three-way valve, and the mixed water at the set temperature can be supplied to the hot water supply destination. For this reason, reheating of warm water by a heat pump can be controlled effectively using high temperature water. Therefore, stable hot water supply can be performed while maintaining the COP of the heat pump at a high level.

In some embodiments,
A high-temperature water temperature sensor for detecting the temperature of the high-temperature water in the high-temperature layer stored in the upper part of the sealed hot water tank,
When the detected value of the high temperature water temperature sensor detects a temperature lower than a set temperature, the control device activates the heat pump to heat the low temperature water flowing out from the lower part of the sealed hot water storage tank with the heat pump. It is comprised so that it may return to the upper part of the said closed type hot water storage tank.

  In this case, when the detected value of the high temperature layer temperature sensor detects a temperature lower than the set temperature, the control device operates the heat pump. For this reason, the supply water pressure from the water supply source is transmitted to the sealed hot water storage tank through the high temperature water pipe, and the low temperature water taken out from below in the sealed hot water storage tank is heated via the heat pump to be sealed the hot water storage tank. Return to the top of the. Therefore, the high temperature water stored in the upper part of the sealed hot water storage tank can be stored at a temperature higher than the set temperature.

In some embodiments,
At the portion where the intermediate hot water pipe and the feed water branch pipe intersect, the intermediate hot water pipe is opened and the hot water branch pipe is shut off and the hot water flowing through the intermediate hot water pipe is supplied to the three-way valve, or A direction switching valve is provided that shuts off the medium-temperature water pipe and opens the water supply branch pipe to supply water flowing through the water supply branch pipe to the three-way valve,
An intermediate warm water temperature sensor for detecting the temperature of the intermediate warm water stored in the middle temperature layer in the vertical middle part of the sealed hot water storage tank is provided,
When the detected value of the intermediate temperature water temperature sensor is smaller than a set temperature, the control device switches the direction switching valve so that intermediate temperature water flows through the intermediate temperature water pipe and is supplied to the three-way valve. Configured as follows.

  In this case, when the detected value of the medium temperature water temperature sensor is smaller than the set temperature, the control device switches and controls the direction switching valve so that the medium temperature water flows through the medium temperature water pipe and is supplied to the three-way valve. For this reason, the medium temperature water flowing through the medium temperature water pipe is supplied to the three-way valve, and the flow rate of the high temperature water flowing through the high temperature water pipe and the flow rate of the medium temperature water flowing through the medium temperature water pipe are controlled by the three-way valve. Can be supplied to the hot water supply destination. For this reason, even if the temperature of the outside air decreases and the temperature of the medium temperature water becomes lower than the predetermined temperature, the high temperature water is effectively used, so that the set temperature can be mixed without reheating the hot water by the heat pump. You can get water. Therefore, even if the temperature of the outside air changes, stable hot water supply can be performed while maintaining the COP of the heat pump at a high level.

In some embodiments,
The control device switches the direction so that water from a water supply source flows through the water supply branch pipe and is supplied to the three-way valve when the detected value of the intermediate temperature water temperature sensor exceeds the set temperature. The valve is configured to switch and control.

  In this case, when the detected value of the medium hot water temperature sensor exceeds the set temperature, the control device supplies the hot water flowing from the water supply source to the three-way valve through the water supply branch pipe and flowing through the hot water pipe. The flow rate of water and the flow rate of water flowing through the water supply branch pipe are controlled by the three-way valve, so that the mixed water at the set temperature can be supplied to the hot water supply destination. For this reason, reheating of warm water by a heat pump can be controlled effectively using high temperature water. Therefore, stable hot water supply can be performed while maintaining the COP of the heat pump at a high level.

In some embodiments,
A high-temperature water temperature sensor for detecting the temperature of the high-temperature water in the high-temperature layer stored in the upper part of the sealed hot water tank,
When the detected value of the high-temperature water temperature sensor detects a temperature lower than a set temperature, the control device switches and controls the direction switching valve so that medium-temperature water and water from a water supply source are not supplied to the three-way valve. The low temperature water flowing out from the lower part of the sealed hot water tank is heated by the heat pump and returned to the upper part of the sealed hot water tank by operating the heat pump.

  In this case, when the control device detects a temperature at which the detection value of the high-temperature water temperature sensor is lower than the set temperature, the control device switches the direction switching valve so that the water from the medium temperature water and the water supply source is not supplied to the three-way valve, Activate the heat pump. For this reason, the low temperature water which flows out from the lower part of a sealed hot water storage tank is heated with a heat pump, and is returned to the upper part of a sealed hot water tank. For this reason, the high temperature water stored in the upper part of a sealed hot water storage tank can be stored at a temperature higher than the set temperature.

  According to at least some embodiments of the present invention, a hot water supply system including a heat pump can provide a hot water supply system that can stably supply hot water while maintaining a high COP even when the temperature of the outside air changes. .

1 is a schematic configuration diagram of a hot water supply system according to a first embodiment of the present invention. It is a schematic block diagram at the time of the chasing mode by the high temperature water and water of the hot water supply system which concerns on 1st Embodiment of this invention. It is a schematic block diagram at the time of the chasing mode by the high temperature water / medium temperature water of the hot water supply system which concerns on 1st Embodiment of this invention. It is a schematic block diagram of the hot water supply system at the time of the thermal storage mode of the hot water supply system which concerns on 1st Embodiment of this invention. It is a flowchart in the chase mode of the hot water supply system which concerns on 1st Embodiment of this invention. It is a flowchart in the heat storage mode of the hot water supply system which concerns on 1st Embodiment of this invention. It is a schematic block diagram at the time of the chasing mode by the high temperature water and water of the hot water supply system which concerns on 2nd Embodiment of this invention. It is a schematic block diagram at the time of the chasing mode by the high temperature water / medium temperature water of the hot water supply system which concerns on 2nd Embodiment of this invention. It is a schematic block diagram at the time of the thermal storage mode of the hot water supply system which concerns on 2nd Embodiment of this invention. It is a flowchart in the chase mode of the hot water supply system which concerns on 2nd Embodiment of this invention. It is a flowchart in the heat storage mode of the hot water supply system according to the second embodiment of the present invention.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

[First embodiment]
FIG. 1 is a schematic configuration diagram of a hot water supply system according to a first embodiment of the present invention. As shown in FIG. 1, the hot water supply system stores hot water heated by a heat pump in a sealed hot water storage tank 1 (hereinafter simply referred to as “hot water storage tank 1”), and supplies a necessary amount when hot water is used. It has a hot water supply function.

  The hot water supply system includes one hot water tank 1 and a heat pump 3 that heats low-temperature water taken out from the lower part of the hot water tank 1 and returns it to the upper part of the hot water tank 1. The heat pump 3 is a heat exchanger that can heat low-temperature water using CO2 as a refrigerant, and has, for example, a heating capability capable of heating water supplied from a water supply source to 90 ° C. The hot water supply system includes a water supply pipe 5 that can supply water supplied from a water supply source to the heat pump 3. A low temperature water pipe 7 branched from the water supply pipe 5 and connected to the bottom of the hot water tank 1 is provided on the downstream side of the water supply pipe 5. Further, on the upstream side of the water supply pipe 5, there is provided a water supply branch pipe 11 that is connected to a medium-temperature water pipe 9 that branches from the water-supply pipe 5 and flows middle-temperature water that is taken out from an intermediate portion in the vertical direction of the hot water tank 1. .

  The hot water heated by the heat pump 3 flows out through a heating pipe 13 having one end connected to the heat pump 3 and the other end connected to the upper part of the hot water tank 1. For this reason, the hot water heated by the heat pump flows through the heating pipe 13 and flows into the upper part of the hot water tank 1. In the middle of the heating pipe 13, a high-temperature water pipe 15 branched from the discharge pipe and connected to the three-way valve 30 is provided. The three-way valve 30 is connected to a medium-temperature water pipe 9 that can take out the medium-temperature water stored in the intermediate portion in the vertical direction of the hot water tank 1. A hot water supply pipe 17 extending to the hot water supply destination is connected to the three-way valve 30.

  That is, the high-temperature water pipe 15, the medium-temperature water pipe 9, and the hot water supply pipe 17 are connected to the three-way valve 30. The three-way valve 30 is configured to adjust the flow rate of the high-temperature water flowing through the high-temperature water pipe 15 and the flow rate of the intermediate-temperature water flowing through the intermediate-temperature water pipe 9 so that the mixed water having a desired temperature can flow through the hot water supply pipe 17. ing. The three-way valve 30 is provided with a flow rate adjusting mechanism (not shown) capable of adjusting the flow rates of the high-temperature water and the medium-temperature water, and the flow rate adjusting mechanism is configured to operate by the motor M to adjust the flow rate. Has been. Control of the motor M is performed by the control device 40.

  A first on-off valve 31 is provided on the hot water tank 1 side of the intermediate temperature water pipe 9 to block or allow the distribution of the intermediate temperature water flowing through the intermediate temperature water pipe 9. Further, the water supply branch pipe 11 is provided with a second on-off valve 32 that blocks and allows the flow of water flowing through the water supply branch pipe 11. The first on-off valve 31 and the second on-off valve 32 are electromagnetic or electric on-off valves, and their operations are controlled by the control device 40.

  The hot water supply pipe 17 is provided with a temperature sensor T4 that detects the temperature of the water flowing in the hot water supply pipe 17. In addition, temperature sensors T1, T2, and T3 capable of detecting the temperatures of the hot water stored in the upper, middle, and bottom portions of the hot water tank 1 are provided at the upper, middle, and bottom portions of the hot water tank 1, respectively. It has been. The position where the temperature sensor T2 is provided is disposed at substantially the same position as the vertical position of the intermediate hot water pipe 9. These temperature sensors T <b> 1 to T <b> 4 are electrically connected to the control device 40.

  The control device 40 controls the operation of the three-way valve 30, the first on-off valve 31, and the second on-off valve 32, and the high-temperature water flowing through the high-temperature water pipe 15 and the intermediate-temperature water flowing through the intermediate-temperature water pipe 9 or the water of the water supply source And a chasing mode in which mixed water at a predetermined temperature can be supplied to a hot water supply destination, and a heat storage mode for storing hot water at a predetermined temperature in the hot water tank 1. Details of the control device 40 will be described later.

  Next, the operation of the hot water supply system will be described with reference to FIGS. First, the chasing mode will be described. As shown in FIG.2 and FIG.5, the control apparatus 40 judges whether the temperature of the middle temperature water in the vertical direction intermediate part of the hot water tank 1 exceeds 60 degreeC based on the detected value of the temperature sensor T2. (Step 100). If the temperature of the medium temperature water exceeds 60 ° C., the process proceeds to step 101, and if not, the process proceeds to step 103.

  In step 101, when it is determined that the temperature of the medium temperature water exceeds 60 ° C., the first on-off valve 31 (V1) is closed and the second on-off valve 32 (V2) is opened. When the first on-off valve 31 is in a closed state and the second on-off valve 32 is in an open state, high-temperature water flows from the upper part of the hot water tank 1 through the high-temperature water pipe 15 to the three-way valve 30 by the water supply pressure of the water supply source. At the same time, water from the water supply source flows through the water supply branch pipe 11 and the intermediate temperature water pipe 9 and flows into the three-way valve 30. The high-temperature water and water are mixed by adjusting the flow rates of the three-way valve 30 when passing through the three-way valve 30. For this reason, the high temperature water and the mixed water of water become predetermined temperature, and are supplied to a hot-water supply destination.

  Here, when the mixed water is supplied to the hot water supply destination, it is determined whether or not the temperature of the medium temperature water is 55 ° C. or less (step 102). If it is determined that the temperature of the medium-temperature water is 55 ° C. or lower, the process proceeds to step 103. If not determined, the determination in step 102 is repeated. In step 103, the first on-off valve 31 (V1) is opened, and the second on-off valve 32 (V2) is closed. When the first on-off valve 31 is in the open state and the second on-off valve 32 is in the closed state, as shown in FIG. 3, when the mixed water is supplied at the hot water supply destination, the hot water storage tank is caused by the supply water pressure of the water supply source. From the upper part of 1, hot water flows through the high-temperature water pipe 15 and flows into the three-way valve 30, and medium-temperature water from the middle in the vertical direction of the hot water tank 1 flows through the medium-temperature water pipe 9 and flows into the three-way valve 30. The flow rates of the high-temperature water and the medium-temperature water are adjusted at the time of passage so as to become mixed water having a predetermined temperature of the three-way valve 30. Accordingly, the mixed water having a predetermined temperature is supplied to the hot water supply destination. Then, at the time of supplying the mixed water to the hot water supply destination, it is determined whether or not the temperature of the medium temperature water is 60 ° C. or higher (step 100), and then the above-described steps 101 to 103 are executed.

  Next, the heat storage mode in the operation of the hot water supply system will be described. As shown in FIGS. 4 and 6, the control device 40 determines whether or not the temperature of the low-temperature water in the lower part of the hot water tank 1 is lower than 60 ° C. based on the detection value of the temperature sensor T3 (step). 110). If the temperature of the low-temperature water exceeds 60 ° C., step 110 is repeated. If it is determined that the temperature of the low-temperature water is lower than 60 ° C., the process proceeds to step 111.

  In step 111, the heat pump 3 is operated by the control device 40. Therefore, as shown in FIG. 4, water flows through the water supply pipe 5 and is supplied to the heat pump 3 by the supply water pressure of the water supply source. The low temperature water supplied to the heat pump 3 is heated by the heat pump 3 to become high temperature water, and the high temperature water flows through the heating pipe 13 and flows into the upper part of the hot water tank 1. When hot water flows into the upper part of the hot water tank 1, low temperature water flows out from the bottom of the hot water tank 1, flows through the low temperature water pipe 7 and the water supply pipe 5, and is supplied to the heat pump 3. The low-temperature water supplied to the heat pump 3 is heated by the heat pump 3, flows through the heating pipe 13, and is returned to the upper part of the hot water tank 1. Then, this series of operations is repeated. And if it is judged that the detected value of temperature sensor T3 exceeded 65 degreeC (step 112), thermal storage mode will be complete | finished. On the other hand, if the detected value of the temperature sensor T3 does not exceed 65 ° C., step 111 is continued.

  As described above, the hot water supply system according to the first embodiment of the present application supplies mixed hot water by adjusting the flow rates of the high-temperature water and the intermediate-temperature water stored in the sealed hot water storage tank 1 with the three-way valve 30. For this reason, while being able to suppress the frequency which reheats the hot water stored in the enclosed hot water storage tank 1 with the heat pump 3 and supplies hot water, high temperature water can be utilized effectively. Therefore, it is possible to realize a hot water supply system that can stably supply hot water while maintaining the COP at a high level even when the temperature of the outside air changes (decreases). Further, since the three-way valve 30 can control the flow rate, the control of the three-way valve 30 is complicated. However, since there is only one three-way valve 30 in the hot water supply system of the present application, the control burden of the three-way valve 30 in the control device 40 Can be suppressed.

[Second Embodiment]
Next, a hot water supply system according to a second embodiment of the present invention will be described with reference to FIGS. In addition, about 2nd Embodiment, only a different point from 1st Embodiment is demonstrated, about the same aspect part as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 7, a direction switching valve 43 is provided at a portion where the intermediate temperature water pipe 9 and the water supply branch pipe 11 intersect. The direction switching valve 43 is electrically driven to open the intermediate warm water pipe 9 side and close the water supply branch pipe 11 side to supply intermediate warm water flowing through the intermediate warm water pipe 9 to the three-way valve 30 or the intermediate warm water pipe 9. The flow path is switched so that the water flowing in the water supply branch pipe 11 is supplied to the three-way valve 30 by closing the side and opening the water supply branch pipe 11 side. Switching control of the direction switching valve 43 is performed by the control device 40. Note that the hot water supply system according to the second embodiment is not provided with the first on-off valve 31 (see FIG. 1) and the second on-off valve 32 (see FIG. 1).

  When the chasing mode is performed in the hot water supply system configured as described above, as shown in FIG. 7 and FIG. 10, the control device 40 is based on the detected value of the temperature sensor T2 in the middle portion in the vertical direction of the hot water tank 1. It is determined whether the temperature of the medium temperature water exceeds 60 ° C. (step 100). If the temperature of the medium temperature water exceeds 60 ° C., the process proceeds to step 101 ′, and if not, the process proceeds to step 103 ′.

  In Step 101 ′, when it is determined that the temperature of the medium temperature water exceeds 60 ° C., the direction switching valve 43 is switched so that the water supply branch pipe 11 side is opened and the medium temperature water pipe 9 side is closed. When the direction switching valve 43 is switched in this way, high-temperature water flows from the upper part of the hot water tank 1 through the high-temperature water pipe 15 and flows into the three-way valve 30 by the supply water pressure of the water supply source, and the water from the water supply source is branched. It flows through the pipe 11 and the intermediate hot water pipe 9 and flows into the three-way valve 30. The high-temperature water and water are mixed by adjusting the flow rates of the three-way valve 30 when passing through the three-way valve 30. For this reason, the high temperature water and the mixed water of water become predetermined temperature, and are supplied to a hot-water supply destination.

  Here, when the mixed water is supplied to the hot water supply destination, it is determined whether or not the temperature of the medium temperature water is 55 ° C. or less (step 102). If it is determined that the temperature of the medium temperature water is 55 ° C. or lower, the process proceeds to step 103 ′, and if it is not determined, the determination in step 102 is repeated. In step 103 ′, the direction switching valve 43 is switched so as to close the water supply branch pipe 11 side and open the intermediate hot water pipe 9 side. When the direction switching valve 43 is switched in this manner, as shown in FIG. 8, when the mixed water is supplied at the hot water supply destination, the hot water is supplied from the upper part of the hot water tank 1 to the hot water pipe 15 by the supply water pressure of the water supply source. While flowing into the three-way valve 30, medium-temperature water from the middle in the vertical direction of the hot water tank 1 flows through the medium-temperature water pipe 9 and flows into the three-way valve 30. The flow rates of the high-temperature water and the medium-temperature water are adjusted at the time of passage so as to become mixed water having a predetermined temperature of the three-way valve 30. Accordingly, the mixed water having a predetermined temperature is supplied to the hot water supply destination. Then, at the time of supplying the mixed water to the hot water supply destination, it is determined whether or not the temperature of the medium temperature water is 60 ° C. or higher (step 100), and then the above-described step 101 ′, step 102, and step 103 ′ are executed. The

  Next, the heat storage mode in the operation of the hot water supply system will be described. As shown in FIGS. 9 and 11, the control device 40 determines whether or not the temperature of the low-temperature water in the lower portion of the hot water tank 1 is lower than 60 ° C. based on the detection value of the temperature sensor T3 (step). 110). If the temperature of the low-temperature water exceeds 60 ° C., step 110 is repeated. If it is determined that the temperature of the low-temperature water is lower than 60 ° C., the routine proceeds to step 111 ′.

  In step 111 ′, the controller 40 closes the water supply branch pipe 11 side of the direction switching valve 43 and opens the intermediate hot water pipe 9 side, and closes the hot water pipe side of the three-way valve 30 and opens the intermediate hot water pipe. While controlling the switching valve 43 and the three-way valve 30, the heat pump 3 is operated. Therefore, as shown in FIG. 9, water flows through the water supply pipe 5 and is supplied to the heat pump 3 by the water supply pressure of the water supply source. The low temperature water supplied to the heat pump 3 is heated by the heat pump 3 to become high temperature water, and the high temperature water flows through the heating pipe 13 and flows into the upper part of the hot water tank 1. When hot water flows into the upper part of the hot water tank 1, low temperature water flows out from the bottom of the hot water tank 1, and the low temperature water flows through the low temperature water pipe 7 and the water supply pipe 5 and is supplied to the heat pump 3. The low-temperature water supplied to the heat pump 3 is heated by the heat pump 3, flows through the heating pipe 13, and is returned to the upper part of the hot water tank 1. Then, this series of operations is repeated. And if it is judged that the detected value of temperature sensor T3 exceeded 65 degreeC (step 112), thermal storage mode will be complete | finished. On the other hand, if the detected value of the temperature sensor T3 does not exceed 65 ° C., step 111 ′ is continued.

  Thus, in the hot water supply system of the second embodiment of the present application, the direction switching valve 43 is used in place of the first on / off valve 31 and the second on / off valve 32 of the hot water supply system of the first embodiment described above. As in the case of the first embodiment, it is possible to obtain the effect of suppressing the frequency of reheating the hot water stored in the sealed hot water tank 1 with the heat pump 3 and supplying hot water, and the effect of effectively using the high-temperature water. Can be obtained. Therefore, it is possible to realize a hot water supply system that can stably supply hot water while maintaining the COP at a high level even when the temperature of the outside air changes (decreases). In the hot water supply system of the second embodiment, since the direction switching valve 43 is used instead of the first on-off valve 31 and the second on-off valve 32, the cost can be reduced.

  In the above-described embodiment, the first open / close valve is provided in the intermediate hot water pipe and the second open / close valve is provided in the feed water branch pipe. Instead of these open / close valves, the intermediate hot water pipe and the feed water branch pipe can be opened and closed. A three-way valve may be provided.

DESCRIPTION OF SYMBOLS 1 Sealed hot water storage tank 3 Heat pump 5 Water supply pipe 7 Low temperature water pipe 9 Medium temperature water pipe 11 Water supply branch pipe 13 Heating pipe 15 High temperature water pipe 17 Hot water supply pipe 30 Three-way valve 31 1st on-off valve 32 2nd on-off valve 40 Controller 43 Direction Switching valve M Motor T1 Temperature sensor (High temperature water temperature sensor)
T2 temperature sensor (medium temperature water temperature sensor)
T3 temperature sensor (low temperature water temperature sensor)
T4 temperature sensor (hot water temperature sensor)
T5 temperature sensor (environmental temperature sensor)

Claims (7)

A hot water supply system that heats water with a heat pump, stores the heated hot water in a sealed hot water storage tank and uses it for hot water supply,
A water supply pipe capable of supplying water from a water supply source to the lower part of the sealed hot water storage tank using a water supply pressure and connected to the heat pump;
A heating pipe that heats the low-temperature water taken out from the lower part of the sealed hot water tank by the heat pump and returns it to the upper part of the sealed hot water tank;
One end is connected to the upper part of the sealed hot water storage tank, and the other end is connected to a three-way valve whose opening is adjustable,
Medium hot water piping with one end connected to the middle in the vertical direction of the sealed hot water storage tank and the other end connected to the three-way valve;
A hot water supply pipe having one end connected to the three-way valve and the other end connected to the hot water supply destination;
A water supply branch pipe having one end branched from the water supply pipe and the other end connected to the medium temperature water pipe;
The hot water pipe is provided with a hot water temperature sensor for detecting the temperature of hot water flowing through the hot water pipe,
The hot water flowing through the hot water pipe by controlling the opening of the three-way valve according to the detection value detected by the hot water temperature sensor so that the temperature of the hot water supplied to the hot water supply destination becomes a set temperature. And a control device for adjusting the flow rate of the water flowing through the intermediate temperature water pipe is provided. The intermediate temperature water pipe is provided with a first on-off valve that blocks or allows the flow of the intermediate temperature water flowing through the intermediate temperature water pipe.
The water supply branch pipe is provided with a second on-off valve that blocks and allows the flow of water flowing through the water supply branch pipe,
An intermediate warm water temperature sensor for detecting the temperature of the intermediate warm water stored in the middle temperature layer in the vertical middle part of the sealed hot water storage tank is provided,
The control device opens the first on-off valve and closes the second on-off valve when the detected value of the intermediate temperature water temperature sensor is lower than a set temperature, and the high temperature water flowing through the high temperature water pipe The hot water supply system according to claim 1, wherein intermediate temperature water flowing through the intermediate temperature water pipe is supplied to the three-way valve. The control device closes the first on-off valve and opens the second on-off valve when the detected value of the intermediate temperature water temperature sensor exceeds a set temperature, and opens the high-temperature water flowing through the high-temperature water pipe. The hot water supply system according to claim 2, wherein water flowing through the water supply branch pipe is supplied to the three-way valve. A high-temperature water temperature sensor for detecting the temperature of the high-temperature water in the high-temperature layer stored in the upper part of the sealed hot water tank,
When the detected value of the high temperature water temperature sensor detects a temperature lower than a set temperature, the control device activates the heat pump to heat the low temperature water flowing out from the lower part of the sealed hot water storage tank with the heat pump. The hot water supply system according to claim 2, wherein the hot water supply system is configured to return to an upper portion of the sealed hot water storage tank. At the portion where the intermediate hot water pipe and the feed water branch pipe intersect, the intermediate hot water pipe is opened and the hot water branch pipe is shut off and the hot water flowing through the intermediate hot water pipe is supplied to the three-way valve, or A direction switching valve is provided that shuts off the medium-temperature water pipe and opens the water supply branch pipe to supply water flowing through the water supply branch pipe to the three-way valve,
An intermediate warm water temperature sensor for detecting the temperature of the intermediate warm water stored in the middle temperature layer in the vertical middle part of the sealed hot water storage tank is provided,
When the detected value of the intermediate temperature water temperature sensor is smaller than a set temperature, the control device switches the direction switching valve so that intermediate temperature water flows through the intermediate temperature water pipe and is supplied to the three-way valve. The hot water supply system according to claim 1. The control device switches the direction so that water from a water supply source flows through the water supply branch pipe and is supplied to the three-way valve when the detected value of the intermediate temperature water temperature sensor exceeds the set temperature. The hot water supply system according to claim 5, wherein the valve is switched and controlled. A high-temperature water temperature sensor for detecting the temperature of the high-temperature water in the high-temperature layer stored in the upper part of the sealed hot water tank,
When the detected value of the high-temperature water temperature sensor detects a temperature lower than a set temperature, the control device switches and controls the direction switching valve so that medium-temperature water and water from a water supply source are not supplied to the three-way valve. 6. The hot water supply system according to claim 5, wherein the heat pump is operated so that the low-temperature water flowing out from the lower part of the sealed hot water storage tank is heated by the heat pump and returned to the upper part of the sealed hot water storage tank.

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