JP7135910B2 - Storage hot water heater - Google Patents

Description

The present invention relates to a hot water storage type hot water supply apparatus.

In the hot water storage type hot water supply apparatus disclosed in Patent Document 1 below, energy efficiency can be improved by performing a bath heat recovery operation in which waste heat of hot water remaining in a bathtub after bathing is recovered in a hot water storage tank.

JP 2018-91504 A

There is a demand for further improvement in energy efficiency in hot water storage type hot water supply apparatuses.

An object of the present invention is to provide a hot water storage type hot water supply apparatus capable of improving energy efficiency.

A hot water storage type hot water supply apparatus according to the present invention is capable of storing heating means for heating water, hot water heated by the heating means, and has an upper portion, a lower portion, and an intermediate portion between the upper portion and the lower portion. a tank, a heat exchanger having a primary side channel and a secondary side channel, and exchanging heat between a primary fluid flowing in the primary side channel and a secondary fluid flowing in the secondary side channel; A piping device having a flow path switching means capable of switching the flow path in which the is circulated, a heating operation in which the primary fluid heats the secondary fluid in the heat exchanger, and a control that can perform the heat recovery operation after the heating operation wherein the flow path switching means supplies hot water taken out from the top of the hot water storage tank as a primary fluid to the primary side flow path, and causes the primary fluid that has passed through the primary side flow path to flow into an intermediate portion of the hot water storage tank. A tank-use heating circuit supplies water taken from the lower part of the hot water storage tank as a primary fluid to the primary side flow path without passing through the heating means, and the primary fluid that has passed through the primary side flow path is supplied to the middle part of the hot water storage tank. The first heat recovery circuit to flow in and the water taken out from the lower part of the hot water storage tank are supplied to the primary side flow passage through the heating means as the primary fluid, and the primary fluid that has passed through the primary side flow passage is supplied to the middle of the hot water storage tank. and the second heat recovery circuit that flows into the second heat recovery circuit, and the control means causes water to flow through the first heat recovery circuit if there is no residual heat remaining in the heating means when the heat recovery operation is started. A heat recovery operation is performed, and if residual heat remains in the heating means when the heat recovery operation is started, the heat recovery operation is performed by causing water to flow through the second heat recovery circuit.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the hot-water-storage-type hot-water supply apparatus which can aim at the improvement of energy efficiency.

1 is a diagram showing a hot water storage type hot water supply apparatus according to Embodiment 1. FIG. 2 is a diagram showing a first heat recovery circuit in the hot water storage type hot water supply apparatus shown in FIG. 1. FIG. 2 is a diagram showing a second heat recovery circuit in the hot water storage type hot water supply apparatus shown in FIG. 1. FIG.

Embodiments will be described below with reference to the drawings. Elements that are common or correspond to each figure are denoted by the same reference numerals, and overlapping descriptions are simplified or omitted.

Embodiment 1.
FIG. 1 shows a hot water storage type hot water supply apparatus 35 according to Embodiment 1. As shown in FIG. As shown in FIG. 1 , the hot water storage type hot water supply device 35 of Embodiment 1 includes a tank unit 33 , an HP (heat pump) unit 7 and a remote controller 44 . The HP unit 7 and the tank unit 33 are connected to each other via the HP outgoing pipe 14, the HP return pipe 15, and electric wiring (not shown). A control device 36 is incorporated in the tank unit 33 . The operations of various valves, pumps, etc. provided in the tank unit 33 and the HP unit 7 are controlled by a control device 36 electrically connected thereto. Controller 36 comprises, for example, a microcomputer having at least one memory and at least one processor. The control device 36 corresponds to control means for controlling the operation of the hot water storage type hot water supply device 35 . The control device 36 has a timer function that manages the date and time.

The remote control device 44 has a function of receiving a user's operation relating to a driving operation command, a change of set values, and the like. Remote control device 44 is an example of a user interface. The control device 36 and the remote control device 44 are connected by wire or wirelessly so as to enable bidirectional data communication. Although not shown, the remote control device 44 includes a display section for displaying information such as the state of the hot water storage type hot water supply apparatus 35, an operating section such as switches operated by the user, a speaker, a microphone, and the like. The display section of the remote control device 44 has a function as notification means for notifying the user of information. The remote control device 44 in the present embodiment has a display unit as notification means, but as a modification, it may be provided with other notification means such as a voice guidance device.

In this embodiment, the remote control device 44 may be installed on the wall of the kitchen, living room, bathroom, or the like. A plurality of remote control devices 44 may be able to communicate with the control device 36 . Also, for example, a mobile terminal such as a smartphone may be configured to be usable as the remote control device 44 . The mobile terminal and the control device 36 may communicate via a network.

The HP unit 7 is an example of heating means for heating water. The HP unit 7 includes a refrigerant circuit in which a compressor 1 , a water-refrigerant heat exchanger 3 , an expansion valve 4 , and an air heat exchanger 6 are annularly connected by refrigerant pipes 5 . The HP unit 7 operates a heat pump cycle using this refrigerant circuit. In the water-refrigerant heat exchanger 3, heat is exchanged between the refrigerant compressed by the compressor 1 and the water guided from the tank unit 33, thereby heating the water.

The HP unit 7 includes a hot water outlet temperature sensor 39 provided in a hot water outlet of the water-refrigerant heat exchanger 3 or a pipe communicating with the hot water outlet, and a water inlet of the water-refrigerant heat exchanger 3 or a pipe communicating with the water inlet. and an incoming water temperature sensor 40 provided. The outlet hot water temperature sensor 39 detects the temperature of hot water flowing out from the water-refrigerant heat exchanger 3 . The incoming water temperature sensor 40 detects the temperature of water flowing into the water-refrigerant heat exchanger 3 .

The tank unit 33 incorporates the following various parts, piping, and the like. The hot water storage tank 8 stores hot water. Inside the hot water storage tank 8, temperature stratification can be formed in which the upper side has a higher temperature and the lower side has a lower temperature due to the difference in water density due to temperature.

As shown in FIG. 1, the hot water storage tank 8 has an upper portion, an intermediate portion, and a lower portion. The intermediate portion of the hot water storage tank 8 is a portion of height between the upper portion of the hot water storage tank 8 and the lower portion of the hot water storage tank 8 . Note that the hot water storage tank 8 is not limited to a single tank as shown in the drawing, and may include a plurality of tanks connected in series. In the present disclosure, regarding the position of the hot water storage tank 8 in the height direction, that is, in the vertical direction, if the hot water storage tank 8 is provided with a plurality of tanks connected in series, the top tank to the bottom The vertical position shall be specified in the entire hierarchy up to the tank.

A water inlet 8a, a water outlet 8b, and a water inlet 8c are provided in the lower portion of the hot water storage tank 8. As shown in FIG. A hot water introduction outlet 8d and a hot water introduction outlet 8e are provided in the upper portion of the hot water storage tank 8 . An intermediate hot water inlet 8g and an intermediate hot water inlet 8f are provided in an intermediate portion of the hot water storage tank 8 . In the present embodiment, the middle-temperature water introduction port 8g is positioned higher than the middle-temperature water introduction outlet 8f.

A third water supply pipe 9c is connected to the water inlet 8a. Water supplied from a water source such as tap through the first water supply pipe 9a is regulated to a predetermined pressure by the pressure reducing valve 31, and flows into the hot water storage tank 8 through the third water supply pipe 9c. A plurality of stored hot water temperature sensors 41, 42, 43 are attached to the surface of the hot water storage tank 8 at different height positions. A hot water temperature sensor 41 detects the water temperature in the middle of the hot water tank 8 . In the illustrated example, the stored hot water temperature sensor 41 detects the water temperature at a position at the same height as the intermediate warm water inlet 8f or at a height close to the intermediate warm water inlet 8f. A hot water temperature sensor 42 detects the water temperature in the upper part of the hot water tank 8 . A hot water temperature sensor 43 detects the water temperature in the lower part of the hot water tank 8 . By detecting the temperature distribution of the hot water in the hot water storage tank 8 with these hot water storage temperature sensors 41 , 42 , 43 , the control device 36 can grasp the remaining hot water amount or heat storage amount in the hot water storage tank 8 . Note that four or more stored hot water temperature sensors may be provided in the hot water storage tank 8 without being limited to the illustrated example.

The tank unit 33 incorporates a bath heat exchanger 60 and a bath circulation pump 29 . The bath heat exchanger 60 has a primary side flow path 60a and a secondary side flow path 60b. The bath heat exchanger 60 corresponds to a heat exchanger that exchanges heat between the primary fluid flowing through the primary side flow path 60a and the secondary fluid flowing through the secondary side flow path 60b. In the present embodiment, an example will be described in which bath water circulating from the bath tub 30 flows through the secondary flow path 60b as a secondary fluid, but the secondary fluid in the present disclosure may be fluid other than bath water. . For example, the secondary fluid may be a heating medium for heating or water supplied from a water source.

The bath going pipe 27 connects between the outlet of the secondary side channel 60 b and the bathtub 30 . A bath-going temperature sensor 37 for detecting the temperature of the bath water flowing out from the bath heat exchanger 60 is installed in the middle of the bath-going pipe 27 . The bath return pipe 28 connects between the entrance of the secondary side flow path 60b and the bathtub 30 . In the middle of the bath return pipe 28, a bath circulation pump 29 for circulating the bath water to the secondary flow path 60b, a bath return temperature sensor 38 for detecting the temperature of the bath water discharged from the bathtub 30, A water level sensor 46 for detecting the water level in the bathtub 30 and a flow switch 47 for detecting whether or not bath water is circulating are provided. A drain plug 55 is provided at the bottom of the bathtub 30 . The bath circulation pump 29 corresponds to a secondary fluid pump that causes the secondary fluid to flow through the secondary flow path 60b.

The tank unit 33 further incorporates a three-way valve 11, a circulation pump 12, a four-way valve 16, and a four-way valve . The three-way valve 11, the four-way valve 16, and the four-way valve 18 correspond to channel switching means capable of switching channels in which hot water circulates. The hot-water storage type hot-water supply device 35 includes a piping device including the flow path switching means, the HP-going piping 14 and the HP-returning piping 15, and piping to be described later. The circulation pump 12 is a pump for circulating hot water in this piping system.

The three-way valve 11 has ports a and b serving as inlets and a port c serving as an outlet. The three-way valve 11 is configured to be switchable between two paths of ac and bc. The four-way valve 16 has ports a and b serving as inlets and ports c and d serving as outlets. The four-way valve 16 is configured to be switchable between four paths of ac, ad, bc, and bd. The four-way valve 18 has an a port as an inlet and b, c, and d ports as outlets. The four-way valve 18 is configured to be switchable between three paths ab, ac, and ad.

The tank unit 33 has a low temperature pipe 10, a first water pipe 13a, a first hot water pipe 17a, a second hot water pipe 17b, a third hot water pipe 19a, a fourth hot water pipe 19b, and a fifth hot water pipe 19c. . The low-temperature pipe 10 connects between the water outlet 8 b and the a port of the three-way valve 11 . The first water supply pipe 13 a connects between the c port of the three-way valve 11 and the inlet of the circulation pump 12 . The HP outgoing pipe 14 connects between the outlet of the circulation pump 12 and the water inlet of the water-refrigerant heat exchanger 3 . The HP return pipe 15 connects between the hot water outlet of the water-refrigerant heat exchanger 3 and the b port of the four-way valve 16 . The first hot water pipe 17 a connects between the d port of the four-way valve 16 and the a port of the four-way valve 18 . The second hot water pipe 17b connects between the c port of the four-way valve 16 and the water inlet 8c. The third hot water pipe 19a connects between the b port of the four-way valve 18 and the hot water introduction outlet 8e. The fourth hot water pipe 19b connects between the d port of the four-way valve 18 and the hot water introduction outlet 8d. The fifth hot water pipe 19c connects between the c port of the four-way valve 18 and the medium temperature water inlet 8g.

The pipe 20a connects between the hot water introduction outlet 8e and the inlet of the primary side flow path 60a. The pipe 20c connects between the outlet of the primary side passage 60a and the b port of the three-way valve 11 . The second water supply pipe 13 b branches from a branch portion 51 formed in the middle of the HP going pipe 14 and is connected to the a port of the four-way valve 16 .

The tank unit 33 includes a medium temperature pipe 79, a first water supply pipe 9a, a second water supply pipe 9b, a third water supply pipe 9c, a fourth water supply pipe 9d, a hot water supply mixing valve 22, a bath mixing valve 23, and a medium temperature water switching valve 78. , a hot water supply pipe 24, a bath pipe 25, a pipe 20b, and a check valve 50.

The medium-temperature water switching valve 78 is flow path switching means having ports a and b serving as inlets and a port c serving as an outlet. The medium-temperature water switching valve 78 is configured to be capable of switching between two paths ac and bc.

The hot water supply mixing valve 22 is mixing means having a first inlet, a second inlet, and an outlet. The bath mixing valve 23 is mixing means with a first inlet, a second inlet and an outlet.

One end of the first water supply pipe 9a is connected to a water source such as tap water. A second water supply pipe 9b and a third water supply pipe 9c are connected to the other end of the first water supply pipe 9a through a pressure reducing valve 31 . The second water supply pipe 9 b is connected to the a port of the medium-temperature water switching valve 78 . The medium-temperature pipe 79 connects between the medium-temperature water introduction outlet 8 f and the b port of the medium-temperature water switching valve 78 . One end of the pipe 20b is connected to a branch portion 52 formed in the middle of the pipe 20c. The other end of the pipe 20b is connected to a branch portion 53 formed in the intermediate temperature pipe 79 . The check valve 50 is installed in the middle of the pipe 20b. The check valve 50 prevents the water in the middle portion of the hot water storage tank 8 from flowing to the lower portion of the hot water storage tank 8 through the pipe 20b. One end of the fourth water supply pipe 9 d is connected to the c port of the medium-temperature water switching valve 78 . The other end of the fourth water supply pipe 9d is connected to the first inlets of the hot water supply mixing valve 22 and the bath mixing valve 23, respectively. One end of the high-temperature pipe 21 communicates with the hot water introduction outlet 8d. The other end of the high-temperature pipe 21 is connected to the second inlets of each of the hot water supply mixing valve 22 and the bath mixing valve 23 .

The medium-temperature water switching valve 78 has two flow states: a first flow path state in which the second water supply pipe 9b and the fourth water supply pipe 9d communicate, and a second flow state in which the medium temperature pipe 79 and the fourth water supply pipe 9d communicate. Used by switching road conditions. When the medium-temperature water switching valve 78 is set to the first flow path state, low-temperature water supplied from the water source is supplied to the hot water supply mixing valve 22 and the bath mixing valve 23 through the second water supply pipe 9b and the fourth water supply pipe 9d. be in a state where When the medium-temperature water switching valve 78 is set to the second flow path state, the medium-temperature water supplied from the hot water storage tank 8 through the medium-temperature water introduction outlet 8f and the medium-temperature pipe 79 passes through the fourth water supply pipe 9d and flows through the hot water supply mixing valve. 22 and the mixing valve 23 for bath.

A medium-temperature pipe temperature sensor 54 is attached to the medium-temperature pipe 79 between the medium-temperature water introduction outlet 8 f and the branch portion 53 . The medium-temperature pipe temperature sensor 54 detects the temperature of water passing through the medium-temperature pipe 79 between the medium-temperature water introduction outlet 8 f and the branch portion 53 .

The hot water supply mixing valve 22 adjusts the flow rate ratio between the high temperature water supplied from the hot water storage tank 8 through the high temperature pipe 21 and the low temperature water or medium temperature water supplied from the fourth water supply pipe 9 d so that the user can generates hot water at a set temperature set by the remote control device 44 and flows it into the hot water supply pipe 24 . The hot water whose temperature is adjusted by the hot water supply mixing valve 22 is supplied from the hot water supply pipe 24 via the hot water supply tap 34 to, for example, a faucet (not shown) such as a shower or a faucet.

The bath mixing valve 23 adjusts the flow rate ratio between the high-temperature water supplied from the hot water storage tank 8 through the high-temperature pipe 21 and the low-temperature water or medium-temperature water supplied from the fourth water supply pipe 9d, thereby allowing the user to generates hot water at a set temperature set by the remote controller 44 and flows it into the bath pipe 25. - 特許庁The hot water adjusted to the set temperature by the bath mixing valve 23 flows into the bathtub 30 through the bath flow sensor 45, the bath solenoid valve 26, the bath pipe 27, and the bath return pipe 28.

The control device 36 determines the completion of hot water filling of the bathtub 30 based on the information detected by the bath flow rate sensor 45 and the water level sensor 46, and determines the amount of bath water in the bathtub 30 when hot water filling is completed. The amount of hot water to be filled can be controlled to be equal to the amount of hot water set by the user with the remote control device 44. - 特許庁The hot water storage type hot water supply device 35 of the present embodiment may be one capable of executing automatic bath operation. When automatic bath operation is set by the remote control device 44, the control device 36 maintains the temperature and amount of the bath water in the bathtub 30 at the temperature and amount set by the remote control device 44 after the hot water filling is completed. As required, the temperature of the bath water is increased, cooled, and water is added.

A control device 36 controls the boiling operation. The boiling operation is an operation for accumulating hot water heated by the HP unit 7, ie, high-temperature water, in the hot water storage tank 8. FIG. The control device 36 controls the start and stop of the boiling operation according to the amount of hot water remaining in the hot water storage tank 8 or the amount of stored heat. In the boiling-up operation, the HP unit 7 and the circulation pump 12 are operated as follows. The low-temperature water in the lower part of the hot water storage tank 8 passes through the water outlet 8b, the low-temperature pipe 10, the three-way valve 11, the first water supply pipe 13a, the circulation pump 12, and the HP outgoing pipe 14 to the water-refrigerant heat exchanger 3. influx. The high-temperature water generated by heating this low-temperature water in the water-refrigerant heat exchanger 3 passes through the HP return pipe 15, the four-way valve 16, the first hot water pipe 17a, the four-way valve 18, and the fourth hot water pipe 19b. Then, the hot water flows into the hot water storage tank 8 from the hot water introduction outlet 8d. By executing such a boiling-up operation, high-temperature water is stored from the top to the bottom in the hot water storage tank 8, and the layer of this high-temperature water gradually thickens. When the amount of hot water stored in the hot water storage tank 8 or the amount of heat stored in the hot water storage tank 8 ascertained by the hot water storage temperature sensors 41, 42, 43 exceeds a predetermined amount, the control device 36 ends the boiling operation.

The control device 36 can perform a reheating operation in which bath water circulating from the bathtub 30 is heated by the bath heat exchanger 60 . The control device 36 may perform a reheating operation to maintain the temperature of the bath water stored in the bathtub 30, or perform a reheating operation to raise the temperature of the bath water stored in the bathtub 30. good too. The reheating operation in the present embodiment corresponds to a heating operation in which the primary fluid heats the secondary fluid in the bath heat exchanger 60 .

During the reheating operation, the control device 36 performs control as follows. The three-way valve 11 communicates between the b port and the c port and closes the a port. In the four-way valve 16, the a port and the d port are in communication, and the b port and the c port are closed. In the four-way valve 18, a port and c port are communicated, and b port and d port are closed. The circulation pump 12 and the bath circulation pump 29 are operated. The hot water flowing out from the upper part of the hot water storage tank 8 through the hot water inlet 8e passes through the pipe 20a, the primary side flow path 60a, the pipe 20c, the three-way valve 11, the first water supply pipe 13a, the circulation pump 12, and the branch portion as the primary fluid. 51, the second water supply pipe 13b, the four-way valve 16, the first hot water pipe 17a, the four-way valve 18, and the fifth hot water pipe 19c. The circuit in which hot water circulates in this way supplies hot water taken out from the upper part of the hot water storage tank 8 as a primary fluid to the primary side flow path 60a, and the primary fluid that has passed through the primary side flow path 60a is transferred to the intermediate portion of the hot water storage tank 8. It corresponds to a tank-based heating circuit that flows into the

When hot water with a higher temperature than the low-temperature water supplied from the water source remains in the pipe, it can be said that there is residual heat in the pipe because the residual water in the pipe has an effective amount of heat. In such a case, if the residual water in the pipe is left as it is, the residual heat will dissipate into the ambient air and be wasted. On the other hand, if the residual heat in the pipe can be recovered to the middle portion of the hot water storage tank 8, the amount of heat required to be generated by the HP unit 7 during the boiling operation in the midnight hours can be reduced, thereby improving the energy efficiency.

The control device 36 can control the heat recovery operation that follows after the end of the reheating operation. After the reheating operation ends, heat remains in the piping of the tank-use heating circuit. In the present embodiment, residual water in at least a portion of the piping of the tank-use heating circuit can be caused to flow into the middle portion of the hot water storage tank 8 by performing the heat recovery operation after the reheating operation ends. As a result, the residual heat of the residual water can be recovered to the intermediate portion of the hot water storage tank 8, thereby improving the energy efficiency.

In the present embodiment, a first heat recovery circuit and a second heat recovery circuit can be formed as circuits through which hot water flows during the heat recovery operation. The first heat recovery circuit and the second heat recovery circuit can be switched by the four-way valve 16 and the four-way valve 18 . The first heat recovery circuit supplies the water taken out from the lower part of the hot water storage tank 8 to the primary side flow path 60a as a primary fluid without passing through the water-refrigerant heat exchanger 3, and the primary side flow path 60a It is a circuit that allows fluid to flow into the middle portion of the hot water storage tank 8 . The second heat recovery circuit supplies water taken out from the lower part of the hot water storage tank 8 to the primary side flow path 60a as a primary fluid via the water-refrigerant heat exchanger 3, and the primary fluid that has passed through the primary side flow path 60a is made to flow into the middle portion of the hot water storage tank 8. The first heat recovery circuit that does not pass through the HP going pipe 14 and the HP return pipe 15 has a shorter circuit length than the second heat recovery circuit that passes through the HP going pipe 14 and the HP return pipe 15 .

After the boiling-up operation ends, residual heat remains in the water-refrigerant heat exchanger 3, the HP return pipe 15, and the like for a while. In such a case, if the residual water inside the water-refrigerant heat exchanger 3, the HP return pipe 15, etc. is left as it is, the residual heat will be dissipated into the surrounding air and wasted. On the other hand, if the residual heat can be recovered in the intermediate portion of the hot water storage tank 8, the energy efficiency can be improved.

If the heat recovery operation is performed within a short period of time after the boiling-up operation is finished, residual heat may remain in the water-refrigerant heat exchanger 3, the HP return pipe 15, and the like. In the present embodiment, the control device 36 executes the heat recovery operation by causing water to flow through the first heat recovery circuit if no residual heat remains in the water-refrigerant heat exchanger 3 when starting the heat recovery operation. If residual heat remains in the water-refrigerant heat exchanger 3 when the heat recovery operation is started, the heat recovery operation is performed to allow water to flow through the second heat recovery circuit. This provides the following effects. When residual heat remains in the water-refrigerant heat exchanger 3, by flowing water through the second heat recovery circuit, not only the residual heat of the tank-use heating circuit, but also the water-refrigerant heat exchanger 3 and the HP return pipe 15 The residual heat remaining in the hot water storage tank 8 can also be recovered in the intermediate portion. As a result, energy efficiency can be further improved. On the other hand, when there is no residual heat remaining in the water-refrigerant heat exchanger 3, the driving load of the circulation pump 12 can be reduced by causing water to flow through the first heat recovery circuit, which has a short circuit length. power consumption can be reduced.

The control device 36 may determine whether residual heat remains in the water-refrigerant heat exchanger 3 when starting the heat recovery operation, for example, as follows. The control device 36 determines that residual heat remains in the water-refrigerant heat exchanger 3 when the elapsed time since the operation of the compressor 1 of the HP unit 7 was stopped is within the reference time. exceeds the reference time, it may be determined that no residual heat remains in the water-refrigerant heat exchanger 3 . Note that the control device 36 may change the reference time according to conditions such as the outside air temperature. The control device 36 may also determine whether residual heat remains in the water-refrigerant heat exchanger 3 based on the temperature detected by the temperature sensor provided in the HP unit 7 . For example, the control device 36 determines that residual heat remains in the water-refrigerant heat exchanger 3 when the detected temperature of the outlet hot water temperature sensor 39 exceeds the threshold, and the detected temperature of the outlet hot water temperature sensor 39 is equal to or less than the threshold. In this case, it may be determined that no residual heat remains in the water-refrigerant heat exchanger 3 .

FIG. 2 is a diagram showing the first heat recovery circuit in the hot water storage type hot water supply device 35 shown in FIG. The heat recovery operation of the first heat recovery circuit shown in FIG. 2 is controlled by the control device 36 as follows. In the three-way valve 11, the a port and the c port are communicated, and the b port is closed. In the four-way valve 16, the a port and the d port are communicated, and the b port and the c port are closed. In the four-way valve 18, the a port and the b port are in communication, and the c port and the d port are closed. Circulation pump 12 is operated. Water is a water outlet 8b, a low-temperature pipe 10, a three-way valve 11, a first water pipe 13a, a circulation pump 12, a branch 51, a second water pipe 13b, a four-way valve 16, a first hot water pipe 17a, a four-way valve 18, The water flows through the third hot water pipe 19a, the pipe 20a, the primary flow path 60a, the branch 52, the pipe 20b, the branch 53, and the intermediate temperature pipe 79 in this order, and flows into the intermediate portion of the hot water storage tank 8 from the intermediate temperature water introduction outlet 8f. When the heat recovery operation of the first heat recovery circuit is performed in this way, the heat recovery water that recovers the residual heat in the piping after the end of the reheating operation flows from the medium temperature water introduction outlet 8f, and the hot water storage tank 8 The hot water is stored near the middle-temperature water introduction outlet 8f.

FIG. 3 is a diagram showing a second heat recovery circuit in the hot water storage type hot water supply device 35 shown in FIG. The heat recovery operation of the second heat recovery circuit shown in FIG. 3 is controlled by the control device 36 as follows. In the three-way valve 11, the a port and the c port are communicated, and the b port is closed. In the four-way valve 16, the b port and the d port are in communication, and the a port and the c port are closed. In the four-way valve 18, the a port and the b port are in communication, and the c port and the d port are closed. Circulation pump 12 is operated. Water is a water outlet 8b, a low-temperature pipe 10, a three-way valve 11, a first water supply pipe 13a, a circulation pump 12, an HP outgoing pipe 14, a water-refrigerant heat exchanger 3, an HP return pipe 15, a four-way valve 16, and a first hot water. The pipe 17a, the four-way valve 18, the third hot water pipe 19a, the pipe 20a, the primary side flow path 60a, the branch 52, the pipe 20b, the branch 53, the medium temperature pipe 79 flow in this order, and the medium temperature water inlet 8f to the hot water storage tank 8. flow into the middle part of In this way, when the heat recovery operation of the second heat recovery circuit is performed, in addition to the heat recovery water that recovers the residual heat in the piping after the reheating operation is completed, the water refrigerant heat after the boiling operation is completed The heat recovery water that recovers the residual heat from the heat exchanger 3 and the HP return pipe 15 flows into the medium-temperature water inlet 8f and is stored in the hot water storage tank 8 near the medium-temperature water inlet 8f.

As described above, when the heat recovery operation is performed, the heat recovery water is stored in the hot water storage tank 8 near the intermediate water introduction outlet 8f. In the present embodiment, the heat recovery water in the hot water storage tank 8, that is, the medium-temperature water is passed through the medium-temperature water introduction outlet 8f, the medium-temperature pipe 79, the medium-temperature water switching valve 78, and the fourth water supply pipe 9d to the hot water supply mixing valve 22 and the bath. It can be supplied to the water mixing valve 23 and used for hot water supply. Therefore, it is more advantageous in improving energy efficiency. In particular, in the present embodiment, the middle-temperature water introduction outlet 8f serves as an outlet for taking out the middle-temperature water supplied to the hot water supply mixing valve 22 and the bath mixing valve 23, and the inlet into which the heat recovery water flows. The middle-temperature water introduction outlet 8f is common. As a result, the heat recovery water in the hot water storage tank 8 can be more reliably used for hot water supply.

The control device 36 may control to stop the circulation pump 12 and end the heat recovery operation when the time during which the heat recovery operation is executed, that is, the operation time of the circulation pump 12 exceeds a predetermined upper limit time. . Thereby, the timing of ending the heat recovery operation can be appropriately controlled. This upper limit time may be, for example, 10 seconds. In addition, the control device 36 sets the upper limit time for the heat recovery operation of the second heat recovery circuit having a long circuit length to be longer than the upper limit time for the heat recovery operation of the first heat recovery circuit having a short circuit length. may

The stored hot water temperature sensor 43 corresponds to tank bottom water temperature detection means for detecting the tank bottom water temperature, which is the temperature of the water in the bottom of the hot water storage tank 8 . The medium-temperature pipe temperature sensor 54 corresponds to a recovered water temperature detecting means for detecting the temperature of the heat recovery water flowing into the intermediate portion of the hot water storage tank 8 during the heat recovery operation. In the following description, the temperature detected by the stored hot water temperature sensor 43 will be referred to as the tank bottom water temperature, and the temperature detected by the intermediate temperature pipe temperature sensor 54 during the heat recovery operation will be referred to as the heat recovery water temperature.

The control device 36 may perform the heat recovery operation when the tank bottom water temperature is lower than the heat recovery water temperature, or when the tank bottom water temperature is lower than the heat recovery water temperature by a predetermined value or more. That is, the control device 36 may set the condition for starting the heat recovery operation to be that the tank bottom water temperature is lower than the heat recovery water temperature, or that the tank bottom water temperature is lower than the heat recovery water temperature by the predetermined value or more. By doing so, it is possible to appropriately judge whether there is merit in implementing the heat recovery operation, and to decide whether to implement the heat recovery operation.

In addition, when the temperature of the tank bottom water becomes equal to or higher than the heat recovery water temperature during execution of the heat recovery operation, or when the temperature difference between the heat recovery water temperature and the tank bottom water temperature becomes less than a predetermined value, the control device 36 , the heat recovery operation may be stopped. That is, the control device 36 may set the temperature of the water at the bottom of the tank equal to or higher than the temperature of the heat recovery water or the temperature difference between the temperature of the heat recovery water and the temperature of the water at the bottom of the tank to be less than the predetermined value as a condition for terminating the heat recovery operation. good. By doing so, the heat recovery operation can be terminated at an appropriate timing.

Further, the control device 36 may perform the heat recovery operation when the tank bottom water temperature is lower than the reference temperature (for example, 30° C.). That is, the control device 36 may set the lower tank bottom water temperature lower than the reference temperature as a condition for starting the heat recovery operation. By doing so, it is possible to appropriately judge whether there is merit in implementing the heat recovery operation, and to decide whether to implement the heat recovery operation. Further, the control device 36 may stop the heat recovery operation when the water temperature at the bottom of the tank becomes equal to or higher than the reference temperature during the execution of the heat recovery operation. That is, the control device 36 may set the temperature of the water at the bottom of the tank equal to or higher than the reference temperature as a condition for terminating the heat recovery operation. By doing so, the heat recovery operation can be terminated at an appropriate timing.

During the heat recovery operation, the controller 36 preferably operates the circulation pump 12 at a preset constant number of revolutions (eg, 2000 rpm). This is advantageous in reducing power consumption of the circulation pump 12 .

It is preferable that the control device 36 starts the heat recovery operation after the bath circulation pump 29 that has been operated in the reheating operation is stopped. After the start of the heat recovery operation, low-temperature water may flow into the primary side passage 60a of the bath heat exchanger 60, so the bath water in the secondary side passage 60b may be cooled by the low-temperature water. have a nature. If the heat recovery operation is started after the bath circulation pump 29 has stopped, it is possible to reliably prevent the thus cooled bath water in the secondary flow path 60 b from flowing into the bathtub 30 . It is possible to reliably prevent the temperature of the bath water inside from dropping.

The controller 36 preferably controls the rotation speed of the circulation pump 12 during the heat recovery operation to be lower than the minimum rotation speed of the circulation pump 12 during the reheating operation. For example, when the minimum rotation speed of the circulation pump 12 during the reheating operation is set to 3500 rpm, the control device 36 controls the rotation speed of the circulation pump 12 to 2000 rpm during the heat recovery operation. You may This is advantageous in reducing power consumption of the circulation pump 12 .

When the temperature of the water flowing into the HP unit 7 increases, the COP (Coefficient Of Performance) of the HP unit 7 tends to decrease. Therefore, the COP of the HP unit 7 tends to decrease when the tank bottom temperature rises. In contrast, in the present embodiment, the heat recovery water that has flowed into the hot water storage tank 8 is stored in the middle portion of the hot water storage tank 8, so that the tank lower portion temperature is less likely to rise. Therefore, it is advantageous in preventing the COP of the HP unit 7 from decreasing.

In the present embodiment, when residual heat remains in the water-refrigerant heat exchanger 3, the water-refrigerant heat exchanger 3 can be cooled by performing a heat recovery operation in which water flows through the second heat recovery circuit. Therefore, it is possible to suppress the formation of scale within the water-refrigerant heat exchanger 3 .

In the explanation so far, the case where the hot water taken out from the upper portion of the hot water storage tank 8 is supplied as the primary fluid to the primary side passage 60a during the reheating operation has been explained. Such reheating operation is hereinafter referred to as "tank-based reheating operation". In the present embodiment, during the reheating operation, the HP unit 7 can be operated and the hot water heated by the HP unit 7 can be supplied to the primary side passage 60a as the primary fluid. Such reheating operation is hereinafter referred to as "HP reheating operation".

During the HP reheating operation, the control device 36 performs control as follows. The three-way valve 11 communicates between the b port and the c port and closes the a port. In the four-way valve 16, the b port and the d port are in communication, and the a port and the c port are closed. In the four-way valve 18, the a port and the b port are in communication, and the c port and the d port are closed. The HP unit 7, circulation pump 12, and bath circulation pump 29 are operated. The hot water that has flowed out of the water-refrigerant heat exchanger 3 is used as a primary fluid in the HP return pipe 15, the four-way valve 16, the first hot water pipe 17a, the four-way valve 18, the third hot water pipe 19a, the pipe 20a, the primary flow path 60a, It returns to the water-refrigerant heat exchanger 3 via the pipe 20c, the three-way valve 11, the first water pipe 13a, the circulation pump 12, and the HP outgoing pipe 14, and circulates again.

After the HP reheating operation ends, residual heat remains in the water-refrigerant heat exchanger 3, the HP return pipe 15, and the like. After the HP reheating operation ends, the control device 36 executes a heat recovery operation for causing water to flow through the second heat recovery circuit. As a result, residual heat remaining in the water-refrigerant heat exchanger 3, the HP return pipe 15, and the like after the HP reheating operation is completed can be recovered to the intermediate portion of the hot water storage tank 8. As a result, energy efficiency can be improved.

When the HP reheating operation is performed, the control device 36 determines that residual heat remains in the water-refrigerant heat exchanger 3, performs the heat recovery operation of the second heat recovery circuit, and performs the tank-use reheating operation. When it is executed, it may be determined that no residual heat remains in the water-refrigerant heat exchanger 3, and the heat recovery operation of the first heat recovery circuit may be executed.

1 compressor 3 water refrigerant heat exchanger 4 expansion valve 5 refrigerant piping 6 air heat exchanger 7 HP unit 8 hot water storage tank 8a water inlet 8b water outlet 8c water inlet 8d hot water Inlet outlet 8e Hot water inlet outlet 8f Intermediate warm water inlet outlet 8g Intermediate warm water inlet 9a First water supply pipe 9b Second water supply pipe 9c Third water supply pipe 9d Fourth water supply pipe 10 Low temperature pipe 11 Three-way Valve 12 Circulation pump 13a First water supply pipe 13b Second water supply pipe 14 HP outgoing pipe 15 HP return pipe 16 Four-way valve 17a First hot water pipe 17b Second hot water pipe 18 Four-way valve 19a Second 3 hot water pipe 19b fourth hot water pipe 19c fifth hot water pipe 20a pipe 20b pipe 20c pipe 21 high temperature pipe 22 hot water mixing valve 23 bath mixing valve 24 hot water pipe 25 bath pipe 26 Solenoid valve for bath 27 Bath going pipe 28 Bath returning pipe 29 Bath circulation pump 30 Bathtub 31 Pressure reducing valve 33 Tank unit 34 Hot water tap 35 Hot water storage type hot water supply device 36 Controller 37 Bath going temperature sensor , 38 bath return temperature sensor 39 outlet hot water temperature sensor 40 inlet water temperature sensor 41, 42, 43 stored hot water temperature sensor 44 remote controller 45 bath flow rate sensor 46 water level sensor 47 flow switch 50 check valve 51 branching portion 52 branching portion 53 branching portion 54 medium-temperature pipe temperature sensor 55 drain plug 60 bath heat exchanger 60a primary-side channel 60b secondary-side channel 78 medium-temperature water switching valve 79 medium-temperature pipe

Claims (9)

a heating means for heating water;
a hot water storage tank capable of storing hot water heated by the heating means and having an upper portion, a lower portion, and an intermediate portion between the upper portion and the lower portion;
a heat exchanger that has a primary side channel and a secondary side channel, and exchanges heat between a primary fluid flowing through the primary side channel and a secondary fluid flowing through the secondary side channel;
A piping device having a channel switching means capable of switching a channel in which hot water circulates;
a control means capable of executing a heating operation for heating the secondary fluid with the primary fluid in the heat exchanger and a heat recovery operation after the heating operation;
with
The flow path switching means is
A tank-use heating circuit for supplying hot water taken out from the upper portion of the hot water storage tank as the primary fluid to the primary side flow path, and causing the primary fluid that has passed through the primary side flow path to flow into the intermediate portion of the hot water storage tank. When,
Water taken out from the lower portion of the hot water storage tank is supplied to the primary side flow path as the primary fluid without passing through the heating means, and the primary fluid that has passed through the primary side flow path is supplied to the hot water storage tank as the primary fluid. a first heat recovery circuit that flows into the intermediate portion;
Water taken out from the lower portion of the hot water storage tank is supplied to the primary side flow path as the primary fluid through the heating means, and the primary fluid that has passed through the primary side flow path is transferred to the intermediate portion of the hot water storage tank. a second heat recovery circuit that flows into the part;
can be switched,
The control means executes the heat recovery operation by causing water to flow through the first heat recovery circuit if no residual heat remains in the heating means when starting the heat recovery operation, and starts the heat recovery operation. A hot water storage type hot water supply apparatus for executing the heat recovery operation of causing water to flow through the second heat recovery circuit when residual heat remains in the heating means when starting. 2. The hot water storage type hot water supply apparatus according to claim 1, wherein the control means terminates the heat recovery operation when the time during which the heat recovery operation is executed exceeds the upper limit time. a tank bottom water temperature detection means for detecting a tank bottom water temperature, which is the temperature of the water in the bottom of the hot water storage tank;
a recovered water temperature detecting means for detecting the temperature of the heat recovery water flowing into the intermediate portion of the hot water storage tank during the heat recovery operation;
with
The control means performs the heat recovery operation when the tank bottom water temperature is lower than the heat recovery water temperature or when the tank bottom water temperature is lower than the heat recovery water temperature by a predetermined value or more. The hot water storage type hot water supply apparatus according to claim 1 or 2. A tank bottom water temperature detection means for detecting a tank bottom water temperature, which is the temperature of the water in the bottom of the hot water storage tank,
4. The hot water storage type hot water supply apparatus according to any one of claims 1 to 3, wherein the control means performs the heat recovery operation when the water temperature at the lower portion of the tank is lower than a reference temperature. A circulation pump that causes water to flow through the first heat recovery circuit or the second heat recovery circuit during the heat recovery operation,
The hot water storage type hot water supply apparatus according to any one of claims 1 to 4, wherein the circulation pump is operated at a constant rotation speed during the heat recovery operation. comprising a secondary fluid pump that causes the secondary fluid to flow through the secondary flow path;
The hot water storage type hot water supply apparatus according to any one of claims 1 to 5, wherein the control means starts the heat recovery operation after the secondary fluid pump stops. a circulation pump that causes water to flow through the tank-utilizing heating circuit during the heating operation, and causes water to flow through the first heat recovery circuit or the second heat recovery circuit during the heat recovery operation;
7. The controller according to any one of claims 1 to 6, wherein the control means controls the rotation speed of the circulation pump during the heat recovery operation to be lower than the minimum rotation speed of the circulation pump during the heating operation. The hot water storage type hot water supply device according to claim 1. a tank bottom water temperature detection means for detecting a tank bottom water temperature, which is the temperature of the water in the bottom of the hot water storage tank;
a recovered water temperature detecting means for detecting the temperature of the heat recovery water flowing into the intermediate portion of the hot water storage tank during the heat recovery operation;
with
During execution of the heat recovery operation, the control means controls when the temperature of the water at the bottom of the tank becomes equal to or higher than the temperature of the heat recovery water, or when the temperature difference between the temperature of the heat recovery water and the temperature of the water at the bottom of the tank reaches a predetermined value. 8. The hot water storage type hot water supply apparatus according to any one of claims 1 to 7, wherein the heat recovery operation is stopped when the temperature falls below. A tank bottom water temperature detection means for detecting a tank bottom water temperature, which is the temperature of the water in the bottom of the hot water storage tank,
9. The heat recovery operation according to any one of claims 1 to 8, wherein the control means stops the heat recovery operation when the water temperature at the lower part of the tank becomes equal to or higher than a reference temperature during execution of the heat recovery operation. Storage type water heater.

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