JP2008151450A - Heat storage type hot water supply apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a suitable hot water storage state of a hot water storage tank and to attain immediate hot water supply to prevent a fall in the coefficient of performance of a natural coolant heat pump device serving as a heat source machine and a fall in the cooling ability of a cogeneration device in a heat storage type hot water supply apparatus mixing clean water of low temperature into supply hot water of high temperature taken out of the hot water storage tank to set the temperature of supply hot water supplied to a hot water supply part, to a predetermined set hot water supply temperature. <P>SOLUTION: The heat storage type hot water supply apparatus comprises a return conduit 20 extending from a return connection part 20a to a low temperature part 3 of the heat storage tank 1, and a circulating flow setting control means B carrying out supply hot water circulating operation for allowing supply hot water taken out of a high temperature part 2 of the hot water storage tank 1 when not discharging hot water from a hot water supply part 15, to sequentially flow through a forward conduit 10, hot water supply forward piping 11, hot water supply return piping 19 and a return conduit 20, then circulating the supply hot water in a form of returning it to the low temperature part 3 of the hot water storage tank 1 and setting the circulating flow of the supply hot water in the supply hot water circulating operation within a set circulating flow range where the return temperature of the supply hot water returned to the low temperature part 3 of the hot water storage tank 1 is a predetermined low temperature water upper limit temperature or lower. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention comprises a temperature stratified hot water storage tank and a forward pipe line from a high temperature part of the hot water storage tank to a forward connection part to which a hot water supply outgoing pipe is connected, and uses the heat stored in the hot water storage tank. The present invention relates to a regenerative hot water supply apparatus that supplies hot water to a hot water supply section such as a hot water tap connected to the hot water supply outgoing pipe through the outgoing pipe and hot water supply outgoing pipe.

  As a conventional heat storage type hot water supply device, at the time of hot water discharge at the hot water supply section, the hot water supply water is mixed with the hot hot water extracted from the high temperature section of the hot water storage tank to the forward discharge pipe in the mixing section of the forward pipe. Hot water supply temperature setting control means for controlling the mixing ratio of the clean water to water and setting the temperature of hot water discharged from the forward connection portion to the hot water supply forward pipe to a predetermined set hot water supply temperature (for example, about 42 ° C.). (For example, refer to Patent Document 1).

In such a heat storage type hot water supply device, hot water at the set hot water temperature is discharged from the forward pipe to the hot water supply piping when the hot water is discharged from the hot water supply section. Since the flow of the hot water is stopped, the temperature of the hot water that remains is lowered due to heat dissipation. Therefore, immediately after the start of the hot water supply in the hot water supply section, water staying in the outgoing pipe and the hot water supply outgoing pipe and having a temperature that does not reach an appropriate temperature (for example, 30 ° C.) is discharged from the hot water supply section. There was an inconvenience that proper temperature hot water would not come out. At the same time, the discharge of the stagnant water wasted water resources and wasted water and sewage charges.
In particular, in business applications such as hotels, since the hot water supply piping leading to each hot water supply unit becomes long, it is desirable to avoid the inconvenience and waste described above.

  Therefore, as a heat storage type hot water supply apparatus that can discharge hot water at an appropriate temperature immediately after the start of the hot water supply in the hot water supply part so as to avoid such inconvenience and waste, a hot water supply pipe from the high temperature part of the hot water storage tank is used. In addition to the forward pipeline that leads to the connected forward connection, a return pipeline that connects the hot water return piping that takes in hot water after passing through the hot water delivery piping to the low temperature part of the hot water tank is provided. Even during non-hot water supply in the hot water supply section, the hot water taken out from the hot water storage tank is circulated in such a manner that it is passed through the forward pipe, the hot water outgoing pipe, the hot water return pipe, and the return pipe in order and then returned to the hot water tank. Such a structure is known (see, for example, Patent Document 2 or 3). In addition, such a conventional regenerative hot water supply apparatus capable of immediate hot water discharge is configured to discharge hot hot water taken out from the hot water storage tank as it is from the forward pipe to the hot water outlet pipe. Therefore, in the hot water supply section provided in the hot water supply piping, a hot water mixing type hot water tap, etc. is installed, and the adjustment of the mixing ratio of the hot water with respect to the hot hot water supplied from the hot water supply piping is accompanied. By mixing, hot water at a desired temperature is realized.

  Further, in the heat storage type hot water supply apparatus as described above, there may be provided a heat source machine that heats the low temperature water taken out from the low temperature part of the hot water tank and supplies it to the high temperature part of the hot water tank. Specifically, a boiler or a water heater can be used, but a heat pump device, a cogeneration device, or the like can be used.

As the heat pump device, a natural refrigerant such as carbon dioxide (carbon dioxide) is used, the discharge pressure of the compressor is set as the supercritical pressure of the natural refrigerant, and the natural refrigerant is between a gas phase state and a gas-liquid two-phase state. A so-called natural refrigerant heat pump device is known in which heat is forcibly transferred from the evaporator to the condenser side by utilizing heat absorption / radiation when changing the state. And in such a natural refrigerant | coolant heat pump apparatus, since the one where the entering temperature of the said heating object fluid is as low as possible can fully cool a natural refrigerant | coolant in a condenser, a coefficient of performance (COP) improves.
Therefore, the hot water storage tank for storing the heat storage water heated in the evaporator of such a natural refrigerant heat pump device stores the heat storage water in a form in which a high temperature layer is formed at the top and a low temperature layer is formed below the high temperature layer. It is preferable to constitute a temperature stratification type. That is, the temperature-stratified hot water tank draws out low-temperature water from the lower end portion, supplies the low-temperature water to the condenser, and heats hot water that has become hot due to heat exchange with the natural refrigerant in the condenser at the upper end portion. It can be returned and stored.

  On the other hand, in the cogeneration apparatus, all or a part of the obtained heat includes heat recovered by cooling the prime mover (including the fuel cell and the like). For example, the jacket water for cooling the engine and the cooling water for the fuel cell are the same. In particular, in fuel cells that reform hydrocarbons and methanol and use them as fuel, it is necessary to produce pure water for steam reforming by cooling their own exhaust gas. Is also 40 ° C. or lower). That is, depending on the prime mover, the temperature of the cooling water may be regulated below a certain reference temperature, and the hot water storage tank that stores the heat storage water heated by the exhaust heat of cogeneration using such a prime mover is also temperature stratified. It is preferable to configure the mold. That is, the temperature-stratified hot water tank is cooled by the prime mover by circulating low temperature water from the lower end, cooling the prime mover (recovering exhaust heat), and returning hot water to the upper end. The two purposes of exhaust heat recovery are achieved at the same time.

JP 2005-42965 A JP-A-8-121800 JP-A-8-159501

  In the regenerative hot water supply apparatus provided with the hot water supply temperature setting control means as in the above-mentioned Patent Document 1, in order to realize immediate hot water supply, as in the above-mentioned Patent Documents 2 and 3, even in the case of non-hot water supply in the hot water supply part, A configuration in which hot water that has been mixed with low-temperature tap water and has a set hot water supply temperature of about 42 ° C. is sequentially passed through an outgoing pipe, a hot water outgoing pipe, a hot water return pipe, and a return pipe and then returned to the hot water tank. When it is configured to circulate, the temperature of the hot water flowing through the most distal side of the hot water supply piping becomes, for example, about 25 ° C. too low due to the temperature drop due to heat dissipation in the outgoing piping and the hot water supply piping. As a result, there is a problem in that water having a temperature that does not reach the appropriate temperature is discharged immediately after the start of the hot water supply from the hot water supply section.

  In order to avoid such problems, if the temperature of hot water to be circulated at the time of non-hot water in the hot water supply section is set high or the circulation flow rate is set large, the hot water supply water that returns from the return pipe to the low temperature section of the hot water tank The temperature also rises and the temperature of the low temperature part of the hot water tank rises.

  Thus, when the temperature of the low-temperature part of the hot water tank rises, for example, when a natural refrigerant heat pump device is used as a heat source device, the temperature of the low-temperature water supplied to the condenser rises, so that the natural refrigerant heat pump On the other hand, when a cogeneration device such as an engine-driven generator or a fuel cell is used as a heat source device, a problem such as a decrease in the coefficient of performance of the device occurs. Problems such as inadequate cooling of the fuel cell occur.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to mix cold hot water with hot hot water taken out from the hot water tank in the mixing section of the forward pipe and supply it to the hot water supply section. In a regenerative hot water supply device having a hot water supply temperature setting control means for setting the temperature of the hot water to be set to a predetermined set hot water temperature, for example, a decrease in the coefficient of performance of a natural refrigerant heat pump device as a heat source device or cooling of a cogeneration device In order to prevent a decrease in performance, the present invention is to provide a technology capable of realizing immediate hot water supply while maintaining an appropriate hot water storage state of a hot water tank.

In order to achieve the above object, a heat storage type hot water supply apparatus according to the present invention comprises a temperature stratified hot water storage tank,
From the hot part of the hot water storage tank, the outgoing pipe line to the outgoing connection part to which the hot water supply outgoing pipe is connected,
When hot water is discharged from a hot water supply unit connected to the hot water supply outlet pipe, hot water is mixed into hot water extracted from the high temperature part of the hot water storage tank to the outgoing pipe line in the mixing part of the forward pipe, and the hot water supply A heat storage type comprising a hot water supply temperature setting control means for controlling a mixing ratio of the clean water to water and setting a temperature of hot water discharged from the forward connection portion to the hot water supply forward piping to a predetermined hot water supply temperature. A hot water supply apparatus, the first characteristic configuration of which is a return pipe line connected to a low temperature part of the hot water storage tank from a return connection part connected to a hot water return pipe for taking in hot water after passing through the hot water outlet pipe ,
When hot water is not discharged in the hot water supply part, hot water taken out from the high temperature part of the hot water storage tank is passed through the outgoing pipe, the hot water outgoing pipe, the hot water return pipe, and the return pipe in order, The hot water circulating operation is performed so that the hot water is circulated in the form of returning to the low temperature portion of the hot water tank, and the circulating flow rate of the hot water during the hot water circulating operation is set to a predetermined low temperature water. A circulation flow rate setting control means for setting within a set circulation flow rate region that is lower than the upper limit temperature is provided.

According to the first characteristic configuration, the hot water supply circulation operation is performed, and hot water taken out from the high temperature portion of the hot water storage tank at the time of non-hot water at the hot water supply portion is supplied with the forward pipe, the hot water supply forward piping, and the hot water return piping. By circulating in the form of returning to the low temperature part of the hot water tank after passing through the return pipe in order, so-called immediate hot water discharge can be realized in which hot water is discharged at an appropriate temperature even immediately after the start of hot water supply in the hot water supply part. .
Further, the circulating flow rate setting control means sets the circulating flow rate of the hot water during the hot water circulating operation within a sufficiently small set circulating flow rate range (for example, 0.1 L / min), so Since the return temperature of the hot water returning to the low temperature part of the hot water tank can be reduced by heat radiation to a predetermined low temperature upper limit temperature (for example, outside air temperature + 10 ° C., preferably outside air temperature + 5 ° C.), The temperature of the low temperature part of a tank can be maintained below the said low temperature water upper limit temperature.
Therefore, according to the present invention, the temperature of the hot water supplied to the hot water supply unit is set to a predetermined set hot water supply temperature by mixing the low temperature clean water with the high temperature hot water extracted from the hot water storage tank in the mixing unit of the forward pipeline. In the regenerative hot water supply apparatus provided with the hot water supply temperature setting control means, it is possible to provide a technique capable of realizing instantaneous hot water supply while maintaining the hot water storage state of the hot water storage tank at an appropriate level.

  In addition, since the circulating flow rate of hot water at the time of the hot water circulation operation is small, the circulation power can be made extremely small, and further, the return pipe can be constituted by a small diameter and non-insulated pipe. Operation costs and equipment costs can be reduced.

  The second characteristic configuration of the heat storage type hot water supply apparatus according to the present invention is that, in addition to the first characteristic configuration, the low-temperature water upper limit temperature is set to a temperature that does not exceed the outside air temperature by 10 ° C. or more in summer. .

According to the second characteristic configuration, the low-temperature water upper limit temperature is set to a temperature that does not exceed the outside air temperature (for example, about 35 ° C.) by 10 ° C. or more in summer, and preferably that that does not exceed 5 ° C. or more in summer. Therefore, the temperature of the low temperature part of the hot water tank can be kept low throughout the year.
The upper limit temperature of the low-temperature water can be set based on the outdoor temperature in summer as described above, but is set based on the coefficient of performance of the natural refrigerant heat pump device provided as a heat source device and the cooling capacity of the cogeneration device. You can also

In addition to the first and second characteristic configurations described above, the third feature of the heat storage type hot water supply apparatus according to the present invention is such that the hot water storage tank forms a high temperature layer at the top and a low temperature layer below the high temperature layer. The hot water is stored in a form to
The forward pipe is connected to the upper end of the hot water storage tank as the high temperature part, and the return pipe is connected to the lower end of the hot water storage tank as the low temperature part.

  According to the third characteristic configuration, the hot water storage tank can be configured as a hot water storage tank that stores hot water as it is as hot water supply in a form that forms the temperature stratification. Is connected to the upper end of the hot water tank, so that hot water can be taken out from the high temperature layer of the hot water tank to the outgoing pipe, while the return pipe is connected to the lower end of the hot water tank. The hot water taken in can be returned to the low temperature layer of the hot water tank.

According to a fourth characteristic configuration of the heat storage type hot water supply apparatus according to the present invention, in addition to any one of the first to third characteristic configurations, the mixing unit is configured to connect the outgoing pipe line when the hot water is not discharged from the hot water supply unit. Configured to close,
The hot water supply circulation operation is performed by flowing hot water taken out from the high temperature portion of the hot water storage tank to the downstream side of the mixing portion of the forward pipeline through the hot water bypass pipeline bypassing the mixing portion in the outgoing pipeline. In that it is configured to do.

  According to the fourth characteristic configuration described above, the mixing section provided in the outgoing pipe is configured by a combination of a three-way valve or two two-way valves. Based on the above considerations, the mixing unit can be configured to close the forward conduit when no hot water is discharged from the hot water supply unit. Further, in such a configuration, in the hot water circulation operation, when hot water is not discharged from the hot water supply portion, hot hot water taken out from the high temperature portion of the hot water storage tank is passed through the hot water supply bypass conduit. The hot water can be circulated in such a manner that it flows downstream from the mixing section and the hot water is sequentially passed through the forward pipe and the return pipe and then returned to the low temperature section of the hot water tank. Thereby, the hot-water supply water circulating operation mentioned above can be performed irrespective of a structure, a kind, or control of a mixing part.

  The fifth characteristic configuration of the regenerative hot water supply apparatus according to the present invention is, in addition to any one of the first to fourth characteristic configurations, a bypass flow rate regulating means for regulating the flow rate of the hot water supply to the hot water supply bypass line. Is in the point provided.

  According to the fifth characteristic configuration, by providing the bypass flow rate regulating means in the hot water supply bypass line, hot water after the hot water is mixed in the mixing unit and the set hot water temperature is set at the time of hot water discharge in the hot water supply unit Since the amount of hot hot water to be mixed with water via the hot water supply bypass line can be reduced, the deviation of the hot water temperature due to the mixing to the high temperature side can be made minute. Further, by restricting the flow rate of hot water in the hot water supply bypass line by the bypass flow rate regulating means, the circulation flow rate during the hot water supply circulation operation can be set within the set circulation flow rate region.

The sixth characteristic configuration of the heat storage type hot water supply apparatus according to the present invention is, in addition to any one of the first to fifth characteristic configurations described above, a water supply pipeline in which the mixing unit is connected to a low temperature unit of the hot water storage tank. Configured to take in the clean water through
In the low temperature part of the hot water storage tank, there is provided hot water inflow restricting means for restricting inflow of hot water from the return pipe to the forward pipe.

According to the sixth feature, when the water supply pipe connected to the low temperature part of the hot water tank is connected to the mixing part, the hot water inflow restricting means causes the hot water supply circulation operation to be performed from the hot water return pipe. The hot water returning to the return pipe can be restricted from flowing into the water supply pipe connected to the low temperature portion of the hot water storage tank. Therefore, hot water returned to the return pipe can be satisfactorily flowed into the low temperature part of the hot water tank, and hot hot water can be taken out from the high temperature part of the hot water tank to the outgoing pipe.
In the present application, the hot water supply inflow restricting means can completely prevent the hot water from flowing into the water supply pipe, but the temperature of the hot water flowing through the forward pipe is constant when there is no hot water. You may comprise so that inflow of the hot water supply water to a water supply pipe line may be permitted to such an extent that it is maintained above.

  According to a seventh characteristic configuration of the heat storage type hot water supply apparatus according to the present invention, in addition to any one of the first to sixth characteristic configurations, the circulation flow rate setting control unit controls a circulation flow rate during the hot water supply water circulation operation. The point is that it is configured to do.

The temperature of hot water in each part of the hot water supply piping during the hot water circulation operation described above is influenced by the thickness and type of the heat insulating material applied to the hot water supply piping, and also depends on the outside air temperature and the circulation flow rate. . That is, if the temperature of the hot water in the hot water supply section connected to the hot water supply piping during the hot water circulation operation changes due to a change in the outside air temperature, the temperature of the hot water immediately after the start of the hot water changes, which is not preferable. Therefore, according to the seventh feature configuration, by controlling the circulation flow rate during the hot water circulation operation based on the outside air temperature or the like, it is possible to cancel the temperature change of the hot water due to the outside air temperature. Specifically, it is possible to control to increase the circulation flow rate when the outside air temperature decreases and to decrease the circulation flow rate when the outside air temperature rises.
Thereby, the temperature of the hot water in the hot water supply part at the time of the hot water circulation operation can be stabilized throughout the year without being affected by the outside air temperature.

  An eighth feature of the heat storage type hot water supply apparatus according to the present invention is that in addition to any of the first to seventh features, the low temperature water taken out from the low temperature portion of the hot water tank is heated and the hot water tank is used. It is in the point provided with the heat source machine which supplies to the high temperature part.

According to the eighth characteristic configuration, the low temperature water is taken out from the low temperature portion of the hot water tank, the water is heated to the target hot water temperature or higher by the heat source device, and the hot water having the heated target hot water temperature or higher is heated to the high temperature of the hot water tank. By returning to the part, high temperature water higher than the target hot water storage temperature can be stored in the hot water storage tank while maintaining good temperature stratification formed in the hot water storage tank.
Moreover, since the low-temperature water taken out from the low-temperature part of the hot water tank maintained at the temperature below the upper limit temperature of the low-temperature water as described above can be supplied to the heat source unit, a natural refrigerant heat pump device or a cogeneration unit as a heat source unit Etc. can be made favorable.
That is, when the natural refrigerant heat pump device is used as a heat source device and the water heated by the condenser of the natural refrigerant heat pump device is stored in the hot water storage tank, the temperature of the low temperature part of the hot water storage tank is set to the upper limit of the low temperature water. Since it can be maintained below the temperature, the low temperature water taken out from the low temperature part of the hot water tank can be supplied to the condensing part to prevent the coefficient of performance of the natural refrigerant heat pump device from decreasing.
On the other hand, when using a cogeneration device as a heat source unit and storing water heated by exhaust heat from an engine-driven generator or a fuel cell in a hot water storage tank, the temperature of the low temperature part of the hot water storage tank is set as above. Since it can be kept below the upper limit temperature of the low-temperature water, the low-temperature water taken out from the low-temperature part of the hot water tank is recovered as process water by condensing the water contained in the engine cooling water and the reformed gas of the fuel cell. Therefore, it is possible to prevent the cooling capacity of the engine or the fuel cell from being lowered by using it for cooling water or the like.
Further, for example, a general boiler or a water heater other than the natural refrigerant heat pump device or the cogeneration device can be used as the heat source device.

  An embodiment of a heat storage type hot water supply apparatus (hereinafter referred to as “the present hot water supply apparatus”) according to the present invention will be described with reference to the drawings.

[First Embodiment]
The hot water supply apparatus 100 of 1st Embodiment is demonstrated based on FIG.
The hot water supply apparatus 100 includes a temperature stratified hot water tank 1 and an outgoing pipe line 10 extending from an upper end 2a as a high temperature part of the hot water tank 1 to an outgoing connection part 10a to which a hot water supply outgoing pipe 11 is connected. Is provided. Further, when the hot water tap (an example of the hot water supply section) 15 connected to the hot water supply piping 10 is discharged, the mixing section 10b of the outgoing pipe 10 is taken out from the upper end 2a of the hot water tank 1 to the outgoing pipe 10. Hot water supply temperature setting control means A that mixes hot water with hot water and sets the temperature of the hot water to a predetermined set hot water temperature is provided in such a manner that the control device functions, for example.

The hot water tank 1 is configured to store hot water heated by the heat source device 40. Specifically, water flows from the lower end 3a of the hot water tank 1 to the upper end 2a via the heat source device 40, and then flows from the lower end 3a side to the upper end 2a side of the hot water tank 1. A cooling water pump 42 (for example, built in the heat source device 40) is provided, and the cooling water pump 42 is operated to cause water to flow through the cooling water pipe 41. Then, the water taken out from the lower end 3a side of the hot water tank 1 to the cooling water pipe 41 is heated by the heat source unit 40, and the heated hot water is supplied to the upper end part 2a side of the hot water tank 1 as hot water. .
As the heat source device 40, a boiler or a water heater is usually used, but a natural refrigerant heat pump device, a cogeneration device, or the like can be used.

A water supply line 25 to which clean water is supplied through a water meter (not shown) is connected to the lower end 3 a of the hot water tank 1, and relatively low temperature clean water is supplied from the water supply line 25. . And after heating the low-temperature water in the lower end part 3a of the hot water tank 1 to an appropriate target hot water temperature (for example, 75 ° C.) or higher by the heat source device 40, the hot water tank is returned to the upper end part 2a of the hot water tank 1. Reference numeral 1 denotes a so-called temperature stratification type in which hot water is stored in a form in which a high temperature layer 2 is formed at the top and a low temperature layer 3 is formed below the high temperature layer 2.
Specifically, a temperature sensor 43 that detects the temperature of the hot water supplied to the upper end 2 a side of the hot water tank 1 in the cooling water pipe 41 is provided, and the power of the cooling water pump 42 is controlled based on the detection result of the temperature sensor 43. Since the temperature of the hot water supplied to the upper end 2a side of the hot water tank 1 is controlled to be an appropriate temperature (for example, 75 ° C.), the hot water stored in the hot water tank 1 is as described above. It is stored in the form of a temperature stratification.
In addition, illustrations are omitted for auxiliary equipment or the like normally installed such as a pressure reducing valve (or a pressure reducing check valve) and a relief valve associated with the hot water tank 1 and a flow rate adjusting valve associated with the cooling water pipe 41. There are also things.

In the mixing section 10b of the forward pipe 10, the hot water supply pipe 25 connected to the lower end 3a of the hot water tank 1 is connected to the hot water extracted from the upper end 2a of the hot water tank 1 to the forward pipe 10. The temperature of hot water flowing through the three-way regulating valve 12 (an example of a mixing unit) that can mix the tap water taken in through the mixing ratio adjustment and the downstream side of the three-way regulating valve 12 of the forward pipe 10 is adjusted. A temperature sensor 13 for detection is provided.
In addition, a flow sensor 26 that detects the inflow of clean water into the hot water storage tank 1 is provided in the water supply pipe 25 connected to the lower end 3 a of the hot water storage tank 1.

  The hot water supply temperature setting control means A detects the hot water supply detected by the temperature sensor 13 while the hot water tap 15 is opened and the flow sensor 26 detects the inflow from the water supply pipe 25 to the hot water tank 1. Mixing of clean water with high-temperature hot water extracted from the upper end 2a of the hot water tank 1 by the three-way regulating valve 12 to the outgoing pipe 10 so that the water temperature becomes a preset hot water temperature of about 42 ° C. Control the amount. Then, in the hot water tap 15, hot water at the set hot water temperature is supplied through the outgoing pipe 10 and the hot water outgoing pipe 11, and the hot water can be discharged. Note that the three-way regulating valve 12 may be modified as appropriate, for example, a pair of regulating valves provided in each of the outgoing pipe 10 and the water supply pipe 25.

  The hot-water tap 15 may be a two-valve, single-lever, or various hot-water mixed type hot-water taps such as an automatic temperature control water tap. With the control means A, hot water at a set hot water temperature can be discharged from the hot water tap 15. Accordingly, even if the hot water tap 15 is a two-valve water tap that requires adjustment of the hot water mixing ratio each time it is used, hot water at the set hot water temperature is discharged at a desired flow rate by opening and closing only the handle on the hot water supply side. be able to.

  A check valve 27 for preventing a reverse flow of clean water is provided at a connection portion between the water supply pipe 25 and the lower end portion 3a of the hot water tank 1 and a connection portion between the water supply pipe 25 and the three-way regulating valve 12. 28 is provided.

  The above is the basic configuration of the hot water supply apparatus 100. The hot water supply apparatus 100 maintains the hot water storage state of the hot water tank 1 in an appropriate state even when the hot water supply temperature setting control means A as described above is provided. In addition, it has a characteristic configuration for realizing so-called immediate hot water discharge in which hot water having an appropriate temperature is discharged immediately after the start of hot water supply at the hot-water tap 15, and the characteristic configuration will be described below.

  That is, the present hot water supply apparatus 100 has a return pipe line 20 extending from a return connection part 20a to which a hot water supply return pipe 19 that takes in hot water after passing through the hot water supply going pipe 10 is connected to a lower end part 3a of the hot water tank 1. Is provided. Further, when hot water is not discharged from the hot water tap 15, hot hot water taken out from the upper end 2 a of the hot water storage tank 1 is passed through the outgoing pipe 10, the hot water outgoing pipe 11, the hot water return pipe 19 and the return pipe 20 in order. The hot water is circulated in such a manner that it is circulated back to the lower end 3a of the hot water tank 1, and the circulating flow rate of the hot water at the time of the hot water circulating operation is returned to the lower end 3a of the hot water tank 1. Circulation flow rate setting control means B that is set within a set circulation flow rate region in which the return temperature is equal to or lower than a predetermined low-temperature water upper limit temperature is provided, for example, in a form in which the control device functions.

The return pipe 20 is provided with a circulation pump 21 that sends hot water to the lower end 3 a of the hot water tank 1, and a check valve 22 that prevents back flow of the hot water.
Then, by operating the circulation pump 21, the hot water supply water circulation operation is performed when no hot water is discharged from the hot water tap 15, that is, when the inflow of clean water into the hot water storage tank 1 is not detected by the flow sensor 26. Can do. By performing such hot water supply circulation operation, hot water having a relatively appropriate temperature flows through the forward conduit 10 even when the hot water tap 15 is not hot. Therefore, immediately after the start of the hot water supply when the hot-water tap 15 is opened, the hot water of the appropriate temperature is circulated through the connecting portion 15a of the hot-water tap 15 with the hot-water supply piping 11, so that immediately without any time delay, A so-called immediate hot water supply can be realized such that hot water having an appropriate temperature is supplied to the hot water tap 15 and discharged.

Furthermore, the circulating flow rate setting control means B sets the circulating flow rate of hot water during the hot water circulating operation within the set circulating flow rate range (for example, a range of 0.1 L / min or less), so that the vicinity of the forward connection portion 10a. Then, hot water close to the temperature of the high temperature layer 2 of the hot water tank 1 flows, hot water having a temperature several tens of degrees lower than that flows due to heat dissipation at the end of the hot water supply piping 11, and the outside air temperature near the return connection portion 20a. Hot water having a temperature lower than the upper limit temperature of the low temperature water (for example, a temperature that does not exceed the outside air temperature by 10 ° C. or more in the summer, preferably a temperature that does not exceed the outside air temperature by 5 ° C. or more in the summer) flows.
Accordingly, since the temperature of the hot water returned to the lower end portion 3a of the hot water tank 1 through the return pipe 20 is kept low below the upper limit temperature of the low temperature water, the hot water flows into the low temperature layer 3 of the hot water tank 1. Even if it makes it, the temperature of the low temperature layer 3 of the hot water storage tank 1 will be maintained low so that it may be at least the above low temperature water upper limit temperature, for example, about 25 ° C.
Moreover, since the temperature of the low temperature layer 3 of the hot water tank 1 is maintained at a low temperature, the hot water tank 1 is supplied from the lower end 3a of the hot water tank 1 through the cooling water pipe 41 to the heat source device 40 such as a natural refrigerant heat pump device or a cogeneration device. Since the temperature of the low-temperature water is kept low, a decrease in the coefficient of performance of the natural refrigerant heat pump device and the cooling capacity of the cogeneration device is suppressed.

  Usually, since the hot water temperature at the hot water tap 15 is about 40 ° C., for example, in the hot water outlet pipe 11, the most upstream hot water tap 15 is about 45 ° C., and the most downstream hot water tap 15 is about 35 ° C. As such, if you select a set circulation flow rate area that is an indicator of the circulating flow rate of hot water during the hot water circulation operation, immediate hot water supply can be realized in that hot water that is not too hot and not cold will come out, For example, the set circulation flow rate region can be selected as a very small range such as a range of 0.1 L / min or less.

In addition, the temperature drop of the hot water supply in the going-out pipe line 10 and the hot-water supply going-out pipe 11 can also be adjusted by the thickness of the heat insulating material applied to the surface of the going-out pipe line 10 and the hot water supply going-out pipe line 11. That is, a relatively thin heat insulating material (for example, foamed polyethylene) is used from the hot water tank 1 to the hot water tap 15 on the most upstream side, and a thick heat insulating material is used from the hot water tap 15 on the most upstream side to the hot water supply portion 15 on the most downstream side. Thus, if each part of the outgoing pipe 10 and the hot water outlet pipe 11 is kept warm, the hot water temperature in the hot water tap 15 on the most upstream side is kept relatively low, and the hot water temperature in the hot water tap 15 on the downstream side is relatively low. Kept high. Therefore, any hot water tap 15 can be set to a temperature suitable for hot water supply, and the temperature difference between the hot water taps 15 can be kept small.
Incidentally, the amount of heat released from the forward pipe 10 and the hot water outlet pipe 11 is proportional to the temperature difference between the inside and outside of the pipe, so the hot water circulation operation in which the temperature difference is added to the circulating hot water as described above is the temperature difference. Less than those without.
It should be noted that maintaining the temperature of the outgoing pipe 10 and the hot water outlet pipe 11 sufficiently means to suppress the amount of heat dissipation, but here, the difference in hot water temperature for each hot water tap 15 during hot water circulation operation is reduced. It is also aimed at.
Further, the outgoing pipe 10 and the hot water supply outgoing pipe 11 are piped with a heat resistant pressure resistant material (for example, a copper pipe, a heat resistant PVC pipe, a heat resistant PVC lining steel pipe, etc.).

Furthermore, the hot water supply return pipe 19 and the return pipe line 20 use a small-diameter resin pipe (for example, a crosslinked polyethylene pipe having an inner diameter of 6 mm) without heat insulation.
That is, since the temperature of the hot water returning through the hot water return pipe 19 and the return pipe 20 is kept as low as possible below the upper limit temperature of the low-temperature water in the hot water circulation operation, the return pipe 20 is kept unheated and the flow rate of the hot water is further reduced. However, since it can be small within the set circulation flow rate region, it can be made into a small diameter, and since the operating temperature is low, no special heat resistance is required.

Further, the above-described three-way regulating valve 12 is configured to take in clean water through a water supply pipe 25 connected to the lower end 3 a of the hot water tank 1, and the return pipe 20 is connected to the lower end of the hot water tank 1. It will be connected to the water supply pipe 25 connected to the part 3a.
Therefore, when the hot water supply tap 15 is not discharged and the water supply pipe 25 side of the three-way regulating valve 12 is opened, the hot water supply circulation pipe is operated from the hot water supply return pipe 19 and the return pipe 20. There is a concern that most of the hot water returning to the lower end 3a side of 1 flows into the hot water supply line 25 side without flowing into the hot water storage tank 1.
Therefore, in the water supply pipe 25, the check valve 27 is connected by connecting the return pipe 20 closer to the hot water tank 1 than the check valve 27 provided at the connection portion with the lower end 3 a of the hot water tank 1. Can be made to function as hot water inflow restricting means for preventing the inflow of hot water from the return pipe 20 into the water supply pipe 25 at the lower end 3a of the hot water tank 1.
The hot water supply inflow restricting means is forcibly closing the water supply pipe 25 side of the three-way regulating valve 12 when the hot water tap 15 is not discharged, that is, during the hot water circulation operation, or the water supply pipe 25 itself is closed. It is possible to use various means such as providing an electromagnetic valve for forcibly closing. Further, when the hot water supply inflow restricting means is provided on the connection side of the water supply pipe 25 with the three-way regulating valve 12, the return pipe 20 is located upstream of the hot water flow inflow prevention means of the water supply pipe 25. Can be connected.
Further, the hot water inflow restricting means is omitted, and the hot water inflow from the return line 20 to the water supply line 25 at the lower end 3a of the hot water tank 1 is performed when the hot water tap 15 is not discharged, that is, during the hot water circulation operation. By adjusting the inflow amount, the low-temperature hot water returned to the return pipe 20 is mixed with the high-temperature hot water at an appropriate ratio in the three-way regulating valve 12. Therefore, the temperature of the hot water supplied to the hot-water tap 15 side through the outgoing pipe 10 at the time of the hot water circulation operation can be made appropriate.

Further, when the three-way regulating valve 12 provided in the mixing portion 10b of the outgoing pipe 10 is configured to open the outgoing pipe 10 when the hot water tap 15 is not discharged, the circulation is performed. The flow rate setting control means B simply operates the circulation pump 21 to supply hot water taken out from the hot water storage tank 1 through the three-way regulating valve 12 and the return pipe 10 and the return pipe when the hot water tap 15 is not hot. The hot water supply circulation operation can be performed in the form of circulation through the passage 20.
In addition, the circulation pump 21 can be stopped when the hot water tap 15 is discharged. However, since the circulation amount of the hot water is very small, it is not necessary to stop the circulation pump 21 separately.

[Second Embodiment]
The hot water supply apparatus 200 of 2nd Embodiment is demonstrated based on FIG. In addition, about the structure similar to other embodiment, the description may be omitted using the same code | symbol.
The hot water supply apparatus 200 shown in FIG. 2 is different from the hot water supply apparatus 100 shown in FIG. 1 in that the hot water supply bypass pipe 30 bypasses the three-way regulating valve 12 provided in the mixing section 10b in the forward pipe 10 and the hot water supply bypass. An orifice 31 for regulating the flow rate of clean water flowing through the pipeline 30 is added.

  That is, in the hot water supply apparatus 200, the three-way regulating valve 12 provided in the mixing portion 10b of the forward pipe 10 closes the forward pipe 10 when the hot water tap 15 is not discharged (during hot water circulation operation). When the hot water supply bypass pipe 30 is provided, the hot water storage tank 1 is provided with the hot water supply bypass pipe 30 through the hot water supply bypass pipe 30 when the hot water tap 15 is not discharged (during hot water circulation operation). The hot water taken out from the upper end 2a can be made to flow downstream from the three-way regulating valve 12 of the outgoing pipe 10 and circulated through the hot water outgoing pipe 11 and the hot water return pipe 19 or the like.

With this configuration, when the hot water supply at the hot water tap 15 is started, the hot hot water taken out from the upper end portion 2a of the hot water storage tank 1 is mixed with clean water by the three-way regulating valve 12, and the hot water supply described above Although the temperature setting by the temperature setting control means A is performed, hot hot water from the hot water supply bypass line 30 is mixed downstream, and the hot water temperature is shifted to the high temperature side.
Therefore, the temperature difference can be suppressed by providing the hot water supply bypass line 30 with an orifice 31 as bypass flow rate regulating means for regulating the flow rate of the hot water. Of course, the orifice 31 can also serve as a flow restrictor for setting the circulation flow rate in the hot water supply circulation operation within the set circulation flow rate region.

  The temperature sensor 13 used in the hot water supply temperature setting control means A may be installed upstream of the inflow side connection portion of the hot water supply bypass line 30 of the forward line 10. The accuracy of temperature setting in the hot water supply temperature setting control means A is improved by installing it on the downstream side of the outflow side connection portion of the bypass conduit 30. It is because the temperature deviation generation | occurrence | production of the hot water flowing through the hot water supply bypass line 30 can be suppressed by installing on the downstream side. However, if the flow rate of hot water in the hot water supply bypass line 30 is large, it is apparent that the characteristic (linearity) of the three-way regulating valve 12 has changed (deteriorated). The flow rate of hot water is never small.

  Further, the circulation flow rate setting control means B may control the circulation flow rate during the hot water supply circulation operation within the set circulation amount range so as to cancel the temperature change of the hot water supply due to the outside air temperature. Furthermore, the circulation flow rate of hot water is automatically adjusted by controlling the output of the circulation pump 21 so that the temperature of the hot water detected by the temperature sensor 13 or the like becomes appropriate during the hot water circulation operation. You may comprise as follows.

Next, based on FIG. 5, the result of having measured about the temperature of the hot water supply water and clean water when this hot water supply apparatus 200 of 2nd Embodiment was actually performed in the hot water supply circulating operation is demonstrated.
Here, the length of the outgoing pipe 10 and the hot water outlet pipe 11 is 14 m, and the hot water bypass pipe 30 has an orifice 31 provided with an opening having a diameter of 0.5 mm in a copper non-insulated pipe (about 1 m). The attached pipe, the hot water supply pipe 10 and the hot water supply pipe 11 have a 20 mm thick polyethylene insulated 15A copper pipe, the hot water return pipe 19 and the return pipe 20 have a 6 mm inner diameter cross-linked polyethylene pipe and a nominal diameter of 16 mm. A vinyl chloride tube was used.
The hot water supply going-out temperature indicates the temperature of hot water at a position about 1 m downstream from the outgoing connection part 10 a that is the outlet of the hot water supply device 200 in the hot water supply going-out pipe 11, and the hot water supply pipe end temperature is the same in the hot water supply going-out pipe 11. It shows the temperature of hot water at a position 14 m downstream from the connecting portion 10 a, and the hot water return temperature is the temperature of the hot water at a location about 1 m upstream from the return connecting portion 20 a that is the entrance of the hot water supply device 200 of the hot water return pipe 19. Indicates. Further, the circulating flow rate of hot water during the hot water circulation operation was set to 0.04 L / min.

From FIG. 5, the hot water pipe end temperature becomes a steady temperature in about 100 minutes. At that time, the hot water feed temperature is 44 ° C. and the pipe end temperature is 32 ° C. Therefore, this range (approximately 1 m to 14 m downstream from the outlet of the hot water supply apparatus 200) If the hot-water tap 15 is connected, the hot-water supply water having a temperature of approximately 32 to 44 ° C. is discharged without waiting time when the hot-water tap 15 is opened, thereby achieving the purpose of immediate hot water supply.
Moreover, since the temperature of the hot water in each part of the hot water supply piping 11 can be increased by increasing the circulating flow rate and can be decreased by decreasing the circulating flow rate, an appropriate temperature distribution can be created by adjusting the circulating flow rate. it can.
Table 1 below summarizes the equilibrium temperature of each part at the time of each circulation flow rate by experimenting under the outdoor air temperature condition in summer. It can be seen that the influence of the opening diameter of the orifice 31 is small.

On the other hand, when the hot water supply at the hot water tap 15 is started from a steady state, the hot water supply having a high temperature existing upstream of the hot water tap 15 in the hot water supply outlet pipe 11 until the hot water supply device 200 sends out the hot water at the set hot water supply temperature. Since the water is discharged, there is a concern about burns and the like.
FIG. 6 shows a state in which hot water is discharged from the hot water tap 15 connected to a position about 10 m downstream from the forward connection portion 10a in the hot water supply piping 11 after the temperature of the hot water in each portion reaches equilibrium under the outdoor temperature in summer. This shows changes in the tapping temperature (transient response characteristics). The hot water supply temperature is controlled from the equilibrium temperature of 45 ° C. to the preset hot water supply temperature of 42 ° C. through a transient characteristic of temperature control for about 5 seconds. Here, the time 0 is not linked to the opening of the hot water tap, and the hot water discharge starts from about 10 seconds. On the other hand, after water having a temperature substantially equal to the outside air temperature in the first branch pipe comes out from the hot water tap 15, the temperature rises because hot water in the upstream of the hot water supply piping 11 is sequentially sent out. After that, the temperature-controlled hot water supply (42 ° C.) is stably discharged. If this overshoot is large, there is a possibility of burns.
As the circulating flow rate during the hot water circulating operation increases, the temperature of the hot water in the hot water supply piping 11 increases, so the overshoot increases. The results of measuring the maximum temperature including overshoot in the experiment are shown in Table 2 below. From Table 2 below, it can be seen that the overshoot can be suppressed by appropriately setting the circulation flow rate during the hot water supply circulation operation (for example, 0.04 L / min or less).

  By the way, at the time of hot water discharge at the hot water tap 15, as described above, a deviation occurs in the temperature control when the bypass flow rate of the hot water supply through the hot water supply bypass line 30 is increased. It is. However, the temperature sensor 13 is installed upstream of the inflow portion of the hot water supply bypass conduit 30 in the forward conduit 10. From Table 3 below, it can be seen that if the aperture diameter of the orifice 31 that regulates the bypass flow rate of the hot water by the hot water supply bypass line 30 is selected to be 1.0 mm or less, the temperature deviation that is concerned can be suppressed.

[Third Embodiment]
This hot water supply apparatus 300 of 3rd Embodiment is demonstrated based on FIG. In addition, about the structure similar to other embodiment, the description may be omitted using the same code | symbol.
The hot water supply apparatus 300 shown in FIG. 3 is composed of a pair of adjustment valves 12a and 12b in which the three-way adjustment valve 12 is provided in each of the forward pipe 10 and the water supply pipe 25 with respect to the hot water supply apparatus 200 shown in FIG. Furthermore, a water supply bypass line 32 extending from the water supply line 25 to the downstream side of the three-way regulating valve 12 of the forward line 10, and an orifice 33 for regulating the flow rate of clean water flowing through the water supply bypass line 32 Is added. Further, in the hot water supply apparatus 300, the hot water supply line 25 is configured to allow the inflow of hot water from the return pipe 20 to the outgoing pipe 10 through the water supply pipe 25 and the water supply bypass line 30 during the hot water circulation operation. The return pipe 20 is connected to the upstream side of the check valve 27 provided at the connection portion with the lower end 3a of the hot water tank 1.

  That is, in the hot water supply device 300, when the hot water tap 15 is not discharged (during hot water circulation), the regulating valve 12a provided on the upstream side of the mixing portion 10b in the forward pipe 10 closes the forward pipe 10. In addition, when the regulating valve 12b provided in the water supply line 25 is configured to close the water supply line 25, the orifice 31 of the hot water supply bypass line 30 and the orifice 33 of the water supply bypass line 32 are provided. If the sizing ratio is appropriately determined, the hot water hot water taken out from the hot water tank 1 is not directly supplied to the hot water tap 15 side of the outgoing pipe 10 during the hot water circulation operation, but an appropriate amount. Hot water at an appropriate temperature (for example, 50 ° C.) mixed with water is supplied. As a result, it is possible to suppress the danger of hot hot water being discharged immediately after the start of hot water supply at the hot water tap 15.

[Fourth Embodiment]
The hot water supply apparatus 400 according to the fourth embodiment will be described with reference to FIG. In addition, about the structure similar to other embodiment, the description may be omitted using the same code | symbol.
In the hot water supply apparatus 400 shown in FIG. 4, the hot water supply apparatus 200 shown in FIG. 2 includes a temperature-stratified hot water storage tank 1 ′ and heat exchange with high-temperature heat storage water taken out from the hot water storage tank 1 ′. It is different in that it is configured to take out the hot water heated to the outgoing pipe 10 as hot water.

That is, in the hot water supply apparatus 400, the hot water storage tank 1 ′ is heated by the heat source device 40 in a form in which the high temperature layer 2 ′ is formed in the upper portion and the low temperature layer 3 ′ is formed in the lower portion of the high temperature layer 2 ′. It is configured as a so-called temperature stratification type for storing heat storage water.
In addition, a circulation pipe 45 extending from the upper end 2a ′ to the lower end 3a ′ of the hot water tank 1 ′ is provided, and the heat storage water taken out from the upper end 2a ′ of the hot water tank 1 ′ is provided in the circulation pipe 45. Heat supply water supplied from the water supply line 25 by heat exchange between the circulation pump 46 that circulates so as to be sent out toward the lower end 3 a ′ and high-temperature heat storage water that circulates through the circulation line 45, A heat exchanger 47 is provided for supplying the heated water after heating to the outgoing pipe 10 as hot water.

  In the hot water supply apparatus 400, when the hot water is discharged from the hot water tap 15, the circulation pump 46 is operated to supply the high-temperature heat storage water taken out from the upper end 2a ′ of the hot water tank 1 ′ to the heat exchanger 47. Thus, the hot water supply water heated by the heat exchange with the heat storage water is taken out from the hot water supply outflow portion 48 of the heat exchanger 47 as the high temperature portion to the outgoing pipe 10. Therefore, the hot water temperature setting control means A described above can mix the hot water with the hot water taken out to the outgoing pipe 10 and set the temperature of the hot water to a predetermined set hot water temperature.

  On the other hand, the return pipe line 20 is connected to the upper water inflow portion 49 of the heat exchanger 47 as a low temperature portion. When the hot water tap 15 is not discharged (during hot water circulation operation), the heat exchanger 47 stores heat. Hot water that has received the heat of the water is circulated in such a manner that it is passed through the forward pipe 10 and the return pipe 20 in order and then returned to the upper water inflow portion 49 side of the heat exchanger 47.

  Since the heat load in the heat exchanger 47 during this hot water supply circulation operation is small, when the circulation pump 46 is operated in the same way as during hot water discharge, the temperature returning to the lower end 3a ′ of the hot water tank 1 ′ increases and the hot water tank 1 Since the lower layer temperature of 'is raised, it is necessary to control the flow rate of the circulation pump 46. A stop signal for the flow sensor 26 can be used as a start signal for this control, and it can be controlled at the hot water tap 15 by controlling the number of revolutions of the circulation pump 46, ON / OFF control at predetermined time intervals, or flow rate control by a valve. It is possible to control the circulation pump 46 at the time of non-hot water (during hot water circulation operation). It is also possible to apply feedback control to the circulation flow rate of the heat storage water by the circulation pump 46 while detecting the temperature of the heat storage water outlet portion side of the heat exchanger 47 with a temperature sensor.

  In the first to fourth embodiments, the hot water storage tank 1 and the hot water storage tank 1 ′ are configured as a sealed tank, but are provided with an air release equipped with a pump or the like for discharging water from the upper part into the lower part. It may be configured in a mold.

  The present invention relates to hot water supply in which the temperature of hot water supplied to the hot water supply unit is set to a predetermined set hot water supply temperature by mixing low temperature clean water with hot hot water extracted from the hot water storage tank in the mixing unit of the outgoing pipe It is a regenerative hot water supply device equipped with temperature setting control means, and in particular, the hot water storage state of the hot water storage tank is set in order to prevent a decrease in the coefficient of performance of the natural refrigerant heat pump device as a heat source device and a decrease in the cooling capacity of the cogeneration device. It can be effectively used as a hot water supply that can be realized while maintaining an appropriate one.

The schematic block diagram which shows 1st Embodiment of the thermal storage type hot-water supply apparatus which concerns on this invention. The schematic block diagram which shows 2nd Embodiment of the thermal storage type hot water supply apparatus which concerns on this invention. The schematic block diagram which shows 3rd Embodiment of the thermal storage type hot water supply apparatus which concerns on this invention. The schematic block diagram which shows 4th Embodiment of the thermal storage type hot-water supply apparatus which concerns on this invention. The graph which shows the time-dependent change of each part temperature during hot water supply circulation operation The graph which shows the time-dependent change of each part temperature at the time of tapping

Explanation of symbols

A: Hot water supply temperature setting control means B: Circulating flow rate setting control means 1, 1 ': Hot water storage tanks 2a, 2a': Upper end (high temperature part)
3a, 3a ′: lower end (low temperature part)
10: Outward pipe line 10a: Outward connection part 10b: Mixing part 11: Hot water supply outgoing pipe 12: Three-way regulating valve 15: Hot water tap (hot water supply part)
19: Hot water supply return pipe 20: Return pipe line 20a: Return connection section 25: Water supply pipe line 30: Hot water supply bypass pipe 31: Orifice (bypass flow rate regulating means)
32: Water supply bypass pipeline 40: Heat source machine 48: Hot water supply outflow section (high temperature section)
49: Water supply inlet (low temperature part)
100, 200, 300, 400: Regenerative water heater

Claims (8)

A temperature-stratified hot water tank;
From the hot part of the hot water storage tank, the outgoing pipe line to the outgoing connection part to which the hot water supply outgoing pipe is connected,
When hot water is discharged from a hot water supply unit connected to the hot water supply outlet pipe, hot water is mixed into hot water extracted from the high temperature part of the hot water storage tank to the outgoing pipe line in the mixing part of the forward pipe, and the hot water supply A heat storage type comprising a hot water supply temperature setting control means for controlling a mixing ratio of the clean water to water and setting a temperature of hot water discharged from the forward connection portion to the hot water supply forward piping to a predetermined hot water supply temperature. A water heater,
From a return connection part to which a hot water supply return pipe that takes in hot water after passing through the hot water supply outlet pipe is connected, a return pipe line leading to a low temperature part of the hot water storage tank,
When hot water is not discharged in the hot water supply part, hot water taken out from the high temperature part of the hot water storage tank is passed through the outgoing pipe, the hot water outgoing pipe, the hot water return pipe, and the return pipe in order, The hot water circulating operation is performed so that the hot water is circulated in the form of returning to the low temperature portion of the hot water tank, and the circulating flow rate of the hot water during the hot water circulating operation is set to a predetermined low temperature water. A regenerative hot water supply apparatus provided with a circulating flow rate setting control means for setting within a set circulating flow rate region that is equal to or lower than an upper limit temperature.   The regenerative hot water supply apparatus according to claim 1, wherein the low-temperature water upper limit temperature is set to a temperature that does not exceed the outside air temperature by 10 ° C or more in summer. The hot water storage tank stores hot water in a form in which a high temperature layer is formed at the top and a low temperature layer is formed below the high temperature layer,
The heat storage according to claim 1 or 2, wherein the forward pipe is connected to an upper end of the hot water tank as the high temperature part, and the return pipe is connected to a lower end of the hot water tank as the low temperature part. Water heater. The mixing unit is configured to close the forward pipe line when no hot water is discharged from the hot water supply unit,
The hot water supply circulation operation is performed by flowing hot water taken out from the high temperature portion of the hot water storage tank to the downstream side of the mixing portion of the forward pipeline through the hot water bypass pipeline bypassing the mixing portion in the outgoing pipeline. The regenerative hot water supply apparatus according to any one of claims 1 to 3, wherein the regenerative hot water supply apparatus is configured to perform.   The regenerative hot water supply apparatus according to claim 4, wherein a bypass flow rate regulating means for regulating a flow rate of the hot water is provided in the hot water supply bypass line. The mixing unit is configured to take in the clean water through a water supply pipe connected to a low temperature part of the hot water tank,
The regenerative hot water supply apparatus according to any one of claims 1 to 5, further comprising hot water inflow restricting means for restricting inflow of hot water from the return pipe to the forward pipe in a low temperature portion of the hot water tank. .   The regenerative hot water supply apparatus according to any one of claims 1 to 6, wherein the circulation flow rate setting control unit is configured to control a circulation flow rate during the hot water supply water circulation operation.   The regenerative hot water supply apparatus according to any one of claims 1 to 7, further comprising a heat source device that heats low-temperature water taken out from a low-temperature portion of the hot-water storage tank and supplies the low-temperature water to the high-temperature portion of the hot-water storage tank.

Images