JP5268152B2 - Hot water storage water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage water heater capable of improving the COP (coefficient of performance) of the storage water heater and preventing accumulation of separated air within a hot water storage tank. <P>SOLUTION: First and second piping is communicated and connected with upper and lower parts of the hot water storage tank 1. The first piping is connected to a first port of a three-way valve 8 with three first to third ports, and the second piping is connected to the second port. A vent tube 26 for releasing overpressure within the hot water storage tank 1 is connected to the third port. An overpressure relief valve 10 is provided in the vent tube 26. A control device 33 performs opening control of the three-way valve 8 so that the second port and the third port are communicated with each other and the first port is blocked and switch control so that the first port and third port are intermittently communicated with each other, when hot water within the hot water storage tank 1 is boiled up by a heat pump 2. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a hot water storage type hot water supply apparatus, and in particular, when releasing the overpressure of a hot water storage tank, high temperature water is prevented from being drained from an overpressure relief valve as much as possible, and the precipitated air is accumulated in the hot water storage tank. The present invention relates to a hot water storage type hot water supply device that can be prevented.

  In hot water storage water heaters such as heat pump water heaters and electric water heaters, hot water boiled by heat pumps, electric heaters, etc. is temporarily stored in hot water storage tanks, and hot water from hot water storage tanks to baths and hot water taps as needed. Is supplied. Therefore, as the temperature of the hot water in the hot water storage tank rises during boiling, the hot water in the hot water storage tank expands and the internal pressure rises. An overpressure relief valve for releasing the overpressure of the hot water storage tank is provided so that the rising internal pressure does not exceed a certain pressure. As for how to install this overpressure relief valve, those described in Patent Documents 1-6 are known.

  FIG. 4 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Document 1. This hot water storage type hot water supply apparatus includes two stratified hot water storage type hot water storage tanks 101 and 102. The hot water storage tank 101 is a low temperature side hot water storage tank, and the hot water storage tank 102 is a high temperature side hot water storage tank. In FIG. 4, the hot water boiling circuit in the hot water storage tanks 101 and 102 is omitted. The cold water supplied from the water supply pipe 103 is supplied to the lower part of the hot water storage tank 101 on the low temperature side through the pressure reducing check valve 104. The top of the hot water storage tank 101 and the bottom of the hot water storage tank 102 are communicated with each other via a connecting pipe 105. A hot water supply pipe 106 is connected to the top of the hot water storage tank 102, and hot water in the hot water storage tank 102 is discharged through the hot water supply pipe 106. Vent pipes 107 and 108 are connected to the connecting pipe 105 and the hot water supply pipe 106 near the tops of the hot water storage tanks 101 and 102, respectively. The vent pipes 107 and 108 are provided with overpressure relief valves 109 and 110, respectively. Here, the operating pressure of the overpressure relief valve 109 is set lower than the operating pressure of the overpressure relief valve 110.

  When boiling the hot water in the hot water storage tanks 101 and 102, the water at the bottom of the hot water storage tank 101 is sent to the boiling circuit, and after boiling in the boiling circuit, the hot water having a high temperature is stored in the hot water. Returned to the top of the tank 102. When the internal pressure in the hot water storage tanks 101 and 102 rises due to the heated hot water, the operating pressure of the overpressure relief valve 109 is lower than the operating pressure of the overpressure relief valve 110, so the overpressure relief valve 109 is opened first. Thus, the overpressure water in the hot water storage tank 101 is discharged through the vent pipe 107. Here, the temperature of the hot water in the hot water storage tank 101 is lower than that of the hot water in the hot water storage tank 102. Therefore, since the discharged overpressure water becomes a relatively low temperature hot water, heat loss due to discharge of the overpressure water can be suppressed.

  FIG. 5 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Literatures 2 and 3. In FIG. 5, only the main part of the piping is shown, and the other parts are omitted. This hot water storage type hot water supply apparatus includes one stratified hot water storage tank 101, and a hot water supply pipe 103 is connected to the bottom of the hot water storage tank 101, and a hot water supply pipe 106 is connected to the top. As in FIG. 4, the water supply pipe 103 is provided with a pressure reducing check valve 104. In this hot water storage type hot water supply apparatus, the vent pipe 111 is branched and connected to the water supply pipe 103 near the bottom of the hot water storage tank 101, and the vent pipe 111 is provided with an overpressure relief valve 112.

  In this case, when the pressure in the hot water storage tank 101 rises due to boiling of the hot water in the hot water storage tank 101, the overpressure relief valve 112 is opened, and the low pressure water at the bottom of the hot water storage tank 101 is discharged. Accordingly, since the overpressure water discharged in this case also becomes low-temperature water, heat loss due to the discharge of the overpressure water can be suppressed.

  FIG. 6 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Document 4. In addition, in FIG. 6, only the piping of the principal part is shown and other than that is omitted. This hot water storage type hot water supply apparatus includes one stratified hot water storage tank 101, and a hot water supply pipe 103 is connected to the bottom of the hot water storage tank 101. As in FIG. 4, the water supply pipe 103 is provided with a pressure reducing check valve 104. In the hot water storage type hot water supply apparatus of FIG. 6, a hot water discharge pipe 113 is connected to the top of the hot water storage tank 101, a branch water pipe 114 is branched from the water supply pipe 103, and the hot water discharge pipe 113 and the branch water pipe 114 have a mixing valve 115. To the hot water supply pipe 106. Further, in order to release the overpressure of the hot water storage tank 101, vent pipes 107 and 111 are connected to the hot water discharge pipe 113 near the top of the hot water storage tank 101 and the water supply pipe 103 near the bottom of the hot water storage tank 101, respectively. The vent pipes 107 and 111 are provided with overpressure relief valves 109 and 112, respectively. Here, the operating pressure of the overpressure relief valve 112 is set lower than the operating pressure of the overpressure relief valve 109.

  In this case, when the pressure in the hot water storage tank 101 rises due to boiling of hot water in the hot water storage tank 101, the operating pressure of the overpressure relief valve 112 is lower than the operating pressure of the overpressure relief valve 109. The valve 112 is opened, and the overpressure water in the hot water storage tank 101 is discharged through the vent pipe 111. Therefore, since the discharged overpressure water becomes water at the bottom of the hot water storage tank 101, heat loss due to discharge of the overpressure water can be suppressed.

  FIG. 7 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Document 5. In FIG. 7, only the main part of the piping is shown, and the other parts are omitted. This hot water storage type hot water supply apparatus includes one stratified hot water storage tank 101, and a hot water supply pipe 103 is connected to the bottom of the hot water storage tank 101. As in FIG. 4, the water supply pipe 103 is provided with a pressure reducing check valve 104. In the hot water storage type hot water supply apparatus of FIG. 7, a hot water discharge pipe 113 is connected to the top of the hot water storage tank 101, and an intermediate hot water intake pipe 116 is connected to the vicinity of the center of the hot water storage tank 101. The hot water outlet pipe 113 and the intermediate temperature water intake pipe 116 are connected to the hot water outlet pipe 118 via the mixing valve 117. Further, a branch water pipe 114 is branched from the water supply pipe 103, and the hot water discharge pipe 118 and the branch water pipe 114 are connected to the hot water supply pipe 106 via the mixing valve 115. A vent pipe 107 is branchedly connected to the hot water outlet pipe 118. The vent pipe 107 is provided with an overpressure relief valve 109.

  When boiling the hot water in the hot water storage tank 101, the opening degree of the mixing valve 117 is controlled in a direction in which the intermediate hot water intake pipe 116 and the hot water discharge pipe 118 communicate with each other. As a result, when the pressure in the hot water storage tank 101 rises due to boiling of the hot water in the hot water storage tank 101, the overpressure relief valve 109 is opened, and hot water near the center of the hot water storage tank 101 passes through the vent pipe 107. It is discharged as pressurized water. Therefore, since the discharged overpressure water becomes middle temperature water in the central portion of the hot water storage tank 101, heat loss due to discharge of the overpressure water can be suppressed to be relatively low.

  FIG. 8 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Document 6. In addition, in FIG. 8, only the piping of the principal part is shown and other than that is omitted. This hot water storage type hot water supply apparatus includes one stratified hot water storage tank 101, and a hot water supply pipe 103 is connected to the bottom of the hot water storage tank 101. As in FIG. 4, the water supply pipe 103 is provided with a pressure reducing check valve 104. In the hot water storage type hot water supply apparatus of FIG. 8, a hot water discharge pipe 113 is connected to the top of the hot water storage tank 101, and the hot water discharge pipe 113 is branched into two, a bath side hot water discharge pipe 113a and a hot water tap side hot water discharge pipe 113b. On the other hand, a branch water pipe 114 is branched from the water supply pipe 103, and this branch water pipe 114 is also branched into two, a bath side branch water pipe 114a and a hot water tap side branch water pipe 114b. The bath side hot water discharge pipe 113a and the bath side branch water pipe 114a are connected to the bath side hot water supply pipe 106a through a mixing valve 115a. The hot-water tap side hot water outlet pipe 113b and the hot-water tap side hot water outlet pipe 116b are connected to the hot-water tap side hot water supply pipe 106b through the mixing valve 115b. The bath-side hot water supply pipe 106 a is provided with on-off valves 119, 120. A vent pipe 107 is branched on the upstream side of the on-off valves 119, 120, and an overpressure relief valve 109 is provided on the vent pipe 107. It has been.

  When boiling hot water in the hot water storage tank 101, the opening of the mixing valve 115a is controlled in a direction in which the bath side branch water pipe 114a and the bath side hot water supply pipe 106a communicate with each other. As a result, when the pressure in the hot water storage tank 101 rises due to the boiling of hot water in the hot water storage tank 101, the internal pressure of the hot water storage tank 101 passes through the water supply pipe 103, the branch water pipe 114, the bath side branch water pipe 114a, and the bath side hot water supply pipe 106a. It is transmitted to the vent pipe 107. Then, the overpressure relief valve 109 is opened, and the water stored in the bath side hot water supply pipe 106a from the bath side branch water pipe 114a by being pushed by the hot water near the lower part in the hot water storage tank 101 through the vent pipe 107 is used as overpressure water. Discharged. Accordingly, since the discharged overpressure water becomes residual water in the pipe, heat loss due to discharge of the overpressure water can be suppressed. In addition, when boiling is finished, the opening of the mixing valve 115a is controlled in a direction in which the bath-side hot water discharge pipe 113a and the bath-side hot water supply pipe 106a communicate with each other.

JP-A-10-205858 Utility Model Registration No. 3057490 JP 2007-155197 A JP 2004-85060 A JP 2006-64344 A JP 2006-145047 A

  In each of the above conventional hot water storage type hot water supply devices, when the internal pressure in the hot water storage tank rises, each overpressure relief valve releases the pressure, so that the pressure in the hot water storage tank is prevented from becoming an excessive pressure. 5 to 8, when releasing the overpressure of the hot water storage tank, hot water having a low temperature at the bottom or center of the tank is discharged as overpressure water, so that heat loss due to overpressure release is suppressed. Therefore, the COP (coefficient of performance) of the hot water storage type hot water supply apparatus can be improved.

  However, the conventional hot water storage type hot water supply apparatus of the above-described method shown in FIGS. That is, when boiling of hot water in the hot water storage tank is performed, the solubility of hot water gas decreases as the temperature of the hot water rises. Therefore, the gas component dissolved in the hot water is separated and deposited and stored in the upper part of the hot water storage tank. If the hot water tap at the end of the hot water pipe is opened while the precipitated air is stored in the upper part of the hot water storage tank, air and hot water are released together from the hot water tap, causing a noise such as a gobogobo, which surprises the user. . In order to prevent this, an automatic air vent valve must be attached to the upper part of the hot water storage tank, but in that case, there is a problem that costs are increased.

  In that respect, in the hot water storage type hot water supply apparatus of Patent Document 6 shown in FIG. 8, when it is necessary to vent the air stored in the upper part of the hot water storage tank 101, the mixing valve 115a is connected to the bath side hot water discharge pipe 113a and the bath side hot water supply. The opening is set so as to communicate with the pipe 106a. Thus, when a pressure increase due to heating occurs, the mixing valve 115a and the overpressure relief valve 109 whose opening degree is set on the bath side hot water discharge pipe 113a side through the pipe connected to the upper part of the hot water storage tank 101 for the expanded water and air are opened. Through the vent pipe 107. Thereby, the air pool of the hot water storage tank 101 upper part can be suppressed as much as possible.

  However, the boiling of hot water in the hot water storage tank 101 is performed in a state in which the mixing valve 115a is set to open so that the bath side hot water discharge pipe 113a and the bath side hot water supply pipe 106a communicate with each other in order to evacuate the air above the hot water storage tank 101. In this case, the high temperature water in the upper part of the hot water storage tank 101 is discharged from the vent pipe 107 through the overpressure relief valve 109 as expanded water. Therefore, the heat loss accompanying overpressure release becomes large, resulting in a problem that the COP of the hot water storage type hot water supply apparatus is lowered.

  Accordingly, an object of the present invention is to provide a hot water storage type hot water supply apparatus capable of improving the COP of the hot water storage type hot water supply apparatus and preventing accumulation of precipitated air in the hot water storage tank.

A first configuration of a hot water storage type hot water supply apparatus according to the present invention includes a hot water storage tank for storing hot water,
A boiling means for boiling hot water stored in the hot water storage tank;
A first pipe connected to the upper part of the hot water storage tank;
A second pipe connected in communication with the lower part of the hot water storage tank;
A vent pipe for releasing the overpressure in the hot water storage tank;
An overpressure relief valve provided in the vent pipe;
There are three ports, a first port, a second port, and a third port. The first port is connected to the first port, the second port is connected to the second port, and the third port is connected to the third port. Is a three-way valve with a vent pipe,
When boiling the hot water in the hot water storage tank by the boiling means, the three-way valve is opened to the state where the second port and the third port communicate with each other and the first port is shut off. Control means for controlling and switching control so that the first port and the third port communicate intermittently;
It is provided with.

  According to this configuration, when boiling the hot water in the hot water storage tank by the boiling means, the three-way valve is in a state where the second pipe and the vent pipe communicate with each other. As the temperature rises, the low temperature water (or hot water) at the lower part of the hot water storage tank is discharged from the vent pipe through the second pipe and released. Thereby, the heat loss accompanying overpressure release is suppressed, and the COP of the hot water storage type hot water supply apparatus can be improved.

  On the other hand, the control means controls the three-way valve so that the first port and the third port communicate with each other intermittently, so that the air accumulated in the upper part of the hot water tank is vented through the first pipe at the time of the switching. Discharged from the tube. As a result, it is possible to suppress as much as possible the adverse effects of air accumulating on the hot water storage tank. In this air venting operation, the hot water at the upper part of the hot water storage tank is discharged from the vent pipe. However, since the air venting operation is performed intermittently, the heat loss due to the air venting is small. Therefore, the COP of the hot water storage type hot water supply apparatus can be kept high.

  According to a second configuration of the hot water storage type hot water supply apparatus of the present invention, in the first configuration, the control means temporarily connects the three-way valve to the first port and the third port every predetermined time. The opening degree is controlled so as to communicate with the port.

  In this way, by performing air venting at predetermined intervals, it is possible to suppress as much as possible the adverse effects caused by the accumulation of air in the upper part of the hot water storage tank.

  According to a third configuration of the hot water storage type hot water supply apparatus according to the present invention, in the first configuration, the control means is configured so that each time the integrated value of the temperature rise in the hot water storage tank increases by a predetermined value, the three-way The opening degree of the valve is temporarily controlled so that the first port and the third port communicate with each other.

  The solubility of the hot water gas in the hot water storage tank decreases as the temperature increases. Therefore, it is considered that air is deposited in the hot water storage tank every time the temperature of the hot water changes by a certain temperature. Accordingly, by performing air venting every time the temperature in the hot water storage tank changes by a predetermined temperature, it is possible to suppress as much as possible the adverse effects caused by the accumulation of air in the upper part of the hot water storage tank.

According to a fourth configuration of the hot water storage type hot water supply apparatus according to the present invention, in any one of the first to third configurations, the hot water storage tank includes a plurality of hot water storage tanks, and each of the hot water storage tanks is provided on the water supply side. The upper part of the previous hot water storage tank is connected in series with the bottom of the subsequent hot water storage tank,
The first pipe is connected in communication with the upper part of the last hot water storage tank,
The second pipe is connected to the lower part of the hot water storage tank in the foremost stage.

  As described above, according to the present invention, when boiling, the second pipe connected to the lower part of the hot water storage tank and the vent pipe are connected to supply water (or hot water) having a lower temperature at the lower part of the hot water storage tank. By discharging and releasing the hot water storage tank, heat loss due to overpressure release can be suppressed, and the COP of the hot water storage hot water supply apparatus can be improved. On the other hand, the three-way valve is controlled to be intermittently connected to the first inflow port and the third outflow port, and the air accumulated in the upper part of the hot water storage tank is discharged from the vent pipe through the first pipe. As a result, it is possible to suppress as much as possible the harmful effects caused by the accumulation of air in the upper part of the hot water storage tank. Further, since the air venting operation is performed intermittently, the heat loss associated with air venting is small, and the COP of the hot water storage type hot water supply device can be kept high.

It is a principal part piping diagram showing the structure of the hot water storage type hot water supply apparatus which concerns on Example 1 of this invention. It is a principal part piping diagram showing the structure of the hot water storage type hot water supply apparatus which concerns on Example 1 when there is no memorial circuit. It is a principal part piping diagram showing the structure of the hot water storage type hot water supply apparatus which concerns on Example 2 of this invention. 6 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Document 1. FIG. It is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Literatures 2 and 3. 6 is a schematic piping diagram showing how to install an overpressure relief valve in a hot water storage type hot water supply apparatus described in Patent Document 4. FIG. 6 is a schematic piping diagram showing how to install an overpressure relief valve in a hot water storage type hot water supply apparatus described in Patent Document 5. FIG. FIG. 10 is a schematic piping diagram showing how to install an overpressure relief valve in the hot water storage type hot water supply apparatus described in Patent Document 6.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a main part piping diagram showing a configuration of a hot water storage type hot water supply apparatus according to Embodiment 1 of the present invention. In the present embodiment, an example of a hot water storage type hot water supply apparatus including one stratified hot water storage tank 1 for storing hot water is shown.

  The hot water storage type hot water supply apparatus of the present embodiment includes a hot water storage tank 1, a heat pump 2, a memorial heat exchanger 3, a boiling pump 4, a memorial pump 5, a bath circulation pump 6, a switching three-way valve 7, 8, an overpressure relief valve. 10, three-way mixing valves 11 and 12, check valves 13 and 14, and on-off valve 15 are provided.

  The hot water storage tank 1 is a stratified hot water storage tank that stores hot water. The heat pump 2 is a boiling means for boiling hot water stored in the hot water storage tank 1. The heat pump 2 includes a heat pump 16 that pumps up heat by exchanging heat with air, and a boiling heat exchanger 17 that heats the heat pumped up by the heat pump 16 to hot water in the hot water storage tank 1. The memorial heat exchanger 3 is a heat exchanger that performs heat exchange between hot water in the hot water storage tank 1 and bathtub water in the bathtub B.

  On the side surface of the hot water storage tank 1, temperature sensors 32a, 32b, 32c and 32d for detecting the temperature of hot water in the tank are installed at respective heights from the upper part to the lower part.

  A water supply pipe 27 for supplying water from the tap water is connected to the bottom of the hot water storage tank 1. The water supply pipe 27 is provided with a pressure reducing check valve 28. A hot water supply pipe 29 for discharging hot water in the hot water storage tank 1 is connected to a hot water tap or the like (not shown) at the top of the hot water storage tank 1. In the middle of the hot water supply pipe 29, a three-way mixing valve 11 having two inflow ports and one outflow port is provided. One inflow port and outflow port of the three-way mixing valve 11 are connected to a hot water supply pipe 29, and a branch pipe 30 is connected to the other inflow port. The branch pipe 30 has an upstream pipe end connected to a water supply pipe 27 between the pressure reducing check valve 28 and the hot water storage tank 1. The three-way mixing valve 11 is a valve for mixing hot water fed from the upstream hot water supply pipe 29 and water fed from the branch pipe 30 at a desired ratio and feeding the water to the downstream hot water supply pipe 29. .

  A boiling circuit is connected from the bottom of the hot water storage tank 1 to the upper part of the hot water storage tank 1 via the boiling pump 4, the boiling heat exchanger 17, and the switching three-way valve 7. A pipe from the bottom of the hot water storage tank 1 to the boiling heat exchanger 17 via the boiling pump 4 is called a boiling forward pipe 18, and the hot water storage tank 1 passes from the boiling heat exchanger 17 via the switching three-way valve 7. The pipe that reaches the top of the tube is referred to as a boiling return pipe 19. A bypass pipe 20 is connected from the switching three-way valve 7 to the bottom of the hot water storage tank 1. Between the heat pump 16 and the boiling heat exchanger 17, a heat medium circulation pipe 21 for circulating the heat medium is provided in an annular shape.

  In addition, a remedy circuit is connected from the upper part of the hot water storage tank 1 to the lower part of the hot water storage tank 1 via the switching three-way valve 8, the remedy heat exchanger 3, and the remedy pump 5. A pipe from the upper part of the hot water storage tank 1 to the remedy heat exchanger 3 via the switching three-way valve 8 is called a remedy forward pipe 22, and the hot water storage tank 1 from the remedy heat exchanger 3 through the remedy pump 5. The piping leading to the lower part of the pipe is called the memorial return pipe 23. The switching three-way valve 8 includes three ports, a first port, a second port, and a third port. The first port and the second port are each connected to the tracking tube 22. A vent tube 26 for releasing overpressure is connected to the third port. An overpressure relief valve 10 is provided in the middle of the vent pipe 26, and its end is released to atmospheric pressure.

  In addition, bath water circulation pipes 24 and 25 are piped between the memory heat exchanger 3 and the bathtub B. The bathtub water circulation pipe 24 is a pipe extending from the bathtub B to the follow-up heat exchanger 3, and the bathtub water circulation pipe 25 is a pipe extending from the follow-up heat exchanger 3 to the bathtub B via the bath circulation pump 6.

  A hot-water pipe 31 is branchedly connected to a hot water supply pipe 29 between the hot water storage tank 1 and the three-way mixing valve 11. The pipe end on the downstream side of the hot water pipe 31 is connected to the bathtub water circulation pipe 25. The hot water filled pipe 31 is provided with a check valve 13, a three-way mixing valve 12, an on-off valve 15, and a check valve 14 in this order from the upstream side to the downstream side. The three-way mixing valve 12 has two inflow ports and one outflow port. One inflow port and outflow port of the three-way mixing valve 12 are connected to the hot water filled pipe 31, and the other inflow port is connected to the branch pipe 30. The three-way mixing valve 12 mixes hot water supplied from the hot water supply pipe 29 through the upstream hot water pipe 31 and water supplied from the branch pipe 30 at a desired ratio, and supplies water to the downstream hot water pipe 31. It is a valve to do.

  Further, a control device 33 is provided for controlling the entire hot water storage hot water supply device such as the boiling pump 4, the recuperation pump 5, the heat pump 16, the bath circulation pump 6, the switching three-way valves 7 and 8, and the three-way mixing valves 11 and 12. It has been.

  In the hot water storage type hot water supply apparatus according to this embodiment configured as described above, the operation during boiling will be described below. In the following description, it is assumed that hot water is not used in the bath and the bath circulation pump 6 is stopped.

  The temperature in the hot water storage tank 1 is constantly monitored by the control device 33 by the temperature sensors 32a, 32b, 32c, and 32d. When the temperature of the hot water in the hot water storage tank 1 falls below a predetermined temperature, or when it becomes a cheap night time zone for electricity bills, the control device 33 starts boiling the hot water in the hot water storage tank 1. At the time of boiling, the control device 33 activates the heat pump 16 to circulate a high-temperature heat medium in the heat medium circulation pipe 21. The bypass pipe 20 drives the boiling pump 4 when the water temperature in the boiling return pipe 19 after passing through the boiling heat exchanger 17 is not sufficiently raised at the initial start of the heat pump 2, and supplies the circulating water to the hot water storage tank 1. Is returned to the upper part of the hot water storage tank 1, the stratified hot water is disturbed by the inflow of cold water and the stratified hot water is disturbed, so that the circulating water is returned to the lower part of the hot water storage tank 1 until the water temperature in the boiling return pipe 19 rises. It is piping. And the boiling pump 4 is started in the state which switched the switching three-way valve 7 in the direction where the boiling return pipe 19 communicates. As a result, the hot water having a low temperature at the bottom of the hot water storage tank 1 is heated by the boiling heat exchanger 17 and sent to the upper part of the hot water storage tank 1, and is stored in the hot water storage tank 1.

  Further, when boiling is started, the control device 33 causes the switching three-way valve 8 to be connected to a port (hereinafter referred to as a “second port”) to which the follow-up outgoing pipe 22 on the side of the add-on heat exchanger 3 is connected and a vent pipe. 26 is connected to a port (hereinafter referred to as “third port”) 26, and is connected to a tracking pipe 22 on the side connected to the upper part of the hot water storage tank 1 (hereinafter referred to as “first port”). Switch to the state where is blocked. Then, the control device 33 switches the switching three-way valve 8 in a direction in which the first port and the third port communicate with each other at regular intervals (for example, once every hour) temporarily (for example, for 5 seconds). Take control.

  By performing such control, the pressure release in the hot water storage tank 1 is performed as follows. First, when the temperature of the hot water in the hot water storage tank 1 rises due to boiling and the volume of the hot water in the hot water storage tank 1 expands, the pressure in the hot water storage tank 1 increases. The increased pressure is transmitted to the water in the vent pipe 26 through the water in the tracking return pipe 23 and the tracking outgoing pipe 22. When the pressure exceeds a predetermined pressure, the overpressure relief valve 10 is opened, and the expansion water is released from the vent pipe 26 to the outside, and the pressure is released. At this time, since the switching three-way valve 8 is in a state where the second port and the third port communicate with each other, the water in the retrace return pipe 23 and the retrace forward pipe 22 or the water having a low temperature at the bottom of the hot water storage tank 1 is used. Is released as expanded water. Therefore, heat loss due to pressure release is minimized.

  On the other hand, when the temperature of the hot water in the hot water storage tank 1 rises, the gas solubility of the water decreases, so that the air dissolved in the water in the hot water storage tank 1 is deposited and connected from the upper part of the hot water storage tank 1 to the upper part thereof. Accumulate in existing pipes. However, when the control device 33 switches the switching three-way valve 8 in a direction in which the first port and the third port communicate with each other at regular intervals, the accumulated air passes through the follow-up pipe 22 and the vent pipe 26 together with hot water. It flows in and is discharged to the outside through the overpressure relief valve 10. Accordingly, the upper part of the hot water storage tank 1 is vented at regular intervals, and a large amount of air does not accumulate in the upper part of the hot water storage tank 1. Therefore, when the user opens a hot water tap (not shown) at the end of the hot water supply pipe 29, a situation in which air and hot water are discharged together from the hot water tap is prevented.

  In the present embodiment, the control device 33 temporarily controls the switching three-way valve 8 in a direction in which the first port and the third port communicate with each other at regular intervals. As an example of other control, the control device 33 temporarily changes the accumulated value of the temperature rise in the hot water storage tank 1 detected by the temperature sensors 32a, 32b, 32c, 32d every time a predetermined value increases. It is also possible to perform control for switching the switching three-way valve 8 in a direction in which the first port and the third port communicate with each other. Here, when the temperature change from time t to time t + Δt is Δθ (t), the function f (t) is expressed as f (t) = Δθ (t), Δθ (when Δθ (t)> 0. If f (t) = 0 is defined when t) ≦ 0, the integrated value of temperature rise refers to a value obtained by integrating f (t) over time.

  In the present embodiment, the hot water storage type hot water supply apparatus provided with a bath chase circuit has been described. However, the present invention can be similarly applied to a hot water supply type hot water supply apparatus without a chase circuit. The principal part piping diagram showing the structure of the hot water storage type hot-water supply apparatus which concerns on Example 1 in case there is no memorial circuit in FIG. 2 is shown. In this case, except that there is no remedy heat exchanger 3, remedy pump 5, bath circulation pump 6, check valves 13 and 14, on-off valve 15, bath water circulation pipes 24 and 25, and hot water pipe 31. 1 and the operation of the control device 33 is the same.

In this embodiment, an example in which the present invention is applied to a hot water storage type hot water supply apparatus having a plurality of hot water storage tanks will be described. FIG. 3 is a principal piping diagram showing a configuration of a hot water storage type hot water supply apparatus according to Embodiment 2 of the present invention.

  In FIG. 3, heat pump 2, recuperation heat exchanger 3, boiling pump 4, recuperation pump 5, bath circulation pump 6, switching three-way valves 7 and 8, overpressure relief valve 10, three-way mixing valves 11 and 12, reverse Stop valves 13, 14, open / close valve 15, heat pump 16, boiling heat exchanger 17, boiling forward pipe 18, boiling up return pipe 19, bypass pipe 20, heat medium circulation pipe 21, follow-up forward pipe 22, follow-up Return pipe 23, bathtub water circulation pipes 24 and 25, vent pipe 26, water supply pipe 27, pressure reducing check valve 28, hot water supply pipe 29, branch pipe 30, hot water filled pipe 31, temperature sensors 32a, 32b, 32c and 32d, control device 33 and bathtub B are the same as in FIG.

  In the present embodiment, the hot water storage tank is divided into two, a low temperature side hot water storage tank 1a and a high temperature side hot water storage tank 1b. The top of the low temperature side hot water storage tank 1 a and the bottom of the high temperature side hot water storage tank 1 b are connected in series by a bend tube 41. The temperature sensors 32a, 32b, 32c, and 32d are installed at respective heights from the upper part to the lower part of the low temperature side hot water storage tank 1a. Further, temperature sensors 32e, 32f, and 32g are installed at respective heights from the upper part to the lower part of the high temperature side hot water storage tank 1b.

  The upstream side of the hot water supply pipe 29 is branched into hot water supply pipes 29a and 29b. The hot water supply pipe 29a is connected to the top of the low temperature side hot water storage tank 1a, and the hot water supply pipe 29b is connected to the top of the high temperature side hot water storage tank 1b. A three-way mixing valve 42 is provided at a branch point where the hot water supply pipe 29 branches into the hot water supply pipes 29a and 29b.

  In the three-way mixing valve 42, the hot water set temperature set by the hot water supply temperature setting device (not shown) and the hot water temperature setting device (not shown) is compared with the hot water temperature, and the predetermined temperature is higher than the higher temperature. Hot water having a temperature higher than (3 ° C. in the embodiment) is discharged, adjusted to the hot water supply temperature set by the hot water supply temperature setting device with the three-way mixing valve 11 and adjusted to the hot water temperature with the three-way mixing valve 12 and discharged. The three-way mixing valve 42 is adjusted to a temperature equal to or higher than the aforementioned predetermined temperature according to the temperature detected by the temperature sensor 47 and discharges hot water. At this time, the hot water of the low temperature side hot water storage tank 1a is controlled so as to be used preferentially, for the purpose of efficiently performing the bath chasing operation. That is, the higher the temperature of hot water sent to the memory heat exchanger 3 is, the faster and more efficient it can be. Therefore, in order to keep the temperature of the hot water in the high temperature side hot water storage tank 1b high, the low temperature side hot water storage tank 1a is preferentially used.

  The hot water supply pipes 29a and 29b are provided with check valves 43 and 44, respectively.

  Further, in the hot water supply pipe 29, a check valve 45 is provided between the branch point of the hot water filled pipe 31 and the three-way mixing valve 11, and in the branch pipe 30, a check valve 46 is provided in the vicinity of the three-way mixing valve 11. ing. Further, temperature sensors 47, 48, 49, 50, and 51 are disposed at various locations on the piping.

  In this embodiment, the upstream end of the follow-up pipe 22 is connected to the upper part of the high-temperature hot water storage tank 1b, and the downstream end of the follow-up return pipe 23 is connected to the lower part of the low-temperature hot water storage tank 1a. The upstream end of the boiling outlet pipe 18 is connected to the lower part of the low temperature hot water storage tank 1a, and the downstream end of the boiling return pipe 19 is connected to the upper part of the high temperature hot water storage tank 1b.

In this embodiment, the control device 33 is
When boiling the hot water in the low temperature side hot water storage tank 1a and the high temperature side hot water storage tank 1b, the same control as that described in the first embodiment is performed.

  By adopting such a configuration, even when there are a plurality of hot water storage tanks, the heat loss due to the pressure release by the overpressure relief valve 10 can be minimized and the high temperature side hot water storage tank as in the first embodiment. Air is prevented from accumulating at the top of 1b, and when the user opens the hot water tap at the end of the hot water supply pipe 29, the situation where air and hot water are discharged together from the hot water tap is prevented.

  In this embodiment, since the hot hot water boiled is returned to the high temperature side hot water storage tank 1b, air precipitation occurs in the high temperature side hot water storage tank 1b, and air precipitation occurs in the low temperature side hot water storage tank 1a. It hardly occurs. Therefore, it is only necessary to vent the high temperature side hot water storage tank 1b.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 1a Low temperature side hot water storage tank 1b High temperature side hot water storage tank 2 Heat pump 3 Remembrance heat exchanger 4 Boiling pump 5 Remembrance pump 6 Bath circulation pumps 7, 8 Switching three-way valve 10 Overpressure relief valves 11, 12, 42 Three-way Mixing valve 13, 14, 43, 44, 45, 46 Check valve 15 On-off valve 16 Heat pump 17 Boiling heat exchanger 18 Boiling forward pipe 19 Boiling return pipe 20 Bypass pipe 21 Heating medium circulation pipe 22 Tracking pipe 23 Remembrance return pipes 24, 25 Bath water circulation pipe 26 Vent pipe 27 Water supply pipe 28 Depressurization check valve 29, 29a, 29b Hot water supply pipe 30 Branch pipe 31 Hot water pipe 32a, 32b, 32c, 32d, 32e, 32f, 32g Sensor 33 Control device 41 Bend pipe 47, 48, 49, 50, 51 Temperature sensor B Bathtub

Claims (4)

A hot water storage tank for storing hot water,
A boiling means for boiling hot water stored in the hot water storage tank;
A first pipe connected to the upper part of the hot water storage tank;
A second pipe connected in communication with the lower part of the hot water storage tank;
A vent pipe for releasing the overpressure in the hot water storage tank;
An overpressure relief valve provided in the vent pipe;
There are three ports, a first port, a second port, and a third port. The first port is connected to the first port, the second port is connected to the second port, and the third port is connected to the third port. Is a three-way valve with a vent pipe,
When boiling the hot water in the hot water storage tank by the boiling means, the three-way valve is opened to the state where the second port and the third port communicate with each other and the first port is shut off. Control means for controlling and switching control so that the first port and the third port communicate intermittently;
A hot water storage type hot water supply apparatus characterized by comprising:   The hot water storage hot water supply according to claim 1, wherein the control means controls the opening degree of the three-way valve so that the first port and the third port are temporarily communicated with each other at predetermined time intervals. apparatus.   The control means controls the opening degree of the three-way valve so that the first port and the third port are temporarily communicated each time the integrated value of the temperature rise in the hot water tank increases by a predetermined value. The hot water storage type hot water supply apparatus according to claim 1. The hot water storage tank is composed of a plurality of hot water storage tanks, and each hot water storage tank has a series connection in which the upper part of the preceding hot water storage tank on the water supply side is connected to the bottom of the subsequent hot water storage tank,
The first pipe is connected in communication with the upper part of the last hot water storage tank,
The hot water storage type hot water supply apparatus according to any one of claims 1 to 3, wherein the second pipe is connected in communication with a lower portion of the hot water storage tank in the foremost stage.

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