JP2009162481A - Electric water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric water heater supplying pressure-raised hot water. <P>SOLUTION: The electric water heater is equipped with a heat pump H for heating water in a hot water storage tank 1 and includes a feed water hot water mixing valve 7 for mixing feed water from feed water piping 6 with hot water having a temperature higher than that of the feed water drawn out of the hot water storage tank 1. A pump 11 for raising the pressure of the hot water after being mixed and supplying the hot water is disposed on the downstream side of the feed water hot water mixing valve 7. The electric water heater includes drawing piping 9 for drawing out high temperature water from an upper part of the hot water storage tank 1, and middle temperature water drawing piping 3 for drawing out middle temperature water from a middle part of the hot water storage tank 1. A high temperature water middle temperature water mixing valve 5 for mixing high temperature water from the drawing piping 9 with middle temperature water from the middle temperature water drawing piping 31, is provided on the upstream side of the feed water hot water mixing valve 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric water heater, and in particular, in an electric water heater that stores hot water in a hot water storage tank by a heat pump heating method, the efficiency (COP) at the time of boiling water is improved by lowering the incoming temperature of the heat pump. It is related with the electric water heater which can be made to.

For example, as shown in FIG. 6, in an electric water heater provided with a hot water supply heat exchanger 2 that indirectly heats tap water in a water supply pipe 6 with hot water in a hot water storage tank 1, 9, high-temperature water is led out by the circulation pump 15, returned to the lower part of the tank through the primary side of the hot water supply heat exchanger 2, and tap water is passed through the secondary side of the hot water supply heat exchanger 2 to a predetermined temperature. This is done by heating (Patent Document 1).
At this time, the hot water in the upper part of the tank exchanges heat with tap water in the heat exchanger 2 for hot water supply, and the outlet temperature decreases to a temperature corresponding to the capacity of the heat exchanger and is returned to the lower part of the tank. Since the temperature of the hot water returned to the water becomes higher than the temperature of the tap water, a higher temperature layer is formed in the lower part of the tank than the tap water.

In addition, the hot water mixes high-temperature water in the upper part of the tank and tap water in the water supply pipe 6 ′ at a predetermined temperature by the mixing valve 20, and conveys it to the bathtub through the hot water circuit 12. At this time, since the high-temperature water side is taken out from the upper part of the tank, tap water is supplied from the water supply port at the lower part of the tank by the taken-out amount. Further, the mixing valve 20 has a water supply pipe 6 ′ that is directly sent to the mixing valve 20 without passing through the hot water storage tank 1. At this time, tap water is not supplied into the tank.
Usually, since the hot water is stored at a high temperature of 75 to 90 ° C. in the tank, the amount of hot water taken out from the tank at the time of hot water is not so much as half or less of the hot water amount. Further, when the tap water is supplied to the lower part of the tank by the amount taken out, the temperature in the lower part of the tank is mixed with the hot water remaining in the lower part of the tank.

On the other hand, in the electric water heater of the heat pump heating method in which the water in the hot water storage tank 1 is heated by the heat pump H, the water in the lower part of the tank is introduced into the heat exchanger of the heat pump, heated and then returned to the upper part of the tank. In particular, in the case of the heat pump heating method, the higher the incoming water temperature of this heat exchanger, the lower the efficiency (COP) when boiling water.
Therefore, it is necessary to lower the temperature at the bottom of the tank. However, in the case of the conventional electric water heater, the temperature of the hot water at the bottom of the tank cannot be lowered sufficiently even if hot water is supplied.
Also, since there is not much water supplied to the bottom of the tank during hot water filling, it becomes easy to form medium temperature water such as a mixed layer in the tank, and in the heat pump type heating method, the efficiency (COP) when boiling water is lowered I will let you.

Japanese Patent Application No. 2004-355219

  An object of the present invention is to provide an electric water heater capable of increasing the temperature of hot water and supplying hot water.

  An electric water heater according to the present invention is an electric water heater provided with a heat pump for heating water in a hot water storage tank. And a pump for raising the hot water after mixing and supplying hot water is disposed downstream of the hot water / hot water mixing valve.

  In this case, an outlet pipe for taking out hot water from the upper part of the hot water storage tank and an intermediate hot water outlet pipe for taking out hot water from an intermediate part of the hot water storage tank are provided. It is preferable that a high-temperature water warm water mixing valve for mixing the high-temperature water and medium-temperature water from the medium-temperature water extraction pipe is provided.

  Moreover, it is preferable that two pipes extending to the bathtub are branched and provided on the downstream side of the pump.

  According to the electric water heater of the present invention, by operating the pump, the hot water after mixing can be pressurized to supply hot water.

It is a circuit diagram which shows one Example of the electric water heater of this invention. It is a circuit diagram which shows the state of the hot water supply of the same electric water heater. It is a circuit diagram which shows the state of the hot water beam when middle temperature water is high temperature. It is a circuit diagram which shows the state of the hot water beam when middle temperature water is low temperature. It is a circuit diagram which shows the state of chasing. It is a front view which shows the conventional electric water heater.

  Hereinafter, an embodiment of an electric water heater of the present invention will be described with reference to the drawings.

1 to 2 show a first embodiment of an electric water heater according to the present invention.
The electric water heater includes a heat pump H that heats the water in the hot water storage tank 1, and a hot water supply heat exchanger 2 that indirectly heats tap water with the hot water in the hot water storage tank 1.
This electric water heater is provided with an intermediate hot water outlet 3 for extracting intermediate hot water in the middle portion of the hot water storage tank 1, a temperature sensor 4 is disposed in the vicinity of the intermediate hot water outlet 3, and the intermediate hot water outlet 3 One of the intermediate hot water extraction pipes 31 extending from the first mixing valve 5 is connected to the extraction pipe 9 at the upper part of the hot water storage tank, the downstream pipe 51 of the first mixing valve 5 is connected to the water supply pipe 6. It connects to the 2nd mixing valve 7 connected to.

A water supply pipe (water pipe) 6 is connected to the lower part of the hot water storage tank 1 via a pressure reducing valve 8 and a hot water supply pipe H1 of the heat pump H is connected. The hot water supply pipe H1 passes through the heater of the heat pump H and is connected to the upper part of the hot water storage tank 1 as a hot water supply pipe H2.
The water introduced into the hot water storage tank 1 from the water supply pipe 6 is heated by the heat pump H and stored in the hot water storage tank 1. The temperature is higher at the upper part of the hot water storage tank 1, for example, about 90 ° C. at the upper part, The water temperature is about 50 ° C.

On the other hand, an extraction pipe 9 for taking out high-temperature water is provided in the upper part of the hot water storage tank 1, and a heat exchanger 10 for reheating the bath is provided between the extraction pipe 9 and the first mixing valve 5. Yes.
The extraction pipe 9 is connected to the first mixing valve 5 as a high temperature side, and the intermediate temperature water extraction pipe 31 from the intermediate temperature water outlet 3 is connected as a low temperature side.
A downstream pipe 51 of the first mixing valve 5 is connected to the second mixing valve 7 as a high temperature side, and a water supply pipe 6 is connected as a low temperature side.
A first mixing valve temperature sensor 52 is provided in the downstream pipe 51 of the first mixing valve 5, and a second mixing valve temperature sensor 72 is provided in the downstream pipe 71 of the second mixing valve 7. It is arranged.
A circulation pump 11 and a switching valve 14 for switching the hot water circuit 12 to the tank return pipe 13 are provided on the downstream side of the second mixing valve 7.

Next, the piping system of this electric water heater will be described.
As shown in FIG. 2, hot water is supplied from the hot water stored in the upper part of the hot water tank 1 by the circulation pump 15 and returned to the lower part of the hot water tank 1 through the hot water heat exchanger 2. The heat exchanger 2 is heated by passing tap water from the water supply pipe 6 to a predetermined temperature.

The bath circuit is provided with a reheating heat exchanger 10 between the extraction pipe 9 at the upper part of the tank and the high temperature side of the first mixing valve 5, and a circulation pump 11 and a hot water beam are provided downstream of the second mixing valve 7. A switching valve 14 for switching to the tank return pipe 13 for returning the circuit 12 to the hot water storage tank 1 is provided.
During hot water filling, the switching valve 14 is switched to the hot water circuit 12 side.

For example, when the hot water temperature is 40 ° C., the tank upper temperature is 80 ° C., and the temperature detected by the temperature sensor 4 provided near the intermediate temperature water outlet 3 is 60 ° C., the temperature is sufficient for hot water pouring. As shown in FIG. 3, the low temperature side of the first mixing valve 5 is fully opened, and the high temperature side is fully closed.
Thereby, 60 degreeC hot water is supplied to the high temperature side of the 2nd mixing valve 7, and the valve opening degree of the 2nd mixing valve 7 is controlled so that it may become 40 degreeC with the 2nd mixing valve 7.
In this case, the intermediate temperature water in the tank can be efficiently taken out from the intermediate temperature water outlet 3, and not only can the low temperature tap water be supplied to the lower part of the tank, but the upper part of the hot water storage tank 1 is hot. Since hot water remains, the high-temperature water required for the hot water supply heat exchanger 2 and the reheating heat exchanger 10 can be used efficiently.

In addition, when the hot water temperature is 40 ° C., the tank upper temperature is 80 ° C., and the temperature detected by the temperature sensor 4 provided near the intermediate temperature water outlet 3 is 30 ° C., the temperature is not sufficient for hot water pouring.
For this reason, as shown in FIG. 4, after mixing to a temperature slightly higher than 40 ° C. controlled by the second mixing valve 7 (for example, 45 to 50 ° C.) at the stage of the first mixing valve 5, the second mixing is performed. Mix with tap water with valve 7 and control to 40 ° C.
At this time, since the temperature difference is small in the second mixing valve 7, a large amount of tap water on the low temperature side is not required, and therefore the first mixing valve 5 takes out more intermediate temperature water at 30 ° C. on the low temperature side from the tank. As a result, a large amount of low-temperature tap water can be stored in the lower part of the hot water storage tank 1.
In addition, by operating the circulation pump 11 during hot water filling, the pressure of the hot water circuit 12 increases, and the hot water time can be shortened.

As shown in FIG. 5, in the reheating, the switching valve 14 is switched to the tank return pipe 13 side, and the hot water in the hot water storage tank 1 is circulated by the circulation pump 11 to reheat the reheating heat exchanger 10. Supply heat.
And the bathtub side drives the circulation pump 16, and circulates bath water so that it may pass through the outlet side piping 18 from the inlet side piping 17 for reheating.

Thus, the electric water heater of the present embodiment includes the heat pump H that heats the water in the hot water storage tank 1, and the electric water heater that includes a heat exchanger that indirectly heats tap water or the like with the hot water in the hot water storage tank 1. In the hot water storage tank 1, an intermediate warm water outlet 3 for extracting intermediate warm water is provided, a temperature sensor 4 is disposed in the vicinity of the intermediate warm water outlet 3, and intermediate warm water extending from the intermediate warm water outlet 3 is provided. By connecting the take-out pipe 31 to the take-out pipe 9 at the upper part of the hot water storage tank 1 and the water supply pipe 6 of the water supply circuit via the mixing valves 5, 7, by supplying hot water or hot water from the intermediate temperature water outlet 3 The medium temperature water such as the mixed layer generated in the lower part of the hot water storage tank 1 can be taken out from the intermediate part of the hot water storage tank 1, thereby lowering the water temperature in the lower part of the hot water storage tank 1 and lowering the incoming temperature of the heat pump H. Boil water It is possible to improve the efficiency of that.
In this case, in the case where the temperature detected by the temperature sensor 4 provided near the intermediate hot water outlet 3 is sufficient for the hot water temperature, not only the hot water in the lower part of the hot water storage tank 1 can be taken out, but also hot hot water is stored in the hot water storage tank 1. The hot water required for the hot water supply heat exchanger 2 and the reheating heat exchanger 10 can be efficiently used.
When the temperature detected by the temperature sensor 4 is lower than the hot water temperature, the opening of the mixing valves 5 and 7 is controlled so that the mixing temperature becomes the hot water temperature. Medium temperature water can be removed.

Further, the intermediate temperature water extraction pipe 31 is connected to the first mixing valve 5 connected to the extraction pipe 9, and the downstream pipe 51 of the first mixing valve 5 is connected to the water supply pipe 6. By connecting to the mixing valve 7, the opening degree of the first mixing valve 5 or the second mixing valve 7 can be controlled to adjust the temperature of the intermediate temperature water.
That is, when the temperature detected by the temperature sensor 4 is sufficient for the hot water temperature, the hot water storage tank 1 side of the first mixing valve 5 is fully closed, the intermediate hot water outlet 3 side is fully open, and the second mixing valve 7 is opened. The hot water taken out from the medium temperature water outlet 3 is sent.
When the temperature detected by the temperature sensor 4 is lower than the hot water temperature, the valve opening of the first mixing valve 5 is set to be slightly higher than the mixing temperature of the second mixing valve 7 (hot water target temperature). Control.
At this time, since the temperature difference is small in the second mixing valve 7, it is not necessary to use a large amount of tap water on the low temperature side. Therefore, the first mixing valve 5 takes out more medium temperature water on the low temperature side from the hot water storage tank 1. As a result, a large amount of low-temperature tap water can be stored in the lower part of the hot water storage tank 1.

  In addition, a cistern tank (not shown) is disposed above the hot water storage tank 1, and the water in the cistern tank is introduced into the hot water storage tank 1 to open the hot water storage tank 1 to the atmosphere. It can also be applied to systems that do not apply pressure.

  As mentioned above, although it demonstrated based on the Example about the electric water heater of this invention, this invention is not limited to the structure described in the said Example, The structure described in the Example is combined suitably, etc. The configuration can be changed as appropriate without departing from the spirit of the invention.

  The electric water heater of the present invention derives the warm water generated in the lower part of the hot water storage tank 1 and performs hot water supply or hot water heating. Since it has the characteristic of improving the efficiency at the time of boiling water, it can be suitably used for an electric water heater using a heat pump.

DESCRIPTION OF SYMBOLS 1 Hot water storage tank 2 Heat exchanger 3 for hot water supply Middle hot water outlet 31 Medium hot water outlet piping 4 Temperature sensor 5 1st mixing valve (hot water hot water mixing valve)
51 Downstream piping 52 First mixing valve temperature sensor 6 Feed water piping 7 Second mixing valve (feed water warm water mixing valve)
71 Downstream piping 72 Second mixing valve temperature sensor 8 Pressure reducing valve 9 Extraction piping 10 Reheating heat exchanger 11 Circulation pump 12 Hot water circuit 13 Tank return piping 14 Switching valve 15 Circulation pump 16 Circulation pump 17 Inlet side piping 18 Outlet Side piping H Heat pump H1 Hot water piping H2 Hot water piping

Claims (3)

In an electric water heater equipped with a heat pump that heats water in a hot water storage tank,
A water supply / hot water mixing valve that mixes water supplied from the water supply pipe with hot water having a temperature higher than that of the water supplied from the hot water storage tank;
An electric water heater, wherein a pump for raising hot water after mixing and supplying hot water is disposed downstream of the hot water / hot water mixing valve. An extraction pipe for extracting hot water from the upper part of the hot water storage tank;
In addition to an intermediate temperature water extraction pipe for extracting intermediate temperature water from the middle part of the hot water storage tank,
The hot water / hot water mixing valve for mixing high temperature water from the extraction pipe and medium temperature water from the medium temperature water extraction pipe is provided upstream of the feed water / hot water mixing valve. Electric water heater.   The electric water heater according to claim 1, wherein two pipes extending to the bathtub are branched on the downstream side of the pump.

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