JP4876840B2 - Hot water system - Google Patents

Description

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

  Conventionally, there is a hot water supply system in which water is boiled by a heat pump and hot water stored in a hot water storage tank is supplied to a hot water use terminal such as a currant or a dishwasher. FIG. 3 shows an example of a conventional hot water supply system. The hot water supply system includes a hot water storage tank 103 that stores hot water, and a heat pump 102 that is connected to the upper and lower portions of the hot water storage tank 103 by a circulation pipe 100. The hot water storage tank 103 is connected to the hot water supply pipe 105 at the lower part and is connected to the hot water supply pipe 115 at the upper part, and the terminal of the hot water supply pipe 115 is connected to a hot water use terminal such as the dishwasher 122. A branch pipe branches from the water supply pipe 105 and is connected to the hot water supply pipe 115 to mix hot water and water supply.

  In such a hot water supply system, city water having a temperature of about 15 ° C. is supplied into the hot water storage tank 103 from the lower part of the hot water storage tank 103 through the water supply pipe 105, and this low temperature water is supplied into the circulation pipe 100 from the lower part of the hot water storage tank 103. The water is boiled by the heat pump 102 to be hot water having a temperature of 80 ° C. to 90 ° C., and is put into the hot water storage tank 100 from above. The boiled high-temperature water is taken out through the hot water supply pipe 115 by opening an on-off valve provided at the hot water use terminal, mixed with city water at the mixing valve 119, adjusted to an appropriate temperature, and used with hot water such as Karan 124. Hot water is discharged from the terminal. Some of the mixing valves 124 used at this time are adjusted to an appropriate temperature by a shape memory alloy. Also, there is one that controls the mixing valve 124 by feeding back the tapping temperature. In the case of business use, since there are terminals that require a high temperature of 80 ° C. or higher in the dishwasher 122 or the like, a high temperature hot water discharge path for directly taking out hot water from the tank may be provided.

  In a hot water supply system, the value indicated by (heating amount) / (power consumption) at the time of boiling is called COP (coefficient of performance) and becomes an index representing energy efficiency. For example, the COP of an electric heater is 1. In a heat pump, it becomes 3-4. In general, a heat pump has a characteristic that its efficiency decreases as its boiling temperature increases. FIG. 4 shows the relationship between the boiling temperature and COP in a general heat pump. The environmental conditions are an outside air temperature of 16 ° C. and a water temperature of 16 ° C. When the boiling temperature is 70 ° C., the COP is 3.72, but when the boiling temperature is 90 ° C., the COP is 2.91. In the conventional hot water supply system, hot water boiled at a high temperature is also diluted with water and discharged, so that the overall energy efficiency is low.

  Also, a hot water supply system is known in which a large number of hot water outlets are provided in the middle of a hot water storage tank, and the intermediate temperature water in the hot water storage tank is effectively used to improve overall energy efficiency (see, for example, Patent Document 1). ).

However, even in the hot water supply system as shown in Patent Document 1, when the heat pump boils only high-temperature hot water and uses a large amount of medium-temperature water, the high-temperature hot water and city water are mixed and discharged. Energy efficiency is low.
JP 2003-294251 A

  An object of the present invention is to solve the problem of the above-described conventional example, and to provide a hot water supply system capable of performing an operation with high energy efficiency.

In order to achieve the above object, the invention of claim 1 is a hot water supply system capable of discharging hot water and hot water mixed with high temperature hot water and feed water, and is heated by the heat pump for heating the feed water and the heat pump. a hot tank to the hot water storage hot water was, the medium temperature tank for hot water storage of hot water in which by the heat pump has been heated to a temperature lower than the high temperature hot water, is connected via a pipe to the heat pump, which is more heated to the heat pump A switching valve for switching the hot water supply destination to either the high temperature tank or the intermediate temperature tank according to the hot water temperature, a high temperature hot water supply pipe connected to the high temperature tank for discharging high temperature hot water, and a high temperature from the high temperature hot water supply pipe to tapping hot water, and a mixed hot water through the mixing valve for mixing the water supply in which the medium-temperature tank and heat exchange in the heat exchanger provided in the intermediate temperature tank A mixed hot water pipe, but with a.

  According to a second aspect of the present invention, in the hot water supply system according to the first aspect, the high temperature tank is an open-air tank.

  A third aspect of the present invention is the hot water supply system according to the first aspect, wherein the high-temperature tank is a pressure tank.

According to the first aspect of the present invention, the high temperature tank and the medium temperature tank are provided, and the high temperature hot water and the medium temperature hot water are separately boiled up, so that an energy efficient operation can be performed. In addition, the medium and high temperature hot water is separately boiled with a heat pump so that the hot water can be divided into a medium temperature tank and a high temperature tank, and the waste of diluting the high temperature water with water is eliminated. Thereby, energy saving can be aimed at.

  According to the invention of claim 2, since the high-temperature tank is an open-air tank, it can be formed in an arbitrary shape according to the installation location.

  According to the invention of claim 3, since the high-temperature tank is a pressure tank, water supply to the heat pump and hot water discharge can be performed by the supply pressure of city water.

(Implementation form)
For hot water supply system according to implementation embodiments of the present invention will be described with reference to FIG. The hot water supply system of the present embodiment controls an intermediate temperature tank 1 for storing water supply, a heat pump 2 for heating water in the intermediate temperature tank 1, a high temperature tank 3 for storing hot water heated by the heat pump 2, and the entire hot water supply system. The control unit 4 is provided. The intermediate temperature tank 1 is connected via a water supply pipe 5 and a water supply valve 6, and includes a water level sensor 7a for measuring the amount of stored water, a temperature sensor 8a for measuring the water temperature, and a vent hole 9a for ventilating the atmosphere. Have. The intermediate temperature tank 1 includes a heat exchanger 10, a water supply port of the heat exchanger 10 is connected to the water supply pipe 5, and a discharge port is connected to the mixing valve 11.

  The heat pump 2 is connected to the intermediate temperature tank 1 by piping, and a water supply pump 12 that sends water from the intermediate temperature tank 1 to the heat pump 2 is disposed in the middle of the piping. The heat pump 2 compresses a refrigerant such as carbon dioxide gas to raise the temperature, performs heat exchange with water supply via a heat exchanger, and heats the water supply. The heat pump 2 is provided with a switching valve 25 for switching the hot water supply destination between the intermediate temperature tank 1 and the high temperature tank 3 on the outlet side, and the heat pump 2 has a temperature sensor 8e for detecting the heated hot water temperature.

  The high-temperature tank 3 is connected to the heat pump 2 and has a water level sensor 7b for measuring the amount of stored hot water, a temperature sensor 8b for measuring the temperature of hot water, and a vent 9b that ventilates the atmosphere. The high-temperature tank 3 includes an overflow pipe 13 that causes the hot water to overflow into the intermediate temperature tank 1 when the hot water sent from the heat pump 2 exceeds a predetermined water level. Moreover, the high temperature tank 3 is connected to a hot water outlet 15 provided at a lower portion thereof with a high temperature hot water supply pipe 14 for sending hot water stored therein to a hot water use terminal. A hot water supply pipe 16 that sends hot water to a hot water use terminal and a pressure sensor 17 that detects the use of hot water based on the pressure in the pipe are disposed in the high temperature hot water supply pipe 14. The hot hot water supply pipe 14 branches into two directions, one is connected to a terminal using hot water such as the dishwasher 20 and the other is connected to the pipe from the heat exchanger 10 and the mixing valve 11. The mixed hot water supply pipe 18 is connected to a terminal using medium temperature water.

  The high temperature hot water supply pipe 14 is connected to the downstream side of the connection between the rice noodle machine 19 and the dishwasher 20 by an intermediate temperature tank 1 and a high temperature hot water return pipe 21b, and the high temperature hot water return pipe 21b is a check valve on the way. 22b and an immediate hot water valve 23b. The mixed hot water supply pipe 18 is connected to the intermediate temperature tank 1 and the mixed hot water return pipe 21a on the downstream side of the connection with the currant 24, and the mixed hot water return pipe 21a has a check valve 22a and an immediate hot water valve 23a on the way. Have.

  Next, operation | movement of the hot water supply system of this embodiment comprised as mentioned above is demonstrated. The control unit 4 detects the water level of the intermediate temperature tank 1 by the water level sensor 7a, opens the water supply valve 6 to supply water to the intermediate temperature tank 1 according to the detected water level, and supplies water from the lower part of the intermediate temperature tank 1 by the water supply pump 12. Take in water and send to heat pump 2. The control unit 4 supplies water to the intermediate temperature tank 1 or the high temperature tank 3 in the heat pump 2 so that the amount of hot water in the intermediate temperature tank 1 and the high temperature tank 3 becomes the set amount of hot water according to the water levels detected by the water level sensors 7a and 7b. Bring to the required temperature. And the control part 4 detects hot water temperature with the temperature sensor 8e, switches the switching valve 25, and sends hot water to the intermediate temperature tank 1 or the high temperature tank 3 according to hot water temperature. When the amount of hot water stored in the high temperature tank 3 exceeds a certain amount, it is sent to the intermediate temperature tank 1 through the overflow pipe 13.

  The control unit 4 causes the hot water supply pump 16 connected to the high temperature tank 3 to always perform a low speed operation, or arranges an accumulator at the subsequent stage of the hot water supply pump 16 to store pressure, thereby increasing the pressure in the high temperature hot water supply pipe 14. Keep constant. When hot water is used at the hot water use terminal, the control unit 4 senses a pressure drop in the high temperature hot water supply pipe 14 by the pressure sensor 17, causes the hot water supply pump 16 to perform high speed operation, and discharges the hot water in the high temperature tank 3. To do. Moreover, at the time of mixing hot water, the control part 4 opens the mixing valve 11 according to use temperature, mixes high temperature hot water and the hot water and the hot water which exchanged heat with the intermediate temperature tank 1, and discharges hot water.

  The temperature sensors 8 c and 8 d detect the hot water temperature in the mixed hot water supply pipe 18 and the high temperature hot water supply pipe 14. When the hot water is not discharged for a long time and the hot water temperature in the mixed hot water supply pipe 18 or the high temperature hot water supply pipe 14 is lowered, the control unit 4 causes the hot water supply pump 16 to perform high-speed operation and opens the immediate hot water valve 23a or the immediate hot water valve 23b. Hot water whose temperature has fallen in the mixed hot water supply pipe 18 or the high temperature hot water supply pipe 14 is discharged into the intermediate temperature tank 1. As a result, the hot water temperature in the mixed hot water supply pipe 18 and the high temperature hot water supply pipe 14 is always maintained, and when hot water is used at the hot water use terminals of the rice noodle machine 19, the dishwasher 20, and the Karan 24, There is no time. Moreover, since the check valves 22a and 22b are arranged, the hot water in the mixed hot water return pipe 21a and the high temperature hot water return pipe 21b does not return to the mixed hot water pipe 18 and the high temperature hot water pipe 14.

  In addition, the medium-temperature hot water and the high-temperature hot water are separately boiled by the heat pump 2 so that the hot water can be divided into the medium-temperature tank 1 and the high-temperature tank 3 to be sent, and the waste of diluting the high-temperature hot water with water is eliminated. Thereby, energy saving can be aimed at. The amount of mixed hot water was 3,000 l / day in terms of 90 ° C., and the amount of hot hot water was 90 ° in terms of 1,500 l / day, and the medium temperature tank was boiled at 65 ° C. The feed water temperature was 16 ° C. The COP at this time was 3.9 for mixed hot water and 2.9 for high temperature hot water. The power consumption at this time was 66.4 kWh / day for the mixed hot water and 44.7 kWh / day for the hot hot water, totaling 111.1 kWh / day. Assuming that all of these were boiled at a high temperature of 90 ° C., the amount of mixed hot water was 89.3 kWh / day, for a total of 134.0 kWh / day. Therefore, energy saving of 17% can be achieved by switching the boiling temperature.

  Further, since the high temperature tank 3 is open to the atmosphere, there is no need to make the shape cylindrical or to make the upper and lower ends hemispherical in order to withstand the internal pressure unlike the high pressure tank described later. And can be installed in a narrow place.

( Reference form)
A hot water supply system according to a reference embodiment of the present invention will be described with reference to FIG. Hot water supply system according to this reference embodiment, the hot water system according to the above you facilities embodiment is replaced with a high-pressure tank 3b the hot tank 3 from the atmosphere open. Hot water supply system according to this reference embodiment includes a high-pressure tank 3b as hot water storage tank of hot water. The high pressure tank 3 b is connected to the water supply pipe 5 and the heat pump 2 at the lower part. The high-pressure tank 3b is connected to the switching valve 25 at the upper part, and high-temperature hot water sent from the heat pump 2 is introduced from the upper part. The high-pressure tank 3b is connected to the high-temperature hot water supply pipe 14 at the upper part, and discharges the high-temperature hot water. The high-pressure tank 3b has n temperature sensors 8b1 to 8bn from the upper part to the lower part of the tank. The high temperature hot water supply pipe 14 is connected to the rice noodle machine 19 and the dishwasher 20, and the pipe branched from the high temperature hot water supply pipe 14 is connected to the auxiliary valve 27. The high temperature hot water supply pipe 14 is connected to the intermediate temperature tank 1 through a safety valve 28.

  The intermediate temperature tank 1 includes an intermediate temperature tank outlet pipe 29 connected to the mixing valve 11, and has a hot water supply pump 16 a and a pressure sensor 17 a in the middle of the intermediate temperature tank outlet pipe 29. A pipe branched from the medium temperature tank hot water supply pipe 29 is connected to the auxiliary valve 27. The intermediate temperature tank hot water supply pipe 29 is connected to the branch pipe from the water supply pipe 5 through the mixing valve 11, and becomes the mixed hot water supply pipe 18.

The hot water system of this preferred embodiment, the high-pressure tank 3b is subjected to the water supply from the water supply pipe 5 in the tank bottom. The water in the lower part of the high-pressure tank 3 b is sent to the heat pump 2 by the feed water pressure of the feed water pipe 5. The control part 4 grasps | ascertains the hot water storage amount from the data which the water level sensor 7a, the temperature sensor 8a, and temperature sensor 8b1 thru | or 8bn detected, and heats water supply to required temperature with the heat pump 2. FIG. And the switching valve 25 is switched according to the heated hot water temperature, and hot water is sent to the intermediate temperature tank 1 or the high pressure tank 3b.

  When high-temperature hot water is used in the rice noodle machine 19 or the dishwasher 20, the high-temperature hot water is discharged from the high-pressure tank 3b through the high-temperature hot water piping 14 by the pressure of the high-pressure tank 3b. When the hot water is used in the currant 24, the control unit 4 senses the pressure drop in the mixed hot water supply pipe 18 by the pressure detected by the pressure sensor 17a, and drives the hot water supply pump 16a to supply the hot water in the intermediate temperature tank 1. The hot water is fed, and the mixing valve 11 is adjusted and mixed with the water supply to discharge the hot water. At this time, if there is no medium temperature hot water in the intermediate temperature tank 1, the auxiliary valve 27 is opened to mix the high temperature hot water and the water supply and discharge the hot water.

In addition, since the high-temperature tank is replaced with a high-pressure tank, water supply to the heat pump 2 and hot water hot water can be performed by the supply pressure of city water. For example, a pump for supplying water to the heat pump 2 and hot water hot water The pump can be omitted as appropriate, such as no need for a pump. Further, for example, even when the hot water supply pump 16a fails, the hot water in the high-pressure tank 3b can be mixed with the supply water to discharge the mixed hot water. Moreover, compared with the said embodiment, a part which does not use medium temperature water for boiling, COP does not fall. Further, since the hot water is directly discharged, the use efficiency of the hot water is good and the heat exchanger can be omitted.

The present invention is not limited to the configuration above you facilities embodiment and reference embodiment, and various modifications are possible within a range not changing the gist of the invention. For example, the piping route for high-temperature hot water or mixed hot water, or the configuration relating to hot water may be freely changed according to the use situation.

Configuration diagram of a hot water supply system according to implementation embodiments of the present invention. The block diagram of the hot-water supply system which concerns on the reference form of this invention. The block diagram of the conventional hot-water supply system. The figure which shows the boiling temperature in a general heat pump, and the relationship of COP.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Medium temperature tank 2 Heat pump 3 High temperature tank 3b High pressure tank 11 Mixing valve 14 High temperature hot water piping (hot water piping)
18 Mixed hot water piping (hot water piping)
25 Switching valve

Claims (3)

In a hot water supply system that can discharge hot water and hot water mixed with high temperature hot water and water supply,
A heat pump for heating the feed water;
A high-temperature tank for storing hot water heated by the heat pump;
A medium temperature tank for storing medium temperature hot water heated to a temperature lower than the high temperature hot water by the heat pump;
Is connected via a pipe to the heat pump, a switching valve for switching to any one of the medium-temperature tank and the hot tank in accordance with the hot water temperature to Okuyu destination of the hot water which is heated more in the heat pump,
A high-temperature tap piping connected to the high-temperature tank for discharging hot water;
And a mixed hot water pipe for tapping the mixed hot water through the mixing valve for mixing the water supply in which the medium-temperature tank and heat exchanger at high temperature hot water, and a heat exchanger provided in the intermediate temperature tank from the high-temperature hot water pipe A hot water supply system characterized by that.   The hot water supply system according to claim 1, wherein the high-temperature tank is an open-air tank.   The hot water supply system according to claim 1, wherein the high-temperature tank is a pressure tank.

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