JP4876899B2 - Hot water system - Google Patents

Description

  The present invention relates to a hot water supply system capable of appropriately discharging hot water and medium hot water.

  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. Hot water storage tanks are often installed outdoors together with heat pumps, and the distance from the tank to the hot water use terminal is long, so it is necessary to wait until the hot water remaining in the pipe is replaced at the start of hot water use. Waiting time is called “hot water waiting time”). In order to be able to use hot water without waiting for hot water (making hot water available without hot water waiting time is called "immediate hot water"), piping in large-scale hot water facilities such as hotels A system that constantly circulates the hot water inside is used. In relatively small-scale facilities and household applications, a method of installing a small heater with a hot water storage tank called an immediate hot water unit in the vicinity of the hot water outlet may be used. Moreover, in business use, since the high temperature of 80-90 degreeC is required for tableware washing | cleaning, the hot water supply heating apparatus which uses the electricity or gas called a booster as a heat source is provided. However, these heating means have higher energy costs than heat pump hot water supply.

  The temperature of the hot water in the hot water storage tank is highest at the top, lower than that at the middle layer, and lowest at the bottom, and the hot water in the hot water storage tank is taken out from the top region and the cold water from the water supply pipe is removed. The mixture is mixed to a predetermined temperature and supplied to the hot water use terminal. When hot water is discharged from the top of the hot water storage tank, city water (low temperature water) is supplied from the bottom of the hot water storage tank for the amount of use. In a tank with such a configuration, for example, when the hot water storage time is long and the hot water temperature in the tank has decreased, or when the heat exchanger used for floor heating or the like is built in the tank The hot water in the tank may be about 30-70 ° C.

  A value indicated by (heating amount) / (power consumption) when boiling hot water in a water heater is called COP (coefficient of performance), which is an index representing energy efficiency. For example, the COP of an electric heater is 1. In a heat pump, it becomes 3-4. However, since the heat pump has a characteristic that the COP increases as the inlet water temperature decreases, the COP decreases to 1 to 2 when the inlet water temperature increases to 30 to 70 ° C. Reheating the hot water or the intermediate hot water that has been returned by circulating the pipe for immediate hot water decreases the energy efficiency. If the operation of the heat pump is stopped when the inlet water temperature rises in order to avoid a decrease in energy efficiency, the hot water is discharged even though high temperature water of 80 ° C. or higher is desired.

  Further, the heat pump has a characteristic that the efficiency decreases as the boiling temperature of hot water increases, as shown in FIG. Therefore, in the case of medium hot water, if the hot water boiled at a high temperature is diluted with water and discharged, the operation is performed with low overall energy efficiency.

In order to increase energy efficiency, hot water is discharged from the middle layer of the hot water storage tank,
There is known a hot water supply system in which the boiling temperature is made high and medium, hot water is stored at the top of the hot water storage tank, and hot water is stored in the middle layer of the hot water storage tank (see, for example, Patent Document 1).

  However, in the hot water supply system as shown in Patent Document 1, the hot water supply pipe for feeding hot water to the middle layer of the hot water storage tank is the same as the tapping pipe for discharging hot water from the middle layer, so If the low-temperature return hot water circulated is supplied to the middle layer by the hot-water supply pipe, the low-temperature hot water is discharged as it is when the medium-temperature hot water is discharged.

In addition, in a conventional hot water supply system capable of supplying hot hot water as well as medium hot water, a configuration when a hot water storage tank is added will be described with reference to FIG. The hot water supply system 101 includes a plurality of expansion tanks 122 and 123 added to the hot water storage tank 121, and the bottom of the hot water storage tank 121 is connected to the top of the adjacent expansion tank 122. The top of the additional tank 123 is connected. In this configuration, when high-temperature hot water heated by the heating source 130 is introduced from the top of the hot water storage tank 121, the medium hot water region sequentially moves to the adjacent expansion tank 122 and further to the next expansion tank 123. As described above, since the region of the intermediate temperature hot water moves, even if the hot water storage tank 121 is provided with an outlet for the intermediate temperature hot water, the intermediate temperature hot water cannot be effectively used.
JP-A-60-269

  The present invention has been made to solve the above-described conventional problems, and an object thereof is to provide a hot water supply system capable of efficiently discharging hot water generated by instant hot water.

In order to achieve the above object, according to the first aspect of the present invention, a water supply pipe is connected to the bottom, a hot water storage tank for storing the water supply and heated hot water, and heating for heating the water sent from the bottom of the hot water storage tank. A hot water supply pipe connected to the top of the hot water storage tank and the hot water stored in the top from the top of the hot water storage tank. In the hot water supply system, the hot water storage system includes: A medium temperature hot water discharge pipe for discharging the medium temperature hot water stored in the middle layer from the middle layer of the tank ;
A control unit that controls the entire hot water supply system; and a switching unit that is provided in the hot water supply pipe and switches a hot water supply destination heated by the heating source to a top part of the hot water storage tank and a middle layer part of the hot water storage tank; The intermediate temperature hot water discharge pipe is provided separately from the return pipe in the middle layer portion of the hot water storage tank, and the control unit is configured to switch the switching unit when boiling water in the hot water storage tank to a high temperature. When switching to the top side of the hot water storage tank and boiling the water in the hot water storage tank to an intermediate temperature, the switching portion is switched to the middle layer of the hot water storage tank .

  According to a second aspect of the present invention, there is provided the hot water supply system according to the first aspect, wherein the additional tank, switching means for switching a hot water supply destination heated by the heating source to the hot water storage tank and the additional tank, and the hot water storage And a pipe connecting the bottom of the tank and the bottom of the additional tank.

  According to the invention of claim 1, even if the low temperature hot water returns from the return pipe to the hot water storage tank, the low temperature hot water is not directly discharged from the intermediate temperature hot water discharge pipe because it enters the tank once. The hot water generated by the instant hot water can be heated and discharged efficiently.

  According to the invention of claim 2, by appropriately switching the hot water supply destination tank of hot water heated to a high temperature, the intermediate hot water region is always in the middle layer of the hot water storage tank having the middle hot water outlet piping in the middle layer. Since it can be ensured, there is no need to provide an outlet tank for medium hot water.

  A hot water supply system according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a configuration of a hot water supply system. The hot water supply system 1 includes a hot water storage tank 2 and additional tanks 21a and 21b for storing hot water and heated hot water, a heating source 3 that is a heat pump for heating the hot water supply, and a controller 4 for controlling the entire hot water supply system 1. Yes. The hot water storage tank 2 is connected to the water supply pipe 5 at the bottom and receives water to store water. The heating source 3 is connected to the bottom of the hot water storage tank 2 by a pipe 51a, and the water at the bottom of the hot water storage tank 2 is sucked and heated by a built-in hot water supply pump. The hot water outlet of the heating source 3 is connected to the switching valve 6a by a pipe 51b. The switching valve 6a switches the hot water supply destination from the heating source 3 to a pipe 51c connected to the middle layer of the hot water storage tank 2 and a pipe 51d connected to the high-temperature hot-water supply pipe 52a. One end of the high-temperature hot-water supply piping 52a is connected to the switching valve 6b, and the switching valve 6b switches the hot water supply destination from the high-temperature hot-water supply piping 52a to the top of the hot water storage tank 2 and the top of the expansion tank 21a. And the bottom part of the expansion tank 21a and the top part of the expansion tank 21b are connected by the piping 51f, and the bottom part of the expansion tank 21b is connected with the heating source 3 via the piping 51g and 51a.

  The other end of the high temperature hot water supply pipe 52a is connected to the high temperature hot water outlet, and is connected to the return pipe 53 in the middle. The return pipe 53 has a hot water supply pump 7 and a water stop valve 6c in the pipe, and is connected to the middle layer of the hot water storage tank 2 via the pipe 51c. An intermediate temperature hot water discharge pipe 52b is connected to the middle layer of the hot water storage tank 2, and the intermediate temperature hot water discharge pipe 52b is connected to the switching valve 6d. The switching valve 6d is also connected to a pipe 51h branched from the high-temperature hot water discharge pipe 52a, and switches between high-temperature hot water from the top of the hot water storage tank 2 and medium-temperature hot water from the middle layer, and supplies hot water to the mixing valve 6e. The mixing valve 6e is connected to a pipe from the switching valve 6d and a pipe 51 branched from the water supply pipe 5. The hot water from the switching valve 6d and the water supplied from the pipe 51 are mixed to supply hot water to the intermediate temperature outlet. To do.

  Next, the operation of the hot water supply system 1 according to the present embodiment configured as described above will be described with reference to the drawings. FIG. 2 shows the operation during boiling of hot water. When the water in the hot water storage tank 2 is heated to a high temperature, the control unit 4 switches the switching valve 6a to the top side (pipe 51d) of the hot water storage tank 2 and switches the switching valve 6b to the hot water storage tank 2 side. The controller 4 drives the hot water supply pump of the heating source 3, sucks the water at the bottom of the hot water storage tank 2 into the heating source 3, and sends the heated hot water to the switching valve 6a through the pipe 51b. The sent hot water flows to the pipe 51d through the switching valve 6a, passes through the high-temperature hot water tap pipe 52a, and is sent to the top of the hot water storage tank 2 through the switching valve 6b (arrows A, B, C).

  When boiling the water in the expansion tanks 21a and 21b to a high temperature, the control unit 4 switches the switching valve 6a to the top side (pipe 51d side) of the hot water storage tank 2, and switches the switching valve 6b to the expansion tank 21a side (pipe 51e). Switch to. The controller 4 drives the hot water supply pump of the heating source 3, sucks the water at the bottom of the expansion tank 21b into the heating source 3, and sends the heated hot water to the switching valve 6a through the pipe 51b. The sent hot water flows to the pipe 51d through the switching valve 6a, passes through the high-temperature hot water tap pipe 52a, passes through the pipe 51e through the switching valve 6b, and is sent to the top of the expansion tank 21a. (Arrows G, B, E, F).

  The hot water heated to a high temperature is appropriately switched to one of the hot water storage tank 2 and the additional tanks 21a and 21b, and the hot water is always supplied to the hot water storage tank 2 having the intermediate hot water outlet piping 52b in the middle layer. Since it can be secured in the middle layer portion, it is not necessary to provide the hot water outlet piping in the additional tanks 21a and 21b.

  When boiling the water in the hot water storage tank 2 to an intermediate temperature, the control unit 4 switches the switching valve 6a to the middle layer side (the piping 51c side) of the hot water storage tank 2. The control unit 4 causes the heated hot water to flow through the switching valve 6a to the pipe 51c and supply the hot water to the middle layer of the hot water storage tank 2 (arrows A and D). The medium temperature hot water is not made by mixing hot water and feed water, but is boiled to a medium temperature, so that energy efficiency can be increased.

  FIG. 3 shows the operation at the time of hot water. When discharging hot water from the hot water storage tank 2, the control unit 4 switches the switching valve 6b to the hot water storage tank 2 side. When the high temperature hot water outlet is opened, the supply water enters the bottom of the hot water storage tank 2 from the water supply pipe 5 due to the supply water pressure, and the high temperature hot water at the top of the hot water storage tank 2 passes through the high temperature hot water tap pipe 52a via the switching valve 6b. Hot water is fed to the hot outlet (arrows H, I, J). When discharging hot water from the expansion tanks 21a and 21b, the control unit 4 switches the switching valve 6b to the expansion tank 21a side. When the high temperature hot water outlet is opened, water supply enters the bottom of the hot water storage tank 2 from the water supply pipe 5 due to the water supply pressure, and enters the bottom of the expansion tank 21b through the pipes 51a and 51g. Since the top of the expansion tank 21b and the bottom of the expansion tank 21a are connected by the pipe 51f, the hot water at the top of the expansion tank 21a passes through the pipe 51e due to the feed water pressure, and passes through the switching valve 6b to the high temperature hot water supply pipe 52a. And is sent to the hot tap (arrows H, K, L, M, J).

  When discharging the medium temperature hot water, the control unit 4 switches the switching valve 6d to the medium temperature hot water discharge pipe 52b side when the hot water storage tank 2 has the medium temperature hot water. Moreover, the control part 4 switches the switching valve 6b to the expansion tank 21a side, and stops the hot water from the top part of the hot water storage tank 2. FIG. When the intermediate temperature hot water outlet is opened, the supply water enters the bottom of the hot water storage tank 2 from the water supply pipe 5 due to the supply water pressure, and the intermediate temperature hot water in the middle layer of the hot water storage tank 2 is sent to the intermediate temperature hot water hot water supply pipe 52b. To the mixing valve 6e. The control unit 4 mixes the medium temperature hot water from the medium temperature hot water discharge pipe 52b and the water supplied from the pipe 51 branched from the water supply pipe 5 by the mixing valve 6e, and supplies the hot water to the medium temperature hot water outlet (arrows H, N, O). P, O).

  When there is no medium hot water in the hot water storage tank 2, the control unit 4 mixes the hot water and the feed water from the hot water storage tank 2 or the additional tank 21a in the mixing valve 6e and discharges the hot water. When mixing hot water and hot water in the hot water storage tank 2, the control unit 4 switches the switching valve 6 d to the pipe 51 h side and switches the switching valve 6 b to the hot water storage tank 2. When the intermediate temperature hot water outlet is opened, the hot water at the top of the hot water storage tank 2 is sent to the high temperature hot water hot water piping 52a and the piping 51h via the switching valve 6b and the mixing valve via the switching valve 6d. 6e, mixed with feed water by the mixing valve 6e, and fed to the hot hot water outlet (arrows H, I, J, Q, O. P, O). When mixing the hot water and the feed water in the expansion tank 21a, the control unit 4 switches the switching valve 6d to the piping 51h side, switches the switching valve 6b to the expansion tank 21a side, and discharges the hot water (arrows H, K, L, M, J, Q, O. P, O).

  FIG. 4 shows hot water circulation operation for instant hot water. When circulating the hot water in the hot water storage tank 2, the control unit 4 switches the switching valve 6 b to the hot water storage tank 2 side, opens the immediate hot water valve 6 c, and drives the hot water supply pump 7. High temperature hot water at the top of the hot water storage tank 2 is sent to the high temperature hot water discharge piping 52a through the switching valve 6b, and is sent to the middle layer of the hot water storage tank 2 through the return piping 53 and the piping 51c (arrows R, S, T). .

  When the controller 4 circulates with the hot water in the additional tanks 21a and 21b, the control valve 6b is switched to the additional tank 21a side, the immediate hot water valve 6c is opened, and the hot water supply pump 7 is driven. The high temperature hot water in the expansion tanks 21a and 21b is sent to the high temperature hot water tap piping 52a via the switching valve 6b, and sent to the middle layer of the hot water storage tank 2 through the return piping 53 and the piping 51c (arrows U, V, W, S, T). Even if the hot water in the pipe whose temperature has dropped returns to the hot water storage tank 2, it once enters the hot water storage tank 2, so that low temperature hot water is not directly discharged from the intermediate hot water hot water supply pipe 52b, and is generated by immediate hot water. The hot water can be heated and discharged efficiently.

  In addition, this invention is not restricted to the structure of the said various embodiment, A various deformation | transformation is possible in the range which does not change the meaning of invention. For example, the heating source 3 is not limited to a heat pump, and may be a combustion water heater. The tank top portion includes not only the top portion of the tank but also the entire upper portion of the tank, and the tank bottom portion includes not only the bottom portion of the tank but also the entire lower portion of the tank.

The block diagram of the hot-water supply system which concerns on one Embodiment of this invention. Explanatory drawing of the boiling operation of the hot-water supply system. Explanatory drawing of the hot water operation of the hot water supply system. Explanatory drawing of the hot water operation of the hot water supply system. The figure which shows the relationship between the boiling temperature of a heat pump of a hot-water supply system, and COP. The block diagram of the conventional hot-water supply system.

Explanation of symbols

2 Hot water storage tanks 21a, 21b Additional tank 3 Heating source 5 Water supply pipes 51b, 51c, 51d Piping (hot water feeding piping)
52a High temperature hot water supply piping 52b Medium temperature hot water supply piping 53 Return piping 6b Switching valve (switching means)
7 Hot water pump

Claims (2)

A hot water storage tank connected to the bottom of the water supply pipe and storing water supply and heated hot water;
A heating source for heating water sent from the bottom of the hot water storage tank;
A hot water supply pipe that connects the heating source and the hot water storage tank, and supplies hot water to the top or middle layer of the hot water storage tank;
High-temperature hot-water supply piping for discharging high-temperature hot water stored in the top from the top of the hot water storage tank;
In a hot water supply system provided with a return pipe that branches off from the high temperature hot water supply pipe and returns hot water of the high temperature hot water supply pipe to the middle layer of the hot water storage tank by a hot water supply pump
A medium temperature hot water discharge pipe for discharging the medium temperature hot water stored in the middle layer from the middle layer of the hot water storage tank ;
A control unit for controlling the whole hot water supply system;
A switching unit that is provided in the hot water supply pipe and switches a hot water supply destination of hot water heated by the heating source to a top part of the hot water storage tank and a middle layer part of the hot water storage tank ;
The intermediate temperature hot water discharge pipe is provided separately from the return pipe in the middle layer of the hot water storage tank ,
When the water in the hot water storage tank is boiled to a high temperature, the control unit switches the switching unit to the top side of the hot water storage tank, and when the water in the hot water storage tank is boiled to an intermediate temperature, the control unit switches the switching unit to the hot water tank. hot water supply system, characterized in switching Rukoto the middle layer.   An additional tank, switching means for switching a hot water source heated by the heating source to the hot water storage tank and the additional tank, and a pipe connecting the bottom of the hot water storage tank and the bottom of the additional tank, The hot water supply system according to claim 1, wherein the hot water supply system is provided.

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