JPH0618092A - Centralized hot-water supplying device - Google Patents

Abstract

PURPOSE:To obtain a centralized hot-water supplying device, higher in energy efficiency than a heat pump hot-water supplier and more inexpensive in the running cost than the same. CONSTITUTION:Hot-water reserving tanks 20a, 20b, 20c are arranged in series in a water feeding route from a feed water pipeline 6 to cocks 9a, 9b, 9c. The upper part of an upstream side hot-water reserving tank is connected to the lower part of a downstream side hot-water reserving tank sequentially through pipelines. Heat pumps 22a, 22b are attached to the hot-water reserving tanks 20a, 20b to heat water or hot-water, reserved in respective hot-water reserving tanks, to a set temperature. An electric heater 22c is attached to the hot-water reserving tank 20c to heat hot-water in the hot-water reserving tank 20c to a high temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a central hot water supply device used for hot water supply in apartments and hotels.

[0002]

2. Description of the Related Art FIG. 6 is a schematic diagram showing the overall configuration of a conventional concentrated hot water supply device used in an apartment house, a business hotel, or the like. In the figure, 1 is a hot water storage tank, 2 is piping 3, 4
Heat pump water heater connected to the hot water storage tank 1 by
Is a circulation pump attached to the pipe 4 for circulating hot water between the hot water tank 1 and the heat pump water heater 2, 6 is a water supply pipe connected to the pipe 4 for supplying water, and 7 is attached to the water supply pipe 6. It is a solenoid valve.

Reference numeral 8a denotes a hot water supply pipe connected to the hot water storage tank 1 to supply hot water to each house or guest room. 8b denotes a hot water supply pipe 8a connected to the hot water supply pipe 8a for returning unused hot water to the hot water storage tank 1, 9
Reference numerals a and 9b are faucets attached to each house or guest room, and 10 is a return hot water pump which is attached to a hot water supply pipe 8a and supplies hot water and returns hot water to the hot water storage tank 1. Reference numeral 11 is a water level detector that is attached to the hot water storage tank 1 and detects the water level of the hot water storage tank 1 and sends a water supply signal and a water supply stop signal. 12 is a heat pump water heater 2 and an electric solenoid valve based on the signal of the water level detector 11. 7 is a controller for controlling 7.

The conventional centralized hot water supply system is constructed as described above. When hot water is supplied from the faucets 9a and 9b, the water level in the hot water storage tank 1 is lowered, so that the water level detector sends a water supply signal to the controller 12, Water is supplied by the controller 12 receiving the water supply signal opening the solenoid valve 7. The amount of water supplied at this time is constant at the outlet temperature of the heat pump water heater 2 (about 55 ° C).
Is adjusted to. Therefore, the water temperature in the hot water storage tank 1 is always kept constant, and this constant temperature hot water is supplied for hot water supply. In addition, the return hot water pump 10 is constantly operated to supply the hot water supply pipe 8
a. The hot water in the return hot water pipe 8b is circulated so that hot water can be constantly supplied at a constant temperature.

[0005]

In the conventional centralized hot water supply apparatus as described above, heating is performed by a single heat pump, so the outlet water temperature is 55 ° C to 70 ° C which is the hot water supply temperature.
Must be set to a degree. However, since the heat pump has the property of becoming less efficient as the outlet water temperature becomes higher, setting the outlet water temperature higher and heating as described above is the most inefficient operation as a heat pump, and the running cost is high. There was a problem. Further, since the hot water in the hot water supply pipe 8a is constantly circulated, a large amount of heat is lost due to heat radiation, which is also one of the reasons for increasing the running cost. In addition, higher temperature (8
There is also a problem that it cannot meet the demand for hot water supply of about 5 ° C.

The present invention has been made to solve the above problems, and an object of the invention is to obtain a centralized water heater having higher energy efficiency and lower running cost than the conventional heat pump water heater. An object of the present invention is to obtain a centralized water heater capable of supplying hot water at a temperature (80 to 85 ° C) higher than that of the water heater.

[0007]

A centralized water heater according to the present invention comprises a plurality of hot water storage tanks arranged in series in a water supply path from a water supply pipe to a faucet, and hot water storage tanks upstream between the hot water storage tanks. Pipes for sequentially connecting the upper part of the tank to the lower part of the hot water storage tank on the downstream side, and a plurality of heating means attached to each of the hot water storage tanks for heating water or hot water stored in each hot water storage tank to a set temperature are provided. Be prepared. Moreover, the heating means located at the most downstream side consists of high temperature heating means,
The rest is composed of a heat pump.

[0008]

In the centralized hot water supply device configured as described above, the heating means of the hot water storage tank located on the most downstream side performs heating operation at the temperature setting required for hot water supply, and the heating means of the hot water storage tank located on the upstream side is The heating operation is performed under the most efficient condition according to the type of heating means. When there is a request for high temperature hot water supply, the high temperature heating means heats the hot water to a high temperature according to the request.

[0009]

【Example】

Example 1. FIG. 1 is a schematic diagram showing the overall configuration of the first embodiment of the present invention. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. As shown in the figure, hot water storage tanks 20a, 2 are provided in the water supply path from the water supply pipe 6 to the faucets 9a, 9b, 9c.
0b and 20c are arranged in series from the upstream side to the downstream side. The upper part of the hot water storage tank 20a and the lower part of the hot water storage tank 20b are connected by a pipe 21a, and the upper part of the hot water storage tank 20b and the lower part of the hot water storage tank 20c are connected by a pipe 21b.

A heat pump 2 for heating the stored water or hot water to a set temperature in the hot water storage tanks 20a, 20b, 20c.
Heating means such as 2a and 22b and electric heater 22c are attached via circulation pipes 24a, 24b and 24c, respectively. Water inlets and water outlets of the circulation pipes 24a, 24b are connected to lower portions of the hot water storage tanks 20a, 20b, respectively, and circulation pumps 26a, 26b are attached to respective circulation paths. The water inlet of the circulation pipe 24c is connected to the lower part of the hot water storage tank 20c, and the water outlet is connected to the upper part of the hot water storage tank 20c. The circulation pump 26c is connected to this circulation path.
Is attached.

Temperature sensors 28a, 28b, 28c are installed on the inner bottom surfaces of the hot water storage tanks 20a, 20b, 20c, respectively. The temperature sensors 28a, 28b, 28c detect the temperature of water or hot water in each hot water storage tank and send a signal to a controller (not shown). Send. Temperature sensor 28a, 2
The controller receiving the signals from 8b and 28c controls the operation or stop of each circulation pump and the heating means based on the signals. The temperature sensors 28a, 28b, 28c are set to predetermined set temperatures T1, T2, T3, respectively.
When the temperature becomes equal to or lower than the set temperature, each circulation pump and the heating means are operated to control heating. The set temperatures T1, T2, T3 have a relationship of T1 <T2 <T3.

The hot water supply pipe 8a is connected to the upper part of the hot water storage tank 20c, and after a branch pipe connecting to a hot water supply faucet is connected midway, it is connected to the hot water return pipe 8b.
It is connected to the bottom of 0a. A temperature sensor 30 is installed at the most downstream part of the hot water supply pipe 8a.
Sends a signal to the controller when the temperature of the hot water in the hot water supply pipe 8a becomes equal to or lower than the set value, and the controller receiving this signal operates the return water pump 10 to store the hot water in the pipe in the hot water tank. 20
The hot water in the hot water storage tank 20c is returned to the hot water supply pipe 8a.
Flow into.

Next, the operation will be described. When hot water is used at the faucet 9a or the like, a hot water supply load is generated, and low-temperature water flows into the bottom of the hot water storage tank 20a from the water supply pipe 6, and at the same time, the hot water storage tank 2
0a to the bottom of the hot water storage tank 20b
From the upper part of 0b to the bottom of the hot water storage tank 20c, water moves in a piston flow. The water temperature is detected by the temperature sensor 28a installed at the bottom of the hot water storage tank 20a,
When this temperature is lower than the set temperature T1, the heat pump 22a and the circulation pump 26a are operated, and the low temperature water sucked from the bottom of the hot water storage tank 20a passes through the circulation pump 26a,
It is heated to a medium temperature by the heat pump 22a and returned to the bottom of the hot water storage tank 20a again.

At the same time, the temperature sensor 28b at the bottom of the hot water storage tank 20b detects the water temperature, and this temperature is set to the set temperature T.
When it is lower than 2, the heat pump 22b and the circulation pump 26b are operated, and the hot water sucked from the bottom of the hot water storage tank 20b passes through the circulation pump 26b and is heated to the maximum temperature (60 to 70 ° C) that can be heated by the heat pump 22b. And is returned to the bottom of the hot water storage tank 20b again. At the same time, the water temperature is detected by the temperature sensor 28c at the bottom of the hot water storage tank 20c. If this temperature is lower than the set temperature T3, the electric heater 22c and the circulation pump 26c are operated, and the hot water storage tank 2 is operated.
The hot water sucked from the bottom of 0c passes through the circulation pump 26c, is heated to a higher temperature (80 to 85 ° C) by the electric heater 22c, and is returned to the upper part of the hot water storage tank 20c again.

When the temperature in the hot water supply pipe 8a falls below the set temperature of the temperature sensor 30 without hot water supply, the hot water return pump 10 is operated to return the hot water in the hot water return pipe to the hot water storage tank 20a. The high temperature water in the hot water storage tank 20c is caused to flow into the hot water supply pipe 8a to keep the temperature of the hot water in the hot water supply pipe 8a at the required hot water supply temperature. In this case, the hot water return pump is operated at least until the hot water in the hot water supply pipe 8a reaches or exceeds the set temperature of the temperature sensor 30, and is stopped when it reaches or exceeds the set temperature.

FIG. 2 is a diagram showing the relationship between the outlet hot water temperature of the heat pump and the efficiency. In the first embodiment, since the heat pump is used as the heating means, there is a large difference in heating performance depending on the temperature of hot water to be heated, and the efficiency decreases as the outlet water temperature rises as shown in FIG. Therefore, in order to obtain a certain amount of heat, it is preferable to set the outlet temperature as low as possible for heating.

Therefore, as shown in the first embodiment, the heating by the heat pump is divided into two stages. In the first stage, the outlet temperature is set to be low and the hot water is gradually raised while circulating the hot water at the most efficient temperature setting. Allow to moderate temperature (30-40
C.), and in the second stage, the outlet temperature is set to the maximum temperature (60 to 70.degree. C.) that can be heated by the heat pump and heating is performed. In the heating in the first stage, the water absorption temperature is constant and thus the outlet temperature is also constant, but since the rated flow rate can be flown, a large amount of heat can be efficiently obtained. Thus, by dividing the heating by the heat pump into two stages, efficient operation becomes possible. Further, in the final stage, the electric heater 22c heats and heats to a higher temperature (80 to 85 ° C.), so that hot water can be supplied.

In the hot water storage tanks of the first and second stages, water is sucked from one side of the bottom of the hot water storage tank and heated hot water is returned to the bottom of the other side to heat the inside of the hot water storage tank while mixing. It uses a mixed formula. Therefore, the temperature of the hot water in the hot water storage tank can always be kept constant. Further, in the third-stage hot water storage tank 20c, the heated hot water is returned to the upper portion of the hot water storage tank 20c to store the hot water while forming a layer of hot water. And hot water storage tank 2
Since hot water from 0b flows into the bottom of the hot water storage tank 20c,
At the time of hot water supply, the hot water flowing from the hot water storage tank 20b pushes up the upper high temperature layer, and the high temperature layer is supplied without being destroyed. Therefore, even if a large amount of hot water is supplied at one time, high-temperature hot water can be supplied without lowering the hot water supply temperature.

In order to operate the entire apparatus with high efficiency, the first-stage hot water storage tank 20a is calculated by the following equation.
The heating set temperature Ts may be determined. Heating set temperature T
s is the target temperature that the hot water stored in the hot water storage tank 20a finally reaches. Ts = V2 × HP2 × (Tst2−TW) / (V1 × H
P1 + V2 × HP2) where V1 is the capacity of the hot water storage tank 20a, HP1 is the heating capacity of the heat pump 22a, Tst2 is the set temperature of the hot water storage tank 20b, V2 is the capacity of the hot water storage tank 20b, HP2 is the heating capacity of the heat pump 22b, Tw is the city water temperature.

Example 2. FIG. 3 is a schematic diagram showing the overall configuration of the second embodiment of the present invention. The same parts as those of FIG. 1 showing the first embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment relates to return hot water piping. In the figure, 32 is a temperature sensor installed in the return hot water pipe 8b, 34 is a first three-way valve installed upstream of the return hot water pipe 8b, and 36 is a second temperature sensor installed downstream of the return hot water pipe 8b. It is a three-way valve. One end of the return hot water pipe 8c is connected to the first three-way valve 34, and the other end of the return hot water pipe 8c is connected to the bottom of the hot water storage tank 20c. In the second three-way valve 36, one end of the return hot water pipe 8d is
The other end of each is connected to the bottom of the hot water storage tank 20b. The return hot water pump 10 is mounted in the return hot water path and upstream of the first three-way direction 34.

In the present embodiment constructed as described above, the temperature sensor 32 detects the water temperature in the return hot water pipe 8b,
If this temperature is higher than the bottom temperature of the hot water storage tank 20b, the first
Switching the three-way valve 34 to the return hot water pipe 8c side, the hot water storage tank 20c
Water is returned to the bottom of the hot water tank 2
If the temperature is lower than the bottom temperature of 0b and higher than the bottom temperature of the hot water storage tank 20a, the second three-way valve 36 is switched to the return hot water pipe 8d side to return water to the bottom of the hot water storage tank 20b. When the detected temperature is lower than the bottom temperature of the hot water storage tank 20a, the hot water storage tank 2
Return to 0a. By controlling in this way, heating in a high temperature stage can be reduced and heating in an inefficient stage can be reduced. That is, the energy possessed by the high-temperature return hot water can be efficiently and effectively utilized without heating the hot water having a temperature lower than the temperature of the return hot water.

Example 3. FIG. 4 is a schematic diagram showing the entire configuration of the third embodiment of the present invention. The same parts as those in FIG. 1 showing the first embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment differs from that of the first embodiment in that the third hot water storage tank is of an open type. In the figure, 42 is a water level detector attached to the upper part of the hot water storage tank 40c to detect the water level in the hot water storage tank 40c, 44 is a solenoid valve attached to the pipe 21b connecting the hot water storage tank 20b and the hot water storage tank 40c, 46 Is a controller that is connected to the water level detector 42 and controls the opening and closing of the solenoid valve 44 based on the detection signal of the water level detector 42.

In the present embodiment constructed as described above, when the water level in the hot water storage tank 40c is lowered by supplying hot water, the water level detector 42 detects the water level and sends a detection signal to the controller 46, Upon receiving this signal, the controller 46 opens the electromagnetic valve 44 to supply water, and when the set water level is reached, closes the electromagnetic valve to stop water supply. At the same time, electric heater 2
2c starts the heating operation and heats the hot water in the hot water storage tank 40c until it reaches the set temperature. By making the third-stage hot water storage tank 40c of the open type as described above, the hot water storage tank can be manufactured at a lower cost than the closed type. Also,
If the device is installed on the roof of a building or the like, hot water for hot water supply can be naturally supplied by the head even if it is not forced to be pumped out, so it is economical because the pump does not have to be constantly operated.

Even when the water level in the hot water storage tank 40c is lowered by hot water supply, the hot water supply load pattern is set in advance without constantly supplying water, and the time zone is determined based on this pattern to set the solenoid valve 44. If the water is supplied by opening it, it is possible to reduce the heat loss due to heat radiation without constantly filling the high temperature water.

Example 4. FIG. 5 is a schematic diagram showing the overall configuration of the fourth embodiment of the present invention. The same parts as those of FIG. 1 showing the first embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment is different from that of the first embodiment in that the third hot water storage tank 20c and the electric heater 22c are omitted.

Further, in the hot water storage tank 20b of the second stage, heated hot water is returned to the upper part of the hot water storage tank 20b to store the hot water while forming a layer of hot water. And
Since the hot water from the hot water storage tank 20a flows into the bottom of the hot water storage tank 20b, the hot water flowing from the hot water storage tank 20a pushes up the high temperature layer at the time of hot water supply, and the high temperature layer is supplied without being destroyed. . Therefore, even if a large amount of hot water is supplied at one time, high-temperature hot water can be supplied without lowering the hot water supply temperature.

[0027]

As described above, according to the present invention, a plurality of hot water storage tanks are arranged in series, and a heating means is provided in each hot water storage tank. Therefore, in the heating means for the hot water storage tank located on the most downstream side. The heating operation is performed at the required hot water supply temperature setting, and in the heating means of the hot water storage tank located on the upstream side, the heating operation can be performed under the most efficient conditions according to the type of heating means. Can be increased. Further, since the heating means of the hot water storage tank located on the most downstream side is the high temperature heating means, it is possible to heat the hot water to a high temperature according to the demand for high temperature hot water supply.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between outlet hot water temperature of a heat pump and efficiency.

FIG. 3 is a schematic diagram showing an overall configuration of a second embodiment of the present invention.

FIG. 4 is a schematic diagram showing an overall configuration of a third embodiment of the present invention.

FIG. 5 is a schematic diagram showing an overall configuration of a fourth embodiment of the present invention.

FIG. 6 is a schematic diagram showing an overall configuration of a conventional electric centralized water heater.

[Explanation of symbols]

 6 Water supply piping 9a, 9b, 9c Faucet 20a, 20b, 20c Hot water storage tank 21a, 21b, Pipe 22a, 22b Heat pump (heating means) 22c Electric heater (high temperature heating means) 40c Hot water storage tank

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location F24H 4/00 9251-3L F24H 1/00 311 B

Claims (2)

[Claims] 1. A plurality of hot water storage tanks arranged in series in a water supply path from a water supply pipe to a faucet, and between these hot water storage tanks are sequentially arranged from an upper part of the upstream hot water tank to a lower part of the downstream hot water tank. A central hot water supply device comprising: a pipe to be connected; and a plurality of heating means attached to each of the hot water storage tanks to heat water or hot water stored in each hot water storage tank to a set temperature. 2. The centralized hot water supply apparatus according to claim 1, wherein the heating means located on the most downstream side is a high temperature heating means, and the rest is a heat pump.