JPH0459538B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to improvement of a hot water storage type water heater. BACKGROUND ART As shown in FIG. 3, a conventional hot water system of this type includes a refrigerant circuit in which a compressor 1, a condenser 2, a throttle device 3, and an evaporator 4 are sequentially connected, a hot water storage tank 5, and a circulation pump 6. A configuration is known that includes a hot water supply circuit that connects the condenser 2 and a water heat exchanger 7 having a heat exchange relationship. 8 is a hot water outlet pipe, and 9 is a water supply pipe. Problems to be Solved by the Invention The method of applying a heat pump and heating with its condensed heat as shown in FIG. 3 has a small instantaneous heating capacity, so it takes a long time to store hot water in the hot water storage tank 5. In particular, the heating capacity is greatly affected by the outside air, so in summer and mid-season it is possible to obtain the specified hot water temperature, but in winter and other low outside temperatures, the hot water is not effective even if heated for a long time. The problem was that there were many days when it was impossible to get warm. In addition, when hot water is discharged from hot water pipe 8 during heating by the condensation heat of the heat pump and the temperature of hot water in hot water storage tank 5 is low, the water coming in from water supply pipe 9 and the hot water in hot water storage tank 5 mix and the hot water is stored. Another problem was that the temperature of the hot water stored in the tank 5 decreased. moreover,
At this time, the temperature of the water sent to the water heat exchanger 7 by the circulation pump 6 is higher than the temperature of the water coming in from the water supply pipe 9, which also has the disadvantage of poor efficiency. The present invention solves such conventional problems,
When the temperature of the hot water in the hot water storage tank is low, the water heating circuit is switched from the hot water storage tank side to the hot water outlet pipe side and the hot water is reheated at the time of hot water dispensing. The purpose is to prevent mixing of hot water and water. Means for Solving the Problems In order to solve the above problems, the water heating device of the present invention connects a water heat exchanger for heating water in a hot water storage tank and a hot water outlet pipe in parallel, so that the water in the hot water storage tank and the outlet pipe are connected in parallel. The configuration allows selection by switching the heating of hot water. Effects According to the above-described configuration, when the water temperature in the hot water storage tank is low, the present invention heats the hot water by switching the water heating circuit including the water heat exchanger from the hot water storage tank side to the hot water tap pipe side. and heat it up to high temperatures. moreover,
Since the water in the hot water storage tank is not heated when hot water is dispensed, the water supplied from the water supply pipe in response to the hot water dispensed does not mix with the hot water in the hot water storage tank. Embodiments Hereinafter, embodiments of the present invention will be described based on FIG. 1 of the accompanying drawings. In FIG. 1, a refrigerant circuit in which a compressor 1, a condenser 2, a throttle device 3, and an evaporator 4 are sequentially connected, a hot water storage tank 5, a first on-off valve 10, a circulation pump 6, and the condenser 2 are heat exchanged. It is composed of a water circuit in which a water heat exchanger 7 and a second on-off valve 11 are connected. Further, a third on-off valve 12 is provided in the middle of the hot water tap pipe 8, and one end of the first reheating pipe 14 equipped with a fourth on-off valve 13 is connected to the hot water storage tank 5 and the third on-off valve 12. The other end is connected between the first on-off valve 10 and the circulation pump 6.
One end of a second reheating pipe 16, which is connected between the above and provided with the fifth on-off valve 15, is connected to the hot water tapping pipe 8 downstream of the third on-off valve 12, and the other end is connected between the It is connected between the second on-off valve 11 and the water heat exchanger 7. 9 is a water supply pipe. In addition, a temperature sensor 1 provided near the connection between the hot water storage tank 5 and the hot water outlet pipe 8
7, the controller 18 controls the first, second, third, fourth and fifth on-off valves 10, 11,
12, 13, and 15. First, the case of heating the inside of the hot water storage tank 5 will be explained. In this case, the first on-off valve 10 and the second on-off valve 11 are opened, and the fourth on-off valve 13 and the fifth on-off valve 15 are closed, regardless of the temperature detected by the temperature sensor 17. Note that the third on-off valve 12 may be opened or closed in either state. If you do this, the third
Similar to the conventional example shown in the figure, the water in the hot water storage tank 5 is sent to the water heat exchanger 7 by the circulation pump 6 to be heated, and then returned to the hot water storage tank 5 to gradually heat the entire hot water storage tank 5. . In this case, the instantaneous heating capacity is small,
Furthermore, the entire water in the hot water storage tank 5 is heated, and it takes a long time to heat the water in the hot water storage tank 5 to a predetermined temperature. FIG. 2 schematically shows the time course of the hot water temperature in the hot water storage tank 5 in summer, mid-season, and winter. In the figure, the horizontal axis shows the heating time, and the vertical axis shows the hot water temperature in the hot water storage tank.
Moreover, the dotted line is the desired temperature for boiling. As can be seen from the figure, the set temperature is reached in the summer and mid-season, but there are days in the winter when the set temperature is not reached. Next, the case of tapping hot water will be explained. First of all,
Discharge of hot water when the temperature of hot water in the hot water storage tank 5 reaches the set temperature will be explained. In this case, temperature sensor 1
Since the temperature detected by 7 is at or above the set temperature, the controller 18 operates to open the third on-off valve 12 and close the fourth on-off valve 13 and the fifth on-off valve 15. Note that the first on-off valve 10 and the second on-off valve 11 may be opened or closed. In this way, as in the conventional example shown in FIG. 4, hot water reaching the set temperature in the upper layer of the hot water storage tank 5 can be dispensed. Next, a description will be given of hot water dispensing when the temperature of the hot water in the hot water storage tank 5 does not reach the set temperature, as in the case of winter shown in FIG. 2. In this case, since the temperature detected by the temperature sensor 17 is below the set temperature, the controller 18 closes the first on-off valve 10, the second on-off valve 11 and the third on-off valve 12, and closes the first on-off valve 10, the second on-off valve 11, and the third on-off valve 12. The fourth on-off valve 13 and the fifth on-off valve 15 are opened. In this way, the hot water in the hot water storage tank 5 is guided to the water heat exchanger 7 through the first reheating pipe 14 by the circulation pump 6 and heated. Furthermore, the second reheating tube 1
6, the hot water reaches a high temperature and is discharged. In addition, the following table shows the first to fifth on-off valves 10, 11, 12, 1.
3 and 15 are shown in the open and closed states.

[Table] ○: Open state ×: Closed state -: Either open or closed is fine As explained above, when dispensing hot water, the temperature sensor 1
7 detects a temperature lower than the set temperature, the water heating circuit is switched from the hot water storage tank 5 side to the hot water outlet pipe 8 side,
Since hot water is dispensed while reheating the hot water in the hot water tank 5,
The effect is that hot water can be dispensed. Furthermore, at this time, the water coming in from the water supply pipe 9 and the hot water in the hot water tank 5 do not mix, so there is no decrease in the temperature of the hot water in the hot water tank 5 and rise in the temperature of the supplied water due to mixing of hot water and water, as in the conventional example. When heating the hot water storage tank 5 after hot water is tapped, the water at the water temperature that comes in from the water supply pipe 9 is transferred to the water heat exchanger 7.
This has the effect of improving the disadvantage of poor efficiency. Effects of the Invention As described above, according to the hot water device of the present invention, the following effects can be obtained. (1) When the temperature of the water in the hot water storage tank is low, only the hot water to be tapped is reheated, so the effect is that hot water can be tapped at a high temperature. (2) When the water temperature in the hot water storage tank is low, and when hot water is tapped and heated at the same time, the water heating circuit is switched from the hot water storage tank side to the hot water tap side, which causes the problem of a drop in the hot water temperature in the hot water storage tank due to mixing of hot water and water. This has the effect of solving the problem. (3) Similarly, since the water heating circuit is switched from the hot water storage tank side to the hot water outlet pipe side, the water coming in from the water supply pipe does not mix with the hot water in the hot water storage tank, but instead forms a single layer at the bottom of the hot water storage tank. Therefore, when heating the hot water storage tank after hot water is tapped, the water at the same temperature that comes in from the water supply pipe is sent to the water heat exchanger, which has the effect of solving the problem of poor efficiency as in conventional systems. be.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a hot water device showing an embodiment of the present invention, Fig. 2 is an explanatory diagram showing changes in water temperature in a hot water storage tank with respect to heating time of the same device, and Fig. 3 shows a conventional water hot water device. FIG. 5... hot water storage tank, 6... circulation pump, 7... water heat exchanger, 8... hot water outlet pipe, 10... first on-off valve,
11...Second on-off valve, 12...Third on-off valve,
13... Fourth on-off valve, 14... First reheating pipe, 15... Fifth on-off valve, 16... Second reheating pipe, 17... Temperature detector, 18... Controller .

Claims (1)

[Claims] 1. Both ends of a water heating circuit in which a first on-off valve, a circulation pump, a water heat exchanger, and a second on-off valve are sequentially connected are connected to a hot water storage tank, and a third on-off valve is provided at the top of the hot water storage tank. One end of a first reheating pipe provided with a fourth on-off valve is connected between the hot water storage tank and the third on-off valve, and the other end is connected between the first on-off valve and the circulation valve. A second reheating pipe is connected between the pump and has a fifth on-off valve, one end of which is connected to a hot water tap downstream of the third on-off valve, and the other end is connected to the second on-off valve. When dispensing hot water, if a temperature sensor installed near the connection between the hot water storage tank and the hot water supply pipe detects a temperature lower than a certain set temperature in the water circuit connected between the hot water storage tank and the hot water supply pipe, A hot water device capable of reheating by opening fourth and fifth on-off valves and closing the first, second and third on-off valves.