Hot water supply system

Abstract

This hot water supply system recovers and reuses the heat from wastewater, while also enabling the effective use of the wastewater from which the heat has been recovered. [Solution] The hot water supply system 1 includes a water heater 3 that supplies first hot water 41 which is heated supply water 2, a heat exchanger 4 that supplies second hot water 42 which is heated supply water 2 by recovering heat from wastewater 51 from hot water users 6, a buffer tank 5 that mixes the first hot water 41 and the second hot water 42 and temporarily stores it as third hot water 43, a third pipe 13 that supplies the third hot water 43 from the buffer tank 5 to the hot water users 6, a water temperature controller 31 that adjusts the mixing ratio of the first hot water 41 and the second hot water 42 to maintain the temperature of the third hot water at a desired temperature, a drain tank 7 that stores heat-recovered wastewater 52 which is heat-recovered from the heat exchanger 4, and a liquid volume controller 33 that maintains the amount of liquid stored in the drain tank 7 at a specified amount, and the heat-recovered wastewater 52 can be supplied from the drain tank 7 to the wastewater users 9.

Description

Technical Field

[0004] ,

[0006] , , , , , ,

[0005] , , , , , ,

[0001] The present invention relates to a hot water supply system.

Background Art

[0002] Conventionally, in a hot water supply system, there is known a system capable of recovering and reusing the heat of drainage. In the technology disclosed in Patent Document 1, by mixing water heated by drainage in a heat exchanger with the heated hot water supplied by a hot water supply device and supplying it to a faucet or a shower, it is possible to reduce the energy consumption in the hot water supply device. [[ID=十三]]

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

Means for Solving the Problems

[0007] According to the first invention, by supplying a second supply of hot water, heated by recovering heat from wastewater from hot water users in a heat exchanger, to a buffer tank, the total heat content of the first supply of hot water can be reduced, thereby lowering energy consumption in the water heater. In addition, by storing the wastewater with recovered heat from the heat exchanger in a wastewater tank and supplying it to wastewater users, the effective utilization of wastewater from hot water users can be ensured in a stable manner.

[0008] The second invention of the present invention is characterized in that, in the first invention described above, the supply water can be mixed with the first supply hot water and supplied to the buffer tank, and the mixing ratio of the supply water and the first supply hot water can be adjusted by the temperature controller.

[0009] According to the second invention, when the temperature of the third hot water supply in the buffer tank exceeds a desired temperature even when the supply amount of the second hot water supply is increased, the supply water can be mixed with the first hot water supply to adjust the temperature of the third hot water supply to the desired temperature.

[0010] The third invention of the present invention is characterized in that, in the first or second invention described above, a drain pipe is provided to connect the buffer tank and the drain tank, and the system is configured such that an on / off valve can be opened as needed to allow the water in the buffer tank to flow into the drain tank.

[0011] According to the third invention, if the hot water supply system is not used for a long period of time, such as during winter, the water in the buffer tank, which is significantly colder than the desired temperature, can be drained without being supplied to the hot water user. [Brief explanation of the drawing]

[0012] [Figure 1] A hot water supply system, which is an embodiment of one invention, is a block diagram. [Modes for carrying out the invention]

[0013] A hot water supply system 1 according to one embodiment of the present invention will be described with reference to Figure 1. The hot water supply system 1 is a system that continuously supplies hot water at a desired temperature to a bathhouse, lodging facility, etc. In Figure 1, the solid arrows connecting each element shown in the rectangular frame represent the piping and the direction of the water flowing through it. The dashed lines represent electrical wiring.

[0014] The supply water 2, such as tap water, is supplied to the water heater 3 and heat exchanger 4 via the first pipe 11. The first pipe 11 branches off after passing through a first on / off valve 21 installed along its length, and is connected to the water heater 3 and heat exchanger 4 respectively. The water heater 3 is a device that heats the supply water 2 supplied by electricity, gas, etc., to make hot water, which is then supplied as the first supply hot water 41 to the buffer tank 5 via the second pipe 12. A second on / off valve 22 is installed along the second pipe 12. The buffer tank 5 has the function of storing a predetermined amount of third supply hot water 43 and supplying it to the hot water users 6 via the third pipe 13. A third on / off valve 23 is installed along the third pipe 13. The wastewater 51 discharged from the hot water users 6 is sent to the heat exchanger 4 via the fourth pipe 14. The heat exchanger 4 performs heat exchange between the sent wastewater 51 and the supplied water 2, heating the water 2 to produce the second hot water supply 42. The second hot water supply 42 produced by the heat exchanger 4 is supplied through the fifth pipe 15 to the portion of the second pipe 12 downstream of the second on-off valve 22, where it is mixed with the first hot water supply 41 from the water heater 3 to become the third hot water supply 43, which enters the buffer tank 5. A fifth on-off valve 25 is installed in the middle of the fifth pipe 15. The portion of the first pipe 11 downstream of the first on-off valve 21 and the portion of the fifth pipe 15 downstream of the fifth on-off valve 25 are connected by the sixth pipe 16. A sixth on-off valve 26 is installed in the middle of the sixth pipe 16. The heat-recovered wastewater 52, which has been cooled by the heat exchanger 4, is sent to the wastewater tank 7 through the seventh pipe 17. A seventh on-off valve 27 is installed in the middle of the seventh pipe 17. Upstream of the seventh on / off valve 27 of the seventh pipe 17, the eighth pipe 18 branches off and is connected to the drain outlet 8. The eighth on / off valve 28 is installed in the middle of the eighth pipe 18. The heat-recovered wastewater 52 from the wastewater tank 7 is sent to the wastewater use destination 9 through the ninth pipe 19. The ninth on / off valve 29 is installed in the middle of the ninth pipe 19. At the wastewater use destination 9, the heat-recovered wastewater 52 is used as toilet flushing water, water for flowerbeds, emergency water, etc. From the wastewater tank 7, the tenth pipe 10 is connected to the drain outlet 8. The tenth on / off valve 20 is installed in the middle of the tenth pipe 10.The buffer tank 5 and the drain tank 7 are connected by the 11th pipe 101, and the 11th on / off valve 201 is installed in the middle of the 11th pipe 101. Here, the 11th pipe 101 and the 11th on / off valve 201 correspond to the "drain pipe" and "on / off valve" in the claims, respectively.

[0015] The water temperature controller 31 sets the temperature of the third supply hot water 43 in the buffer tank 5 and controls the setting temperature of the water heater 3, as well as the opening and closing of the second on / off valve 22, the third on / off valve 23, the fifth on / off valve 25, the sixth on / off valve 26, and the eleventh on / off valve 201, so that the third supply hot water 43 reaches that temperature. The flow rate controller 32 measures the flow rate of the third supply hot water 43 flowing through the third pipe 13 and controls the opening and closing of the first on / off valve 21 according to that flow rate. The liquid storage volume controller 33 measures the amount of heat-recovered wastewater 52 stored in the drainage tank 7 and controls the opening and closing of the seventh on / off valve 27, the eighth on / off valve 28, and the tenth on / off valve 20 according to that liquid storage volume. The ninth on / off valve 29 is a manually operated on / off valve that can be manually opened and closed to make the heat-recovered wastewater 52 flowing through the ninth pipe 19 available for use at the wastewater usage destination 9. Here, the water temperature controller 31 and the liquid storage volume controller 33 correspond to the "temperature controller" and "liquid storage volume controller" in the claims, respectively.

[0016] The operation of the hot water supply system 1 will now be explained. First, with the buffer tank 5 empty, the water temperature controller 31 sets the temperature of the third supply hot water 43 in the buffer tank 5 to a desired temperature, and the water heater 3 operates according to the set temperature of the water heater 3 set accordingly. At this time, the first on / off valve 21, the second on / off valve 22, and the seventh on / off valve 27 are in the open state, and all other on / off valves are in the closed state. The supply water sent to the water heater 3 through the first pipe 11 is heated to the set temperature by the water heater 3, and the generated first supply hot water 41 is sent to the buffer tank 5 through the second pipe 12. When the amount of first supply hot water 41 in the buffer tank 5 reaches a predetermined amount, the third on / off valve 23 is opened and the first supply hot water 41 is supplied to the hot water user 6 through the third pipe 13. The wastewater 51 from the hot water user 6 is sent to the heat exchanger 4 through the fourth pipe 14, where heat is recovered, becoming heat-recovered wastewater 52, and is sent to the wastewater tank 7 through the seventh pipe 17. The liquid storage controller 33 measures the amount of heat-recovered wastewater 52 stored in the drainage tank 7. When the amount reaches a specified level, it closes the 7th on / off valve 27 and opens the 8th on / off valve 28 to allow the excess heat-recovered wastewater 52 to flow through the 8th pipe 18 to the drain port 8. If draining through the 8th pipe 18 to the drain port 8 is insufficient to maintain the amount of heat-recovered wastewater 52 stored in the drainage tank 7 at the specified level, the 10th on / off valve 20 is also opened to allow draining through the 10th pipe 10 to the drain port 8 as well. When draining through the 8th pipe 18 to the drain port 8 is sufficient to maintain the amount of heat-recovered wastewater 52 stored in the drainage tank 7 at the specified level, the 10th on / off valve 20 is closed. In this state, the 9th on / off valve 29 is opened to send the heat-recovered wastewater 52 to the wastewater usage destination 9 through the 9th pipe 19 for use.

[0017] When the third shut-off valve 23 is opened, the fifth shut-off valve 25 is also opened, and the supply water 2 sent to the heat exchanger 4 through the first pipe 11 is heated by the wastewater 51 in the heat exchanger 4, becoming the second supply hot water 42, which is then sent to the second pipe 12 through the fifth pipe 15. In this state, the water temperature controller 31 adjusts the set temperature of the water heater 3, the opening of the second shut-off valve 22, the opening of the fifth shut-off valve 25, and the opening of the third shut-off valve 23 to maintain the temperature of the third supply hot water 43 in the buffer tank 5 at the desired temperature. Specifically, when the temperature of the third supply hot water 43 in the buffer tank 5 falls unacceptably below the desired temperature, the opening of the second shut-off valve 22 is increased, and the openings of the fifth shut-off valve 25 and the third shut-off valve 23 are decreased. If the temperature of the third supply hot water 43 in the buffer tank 5 still falls below the desired temperature, the set temperature of the water heater 3 is increased. Conversely, if the temperature of the third supply hot water 43 in the buffer tank 5 exceeds the desired temperature to an unacceptable degree, the opening of the second on-off valve 22 and the third on-off valve 23 is reduced and the opening of the fifth on-off valve 25 is increased. If the temperature of the hot water in the buffer tank 5 still exceeds the set temperature, the set temperature of the water heater 3 is lowered. If the temperature of the third supply hot water 43 in the buffer tank 5 still exceeds the desired temperature, the sixth on-off valve 26 is opened and the opening of the second on-off valve 22 and the fifth on-off valve 25 is reduced to introduce the supply water 2 into the second pipe 12 through the sixth pipe 16.

[0018] In winter or other times when the hot water supply system 1 is not used for an extended period, the water temperature in the buffer tank 5 may become significantly lower than the desired temperature. In such cases, the 11th on / off valve 201 is opened to drain all the water inside, and then the process is returned to the beginning to start the hot water supply system 1. The flow controller 32 adjusts the opening of the first on / off valve 21 to maintain the flow rate of hot water flowing through the third pipe 13 at a desired value.

[0019] The hot water supply system 1 of the present embodiment configured as described above has the following effects. By supplying the second supply hot water 42 generated by recovering heat from the drained water 51 from the hot water usage destination 6 through the heat exchanger 4 to the second pipe 12 through the fifth pipe 15, the total heat quantity of the first supply hot water 41 can be reduced, and the energy consumption in the water heater 3 can be decreased. In addition, the drained water 52 after heat recovery from the heat exchanger 4 can be stored in the drain tank 7 through the seventh pipe 17 and supplied to the drain usage destination 9, thereby enabling the effective utilization of the drained water 51 to be stably achieved.

[0020] Also, the supply water 2 is directly introduced into the second pipe 12 through the sixth pipe 16, and the mixing ratio of the supply water 2 and the first supply hot water 41 is configured to be adjustable by the hot water temperature controller 31. As a result, when the temperature of the third supply hot water 43 in the buffer tank 5 exceeds the desired temperature even if the supply amount of the second supply hot water 42 is increased, the supply water 2 can be mixed with the first supply hot water 41 to adjust the temperature of the third supply hot water 43 to the desired temperature.

[0021] Furthermore, it is configured such that the first on-off valve 201 can be opened as necessary to allow the water in the buffer tank 5 to flow into the drain tank 7 through the eleventh pipe 101. Thereby, when the hot water supply system 1 is not used for a long time, such as in winter, the significantly low-temperature water in the buffer tank 5 can be drained without being supplied to the hot water usage destination 6.

[0022] The embodiment disclosed this time should be considered as illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the above-described embodiment, and it is intended that all modifications within the meaning and scope equivalent to the claims are included.

Explanation of Reference Numerals

[0023] 1 Hot water supply system, 2 Water supply, 3 Water heater, 4 Heat exchanger, 5 Buffer tank, 6 Hot water usage point, 7 Drainage tank, 8 Drain outlet, 9 Drainage usage point, 31 Water temperature controller, 32 Flow controller, 33 Liquid storage volume controller, 41 First hot water supply, 42 Second hot water supply, 43 Third hot water supply, 51 Drainage, 52 Drainage with heat recovered, 101 Eleventh piping (drainage pipe), 201 Eleventh on / off valve (on / off valve)

Claims

1. It is a hot water supply system, A water heater that supplies first hot water by heating the supply water, A heat exchanger that supplies a second supply of hot water, which is heated by recovering heat from the wastewater used by the hot water user, A buffer tank that mixes the first hot water supply and the second hot water supply and temporarily stores them as a third hot water supply, and also supplies the third hot water supply to the hot water user, A temperature controller that adjusts the mixing ratio of the first and second hot water supplies to maintain the temperature of the third hot water supply at a desired temperature, A drainage tank for storing the heat-recovered wastewater from the heat exchanger, It has a liquid storage volume controller that maintains the liquid storage volume of the drainage tank at a specified level, A hot water supply system capable of supplying the heat-recovered wastewater from the aforementioned wastewater tank to the wastewater usage destination.

2. In claim 1, A hot water supply system configured to mix the supply water with the first supply hot water and supply it to the buffer tank, and to adjust the mixing ratio of the supply water and the first supply hot water using the temperature controller.

3. In claim 1 or claim 2, A drain pipe is provided to connect the buffer tank and the drain tank. A hot water supply system configured to allow water in the buffer tank to flow into the drain tank by opening an on / off valve as needed.

Images