JP2001248906A - Exhaust heat recovering hot water supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an exhaust heat recovering hot water supply system for heating water in a hot water storage tank by circulating heating medium between a gas engine and the hot water storage tank in which dew formation is prevented in an exhaust heat generating unit when the temperature of hot water in the hot water storage tank is low. SOLUTION: A cooling water circulation passage 4 is constituted by coupling a primary heat exchanger 5 disposed in a gas engine 2 with a secondary heat exchanger 6 disposed in a hot water storage tank 12 through a cooling water return pipe 7 and a cooling water supply pipe 8. The cooling water supply pipe 8 is provided with a mixing valve 10 comprising a thermowax valve and a bypass pipe 11 is laid between the cooling water return pipe 7 and the mixing valve 10. When the temperature of hot water flowing through the cooling water supply pipe 8 drops, the mixing valve 10 opens the bypass pipe 11 to feed high temperature hot water from the cooling water return pipe 7 to the cooling water supply pipe 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust heat recovery / hot water supply system for supplying hot water by effectively using exhaust heat.

[0002]

2. Description of the Related Art Hot water in a hot water storage tank is heated by using waste heat from a power generation device (cogeneration system) using a gas engine, a fuel cell, or the like installed in each region or house. There is known an exhaust heat recovery / hot water supply system for supplying hot water directly or indirectly via a heat exchanger.

FIG. 4 is a diagram showing the configuration of a conventional exhaust heat recovery / hot water supply system 61, in which a cooling water is circulated in a power generation device 62 using a gas engine, a fuel cell, or the like to cool the power generation device 62. A cooling water circulation path 63 is provided. That is, the primary-side heat exchanger 64 provided inside the power generation device 62 cools the power generation device 62 by exchanging heat with the exhaust heat of the power generation device 62, while the cooling water in the cooling water circulation path 63 It is heated to a high temperature such as 80-90 ° C.

[0004] The exhaust heat recovery and hot water supply system 61 supplies hot water by utilizing the heat of the cooling water heated as described above. In the hot water storage tank 65, a secondary heat exchanger 66 for exchanging heat between high-temperature water heated by exhaust heat and water in the hot water storage tank 65 to heat water or hot water in the hot water storage tank 65 is provided. Have been. Primary and secondary heat exchanger 6
4 and 66 are connected via a cooling water circulation pump 67 and a pipe 68 to form a cooling water circulation path 63.

When water or hot water is circulated in the cooling water circulation passage 63 by operating the cooling water circulation pump 67, heat exchange is performed with the exhaust heat generated in the power generator 62, so that the primary heat exchanger 64 is cooled. The water absorbs heat and becomes high-temperature water and is sent to the secondary-side heat exchanger 66 in the hot-water storage tank 65. The high-temperature water in the secondary heat exchanger 66 is supplied to the hot water storage tank 65.
Heat exchange with the water or hot water in the hot water storage tank 65
To heat the water or hot water in the
The temperature of the hot water inside decreases. The warm water in the secondary side heat exchanger 66 whose temperature has been lowered in this way is sent to the primary side heat exchanger 64 again, where it absorbs heat again. By repeating such an operation, the power in the hot water storage tank 65 is heated to a high temperature by the exhaust heat of the power generator 62 while the power generator 62 is cooled.

The hot water storage tank 65 has a hot water supply circulation path 6.
Nine pipes are connected, and hot water can be circulated through the hot water supply circulation path 69 by operating the circulation pump 70 of the hot water supply circulation path 69. And hot water supply circuit 6
The hot water in the bathtub can be reheated by exchanging heat with the bath water flowing in the bath reheating circuit 72 by, for example, a bath heat exchanger 71 provided in the bath 9.

However, in such a hot water storage type exhaust heat recovery / hot water supply system 61, when the temperature of the hot water in the hot water storage tank 65 is low, the bath cannot be reheated to a sufficient temperature.
Therefore, conventionally, a tank tapping temperature sensor 73 and a backup burner 74 are provided at a portion coming out of the hot water storage tank 65, and when the hot water temperature in the hot water storage tank 65 is lower than a predetermined temperature, the hot water storage tank 65 The hot water inside is heated by the backup burner 74 and then sent to the bath heat exchanger 71. When the temperature of hot water discharged from hot water storage tank 65 becomes higher than a predetermined temperature, backup burner 74 is extinguished. Therefore, even when the temperature of the hot water in the hot water storage tank 65 is low, the hot water in the bathtub can be additionally heated to the set temperature.

Reference numeral 75 denotes a hot water supply pipe for supplying hot water from a curan or the like, and reference numeral 76 denotes a water supply pipe for supplying water to a hot water supply tank.

[0009]

However, in the exhaust heat recovery / hot water supply system 1 as described above, there are the following problems on the cooling water circulation path side. Normally, hot water at a temperature of 65 ° C. to 70 ° C. is stored in the hot water supply tank 65, but when the hot water in the hot water supply tank 65 is used at a time and water is supplied from the water supply pipe 76, The temperature of the water in the hot water supply tank 65 becomes low (for example, it drops to about room temperature). The cooling water circulation pump 67 is operated in such a state, and the low-temperature cooling water (hot water supply tank 65) is supplied to the cooling water circulation passage 63.
When the internal water is circulated, only the vicinity of the primary heat exchanger 64 of the power generation device 62 is rapidly cooled, and as a result, there is a problem that dew condensation occurs in the power generation device 62 and the power generation device 62 is damaged.

On the hot water supply circulation path side, a hot water storage tank 65 is provided.
When the temperature of the hot water in the inside is low, the hot water heated by the backup burner 74 is circulated to the hot water supply circulation path 69, but the heating by the backup burner 74 is performed by the hot water storage tank detected by the tank hot water temperature sensor 73. 6
Since the hot water temperature from 5 will continue until it exceeds the predetermined temperature,
After all, the hot water in the hot water storage tank 65 is backed up by the burner 74.
It was irrational to be boiled. That is, once the circulation pump 70 is operated in a state where the temperature of the hot water in the hot water storage tank 65 is low, the hot water in the hot water storage tank 65 is backed up by the backup burner 74 even though the hot water in the hot water storage tank 65 is recovered.
And the efficiency of waste heat utilization is reduced.

The present invention has been made in view of the above-mentioned problems of the prior art, and has been made to solve the above-mentioned problems in the exhaust heat recovery / hot water supply system.

[0012]

According to the first aspect of the present invention, there is provided an exhaust heat recovery / hot water supply system, wherein a heat medium is circulated between a device for generating exhaust heat and a hot water storage tank to thereby store the hot water in the hot water storage tank. In a waste heat recovery hot water supply system that heats water,
A circulation path for circulating a heat medium is formed between the exhaust heat generation device and the hot water storage tank, and a flow path in which the heat medium flows from the exhaust heat generation device to the hot water storage tank and a discharge path from the hot water storage tank. A bypass flow path is provided between the heat generation device and the flow path through which the heat medium flows, and a bypass flow path is provided so that the flow path can be opened and closed. The path is controlled in the opening direction so that a part of the heat medium flowing from the waste heat generator to the hot water storage tank is caused to flow to the flow path through which the heat medium flows from the hot water storage tank to the waste heat generator.

Here, in order to open the bypass flow path when the temperature of the heat medium flowing from the hot water storage tank to the exhaust heat generating device is low, the temperature of the heat medium flowing from the hot water storage tank to the exhaust heat generating device is detected by a temperature sensor. The temperature may be detected, and when the detected temperature falls below a predetermined temperature (or when it is determined that the temperature is low using fuzzy control or the like), the bypass flow passage may be opened by a valve or the like, or a wax thermo valve may be used. For example, the valve itself may detect the temperature drop and open the bypass flow path. Further, the bypass flow passage may be gradually opened in accordance with a decrease in the temperature of the heat medium flowing out of the hot water storage tank.

According to the first aspect of the present invention, when the temperature of the heat medium flowing from the hot water storage tank to the waste heat generator is low, the flow path of the heat medium from the waste heat generator to the hot water storage tank and the hot water storage Open a bypass channel that connects the flow path of the heat medium from the tank to the waste heat generator, and open a part of the heat medium flowing from the waste heat generator to the hot water storage tank. I'm trying to flow to. Therefore,
Even when the temperature of the water in the hot water storage tank is low, a low-temperature heat medium does not flow to the exhaust heat generation device, so that dew condensation in the exhaust heat generation device can be prevented.

The exhaust heat recovery and hot water supply system according to a second aspect of the present invention heats water in the hot water storage tank by circulating a heat medium between a device for generating exhaust heat and a hot water storage tank. In the above, a hot water supply circuit for circulating hot water in the hot water storage tank is connected to the hot water storage tank, a heat exchanger is provided in the hot water supply circuit, and a flow path in which hot water flows from the hot water storage tank to the heat exchanger in the hot water supply circuit Forming a bypass flow path between the heat exchanger side and a flow path of hot water from the heat exchanger side to the hot water storage tank; and providing an auxiliary heat source device on a side of the hot water supply circulation path closer to the heat source device than the bypass flow path, When the machine starts a heating operation, hot water is circulated between the bypass and the heat exchanger.

Here, the heat exchanger is for exchanging heat with a heat medium flowing through, for example, a bath reheating circuit or a heating circuit.
Further, the auxiliary heat source device is for supplementarily heating the hot water flowing in the hot water supply circuit when the temperature of the hot water in the hot water storage tank is low, and is a gas burner, an electric heater, or the like.

In the exhaust heat recovery and hot water supply system according to the second aspect, when the temperature of the hot water in the hot water storage tank is low and the auxiliary heat source unit starts the heating operation, the hot water is heated by the auxiliary heat source unit and the heat is supplied to the bypass passage. Hot water is circulated between the heat exchanger and the exchanger. Therefore, even when the temperature of the hot water in the hot water storage tank is low, the heat exchanger can exchange heat with, for example, a bath reheating circuit or a heating circuit to heat the heating medium in the reheating circuit or the heating circuit. In addition, in this case, the hot water is prevented from flowing into the hot water storage tank by bypassing the hot water storage tank by the bypass flow path, so that it is possible to prevent the irrationality of heating the hot water in the hot water storage tank by the auxiliary heat source device. it can.

In a third aspect of the present invention, there is provided an exhaust heat recovery / hot water supply system for heating water in a hot water storage tank by circulating a heat medium between a device for generating exhaust heat and a hot water storage tank. A hot water supply circuit for circulating hot water in the hot water storage tank is connected to the hot water storage tank, a heat exchanger is provided in the hot water supply circuit, and a flow path and heat of the hot water supply circuit from the hot water storage tank to the heat exchanger side. A bypass flow path is formed between a flow path through which hot water flows from the exchanger side to the hot water storage tank, and an auxiliary heat source device is provided on a side closer to the heat exchanger than the bypass flow path in the hot water supply circulation path, If the hot water temperature falls below the temperature of the hot water returning from the heat exchanger,
It is characterized in that hot water is circulated between the bypass and the heat exchanger.

According to the third aspect of the present invention, when the temperature of the hot water in the hot water storage tank becomes lower than the temperature of the hot water returning from the heat exchanger, the bypass passage and the heat exchanger are connected to each other. Because the hot water is circulated between the hot water storage tanks, the temperature in the hot water storage tank drops and the auxiliary heat source unit heats the hot water sent to the heat exchanger. Since hot water flows, it is possible to prevent irrationality of heating the hot water in the hot water storage tank by the auxiliary heat source device.

[0020]

FIG. 1 is a diagram showing the configuration of an exhaust heat recovery / hot water supply system 1 according to an embodiment of the present invention. The exhaust heat recovery and hot water supply system 1 heats hot water in a hot water storage tank using exhaust heat generated in a cogeneration system. Here, a cogeneration system is shown in which the gas engine 2 burns city gas or propane gas to generate power by rotating the generator 3, but the gas is decomposed into hydrogen and carbon dioxide, and the oxidation of hydrogen gas is performed. A cogeneration system using a fuel cell that generates electric energy by a reaction or the like (in this case, the fuel cell needs to be cooled) may be used.

A primary heat exchanger 5 for circulating cooling water and cooling the gas engine 2 is provided in the gas engine 2 for rotating the generator 3 to generate electric power. On the other hand, a secondary heat exchanger 6 is provided in the hot water storage tank 12, and the primary heat exchanger 5 and the secondary heat exchanger 6 are connected by a cooling water return pipe 7 and a cooling water outflow pipe 8. The connection forms a cooling water circulation path 4. A cooling water circulation pump 9 is provided in the cooling water outflow pipe 8, and a mixing valve 10 is provided upstream of the cooling water circulation pump 9.
Is provided, and a bypass pipe 11 is disposed between the mixing valve 10 constituted by a thermowax valve and the cooling water return pipe 7.

When the cooling water circulating pump 9 is operated, the water circulating in the cooling water circulating passage 4 is supplied to the gas engine 2.
The heat is absorbed by the primary heat exchanger 5 inside and the heat is released by the secondary heat exchanger 6 inside the hot water storage tank 12. As a result, the gas engine 2 is cooled and the hot water in the hot water storage tank 12 is heated, and hot water at 65 ° C. to 70 ° C. is stored in the hot water storage tank.

When the temperature of the hot water flowing through the cooling water outflow pipe 8 is high, the mixing valve 10 constituted by a thermowax valve closes the bypass pipe 11 to allow hot water to flow only through the cooling water outflow pipe 8. But the cooling water going pipe 8
When the temperature of the hot water flowing through the air becomes low (for example, when it becomes 40 ° C. or less), the bypass pipe 11 side is gradually opened. Alternatively, as the temperature of the hot water flowing through the cooling water outlet pipe 8 decreases, the ratio of the valve opening on the bypass pipe 11 side to the valve opening on the upstream side of the cooling water outlet pipe 8 gradually increases.

Therefore, when the temperature of the hot water in the hot water storage tank 12 is relatively high and the temperature of the hot water flowing out to the cooling water discharge pipe 8 is high, the bypass pipe 11 is closed and the cooling water return pipe 7 and the cooling water flow. Hot water flows only in the pipe 8 and the hot water in the hot water storage tank 12 is heated. On the other hand, when the temperature of the hot water in the hot water storage tank 12 decreases and the temperature of the hot water passing through the mixing valve 10 decreases, the mixing valve 10 is gradually opened on the bypass pipe 11 side. As a result, a part of the high-temperature water heated by the primary-side heat exchanger 5 and flowing through the cooling water return pipe 7 is mixed with the low-temperature hot water discharged from the hot water storage tank 12 through the bypass pipe 11. In addition, the temperature of the hot water flowing to the primary heat exchanger 5 increases, and the temperature of the hot water flowing into the primary heat exchanger 5 does not become too low even when the temperature of the hot water in the hot water storage tank 12 is low. Therefore, according to the exhaust heat recovery / hot water supply system 1, the possibility that dew condensation occurs on the gas engine 2 in which the primary heat exchanger 5 is installed is eliminated.

A hot water storage temperature sensor (thermistor) 13 for detecting the temperature of hot water in the tank is attached to the hot water storage tank 12. Further, a water supply pipe 14 for supplying city water is connected to a lower portion of the hot water storage tank 12, and the water supply pipe 14 is provided with a pressure-reducing check valve 15.

On top of the hot water storage tank 12, the hot water storage tank 1
A hot water supply pipe 16 for discharging hot water stored in the pipe 2 is connected, and the hot water supply pipe 16 is connected to a circulation outflow pipe 17 and a hot water supply pipe 31.
And branch into. A branch pipe 18 for bath and a branch pipe 19 for heating are connected in parallel downstream of the circulation pipe 17, and a circulation return pipe 20 is further connected downstream of the branch pipe 18 for heating and branch pipe 19 for heating. The end of the circulation return pipe 20 is connected to the hot water storage tank 12 again. Then
The hot water supply pipe 16, the circulation outflow pipe 17, the bath branch pipe 18, the heating branch pipe 19, and the circulation return pipe 20 constitute a hot water supply circulation path. A three-way switching valve 21 is provided in the circulation return pipe 20.
The remaining connection port (valve opening) of the three-way switching valve 21 is connected to the hot water supply pipe 16 by a bypass pipe 22. The hot water flowing back through the circulation return pipe 20 by the three-way switching valve 21 is supplied to the hot water storage tank 12 and the hot water supply pipe 1.
It can be switched to 6 side.

The hot water supply pipe 16 has a bypass pipe 22
A tank tapping temperature sensor (thermistor) 23 for detecting the temperature of hot tap water from the hot water storage tank 12 is attached to the upstream side of the connection position.
Downstream of the connection position of the backup burner 24
Is provided. A circulation pump 25 is connected to the circulation outgoing pipe 17.
Is provided. The bath branch pipe 18 is provided with a bath heat exchanger 26 and a bath heat valve 27, and the heating branch pipe 19 is provided with a heating heat exchanger 28 and a heating heat valve 29. ing. A circulation return temperature sensor (thermistor) 30 is located upstream of the three-way switching valve 21 of the circulation return pipe 20.
Is provided.

The bath heat exchanger 26 is provided with a bath heat exchange coil 36 of a bath reheating circuit, and a bath return pipe 35 is provided between the bath heat exchange coil 36 and the bath adapter of the bathtub. The bath going pipe 37 is connected to the bath returning pipe 35.
Is provided with a bath circulation pump 38. Similarly, the heating heat exchanger 28 includes the heating heat exchange coil 4 of the heating circuit.
4, a heating return pipe 41 and a heating going pipe 45 are connected between the heating heat exchange coil 44 and the heating device, and the heating return pipe 41 has a heating water tank 42 and a heating circulation pump. 43 are provided. The heating water tank 42 separates gas and liquid so that air is not contained in the warm water flowing in the heating circuit and absorbs expansion and contraction of the warm water. The water level in the heating water tank 42 is kept below a certain level. When the temperature drops, the electromagnetic on-off valve 47 is opened and water is sucked into the heating water tank 42 from the water supply pipe 14 and the water supply pipe 46.

When performing the additional bath heating operation, the bath heat valve 27 is opened, the heating heat valve 29 is closed, and the circulation pump 25 is operated. At this time, it is assumed that the three-way switching valve 21 is closed on the bypass pipe 22 side. When the operation of the circulation pump 25 starts, the hot water in the hot water storage tank 12 flows through the bath branch pipe 18 to the hot water supply circulation path, and is again returned to the hot water storage tank 12.
Return to On the other hand, in the bath reheating circuit, the bath circulation pump 3
8, the hot water in the bathtub is circulated. At this time, the hot water flowing through the hot water supply circulation path exchanges heat with the bath water flowing through the bath heat exchange coil 36 of the bath reheating circuit in the bath heat exchanger 26, so that the hot water in the bathtub is heated by the bath reheating circuit. Fired.

When the heating operation is performed, the heating heat valve 29 is opened, the bath heat valve 27 is closed, and the circulation pump 25 is opened.
To drive. At this time, the three-way switching valve 21 is also connected to the bypass pipe 2.
It is assumed that two sides are closed. On the other hand, in the heating circuit, the heating circulation pump 43 is operated to circulate hot water. Circulation pump 2
When the operation of 5 starts, the hot water in the hot water storage tank 12 flows through the heating branch pipe 19 to the hot water supply circulation path, and returns to the hot water storage tank 12 again. Therefore, the hot water flowing through the hot water supply circulation path exchanges heat with the water flowing through the heating heat exchange coil 44 in the heating heat exchanger 28, so that the hot water in the heating circuit is heated.

The start and stop of the combustion operation of the backup burner 24 are controlled by the temperature detected by the tank outlet temperature sensor 23. That is, the tank tapping temperature sensor 2
When the detected temperature of 3 becomes lower than the minimum temperature required in the bath heat exchanger 26 or the heating heat exchanger 28, the backup burner 24 starts combustion, and when the detected temperature is higher than the minimum temperature, the backup burner 24 burns. Stops. Further, the three-way switching valve 21 switches to the bypass pipe 22 side in conjunction with the combustion of the backup burner 24, and switches to the hot water storage tank 12 side in conjunction with the stop of combustion of the backup burner 24 (or the three-way switching valve 21 also switches to the backup burner 24). Control under the same conditions as above). Therefore, when the additional heating operation or the heating operation of the bathtub is performed, when the temperature of the hot water discharged from the hot water storage tank 12 (the temperature detected by the tank hot water temperature sensor 23) is higher than a predetermined temperature, the hot water storage is performed as described above. A hot water storage tank 12 is provided between the tank 12 and the hot water supply circuit.
The hot water inside circulates. On the other hand, when the temperature of hot water from hot water storage tank 12 becomes lower than the predetermined temperature, three-way switching valve 21
Is switched from the hot water storage tank 12 side to the bypass pipe 22 side, and the backup burner 24 starts the combustion operation.
Therefore, the water circulates in the route of the hot water supply pipe 16 → circulation going pipe 17 → bath branch pipe 18 or heating branch pipe 19 → circulation return pipe 20 → bypass pipe 22, and the temperature of the hot water flowing through this circulation path becomes the circulation return temperature. The combustion of the backup burner 24 is controlled such that the temperature detected by the sensor 30 and detected by the circulation return temperature sensor 30 is maintained at a predetermined temperature.

Therefore, even when the temperature of the hot water in the hot water storage tank 12 is low, the reheating operation and the heating operation of the bath can be performed. Moreover, even if the backup burner 24 is burned, it is heated only when the hot water supply pipe 16 → circulation going pipe 17 → bath branch pipe 18 or heating branch pipe 19 → circulation return pipe 20 → bypass pipe 22 is circulated. Since only the hot water inside the hot water storage tank is used, the backup burner 24
It is possible to avoid the irrationality of the conventional example such as boiling the hot water in 2.

On the other hand, the hot water in the hot water storage tank 12 is heated by the cooling water circulation path 4 even when the three-way switching valve 21 is switched to the bypass pipe 22 and the backup burner 24 is operated for combustion. When the hot water storage temperature sensor 13 detects that the hot water temperature in the hot water storage tank 12 has reached a predetermined temperature or higher, the backup burner 24 stops the combustion, and the three-way switching valve 21 switches again to the hot water storage tank 12 side. The hot water in the hot water storage tank 12 is circulated through the bath branch pipe 18 and the heating branch pipe 19.

The hot water supply pipe 31 is provided with a hot water supply mixing valve 32, and a mixing water supply pipe 33 branched from the water supply pipe 14 is connected to the hot water supply mixing valve 32 via a check valve 34. And the hot water supply pipe 31
When the callan or shower provided at the end of the pipe is opened,
Hot water at a set temperature mixed with hot and cold water is supplied by hot water mixing valve 32.

Further, a bath dropping pipe 39 branched from the hot water supply pipe 31 is connected to a bath outflow pipe 37 via a bath pouring solenoid valve 40. When the bath pouring electromagnetic valve 40 is opened, the bath is supplied from the hot water supply pipe 31 to the bath. Hot water is supplied to the outgoing pipe 37, and the hot water is dropped into the bathtub by the two transports from the bath outgoing pipe 37 and the bath return pipe 35.

The control conditions of the three-way switching valve 21 include a hot water storage temperature sensor 1 provided below the hot water storage tank 12.
The magnitude relationship between the detected temperature 3 and the temperature of the return hot water from the bath heat exchanger 26 or the heating heat exchanger 28 (that is, the temperature detected by the circulation return temperature sensor 30) may be used. That is, when the temperature detected by the hot water storage temperature sensor 13 is lower than the temperature detected by the circulation return temperature sensor 30, the three-way switching valve 2
1 to the bypass pipe 22 side and the hot water storage temperature sensor 13
If the detected temperature is equal to or higher than the temperature detected by the circulation return temperature sensor 30, the three-way switching valve 21 is switched to the hot water storage tank 12 side. As described above, the backup burner 24 starts combustion when the temperature detected by the tank hot water temperature sensor 23 becomes equal to or lower than the minimum temperature required by the bath heat exchanger 26 or the heating heat exchanger 28, and If it is higher than the temperature, the combustion is stopped.

In this case, when the temperature of the hot water in the hot water storage tank 12 becomes lower than the minimum temperature required by the bath heat exchanger 26 or the heating heat exchanger 28, the backup burner 24 starts combustion. When the backup burner 24 starts combustion, the temperature detected by the circulation return temperature sensor 30 becomes higher than the temperature detected by the hot water storage temperature sensor 13, so that the three-way switching valve 21 switches to the bypass pipe 22 side, and the bypass pipe 22 and the bath heat Heat exchanger 28 or heat exchanger 28 for heating
Warm water circulates between and. After that, the hot water in the hot water storage tank 12 is heated, and the temperature of the hot water is
Alternatively, when the temperature becomes higher than the minimum temperature required by the heating heat exchanger 28, the backup burner 24 stops the combustion. When the backup burner 24 stops the combustion, the temperature detected by the circulation return temperature sensor 30 decreases and becomes lower than the temperature detected by the hot water storage temperature sensor 13.
1 is again switched to the hot water storage tank 12 side,
The hot water in 2 is used as a bath heat exchanger 26 or a heating heat exchanger 2
8 circulated.

As shown in FIG. 2, the cooling water circulation path 4 is provided with a flow control valve 48 in the bypass pipe 11 and flows into the primary heat exchanger 5 by a temperature sensor 49 provided in the cooling water outflow pipe 8. The temperature of the hot water may be detected, and when the temperature detected by the temperature sensor 49 decreases, the valve opening of the flow control valve 48 may be increased.

Alternatively, as shown in FIG. 3, a switching valve 50 is provided between the cooling water return pipe 7 and the bypass pipe 11, and flows out from the switching valve 50 to the secondary heat exchanger 6 side and the bypass pipe 11 side. The flow rate ratio can be controlled, and when the temperature detected by the temperature sensor 49 provided in the cooling water discharge pipe 8 becomes low, the switching valve 5
The ratio of hot water flowing from 0 to the bypass pipe 11 may be increased.

Further, without providing the secondary heat exchanger 6 in the hot water storage tank 12, the hot water storage tank
The water inside can be circulated directly.

[0041]

In the exhaust heat recovery / hot water supply system according to the first aspect of the present invention, even when the temperature of the hot water in the hot water supply tank is low, dew condensation is generated on the side of the device that generates the exhaust heat. Can be prevented.

In the exhaust heat recovery / hot water supply system according to the second or third aspect of the present invention, when the backup burner performs a combustion operation, the backup burner does not heat while circulating the hot water in the hot water supply tank.

Therefore, according to the present invention, rationalization of the exhaust heat recovery / hot water supply system can be achieved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an exhaust heat recovery / hot water supply system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a part of an exhaust heat recovery / hot water supply system according to another embodiment of the present invention.

FIG. 3 is a diagram showing a part of an exhaust heat recovery / hot water supply system according to still another embodiment of the present invention.

FIG. 4 is a schematic diagram showing a configuration of a conventional exhaust heat recovery / hot water supply system.

[Explanation of symbols]

 2 Gas engine 4 Cooling water circulation path 5 Primary heat exchanger 6 Secondary heat exchanger 7 Cooling water return pipe 8 Cooling water going pipe 9 Cooling water circulating pump 10 Mixing valve 11 Bypass pipe 12 Hot water storage tank 16 Hot water supply pipe 17 Circulating flow Pipe 18 bath branch pipe 19 heating branch pipe 20 circulation return pipe 21 three-way switching valve 22 bypass pipe 23 tank hot water temperature sensor 24 backup burner 25 circulation pump 26 bath heat exchanger 28 heating heat exchanger 30 temperature sensor 35 bath Return pipe 36 Heat exchange coil for bath 37 Bath pipe 41 Heating return pipe 44 Heat exchange coil for heating 45 Heating pipe

Continued on the front page (72) Inventor Tsutomu Ozu 1-5-20 Kaigan, Minato-ku, Tokyo Inside Tokyo Gas Co., Ltd. (72) Inventor Hiroshi Asakura 93 Edocho, Chuo-ku, Kobe-shi, Hyogo 72) Inventor Takeshi Wakata 93 Edocho, Chuo-ku, Kobe, Hyogo Prefecture Inside Noritz Co., Ltd. (72) Inventor Tomio Miyake 93 Edocho, Chuo-ku, Kobe City, Hyogo Prefecture Noritsu Co., Ltd. (72) Tomohiko Shiroya Inventor 93 Noritsu, Edo-cho, Chuo-ku, Kobe-shi, Hyogo (72) Inventor Hidenori Motooka 93, Edocho, Chuo-ku, Kobe-shi, Hyogo In Noritsu, Ltd. (72) Takao Morigaki Chuo-ku, Kobe, Hyogo 93 Edocho Noritz F-term (reference) 3L025 AA12 AB11 AD01

Claims (3)

[Claims] An exhaust heat recovery and hot water supply system for heating water in a hot water storage tank by circulating a heat medium between a device for generating exhaust heat and a hot water storage tank, wherein the waste heat generation device and the hot water storage tank A circulation path for circulating the heat medium is formed between the heat path and the flow path in which the heat medium flows from the waste heat generator to the hot water storage tank and the flow path in which the heat medium flows from the hot water storage tank to the waste heat generation apparatus. A bypass passage having an openable / closable passage is provided between the passage and the passage, and when the temperature of the heat medium flowing from the hot water storage tank to the exhaust heat generator is low, the bypass passage is controlled in the opening direction to exhaust the heat. An exhaust heat recovery and hot water supply system, wherein a part of the heat medium flowing from the heat generator to the hot water storage tank flows into a flow path through which the heat medium flows from the hot water tank to the exhaust heat generator. 2. An exhaust heat recovery and hot water supply system for heating water in a hot water storage tank by circulating a heat medium between a device for generating exhaust heat and a hot water storage tank, wherein hot water in the hot water storage tank is circulated. The circulation path is connected to the hot water storage tank, a heat exchanger is provided in the hot water supply circulation path, and hot water flows from the hot water storage tank to the heat exchanger side of the hot water supply circulation path and hot water flows from the heat exchanger side to the hot water storage tank. A bypass flow path is formed between the hot water supply path and the auxiliary heat source device on the side closer to the heat exchanger than the bypass flow path in the hot water supply circuit, and when the auxiliary heat source device starts a heating operation, And a system for circulating hot water between the bypass and the heat exchanger. 3. An exhaust heat recovery and hot water supply system for heating water in a hot water storage tank by circulating a heat medium between a device for generating exhaust heat and a hot water storage tank, wherein hot water in the hot water storage tank is circulated. The circulation path is connected to the hot water storage tank, a heat exchanger is provided in the hot water supply circulation path, and hot water flows from the hot water storage tank to the heat exchanger side of the hot water supply circulation path and hot water flows from the heat exchanger side to the hot water storage tank. A bypass flow path is formed between the hot water supply path and the hot water supply tank, and a hot water temperature of the hot water storage tank returns from the heat exchanger. When the temperature of the incoming hot water becomes lower, the hot water is circulated between the bypass and the heat exchanger.