JP2008267652A - Hot water storage type hot water supply system and its hot water supply pipe heat-retaining operation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of achieving an immediate hot water system without consuming wasteful energy by utilizing exhaust heat in a hot water storage type hot water supply system. <P>SOLUTION: A valve V1 is opened during a power generating operation. Thus the stored water of low temperature in a heat retaining circuit R4 is circulated in the circuit, and mixed with the circulated water (hot water) flowing in a hot water storage circuit R3, and heated while passing through a heat exchanger 5, at a joining point P3. Thus the low-temperature water in a hot water supply pipe L2 and a temperature-retaining pipe L5 can be heated and thermally insulated. Here, as the power generating operation is controlled at a time zone of high frequency of use of hot water supply, the water in the heat retaining circuit 4 is kept in a heat retaining state, and a user can comfortably use supplied hot water without waiting. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hot water storage type hot water supply system and a method for operating the hot water storage system, and more particularly to warming a hot water supply pipe of the hot water storage type hot water supply system.

In recent years, a hot water storage hot water supply system that collects exhaust heat generated by power generation or the like and stores it in a hot water storage tank has attracted attention as a domestic cogeneration system. FIG. 8 shows a hot water storage type hot water supply system 100 according to this method. In the hot water storage hot water supply system 100, the operation of the circulation pump 105 is started when the operation of the power generation unit 102 is started, and the heat medium circulates through the exhaust heat recovery circuit R11. At the same time, the operation of the circulation pump 104 is started, and the water (hot water) in the hot water storage tank 101 circulates in the hot water storage circuit R10. The heat recovery circuit R11 and the hot water storage circuit R10 exchange heat with the heat exchanger 103, and the water in the hot water storage tank 101 is heated and stored. On the other hand, when hot water is used, hot water in the hot water storage tank is supplied to the hot water tap 107 via the hot water supply pipe 106 by opening.

  However, in a hot water storage type hot water supply system, an example in which hot water is supplied to a plurality of locations is common, and a hot water storage tank installation location and a hot water tap installation location are often separated. Therefore, the waiting time until the hot water reaches after the hot water tap is opened becomes long, and in particular, when the hot water tap opening and closing is repeated for a short time, the use may end before the hot water reaches. For this reason, cold water is always supplied in winter, and there is a problem that lack of comfort.

  In order to solve such a problem, a technique is disclosed in which a circuit that circulates hot water in a hot water supply pipe is provided and the circuit is intermittently heated to enable instant hot water (see, for example, Patent Document 1). ). FIG. 9 shows the configuration of such an instant hot water storage hot water supply system 200. The hot water supply system 200 includes a hot water storage tank 201, a heater 202, a circulation pump 207, and a first circulation circuit 210 including pipes L22, L24, and L20 that connect these, a heater 202, a hot water tap 204, and a pipe that connects these. And a second circulation circuit 211 composed of L24, L21, and L23. Furthermore, the first circulation circuit 210 and the second circulation circuit 211 are configured so that the flow path of hot water can be appropriately switched by the switching valves 203a and 203b.

In such a system, when hot water is supplied, hot water is supplied from the hot water storage tank 201 to the hot-water tap 204 via the pipes L20 → L21. In addition, a temperature sensor 206 is provided in the second circulation circuit, and when the temperature falls below a predetermined temperature, the second circulation circuit is heated by the heater 202 and kept warm.
JP-A-9-243174

  However, the conventional hot water system has a problem that it is necessary to switch valves in order to perform the hot water operation, and that extra energy is consumed to operate the heater. Moreover, since the heat insulation control is performed based on the temperature in the pipe, there is a problem that the heat insulation operation is performed even during a time period when hot water is not used.

The present invention is for solving such problems, and provides a technique capable of realizing an immediate hot water system without consuming wasteful energy by utilizing exhaust heat in a hot water storage hot water supply system. . The gist of the present invention is as follows. That is,
The invention of claim 1 includes a waste heat recovery circuit that recovers exhaust heat from an exhaust heat source, a hot water storage tank, and a circulation pump, and a hot water storage circuit that receives heat from the exhaust heat recovery circuit and stores it as hot water in the hot water storage tank. ,
A hot water storage hot water supply system comprising a hot water supply pipe for supplying hot water in a hot water storage tank to a terminal hot water tap, branching from the hot water supply pipe in the vicinity of the terminal hot water tap, and connected to a hot water storage circuit upstream of the circulation pump The hot water storage type hot water supply system is characterized in that a hot water supply and heat insulation circuit is configured to include a hot water supply pipe, a hot water supply pipe, a heat insulation pipe, and the circulation pump.
In the above invention, the exhaust heat generated by the gas engine can be used as the exhaust heat source (claim 2).
Furthermore, an auxiliary heat source machine can be further provided in the hot water supply piping path (Claim 3).

According to a fourth aspect of the present invention, in each of the hot water storage hot water systems described above, when the hot water storage circuit receives heat from the exhaust heat recovery circuit, the accumulated water in the hot water hot water storage circuit is circulated. This is a heat insulation operation method.
The invention of claim 5 is the hot water storage type hot water supply system according to claim 3, wherein when the hot water storage circuit is not receiving heat from the exhaust heat recovery circuit, circulation of stagnant water in the hot water supply heat insulation circuit is performed. A hot water supply pipe heat insulation operation method in a hot water storage type hot water supply system, wherein the auxiliary heat source unit is operated.

According to the present invention, it is possible to keep the hot water supply pipe section warm by utilizing exhaust heat, which contributes to the improvement of energy saving performance without requiring additional energy.
Further, in the invention using the power generation exhaust heat from the gas engine as the exhaust heat source, the time zone in which the power generation exhaust heat is generated is also a time zone in which the demand for electric power and heat is large. It is possible to keep the piping section warm.
In addition, since the system can be constructed using the configuration of products already in practical use, there is an effect that the cost can be reduced.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to FIGS. In addition, in order to avoid confusion due to overlapping codes, the same symbols are used for the same components in each figure. Needless to say, the scope of the present invention is described in the claims and is not limited to the following embodiments.

(First embodiment)
FIG. 1 is a diagram showing an overall configuration of a hot water storage type hot water supply system 1 according to the present embodiment. A hot water storage hot water supply system 1 includes a hot water storage tank 2, a power generation unit 3 including a gas engine, a generator, an exhaust heat exchanger, and the like, a heat exchanger 5 that recovers generated exhaust heat, and circulation pumps 6 and 7. The terminal hot water tap 8 and the pipes L1 to L5 connecting them are provided as main components. As a result, the following water supply / hot water supply system R1 and three circulation circuits R2 to R4 are configured. The hot water storage tank 2, the heat exchanger 5, the circulation pumps 6, 7 and the like are stored in the housing 10 as a hot water storage unit indicated by a one-dot chain line in FIG.
The hot water supply / hot water system R1 includes a hot water storage tank 2, a water supply pipe L1 for supplying tap water to the hot water storage tank 2, and a hot water supply pipe L2 for supplying hot water in the hot water storage tank to the hot water tap 8. When the hot-water tap 8 is opened, hot water in the hot water storage tank is supplied along a path indicated by a thick line in FIG.

The exhaust heat recovery circuit R2 includes a power generation unit 3, a heat exchanger 5, a circulation pump 7, and a pipe L4 connecting them, and a heat medium is circulated in the circuit.
The hot water storage circuit R3 includes a hot water storage tank 2, a heat exchanger 5, a circulation pump 6, an on-off valve V2, a pipe L3 connecting them, and a part of the hot water supply pipe L2 (between P1 and P5). Temperature sensors S1 to S4 are arranged in the hot water storage tank so that the temperature of each part in the tank can be measured to check the hot water storage state.
The heat insulation circuit R4 includes a hot water supply pipe L2, a heat insulation pipe L5 connecting the pipe L3 and the hot water tap 8, a part of the pipe L3 (between P1 and P2), an on-off valve V1 disposed in the pipe L5 route, and A circulation pump 6 is used.
Furthermore, the hot water storage type hot water supply system 1 is provided with a control unit (not shown), and in order to make hot water stored in the hot water storage tank 2 in advance at a time when the hot water supply is frequently used, the generator unit 3 can be started by a timer or manually. The stop is controlled, and the power generation exhaust heat is collected in hot water storage tank 2 as hot water.

  Next, with reference to FIG. 2, the hot water storage control to the hot water storage tank 2 at the time of a power generation operation and the thermal insulation control of the thermal insulation circuit R4 performed simultaneously are demonstrated. The operation of the circulation pump 7 is started with the start of the power generation operation, and the heat medium circulates in the exhaust heat recovery circuit R2. At the same time, the valve V2 is opened and the operation of the circulation pump 6 is started, and the water (hot water) in the hot water storage hot water storage tank 2 circulates in the circuit R3. Both circuits exchange heat in the heat exchanger 5, and the water in the hot water storage tank is heated and stored as hot water. During this time, the temperature of the hot water in the tank is measured by the temperature sensors S1 to S4, the amount of heat stored in the hot water storage tank 2 is calculated from the readings of each temperature sensor, and the power generation operation is stopped when the required amount of heat is reached. The

During the power generation operation, the valve V1 is opened. Thereby, the low temperature staying water in the heat retaining circuit R4 circulates in the circuit, and mixes with circulating water (hot water) flowing through the heat exchanger 5 at the junction P3 and flowing in the hot water storage circuit R3. Thereby, the low temperature water in the hot water supply pipe L2 and the heat insulation pipe L5 is also heated and kept warm. In this case, since the power generation operation control is performed in accordance with a time zone in which the hot water supply is frequently used as described above, the water in the heat insulation circuit R4 is also in the heat insulation state during this time zone. Therefore, the user can use hot water comfortably without waiting for hot water.
In this embodiment, the hot water storage in the hot water storage tank 2 is dependent only on the exhaust heat of the power generation unit. However, the hot water storage tank may have another heat source such as a heater and be heated by both. .
Moreover, although the form which collect | recovers power generation waste heat and stores hot water was shown in this embodiment, it is not restricted to this, For example, it is also applicable to the hot water storage system which collect | recovers the condensation heat | fever by a heat pump cycle, and stores hot water.

(Second embodiment)
Next, another embodiment of the present invention will be described. FIG. 3 is a diagram illustrating an overall configuration of the hot water storage type hot water supply system 20 according to the present embodiment. The hot water storage hot water supply system 20 is different from the hot water storage hot water supply system 1 in that an auxiliary heat source device 22 is provided in the hot water supply pipe L2. Thereby, when the hot water storage temperature is low, the auxiliary heat source unit 22 heats the hot water at the set temperature.
Moreover, it is provided with the water supply piping L6 branched from the water supply piping L1 by P2 and connected to the hot water supply piping L2. A mixing proportional valve 23 is disposed at a connection point with the pipe L2, and is configured so that hot water supplied from the hot water storage tank 2 can be supplied at a set temperature.
Furthermore, a temperature sensor S5 for measuring the temperature in the pipe is provided in the hot water supply pipe L2. The other configuration is the same as that of the hot water storage type hot water supply system 1, and thus the description thereof is omitted.
Hereinafter, a heat retention control method of the heat retention circuit R4 in the hot water storage type hot water supply system 20 will be described. First, the heat retention control during the power generation operation is the same as that of the first embodiment, and thus the description thereof is omitted.

  Next, with reference to FIG. 4, the heat insulation operation control when not in the power generation operation time zone and the hot water temperature in the hot water storage tank is low will be described. In this case, when the temperature detected by the temperature sensor S5 becomes lower than the lower limit temperature (for example, 15 ° C.), the valve V1 is opened, the circulation pump 6 and the auxiliary heat source unit 22 are started to operate. When the upper limit temperature (for example, 25 ° C.) is reached, the operation is stopped. As a result, as shown by the thick line in the figure, the accumulated water in the heat retaining circuit R4 circulates and is controlled to be heated so as to be within a certain temperature range, so that the heat in the circuit can be maintained.

(Third embodiment)
Furthermore, another embodiment of the present invention will be described. FIG. 5 is a diagram showing an overall configuration of the hot water storage type hot water supply system 30. The hot water storage hot water supply system 30 is different from the hot water storage hot water supply system 20 in that it further includes a heating circuit R5 and a heating heating circuit R6.
The heating circuit R5 includes a high-temperature heating heat exchanger 33 provided in the pipe L5 path, a low-temperature heating heat exchanger 32 provided in the pipe L4 path, a circulation pump 34, and a terminal device (not shown) (floor heating). Panel) and the heating pipe L7 connecting them.

  The heating and heating circuit R6 includes the auxiliary heat source unit 22, the hot water supply pipe L2 (between P1 and P7), the pipe L8 connecting the hot water supply pipe L2 and the heat insulation pipe L5, the heat insulation pipe L5 (between P8 and P3), and the path thereof. The heat exchanger 33 is provided, an on-off valve V1, and a three-way valve V4 provided on the branch P7. Further, an on-off valve V3 is arranged on the upstream side of the junction P8 with the pipe L8 of the heat retaining pipe L5. Since the other configuration is the same as that of the hot water storage type hot water supply system 20, description thereof is omitted. As with the hot water storage type hot water supply system 20, a branch water supply pipe and a mixing proportional valve for maintaining the set hot water supply temperature are provided, but the illustration is omitted.

Next, hot water supply and heat insulation control of the hot water storage type hot water supply system 30 will be described.
The hot water supply control is the same as that of the first embodiment in that hot water in the hot water storage tank is supplied by opening the hot water tap 8. Moreover, it is the same as that of 2nd embodiment also about the point which heats with the auxiliary heat source machine 22 when hot water storage temperature is low, and enables hot water supply of preset temperature.
Next, with reference to FIG. 6, the hot water storage control to the hot water storage tank 2 at the time of a power generation operation and the thermal insulation control of the thermal insulation circuit R4 performed simultaneously are demonstrated. About operation control of exhaust heat recovery circuit R2 and hot water storage circuit R3, it is the same as each above-mentioned embodiment. Further, during the power generation operation, the valves V1 and V3 are opened, and the three-way valve V4 is set from the hot water supply pipe L2 to the heat insulation pipe L5 side fully opened. Thereby, the low temperature staying water in the heat retaining circuit R4 circulates in the circuit, and mixes with circulating water (hot water) flowing through the heat exchanger 5 at the junction P3 and flowing in the hot water storage circuit R3. Thereby, the low temperature water in the hot water supply pipe L2 and the heat insulation pipe L5 is also heated and kept warm.

Furthermore, with reference to FIG. 7, the control when the power generation operation and the heating operation are performed simultaneously will be described. In this case, the three-way valve V4 is set to an opening considering the flow rate balance between the pipe L8 and the heat retaining pipe L5. As a result, the circulating water (hot water) is in a circulating state as shown by the thick line in FIG.
When there is no power generation operation and only heating operation, only the heating circuit R5 and the heating heating circuit R6 are circulated.

  The present invention can be widely used for a system including a hot water storage tank regardless of a heat source or an exhaust heat supply source.

It is a figure showing composition of hot water storage type hot-water supply system 1 concerning a first embodiment. It is a figure which shows the hot water supply piping heat retention control in the electric power generation driving | operation of the hot water storage type hot water supply system. It is a figure which shows the structure of the hot water storage type hot-water supply system 20 which concerns on 2nd embodiment. It is a figure which shows the hot water supply piping heat retention control in the electric power generation driving | operation of the hot water storage type hot water supply system. It is a figure which shows the structure of the hot water storage type hot-water supply system 30 which concerns on 3rd embodiment. It is a figure which shows the hot water supply piping heat retention control in the electric power generation driving | operation of the hot water storage type hot water supply system. It is a figure which shows the hot water supply piping heat retention control in the electric power generation driving | operation of the hot water storage type hot-water supply system 30, and heating operation. It is a figure which shows the structure of the conventional waste heat recovery type hot water storage hot water supply system. It is a figure which shows the structure of the conventional instant hot water storage type hot water supply system.

Explanation of symbols

1, 20, 30... Hot water storage hot water supply system 2... Hot water storage tank 3 ... Power generation unit 5 ... Heat exchangers 6, 7, 34 ... Circulation pump 8 · Hot water tap 22 ··· Auxiliary heat source device 23 · · · Mixing proportional valves 32 and 33 · · · Heating heat exchangers L1 and L6 · · · Water supply piping L2 · · · Hot water supply piping L5 · · ·・ Heat insulation pipe L7 ... Heating pipe R1 ... Hot water supply system R2 ... Waste heat recovery circuit R3 ... Hot water storage circuit R4 ... Heat insulation circuit R5 ... Heating circuit R6 ... .... Heating heating circuits S1 to S5 ... Temperature sensors V1 to V3 ... Open / close valve V4 ... Three-way valve

Claims (5)

An exhaust heat recovery circuit for recovering exhaust heat from the exhaust heat source;
A hot water storage tank that includes a hot water storage tank and a circulation pump, receives heat from the exhaust heat recovery circuit, and stores the hot water in the hot water storage tank;
A hot water supply pipe for supplying hot water in the hot water storage tank to the terminal hot water tap,
A hot water storage system with
A heat insulation pipe branching from the hot water supply pipe near the terminal hot water tap and connected to the hot water storage circuit on the upstream side of the circulation pump is further provided,
In addition, a hot water storage type hot water supply system comprising a hot water supply and heat insulation circuit including a hot water supply pipe, a heat insulation pipe, and the circulation pump. The hot water storage hot water supply system according to claim 1, wherein the exhaust heat source is power generation exhaust heat from a gas engine. The hot water storage hot water supply system according to claim 1 or 2, wherein the hot water supply pipe further includes an auxiliary heat source unit in a path. In the hot water storage type hot water supply system according to claim 1 to 3,
When the hot water storage circuit receives heat from the exhaust heat recovery circuit, the hot water in the hot water storage hot water system circulates the accumulated water in the hot water heat storage circuit. In the hot water storage type hot water supply system according to claim 3,
When the hot water storage circuit is not receiving heat from the exhaust heat recovery circuit, the auxiliary heat source unit is operated when circulating the accumulated water in the hot water heat insulation circuit, and the hot water supply pipe in the hot water storage hot water system is characterized in that Thermal insulation operation method.

Images