JPH07111260B2 - Heating system and heating / cooling system using heat pump - Google Patents

Description

The present invention relates to a heating (cooling) system using a heat pump or a refrigerator, and is particularly suitable for a large-scale heating or cooling system for performing district heating (cooling) and hot water supply. The present invention relates to a warm (cool) air conditioner / hot water supply system using a simple heat pump.

[Prior art]

In general district heating and hot water supply systems, the mainstream method is to burn hot fossil fuel such as hot water boiler to obtain hot water. In the case of this method, the performance of the boiler remains almost the same even if there is a waste of usage of hot water such as heating and hot water supply, so the return water temperature from the load is high.

For example, FIG. 7 is a diagram showing an example of the temperature loss in the case of the conventional heating air heater, but as shown, there is a large heat exchanger temperature loss. In the figure, the vertical axis is temperature and the horizontal axis is entropy.

In this example, the return temperature to the heat pump is 53 ° C. with respect to the return air temperature of 21 ° C., which is a large temperature difference, that is, a large temperature loss.

Further, FIG. 8 shows the case of the heat exchanger for hot water supply. In this case as well, the return temperature to the heat pump is 10 ° C for the water supply temperature of 10 ° C.
It is 50 ° C, which is a large temperature loss.

Further, in the case of the cooling load, as shown in FIG. 9, the temperature difference between the indoor air, which is the load, and the cold water is small, so the temperature loss is small. That is, even in the case of heating or hot water supply, it should be possible to use the same heat exchanger as in the case of cooling, but conventionally, the temperature loss is large due to the above reason.

In addition, as piping equipment, a total of 4 reciprocating piping between the heat supply sensor and the heat recovery device that is the heat source of the heat pump and a hot water reciprocating piping with the load, and a total of 6 chilled water reciprocating piping when supplying cold water The piping has been constructed.

[Problems to be Solved by the Invention]

Recently, global warming has become a problem due to the greenhouse effect of carbon dioxide released into the atmosphere. For this reason, it seems that even in district heating (cooling) and hot water supply facilities that use a large amount of fossil fuels, primary energy must be drastically reduced in the future. Therefore, a heat pump is recommended as the means. However, since the thermodynamic energy loss of the recent heat pump, that is, the temperature loss is very small, the reduction amount is small when the temperature rise width is large.

Further, as described above, if the temperature loss on the load side is reduced, the return temperature from the load can be lowered, and the performance of the heat pump can be improved. Figures 2 and 3 show the heat exchanger temperature change diagrams with reduced load-side temperature loss in the case of heating and hot water supply, respectively. As shown in the figure, in any case, if a heat exchanger adapted to a small flow rate is designed, the return temperature to the heat pump can be lowered. However, although theoretically the power consumption of the heat pump can be reduced by doing so, the heat pump cannot be used due to the following problems. That is, when the load is low, the temperature from the load becomes high, and
When the load is large, the temperature is low, so this fluctuation is large. Further, when the heat pump heat source temperature is high and the load is large, the return temperature from the load to the heat pump becomes lower than the heat source temperature. For this reason, there is a problem caused by a small pressure difference in the flow of the refrigerant in the heat pump. Therefore, theoretically, the heat pump could not be used although the primary energy could be reduced.

In addition, the conventional 4 or 6 pipe type piping system has a drawback that the piping equipment becomes huge. That is, in the district heating (cooling) system, the proportion of piping equipment is large in the primary energy input to the overall equipment construction, and the amount of primary energy reduction is small as a whole.

The present invention has been made in view of the above points, and by removing the above problems and using a heat pump, it is possible to significantly reduce the primary energy from a comprehensive point of view, including the primary energy that is input to facility construction. It is to provide a hot (cold) air conditioner / hot water supply system.

[Means for Solving the Problems]

A first invention of the present application for solving the above-mentioned problems is a heat pump, a plurality of heating loads heated by the heat pump, a heat recovery device for heating a heat source fluid cooled by the heat pump, the heat pump, the heating load, and the heat. In a heating system using a heat pump composed of a pump and a connecting pipe for transporting a fluid between the recovery devices, a fluid from a heating load is used as a pipe from the heat recovery device for heating the heat source fluid to the heat pump. Characterized by returning.

The second invention includes a heat pump, a refrigerator, a plurality of heating loads heated by the heat pump, a heat recovery device for heating a heat source fluid cooled by the heat pump, a plurality of cooling loads cooled by the refrigerator, and a refrigerator. It is composed of a cooling device for cooling, a pump and connecting piping for transporting fluid between the heat pump and the heating load and heat recovery device, a pump and connecting piping for transporting fluid between the refrigerator and cooling load and cooling device, etc. In a heating / cooling system using a heat pump, at least a part of the fluid from the cooling load is returned to a return pipe from the heat recovery device for heating the fluid to the heat pump.

A third invention is a heat pump, a refrigerator, a plurality of heating loads heated by the heat pump, a heat recovery device for heating a heat source fluid cooled by the heat pump, a plurality of cooling loads cooled by the refrigerator, and a cooling of the refrigerator. Cooling device, heat pump, pump and connecting pipe for transporting fluid between heating load and heat recovery device, pump and connecting pipe for transporting fluid between refrigerator and freezing load and cooling device, etc. In the heating / cooling system configured by, at least a part of the fluid from the heating load and the fluid from the cooling load is returned to the return pipe from the heat recovery device for heating the fluid to the heat pump, and in the winter season. In addition, the piping that sends hot water from the heat pump to the heating load is the same as the piping that sends cold water from the refrigerator to the cooling load in the summer. .

[Action]

According to the present invention, by configuring the cooling / hot water supply system using the heat pump as described above, it becomes possible to use the heat pump in the system in which the return temperature from the cooling / hot water supply load is lowered, and as a result, the primary energy is greatly reduced. be able to.

Moreover, since the flow rate of hot or cold hot water to be supplied to the load can be reduced, as a result, a regional warming (cooling) / hot water supply system with small pump power and narrow piping can be realized.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a configuration of a heating / hot water supply system using a heat pump according to an embodiment of the first invention of the present application. The present heating / hot water supply system is composed of an external heat recovery system 1, a heat supply center 2, a district heating / hot water supply load system 3, and pipes connecting these.

The external heat recovery system 1 is used for condensing condenser cooling water such as refuse incineration power generators, refrigerator cooling water such as large refrigerators, heat engine oil cooler cooling water, engine cooling water, transformer cooling water, and various industrial processes. It is composed of a heat recovery device 4 for cooling and recovering heat from low-temperature hot springs and pipes 5 and 6.

The heat recovery device 1 ′, 1 ″ conventionally discards the load of the district heating / hot water supply load system 3, that is, the waste heat from the hot water supply load via the heat recovery pipes 5 ′, 5 ″ and 6 ′, 6 ″. It is a heat recovery device that recovers the waste heat that was used.

Intermediate hot water is supplied to these heat recovery devices via the pipes 5, 5 ', 5 "connected to the heat recovery main outflow pipe 7 from the heat supply center 2 to recover the heat, and the pipes 6, 6', From 6 ″, it is returned to the heat supply center 2 through the heat recovery main return pipe 8.

The district heating / hot water supply load system 3 has a heat supply center 2
Main water supply main pipe 10 and branch pipes 11 and 1 by the hot water pump 9 inside
Hot water is supplied via 1'and 12,12 '.

The air heater 13 is a heat exchanger for heating indoor air. The temperature condition of this heat exchanger is as shown in Fig. 2, and the return temperature of hot water to the heat pump is 28
It has become ° C. The heat exchanger 15 is a heat exchanger for hot water supply manufacturing. As shown in FIG. 3, for example, the water supplied at 10 ° C is heated by hot water to form hot water at 55 ° C, and the bath 16-1
Etc. Also in this heat exchanger 15, the hot water return 16-2 internal temperature is designed to be 28 ° C. The hot water cooled by the air heater 13 and the heat exchanger 15 joins the main heat recovery pipe 8.

The heat supply center 2 is composed of a heat storage container 16, a heat pump 17, a pump pipe, and the like. Heat pump 17 evaporator
18 and condenser 19 are pumped to the same temperature, for example 28
Intermediate warm water of ℃ is supplied. In the evaporator 18, for example
The intermediate hot water cooled to 23 ° C passes through the pipe 21 to store heat
It is returned to the lowest temperature zone 22 of 16. The water in the lowest temperature part 22 is sent to the heat recovery main outflow pipe 7 by the pump 23, and the heat is recovered and returned to the heat storage tank 16 again through the pipe 24. The hot water heated by the heat pump 17 reaches, for example, 60 ° C. and is returned to the highest temperature section 25 of the heat storage tank 16.

FIG. 4 is a diagram showing a configuration of a heating / hot water supply system showing another embodiment of the first invention of the present application, in a case where the heating / hot water supply system shown in FIG. 1 is also supplying cold water. In the figure, 26 is a cold water main outflow pipe, and 27 is a cold water main return pipe. Four,
4'is a waste heat recovery device. 7, 8 and 10 are the heat recovery main outflow pipe, the heat recovery main return pipe and the hot water supply main pipe, respectively, as in the case of FIG. Further, 28 is, for example, a fan coil unit. While hot water is supplied through the pipes 11 and 30 during heating, cold water is supplied through the pipes 29 and 14 during cooling. Reference numeral 31 is a low temperature heat recovery device. For example, river water or the like is supplied to the heat exchanger 33 by the pump 32, the medium temperature water in the pipe 34 is cooled, and the pipe 35
By returning to the main pipe (heat recovery main return pipe) 8 by this, the intermediate hot water in the intermediate hot water tank 40 of the heat storage tank 16 in the heat supply center 2 is cooled. On the contrary, during heating, the cold water from the inside of the pipe 36 is heated by the river water and returned to the cold water main return pipe 27 via the pipe 37. As the heat pump, the high temperature side heat pump 17 is usually used, but when the heat source from the heat recovery device 4 or the like in winter becomes insufficient, the low temperature side heat pump 38 is operated. As a heat source at this time, a winter cooling load and a low temperature heat source such as a river are used. That is, the cold water in the cold water heat storage tank 39 is used as a heat source to heat the inside of the intermediate hot water tank 40, and the intermediate hot water in the intermediate hot water tank 40 is used as a heat source to produce hot water by the high temperature side heat pump 17. When cooling, the low temperature side heat pump 38 (refrigerator) is cooled by piping.
The intermediate hot water in the intermediate hot water tank 40 is used by 41 and 42. However, the condenser of this heat pump is a double condenser, and when the temperature from the river water is high, it can also radiate heat to the cooling tower.

FIG. 5 is a conceptual diagram of a small flow rate district heating / heat recovery system showing an embodiment of the second invention of the present application. There are four main pipes for district heating and cooling: an ice piece mixed cold water main pipe 43, a hot water supply main pipe 44, an unused heat energy recovery main pipe 45, and a return main pipe 46 that also serves as all return pipes. Therefore, the pipes 14 and 30 from the load can be commonly used.

Further, the multi-tank heat storage tank 47 is also integrated as a whole by the connecting pipe.

The hot water heats a part of the intermediate hot water in the intermediate hot water part 48 by the heat pump 17 and returns it to the maximum temperature part 25, and at the same time cools the remaining intermediate hot water and returns it to the low temperature part 49 of the intermediate hot water.

Reference numeral 50 denotes a refrigerator, and the structure of the ice-making portion on the cooling side of the refrigerator 50 is a cooling device 51 having a structure capable of cooling with cold water and making ice, as disclosed in, for example, Japanese Patent Application No. 2-23744. .
Condenser is a condenser for heating intermediate hot water 52
And, it is a double condenser consisting of condenser 53 that is cooled by a cooling tower. The water in the low temperature part of the intermediate hot water is recovered from the unused heat energy by the pump 54 and the pipes 55, 42 in winter. Although it is heated by the condenser 52. In summer, the condenser 53 of the refrigerator 50 is used and cooled by a cooling tower (not shown). And in the summer, heat is not collected at all, and the return main
The internal temperature of 46 becomes, for example, 14 ° C., and returns from the switching valve 56 to the low temperature part 49 of the intermediate hot water of the heat storage tank 16 via the pipe 57. That is, the pump 54 is not operated during cooling.

As the third invention of the present application, when there is no cooling load in the winter, the cold fluid supply pipe (ice piece warming cold water main pipe) 43 and the hot water supply main pipe 44 can be the same pipe.

Further, in FIG. 4, as an embodiment of the second and third inventions of the present application, the heat pump 17 on the high temperature side and the heat pump 38 on the low temperature side (refrigerator) are operated by switching the pipes and operating depending on the season or the time difference. It is also possible to operate by switching.

〔The invention's effect〕

As described above, the heating system using the heat pump of the present invention has the same temperature as the heat source water sent to the evaporator of the heat pump and the temperature of the hot water for cooling sent to the condenser. effective.

(1) Since the temperature of the water for cooling sent to the condenser becomes low, the performance of the heat pump can be greatly improved.

(2) Since the temperature of the return water of the hot water is low, the heat radiation loss from the pipe can be reduced.

(3) Since the hot water flow rate is reduced, the power of the hot water pump is reduced and the pipe size can be reduced. Further, since the pipe size is reduced, the primary energy input to the equipment can be reduced. FIG. 6 (a) shows a conventional heating system (when the hot water temperature difference is 7 ° C.) and the heating system of the present invention (hot water temperature difference 32 ° C.).
In the case of), the heat transfer amount per unit flow rate of the warm fluid is compared.

(4) The effects (1) to (3) are systematically due to the fact that the heat pump can be used even if the load return water temperature changes. That is, the temperature fluctuation of the load and the heat source fluid flowing into the heat pump is small, and no problems occur in the refrigerant flow in the heat pump, that is, the expansion valve, the electric motor cooling refrigerant flow, and the like.

The heating / cooling system according to the second aspect of the invention has the following effects in addition to the effects (1) to (4).

(5) Since ice pieces are contained in the cold fluid sent to the load, the cold heat supply amount per flow rate becomes large. Fig. 6 (b)
Shows a comparison of the cold heat transport amount between the conventional heating system (when the cold water temperature difference is 7 ° C.) and the heating system of the present invention (cool water return temperature 14 ° C., IRF: 22.5%). Therefore, the primary energy input to the piping equipment can be reduced.

(6) Instead of requiring six main pipes in the past, there are now four. In addition, the number of claim 3 can be three.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of a heating / hot water supply system using a heat pump showing an embodiment of the first invention of the present application, FIG.
FIG. 3 is a diagram showing an example of temperature loss in the case of heating / hot water supply, FIG. 4 is a diagram showing a configuration of a heating / cooling / hot water supply system showing another embodiment of the first invention of the present application, and FIG. 5 is A conceptual diagram of a small flow rate district heating / heat recovery system showing an embodiment of the second invention of the present application, and FIG. 6 is a heat transport amount and a cold fluid per unit flow rate of a warm fluid of a conventional heating system and a heating system of the present invention. FIG. 7 is a diagram showing a comparative example of the cold heat transport amount per unit flow rate, FIG. 7 is a diagram showing an example of temperature loss of a conventional heating air heater, and FIG. 8 is an example of temperature loss of a conventional hot water supply heat exchanger. FIG. 9 is a diagram showing an example of temperature loss of a conventional cooling load. In the figure, 1 ... External heat recovery system, 2 ... Heat supply center, 3 ... District heating / hot water supply load system.

Claims (4)

[Claims] 1. A heat pump, a plurality of heating loads heated by the heat pump, a heat recovery device for heating a heat source fluid cooled by the heat pump, and transporting fluid between the heat pump and the heating load and the heat recovery device. In a heating system using a heat pump configured by a pump and a connecting pipe for performing the heat pump, a fluid from the heating load is returned to a pipe to a heat pump from a heat recovery device that heats the heat source fluid. The heating system used. 2. A heat pump, a refrigerator, a plurality of heating loads heated by the heat pump, a heat recovery device for heating a heat source fluid cooled by the heat pump, a plurality of cooling loads cooled by the refrigerator, the freezing. Cooling device for cooling a machine, pump and connecting pipe for transporting fluid between the heat pump and heating load and heat recovery device, pump and connecting pipe for transporting fluid between the refrigerator and cooling load and cooling device In a heating / cooling system using a heat pump configured by, for example, at least a part of the fluid from the cooling load is returned to a return pipe to a heat pump from a heat recovery device that heats the fluid. Heating / cooling system using a heat pump. 3. A heat pump, a refrigerator, a plurality of heating loads heated by the heat pump, a heat recovery device for heating a heat source fluid cooled by the heat pump, a plurality of cooling loads cooled by the refrigerator, the refrigerator. A cooling device for cooling the heat pump, a pump and a connecting pipe for transporting the fluid between the heat pump, the heating load and the heat recovery device, a pump for transporting the fluid between the refrigerator and the cooling load and the cooling device In the heating / cooling system configured by connecting pipes and the like, at least a part of the fluid from the heating load and the fluid from the cooling load is returned from the heat recovery device for heating the fluid to the return pipe to the heat pump. In addition, there are pipes for sending hot water from the heat pump to the heating load in winter and pipes for sending cold water from the refrigerator to the cooling load in summer. Heating system characterized by being the same. 4. The heating / cooling system according to claim 2, wherein the heat pump and the refrigerator are the same in a broad sense.