JP2006189180A - Heat supply system having a plurality of heat source machines and a group of pumps - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat supply system capable of increasing operation efficiency of a heat source machine, expanding degree of freedom in operation of a group of heat source machines at partial load time, and reducing conveyance power of a heat medium pump to save energy and reduce running cost. <P>SOLUTION: This heat supply system is constituted by connecting the group of pumps connecting a plurality of heat medium pumps in parallel with the group of heat source machines connected in parallel by pipes in series. The heat source machine usable in a scope of flow rate above rated flow rate and below the rated flow rate when operated below the rated output is used, and a flow rate adjusting valve for distributing load is arranged in a heat medium pipe of each heat source machine to set total flow rate of heat medium of the group of pumps to above total rated flow rate. The heat source machine and the heat medium pump operated in accordance with required quantity of heat and required flow rate on a heat load side are selected, a bypass pipe is provided from an outlet side pipe passage to a heat load side return pipe passage of the group of pumps, and each flow rate adjusting valve is adjusted to make load rate of each heat source machine equal and distribute heat medium. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat supply system for facilities such as an air conditioning system or a district heating / cooling system for a large-scale office building, in which a large number of rooms and buildings must be air-conditioned at the same time. The present invention relates to an improvement in a heat supply system including a heat source device group including a heat source device such as a heater and a pump group including a plurality of heat medium pumps for transporting a heat medium (water, refrigerant, etc.).

As a large-scale heat supply system, a heat supply system including a plurality of heat source devices and a plurality of heat medium pumps as water supply power sources to each heat source device has been widely put into practical use. In this type of heat supply system, a pump with a flow rate of heat medium that matches the rated output of each heat source unit is generally prepared for each heat source device. The number of heat source machines that can supply the required amount of heat on the heat load side and the number of heat medium pumps that can supply the required amount of heat medium on the heat load side, whichever is larger, have a heat source machine and a heat medium pump. I'm driving.
The back and forth temperature difference (utilization temperature difference) of the heating medium supplied to the heat load side is not always constant, and changes with the fluctuation of the heat load.

Since the flow rate of each heat source unit is limited to around the rated flow rate, if the temperature difference on the heat load side is larger than the temperature difference at the time of rating, the return heat medium from the heat load side will be It merges with a large amount of heat medium from the bypass pipe provided on the return side pipe from the outlet side pipe to the temperature difference below the rated temperature difference, and the temperature difference is proportional to the load factor of the operating heat source machine. It is supplied to each heat source machine at a corresponding heat medium temperature.
When the use temperature difference on the heat load side is smaller than the temperature difference at the time of rating, the return heat medium from the heat load side merges with the heat medium from the bypass pipe, and the temperature difference becomes even smaller, and the operation It is supplied to each heat source device at a heat medium temperature corresponding to a use temperature difference proportional to the load factor of the heat source device inside.
In either case, an excess amount of heat medium is circulated by the bypass flow rate.
Because the number of heat source units and heat medium pumps to be operated is determined according to the flow rate, the heat medium pump power and the power of the heat source unit incidental equipment (refrigerator cooling tower, cooling water pump, etc.) are consumed and energy is consumed. There have been problems such as excessive consumption and increased running costs.

The following is a conventional example of a heat supply system related to the present invention.
In Japanese Utility Model Laid-Open No. 58-104826 “Air Conditioner”, a plurality of circulating pumps are connected in series to a plurality of chilling units (refrigerators) for producing cold / hot water, and the heat load side heat exchanger is returned to and returned from. By detecting the temperature difference and operating the on-off valve, the same number of chilling units and circulation pumps are controlled. However, if the pair of chilling units and the circulation pump are stopped just because the detected temperature difference is small, there is an inconvenience that the amount of water supplied to the heat load side heat exchanger is insufficient and the required air conditioning capability cannot be achieved. There are drawbacks. Japanese Patent Laid-Open No. 6-94267 “Clean Room Temperature and Humidity Control Device” supports a plurality of refrigerators that can be operated in parallel according to the demand of the heat load, and each refrigerator as a water supply power source for the refrigerator. And a temperature and humidity control device provided with a plurality of pumps that are operated in synchronism with each other. Furthermore, a flow control valve for adjusting the flow rate of the output water of the refrigerator supplied to the heat load and a bypass system for the heat load are provided, and this bypass system is opened when supplying heat near the number of refrigerators being switched. It has become. This conventional example is shown in FIG.

In FIG. 7, the water sent from the seven chilled water pumps 15 a to 15 g is cooled by the seven chillers 14 a to 14 g and is supplied to the heat load (air conditioner for each room) 19 via the flow rate control valve 17. It has been sent. Further, a bypass circuit 21 that bypasses the thermal load 19 is provided.
However, since the cold water pump is provided corresponding to each of the refrigerators as a water supply power source of the refrigerator and is operated in synchronization with the operation target refrigerator, the rating of each cold water pump is The flow rate must match the rated flow rate of the corresponding refrigerator, and the optimum number of chilled water pumps cannot be selected for the required amount of water on the load side. As a result, the chilled water pump operates in an inefficient manner, and there is a disadvantage that the inconvenience occurs that the power consumption of the chilled water pump increases.

The main object of the present invention is to increase the operating efficiency of the heat source unit and reduce the conveyance power of the heat medium (heat medium) pump by expanding the degree of freedom of operation of the heat source unit group at the time of partial load. Is to save energy and reduce running costs.
Another object of the present invention is to optimize the number of operating heat source units and heat medium pumps and improve the load factor of the heat source unit, thereby reducing the power consumption of the auxiliary equipment of the heat source unit and reducing the energy consumption of the heat supply system. The purpose is to reduce running costs.
A further object of the present invention is to make the heat supply system of the heat supply system by greatly reducing the transport power of the heat medium pump by making the supply heat medium amount of the pump group continuously variable by using some heat medium pumps of the pump group as variable flow rate pumps. The goal is to save energy and reduce running costs.

In order to solve the above-described problems, the present invention provides a plurality of heat medium pumps for circulating a heat medium cooled or heated by the heat source apparatus to a heat load side with respect to a plurality of heat source apparatus groups connected in parallel. Provided is a heat supply system in which a group of pumps connected in parallel are connected in series by piping, and the running cost can be greatly reduced. This heat supply system, as its basic mode, uses a heat source unit that can be used in a flow rate range above and below the rated flow rate when operating below the rated output, and distributes the load to the heat medium piping of each heat source unit. For the heat load side, select the heat source unit that operates according to the required heat amount on the heat load side, and set the total heat medium flow rate of the pump group to be equal to or higher than the total rated flow rate of the heat source unit. Select a heat medium pump to be operated in combination, and provide a bypass pipe from the outlet side pipe line to the heat load side return pipe of the pump group so that the excess flow rate can be bypassed, and each flow rate adjustment valve is connected to each heat source unit The heating medium is distributed so as to be adjusted so that the load factor is equal.
Further, a part of the heat medium pump of the pump group is a variable flow pump, and the number of revolutions of the variable flow pump is controlled in accordance with a required flow rate on the heat load side.

Based on this configuration, use a heat source unit that can be used in the flow rate range above and below the rated flow rate when operating below the rated output of the heat source unit, and heat medium pumps according to the required flow rate on the heat load side By selecting and operating, it is possible to operate the optimum heat source unit according to the heat load regardless of the flow rate on the heat load side while ensuring the necessary flow rate on the heat load side.
As a result, the amount of water supplied to the heat load side heat exchanger is insufficient due to stopping the pair of chilling units and the circulation pump just by reducing the detected temperature difference as in the past. Can be avoided.

  Next, the flow rate adjusting valve for load distribution is arranged in the heat medium piping of each heat source device, so that the load factor of each heat source device becomes equal even if the heat medium flow rate fluctuates. Can be adjusted, and the heat source machine can be operated efficiently.

  The total heat medium flow rate of the pump group is equal to or higher than the total rated flow rate of the heat source unit, but the heat medium flow rate of each heat medium pump need not be the same capacity as the rated flow rate of each heat source unit. One or more heat medium pumps larger than the rated flow rate for one heat source unit may be provided in the heat medium pumps constituting the pump group, or the heat medium pump smaller than the rated flow rate for one heat source unit. One or more may be provided. Further, the number of heat medium pumps may or may not be the same as the number of heat source units. Further, one or more heat medium pumps may be variable flow rate pumps.

  As the operation method, select the heat source machine that operates according to the required heat amount on the heat load side, select the heat medium pump that operates according to the required flow rate on the heat load side, and further control the rotation speed of the heat medium pump, By distributing the heat medium by adjusting each flow rate adjustment valve so that the load factor of each heat source unit becomes equal, the bypass flow rate can be reduced or reduced to 0, the conveyance power of the heat medium pump is reduced, and the heat supply system Energy saving and running cost can be reduced.

In addition, a bypass pipe is provided from the outlet side pipe of the pump group to the return line of the heat load so that the excess flow is bypassed, so the required flow on the heat load side and the supply heat medium flow of the pump group And do not have to be completely matched, and the operation of the heat medium pump can be prevented from becoming unstable.
It is also possible to reduce the number of operating heat source units and the number of operating heat pumps by optimizing the selection of the operating units of the heat source units and the heat medium pumps and improving the load factor of the heat source units. When the number of operating machines is reduced, the number of operating cooling towers and cooling water pumps belonging thereto can be reduced, and there is an advantage that energy saving and running cost of the heat supply system can be reduced.

  Hereinafter, aspects of the heat supply system according to the present invention will be further described with reference to embodiments of the accompanying drawings.

1 to 6 is a heat storage tank type heat source machine 14a using a heat storage tank 11 and a heat exchanger 12, and the second machine to the fourth machine are heat source machines 14b using a refrigerator. 14c and 14d, which will be described as a cold heat source machine in the following description, but it should be understood that the present invention can be similarly applied to other types of heat source machines. Moreover, although the heat source machine in the example shown in FIGS. 1-6 has the same rated capacity as the 1st machine-the 4th machine, that the present invention is applicable similarly to the heat source machine from which the rated capacity of each heat source machine differs. I want you to understand.
Furthermore, in the example shown in FIGS. 1 to 6, the pump group is connected to the downstream side of the heat source unit group, but the pump group may be connected to the upstream side of the heat source unit group.

  FIG. 1 is a circuit diagram showing a main part of a heat supply system according to the present invention. Cold water from four cold heat source devices 14a to 14d from No. 1 to No. 4 is supplied to four cold water pumps 15a to 15d. It is sucked out and sent to a heat load (air conditioner for each room) 19. Cooling water is supplied from the cooling water pumps 17b, 17c, 17d to the three refrigerators 14b, 14c, 14d from the second machine to the fourth machine. Further, a bypass circuit 24 is provided between the outlet side pipeline 22 of the cold water pumps 15 a to 15 d and the return pipeline 23 on the heat load side, and the bypass flow rate is controlled by the flow rate control valve 16.

  According to the characteristics of the present invention, the cold heat source devices 14a to 14d can be used in a flow rate range of the rated flow rate (100) or more and the rated flow rate or less when operated at a rated output (rated heat amount 100) or less (corresponding to variable flow rate). ) Consists of a cold heat source machine. Conventionally, generally used cold heat source machines can only operate near the rated flow even when operated at a rated output or lower, and in practice, flow rates that are higher than the rated flow and lower than the rated flow. Use in the range was difficult.

Further, according to another feature of the present invention, a flow meter 26 and a flow rate adjusting valve 28 are provided in the circuits near the outlets of the heat source units 14a to 14d, respectively. In the state of FIG. 1, the cold heat source machine No. 2 14b and No. 3 machine 14c are in operation, the heat amounts here are 80 and 80, the flow rates are 100 and 100, respectively, The flow rates of the chilled water pump 15c and the chilled water pump 15d of Unit 4 are 100 and 100, respectively. At this time, since the amount of heat required for the heat load 19 side is 160 and the flow rate is 160, the flow rate 40 is returned to the cold heat source machine side through the bypass pipe line 24.
Thus, by providing the flow rate adjusting valve 28, it becomes possible to distribute the flow rate of water supplied from each cold heat source machine substantially evenly, and the load factor of the cold heat source machine can also be made substantially equal. In addition, it is possible to prevent a load from being concentrated on some of the cold heat source devices and to prevent the heat medium from flowing to a heat source device that is not in operation, thereby saving energy.

  Further, since it is not necessary to operate the cold heat source unit and the cold water pump in a one-to-one correspondence as in the conventional apparatus, the cold water pump can be operated mutually, and even if the cold water pump breaks down, Backup with a pump becomes possible. In addition, the combination of the cold heat source machine and the cold water pump becomes free, the running time of the cold water pump can be made uniform, and the running cost can be reduced, such as equalizing the life and facilitating maintenance.

  FIG. 2 shows the heat load side by using the variable flow rate compatible cold heat source unit shown in FIG. 1 and further changing some of the chilled water pumps (No. 1 unit 15a ′ and No. 2 unit 15b ′) to variable flow rate pumps. In this example, when the required flow rate is less than the rated flow rate of the cold heat source machine, it is possible to operate according to the required flow rate and reduce the power consumption. In the example of FIG. 2, since the rated flow rate of the cold heat source unit 14b and the variable flow rate pump 15a ′ of the second unit being operated is 100, the required heat amount on the heat load side is 70, and the required flow rate is 70. If the cold heat source unit 14b corresponding to the flow rate is partially loaded with the heat amount 70 and the flow rate 70, the flow rate of the bypass line 24 becomes zero. Thus, the running cost is reduced. In addition, since a cold heat source machine group in which a plurality of cold heat source machines are connected in parallel and a pump group in which a plurality of cold water pumps are connected in parallel are arranged in series, a cold heat source that can be operated during variable flow pump operation The machine can operate not only 14b but also 14a, 14c, and 14d, and even when the cold heat source machine breaks down, backup by another cold heat source machine becomes possible. In addition, the operating time of the cold heat source machine can be made equal to achieve uniform life.

  FIG. 3 is a flow rate (120) larger than the rated flow rate (100) of one cold heat source unit using the variable flow rate pump shown in FIG. 2 and the cold flow source device corresponding to the variable flow rate shown in FIG. This is an example in which the cold water pump (No. 4 machine 15d ') is provided and the operation method of the cold heat source machine and the cold water pump is diversified when an output slightly larger than the rated capacity is required. is there. That is, as shown in FIG. 3, assuming that four cold heat source units with a rated flow rate of 100, three cold water pumps with a flow rate of 100, and one cold water pump with a flow rate of 120 are installed, both the heat quantity and the flow rate on the heat load side are 110. If necessary, by operating the cold water pump 15d ′ having a flow rate of 120, the number of operating cold water pumps is sufficient instead of two. At this time, the calorific power sources 14b and 14c being operated are 55 in heat quantity, 60 in flow rate, and 10 in the bypass line 24, respectively. Thus, it is possible to diversify the operation methods and to save energy and reduce running costs by reducing the conveyance power.

  FIG. 4 shows another application example of the present invention. Even when the temperature difference between the return and return of cold water is smaller than the rated value and the flow rate is larger than the heat amount, the cold heat source device and the variable flow rate corresponding to the variable flow rate are required. By combining with the pump, the chilled water pump can be operated according to the flow rate within the range of the operable flow rate of the cold heat source unit, and the cold heat source unit can be operated according to the amount of heat. This means that reduction of power consumption and power consumption can be achieved. That is, as shown in FIG. 4, when the amount of heat 80 and the flow rate 130 are required on the heat load 19 side, the amount of heat 80 can be obtained by operating only the cold heat source unit 14b, and the cold water pumps 15a 'and 15b' By operating at a flow rate of 65, a flow rate of 130 is obtained. At this time, the flow rate of the bypass line 24 becomes zero. Thus, it is possible to diversify the operation methods and to save energy and reduce running costs by reducing the conveyance power.

  FIG. 5 shows a further application example of the present invention. Even when the temperature difference between the return and return of chilled water is larger than the rated value and the amount of heat is larger than the flow rate, Can be combined with the flow rate of the chilled water pump within the range of the chilled heat source unit's operable flow rate, and the chilled heat source unit can be operated according to the amount of heat, reducing the number of operating chilled water pumps and reducing power consumption. This means that it can be achieved. That is, as shown in FIG. 5, when a heat quantity 110 and a flow rate 90 are required on the heat load 19 side, a heat quantity 110 can be obtained by operating the cold heat source devices 14c and 14d with a heat quantity 55, respectively, and only the cold water pump 15c. Is operated, a flow rate of 90 is obtained. At this time, the flow rate of the bypass conduit 24 is 10. Thus, it is possible to diversify the operation methods and to save energy and reduce running costs by reducing the conveyance power.

  FIG. 6 shows an example where the number of installed cold heat source units and the number of installed cold water pumps are different in the heat supply system of the present invention. That is, four cold heat source machines share five cold water pumps, and it is not necessary to operate the cold heat source machine and the cold water pump in a one-to-one correspondence as in the conventional apparatus. This increases the degree of freedom in selecting the rated flow rate of each chilled water pump, and the combination of chilled water pumps that operate on the operating cold heat source unit becomes free. Not only can the chilled water pump be selected and operated, the power consumption of the chilled water pump can be greatly reduced, but also the operating time of the chilled water pump can be equalized to reduce the energy consumption and running costs by equalizing the life and facilitating maintenance. Can be achieved.

  As described above in detail, according to the present invention, the degree of freedom of operation of the heat source device group and the pump group at the time of partial load is expanded, and as a result, the heat source device that operates according to the required heat amount on the heat load side is provided. Select and select the heat medium pump that operates according to the required flow rate on the heat load side, and / or control the rotation speed of the heat medium pump so that the load factor of each heat source machine becomes equal Heat medium can be distributed with adjustment, the load factor of the heat source machine is improved, the operation efficiency of the heat source machine is increased, the conveyance power of the heat medium pump is reduced, energy saving of the heat supply system and reduction of running cost Can be achieved. In addition, by optimizing the number of operating heat source units, the operating efficiency of the heat source units can be increased, the power consumption of the auxiliary equipment of the heat source unit can be reduced, and the energy saving and running cost of the heat supply system can be further reduced. The technical effect is quite remarkable.

Circuit diagram representing a heat supply system according to the invention The circuit diagram showing the variable flow rate heat source machine and variable flow rate pump in this invention Circuit diagram showing a system with a large flow pump added A circuit diagram representing the system when the load flow is greater than the amount of heat. Circuit diagram showing the system when the amount of heat is greater than the flow rate A circuit diagram representing a system in a shared pump state according to the present invention. System diagram showing control device in conventional air conditioning system

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Heat storage tank 12 Heat exchanger 14a-14d Cold heat source machine 15a-15e, 15a ', 15b', 15d 'Chilled water pump 16 Flow control valve 17b-17d Cooling water pump 19 Thermal load 24 Bypass pipe 26 Flow meter 28 Flow rate adjustment valve

Claims (2)

In order to circulate the heat medium cooled or heated by the heat source device to the heat load side with respect to a plurality of heat source device groups connected in parallel, a pump group in which a plurality of heat medium pumps are connected in parallel is connected by piping. A heat supply system connected to the
Use a heat source unit that can be used in the flow rate range above and below the rated flow rate when operating below the rated output.
A flow control valve for load distribution is arranged in the heat medium piping of each heat source unit,
Make the total heat medium flow rate of the pump group more than the total rated flow rate of the heat source machine,
Select the heat source machine to be operated according to the required heat quantity on the heat load side,
Select the heat medium pump that operates according to the required flow rate on the heat load side,
By providing a bypass pipe from the outlet side pipe line of the pump group to the heat load side return pipe line so that an excessive flow rate can be bypassed,
A heat supply system having a plurality of heat source units and a pump group, wherein the heat medium is distributed by adjusting each flow rate adjusting valve so that the load factor of each heat source unit becomes equal. 2. The heat supply system according to claim 1, wherein a part of the heat medium pump of the pump group is a variable flow pump, and the number of rotations of the variable flow pump is controlled in accordance with a required flow rate on the heat load side.

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