JP2009236465A - Water supply pressure control system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To save energy of secondary pumps under low load without causing insufficient differential pressure of a loading apparatus having a large load requirement under low load of another loading apparatus at a terminal end. <P>SOLUTION: Valve differential pressures ΔPV1-ΔPV3 measured in loading apparatuses 12-1 to 12-3 are transmitted to a control device 11. The control device 11 obtains the valve differential pressures ΔPV1-ΔPV3 from the loading apparatuses 12-1 to 12-3, extracts a minimum differential pressure ΔPVmin from the obtained valve differential pressures ΔPV1-ΔPV3, determines a set value PSsp of the water supply pressure so that the extracted minimum differential pressure ΔPVmin becomes a prescribed value (0.3 kg/cm<SP>2</SP>, for example) or more, and controls the rotational speed of secondary pumps 6-1 to 6-3 and the opening of a bypass valve 8 so that a measurement value PSpv of the water supply pressure becomes the set value PSsp. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water supply pressure control system and a water supply pressure control method for controlling a water supply pressure to a load device (fan coil unit, air conditioner, etc.) of cold / hot water generated by a heat source device.

  Conventionally, as one of the water supply pressure controls for controlling the water supply pressure to the load equipment of the cold / hot water generated by the heat source machine, for example, in the system disclosed in Patent Document 1, the supply pipe of the cold / hot water from the heat source machine The differential pressure between the input side and the output side of the load device located at the end of the plurality of load devices provided between the pipe and the return water pipe is measured as the end differential pressure. Based on the above, the supply pressure of cold / hot water from the heat source device to the load device is set.

  According to the system disclosed in Patent Document 1, cold / hot water from a heat source device to a load device based on a differential pressure (terminal differential pressure) between an input side and an output side of the load device located at the end. The water supply pressure is changed. When the terminal differential pressure is small, the water supply pressure of the cold / hot water is increased, and when the terminal differential pressure is large, the water supply pressure of the cold / hot water is decreased.

For example, if the load equipment is an air conditioner, the differential pressure (terminal air conditioner differential pressure) between the input side and output side of the air conditioner located at the end (terminal air conditioner) is maintained at 1.0 kg / cm ² . Thus, the supply pressure of cold / hot water from the heat source device to the air conditioner is controlled. Thereby, it becomes possible to reduce the conveyance power of the cold / hot water to an air conditioner, and can implement | achieve energy saving.

JP 2005-299980 A

However, according to the conventional water supply pressure control method described above, since the terminal air conditioner differential pressure is maintained at, for example, 1.0 kg / cm ² , the following problem occurs when the terminal air conditioner has a low load. Has occurred. The problem will be described below.

The air conditioner includes a cold / hot water coil and a valve for adjusting the flow rate of the cold / hot water to the cold / hot water coil. In this air conditioner, at the maximum load, for example, a differential pressure of 1.0 kg / cm ² is required. In this case, at the time of maximum load of the air conditioner, joined by differential pressure 0.3 kg / cm ² to the valve, a differential pressure of 0.7 kg / cm ² is applied to the cold water coils.

On the other hand, when the load of the air conditioner is small, the resistance of the valve is high, and a differential pressure of approximately 1.0 kg / cm ² is applied to the valve near the fully closed state of the valve. That is, where the valve of sufficient Kakare differential pressure of 0.3 kg / cm ^2, when terminal air conditioner of low load, results in the differential pressure of Ho Isuzu 1.0 kg / cm ² is applied, the Loss of energy will occur.

Note that it is conceivable to control the water supply pressure so that a differential pressure of 0.3 kg / cm ² is always applied to the valve of the terminal air conditioner. When the load demand in the air conditioner becomes large, the differential pressure in the air conditioner becomes insufficient and the design flow rate cannot be maintained.

  The present invention has been made to solve such a problem, and the object of the present invention is to solve the problem that the differential pressure of another load device having a large load requirement is insufficient when the load device at the end is low. An object of the present invention is to provide a water pressure control system and a water pressure control method capable of saving energy of a secondary pump at low load without causing them.

  In order to achieve such an object, the present invention includes a heat source device that generates cold / hot water, and a plurality of load devices provided between an outlet pipe and a return water pipe of cold / hot water from the heat source machine, In a water supply pressure control system comprising a control device for controlling the supply pressure of cold / hot water from the heat source device to these load devices, each load device has an inlet of a valve for adjusting the flow rate of the cold / hot water flowing to its own load device. A differential pressure measurement unit that measures the differential pressure between the outlet side and the outlet side as a valve differential pressure is provided, and the valve differential pressure obtained by the differential pressure measurement unit of each load device is obtained in the control device. Means, a minimum differential pressure extraction means for extracting a minimum differential pressure from the valve differential pressure acquired by the valve differential pressure acquisition means, and a minimum differential pressure extracted by the minimum differential pressure extraction means is a predetermined predetermined value. From the heat source machine so that it is above the value Is provided with a hydraulically setting means feeding sets a feed pressure of hot and cold water to the load equipment.

  In this invention, each load device measures the differential pressure between the inlet side and the outlet side of the valve that adjusts the flow rate of the cold / hot water flowing through the load device as the valve differential pressure. For example, assuming that the load device is an air conditioner, a valve for adjusting the flow rate of cold / hot water to the cold / hot water coil is provided in the air conditioner, and a differential pressure measuring means is provided as an existing means on the valve. For example, the differential pressure between the inlet side and the outlet side of the valve measured by the differential pressure measuring means is sent to the control device as the valve differential pressure.

  The control device acquires the valve differential pressure sent from each load device, extracts the minimum differential pressure from the acquired valve differential pressure, and the extracted minimum differential pressure becomes equal to or greater than a predetermined value. Thus, the water supply pressure of the cold / hot water from the heat source device to the load device is set.

In this case, for example, if the load device at the end is low load and the load requirement at other load devices is large, and the valve differential pressure of this load device becomes the minimum differential pressure, the minimum differential pressure is a predetermined value (for example, , 0.3 kg / cm ² ) or higher, the supply pressure of cold / hot water from the heat source device to the load device is set.

  Therefore, when the load requirement at the other load device becomes large at the time of low load of the load device at the end, there is no problem that the differential pressure in the load device is insufficient and the design flow rate cannot be maintained. In addition, the differential pressure applied to the valve of the terminal load device is as small as possible while ensuring the differential pressure in the other load devices that have increased the load requirement. Thereby, the energy saving of the secondary pump at the time of low load can be achieved without causing the problem that the differential pressure of other load devices having a large load requirement at the time of low load of the terminal load device is insufficient.

  The present invention can be realized not as a water supply pressure control system but as a water supply pressure control method. In the case of the water supply pressure control method, a heat source device that generates cold / hot water, a plurality of load devices provided between the outgoing and return water pipelines of the cold / hot water from the heat source device, and the load devices In a system equipped with a control device that controls the supply pressure of cold / hot water from the heat source unit, the differential pressure between the inlet side and the outlet side of the valve that adjusts the flow rate of cold / hot water flowing to the load device for each load device The differential pressure measurement step for measuring the differential pressure as a valve differential pressure, the differential valve pressure acquisition step for acquiring the differential valve pressure of each load device measured in the differential pressure measurement step, and the valve acquired by the differential valve pressure acquisition step The minimum differential pressure extraction step for extracting the minimum differential pressure from the differential pressure, and the load device from the heat source unit to the load device so that the minimum differential pressure extracted by the minimum differential pressure extraction step is equal to or greater than a predetermined value. cold Providing a hydraulically setting step sent to set the feed water pressure of the water.

  According to the present invention, the measured valve differential pressure of each load device is acquired, the minimum differential pressure is extracted from the acquired valve differential pressure, and the minimum differential pressure is equal to or greater than a predetermined value. In addition, the supply pressure of cold / hot water from the heat source unit to the load device is set, so for example, the load device at the end is low and the load demand at other load devices is large. If the differential pressure becomes the minimum differential pressure, the supply pressure of the cold / hot water from the heat source unit to the load device is set so that the minimum differential pressure becomes a predetermined value or more. Energy saving of the secondary pump at the time of low load can be achieved without causing the problem that the differential pressure of other load equipment having a large load requirement at the time of load is insufficient.

  Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is an instrumentation diagram showing a configuration of an embodiment of a water supply pressure control system according to the present invention.

  The water supply pressure control system includes heat source devices 1-1 to 1-3 that generate cold / hot water such as a cold / hot water generator, a heat pump, a refrigerator, and a boiler, and auxiliary devices for the heat source devices 1-1 to 1-3. Primary pumps 2-1 to 2-3, forward headers 3-1 and 3-2, return header 4, and first header provided between forward header 3-1 and return header 4. Between the bypass pump 5, the secondary pumps 6-1 to 6-3 provided between the forward headers 3-1 and 3-2, and the forward header 3-1 and the forward header 3-2 A second bypass pipe 7 provided, a bypass valve 8 provided in the bypass pipe 7, a forward water pipe 9, a return water pipe 10, and a control device 11 are provided. In addition, load devices 12-1 to 12-3 such as a fan coil unit and an air conditioner are provided in parallel with the return water pipe 10.

  In this water supply pressure control system, cold / hot water pumped by the primary pumps 2-1 to 2-3 and heated by the heat source units 1-1 to 1-3 is sent to the forward header 3-1, and the secondary pump 6 is supplied. -1 to 6-3 are further pumped, supplied to the outgoing water line 9 via the outgoing header 3-2, and passed to the returning header 4 through the return water pipe 10 via the load devices 12-1 to 12-3. Then, it is again pumped by the primary pumps 2-1 to 2-3 and circulates the above path.

  In this cold / hot water circulation path, the pressure of the cold / hot water discharged from the forward header 3-2 is sent to the load devices 12-1 to 12-3 from the heat source units 1-1 to 1-3 in the outgoing water line 9. A pressure sensor 13 for measuring the cold / hot water feed pressure PSpv is provided. Further, the secondary pumps 6-1 to 6-3 are provided with inverters 6-1a to 6-3a for adjusting the rotation speed of the pump, and the load devices 12-1 to 12-3 are provided with the inverters 6-1a to 6-3a. Valves V1 to V3 for adjusting the flow rate of the cold / hot water flowing through the load devices 12-1 to 12-3 are provided.

  FIG. 2 shows an outline of the internal configuration of the load device 12 (12-1 to 12-3). The load device 12 includes a cold / hot water coil 12A and a fan 12B, and a valve V is provided in the cold / hot water supply passage L to the cold / hot water coil 12A.

  In the valve V, as existing means for measuring a physical quantity necessary for adjusting the opening degree of the valve V, a flow rate measuring means for measuring the flow rate of cold water flowing through the valve V, an inlet side and an outlet side of the valve V, There is provided a measuring means S1 which also serves as a differential pressure measuring means for measuring the differential pressure between the two. In the present embodiment, the flow rate of cold water measured by the measuring means S1 is set as the load device flow rate Q, and the differential pressure between the inlet side and the outlet side is sent to the control device 11 as the valve differential pressure ΔPV. Yes.

  The transmission of the load device flow rate Q and the valve differential pressure ΔPV from the load device 12 to the control device 11 may be wireless or wired.

  The control device 11 is realized by hardware including a processor and a storage device, and a program that realizes various functions as the control device in cooperation with these hardware. Water supply pressure control is a function unique to the present embodiment. It has a function. Hereinafter, the water supply pressure control function of the control device 11 will be described with reference to the flowchart shown in FIG.

  The control device 11 acquires and stores the load device flow rates Q1 to Q3 and the valve differential pressures ΔPV1 to ΔPV3 from the load devices 12-1 to 12-3 (step S101). Then, the minimum differential pressure ΔPVmin having the smallest value is extracted from the obtained valve differential pressures ΔPV1 to ΔPV3 (step S102).

Next, the control device 11 regards the extracted minimum differential pressure ΔPVmin as the differential pressure of the control target, and the differential pressure of the control target is a predetermined value (in this example, 0.3 kg / cm ^2). ) Is determined (step S103).

  The control device 11 then sets the secondary pumps 6-1 to 6-3 so that the measured value PSpv of the water supply pressure from the pressure sensor 13 becomes the set value PSsp based on the determined set value PSsp of the water supply pressure. Adjust the rotation speed. At this time, if the water supply pressure PSpv does not reach the set value PSsp even if the rotation speed of the secondary pumps 6-1 to 6-3 is the lower limit value, the water supply pressure is adjusted by adjusting the opening of the bypass valve 8. PSpv is set to the set value PSsp (step S104).

Here, for example, when the load device 12-1 at the end has a low load, the load requirement of 12-2 is large in other load devices, and the valve differential pressure ΔPV2 of the load device 12-2 becomes the minimum differential pressure. think about. In this case, the control device 11 extracts the valve differential pressure ΔPV2 of the load device 12-2 as the minimum differential pressure ΔPVmin, and sets the set value PSsp of the water supply pressure so that the minimum differential pressure ΔPVmin becomes 0.3 kg / cm ^2. decide.

  Therefore, even when the load requirement at the load device 12-2 becomes large at the low load of the load device 12-1, the differential pressure at the load device 12-2 is insufficient and the design flow rate can be maintained. The problem of not being possible does not occur. In addition, the differential pressure applied to the valve V1 of the terminal load device 12-1 is as small as possible while ensuring the differential pressure at the load device 12-2 where the load requirement is increased.

  Thereby, the energy saving of the secondary pump 6 at the time of low load can be achieved without causing the problem that the differential pressure of the other load device 12-2 having a large load request at the time of low load of the load device 12-1 is insufficient. Figured.

  FIG. 4 shows a functional block diagram of the main part of the control device 11. The control device 11 includes a valve differential pressure acquisition unit 11A, a minimum differential pressure extraction unit 11B, a water supply pressure setting unit 11C, and a water supply pressure control unit 11D.

  The valve differential pressure acquisition unit 11A acquires the valve differential pressures ΔPV1 to ΔPV3 from the load devices 12-1 to 12-3. The minimum differential pressure extraction unit 11B extracts the minimum differential pressure ΔPVmin from the valve differential pressures ΔPV1 to ΔPV3 acquired by the valve differential pressure acquisition unit 11A.

The water supply pressure setting unit 11C determines the water supply pressure set value PSsp so that the minimum differential pressure ΔPVmin extracted by the minimum differential pressure extraction unit 11B is 0.3 kg / cm ² or more.

The water supply pressure control unit 11D adjusts the rotation speed of the secondary pumps 6-1 to 6-3 and opens the bypass valve 8 so that the measured value PSpv of the water supply pressure from the pressure sensor 13 becomes the set value PSsp. Adjust the degree.

  The valve differential pressure acquisition unit 11A, the minimum differential pressure extraction unit 11B, the water supply pressure setting unit 11C, and the water supply pressure control unit 11D are realized as processing functions of the CPU 1-1.

  In the above-described embodiment, the load device 12 is described as being provided with the cold / hot water coil. However, the load device may be provided with only one of the cold water coil and the hot water coil. That is, the present invention can be similarly applied to a system that circulates only cold water and a system that circulates only hot water. Moreover, the system by which the cold water coil and the hot water coil were provided separately may be sufficient.

  Further, in the above-described embodiment, for the sake of simplicity, the example has been described in which three heat source devices and three load devices are used. However, the number of heat source devices, load devices, and the like is the same as the number described above. It is not limited and can be set freely as appropriate.

It is an instrumentation figure which shows the structure of one Embodiment of the water supply pressure control system which concerns on this invention. It is a figure which shows the outline of the internal structure of the load apparatus in this water supply pressure control system. It is a flowchart for demonstrating the water pressure control function which the control apparatus in this water pressure control system has. It is a functional block diagram of the principal part of the control apparatus in this water supply pressure control system.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 (1-1 to 1-3) ... Heat source machine, 2 (2-1 to 2-3) ... Primary pump, 3-1, 3-2 ... Out header, 4 ... Return header, 5 ... Bypass line , 6 (6-1 to 6-3) ... secondary pump, 6-1a to 6-3a ... inverter, 7 ... bypass pipe, 8 ... bypass valve, 9 ... outgoing water pipe, 10 ... return water pipe, 11 ... Control device, 12 (12-1 to 12-3) ... Load equipment, 12A ... Cooled / hot water coil, 12B ... Fan, L ... Cooled / hot water supply passage, V (V1 to V3) ... Valve, S1 ... Measurement means, DESCRIPTION OF SYMBOLS 13 ... Pressure sensor, 11A ... Valve differential pressure acquisition part, 11B ... Minimum differential pressure extraction part, 11C ... Water supply pressure setting part, 11D ... Water supply pressure control part.

Claims (2)

A heat source device that generates cold / hot water, a plurality of load devices provided between the outgoing and return water pipelines of the cold / hot water from the heat source device, and the cold / hot water from the heat source device to these load devices In a water pressure control system comprising a control device for controlling the water pressure,
Each of the load devices is
It is equipped with differential pressure measuring means that measures the differential pressure between the inlet side and the outlet side of the valve that adjusts the flow rate of cold / hot water flowing to its load equipment as the valve differential pressure,
The controller is
Valve differential pressure acquisition means for acquiring the valve differential pressure measured by the differential pressure measurement means of each load device;
Minimum differential pressure extraction means for extracting the minimum differential pressure from the valve differential pressure acquired by the valve differential pressure acquisition means;
Water supply pressure setting means for setting the water supply pressure of the cold / hot water from the heat source unit to the load device so that the minimum differential pressure extracted by the minimum differential pressure extraction means is not less than a predetermined value determined in advance. A water supply pressure control system characterized by comprising: A heat source device that generates cold / hot water, a plurality of load devices provided between the outgoing and return water pipelines of the cold / hot water from the heat source device, and the cold / hot water from the heat source device to these load devices In a water pressure control method applied to a system including a control device for controlling water pressure,
A differential pressure measuring step for measuring the differential pressure between the inlet side and the outlet side of the valve for adjusting the flow rate of the cold / hot water flowing through the load device for each load device;
A valve differential pressure acquisition step of acquiring the valve differential pressure of each load device measured by the differential pressure measurement step;
A minimum differential pressure extraction step for extracting the minimum differential pressure from the valve differential pressure acquired by the valve differential pressure acquisition step;
The minimum differential pressure is extracted from the valve differential pressure extracted in the minimum differential pressure extraction step, and the cooling temperature from the heat source device to the load device is set so that the minimum differential pressure is equal to or greater than a predetermined value. A water supply pressure control method comprising: a water supply pressure setting step for setting water supply pressure.

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