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Optimal control method and device for water system of air conditioning

A technology of system optimization and control method, applied in heating and ventilation safety systems, heating and ventilation control systems, heating methods, etc. Reliability and other issues, to avoid energy-saving benefits, to avoid accurate measurement of differential pressure, to achieve reliable control, and to avoid energy consumption.

Inactive Publication Date: 2010-07-21
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the installation position and measurement of the differential pressure sensor at the end of the most unfavorable loop has a great influence on the control of the system
First, when the differential pressure sensor is installed on both sides of the control valve (without crossing the heat exchange device), when the water valve at the end where the differential pressure sensor is installed is closed, the differential pressure cannot be measured to control the system at this time. The second is, When the two measuring points of the differential pressure sensor cross the heat exchange device, the measured differential pressure value can theoretically roughly represent the differential pressure at the end of the second most unfavorable loop
However, actual field experience shows that when the loop valve is closed, the measured differential pressure on the loop is often unreliable
The third is to use the pressure difference to control the end of the second most unfavorable loop, and the set value of the pressure difference may not be appropriate
Therefore, at part load, the energy saving potential of the variable flow system is greatly reduced
The fifth is that the most unfavorable loop is generally located at the farthest point of the water system, the measurement signal transmission path is long, and the reliability of signal transmission is also affected

Method used

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  • Optimal control method and device for water system of air conditioning
  • Optimal control method and device for water system of air conditioning
  • Optimal control method and device for water system of air conditioning

Examples

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Effect test

Embodiment 1

[0033] Such as figure 2 As shown, the air-conditioning water system optimization control method and device of the present invention are applied to the primary air-conditioning water pumping system when a single water pump and a single refrigerator are directly connected in series.

[0034]When the water system is running, the electrical signal of the pressure difference sensor 2 at the inlet and outlet of the water pump 1 is directly transmitted to the water system optimization controller 3, and the water system optimization controller 3 directly converts the electrical signal into a pressure difference value (generally considered to be the pump head H ), and call the calculation program to directly calculate the water flow Q of the water pump according to the pressure difference value and the real-time frequency fed back to the water system optimization controller 3 by the frequency converter 6, and simultaneously calculate the real-time resistance characteristic value S of t...

Embodiment 2

[0037] Such as Figure 4 As shown, the optimal control method and device for the air-conditioning water system in this embodiment are applied to an air-conditioning primary water pumping system when multiple water pumps and multiple refrigerators are connected in series through the water supply / return main pipe. This kind of water system is a very widely used system. The water pump and the refrigerator are connected in series through the water supply and return main pipe, or connected in series through the water collector and water divider.

[0038] Among the n water pumps 1 in this example, a differential pressure sensor 2 (n is a natural number) is correspondingly installed at the inlet and outlet of each, and is electrically connected with the water system optimization controller 3 . When the water pumps are running, the water system optimization controller 3 directly calculates the water flow of each water pump and the total flow of the water system according to the descri...

Embodiment 3

[0041] Such as Figure 5 As shown, the air-conditioning water system optimization control method and device of this embodiment are applied to the secondary pump water system. This water system is a widely used system. The primary pump provides the required flow for the refrigerator, and the secondary pump provides the required flow for the terminal. The water pump and the refrigerator are connected in series through the water supply and return main pipe, or the water is divided through the water collector. devices in series. There is a decoupling pipe between the primary pump and the secondary pump to ensure that the water flow through the evaporator of the refrigerator remains basically stable when the flow rate of the secondary pump is constantly changing. In this kind of water system, there is often more than one secondary pump.

[0042] In the n secondary water pumps 1 in this embodiment, a pressure difference sensor 2 is correspondingly installed at the inlet and outlet...

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Abstract

The invention relates to an optimal control method and a device for a water system of an air conditioning, which belongs to the field of building energy conservation and green air conditionings. In the invention, according to the measured pressure difference between the inlet and the outlet of a water pump, a certain algorithm is utilized to work out the flow rate of the water pump and the resistance characteristic value of the water system, and the frequency of the water pump is regulated so that the resistance characteristic value of the water system is kept within a certain range. The range of the resistance characteristic value is the system resistance characteristic value when the end valve of the water system is opened. The invention can overcome the defects of high cost for a flow sensor, which is installed in a real water system and is used for controlling the real system, and inaccurate measurement due to insufficient space and position for field installation; And the invention can overcome the defect of high energy consumption of a constant-speed pumping system under the loading condition at the end of the air conditioning, and the defects of high energy consumption and insufficient end cold energy of the constant-speed pumping system due to the unreasonable arrangement position and the unreasonable set value of a pressure difference control point. The invention is suitable for primary pump chilled water systems, secondary pump chilled water systems and air conditioning hot-water systems.

Description

Technical field: [0001] The invention belongs to the field of building energy saving and green air-conditioning, and in particular relates to an optimal control and device for an air-conditioning water system. Background technique: [0002] Due to the development of mechanical refrigeration technology and the improvement of living standards, the application of mechanical comfort air conditioning systems that consume high-grade energy such as electricity and gas is becoming more and more extensive. Air-conditioning systems account for more than half of building energy consumption. The energy consumption of the air-conditioning water transportation system accounts for about 30% of the energy consumption of the air-conditioning system. The current water system generally adopts constant flow system and variable flow system. The transport power in the constant flow water system is provided by the constant speed pump. The air-conditioning load of the building is constantly chan...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): F24F11/00F24F11/02
Inventor 徐新华
Owner HUAZHONG UNIV OF SCI & TECH
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