Optimal control method and device for water system of air conditioning

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...

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

Images