Energy-saving control method for draught fan or water pump of heating, ventilating and air-conditioning system

Abstract

The invention relates to an energy-saving control method for a draught fan or a water pump of a heating, ventilating and air-conditioning system. The energy-saving control method comprises the following steps that firstly, when the heating, ventilating and air-conditioning system is switched on, the pressure of a main pipeline is preset to be an initial value; secondly, if electrically operated valve executers at the tail ends of the demand sides can send out feedback signals of the actual positions of air valves or water valves, the third step is executed, and if not, the fourth step is executed; thirdly, a central controller receives the feedback signals sent out by the electrically operated valve executers at the tail ends of all the demand sides, obtains the valve position of the maximum air valve or the maximum water valve, compares the valve position with a preset value and then adjusts the pressure of the main pipeline; and fourthly, the central controller detects the number of the received demand signals send out by the tail ends of all the demand sides, if the number of the demand signals is smaller or equal to a minimum ignoring value, the pressure at a static pressure set point is lowered by a preset pressure value, and if not, the pressure at the static pressure set point is raised by the product of the number of the demand signals and the preset value. The energy-saving control method for the draught fan or the water pump of the heating, ventilating and air-conditioning system can guarantee the stability of the air pressure and the water pressure.

Description

technical field [0001] The invention relates to an energy-saving control method, in particular to an energy-saving control method for fans or water pumps in HVAC systems. Background technique [0002] In a large-scale HVAC system, in order to achieve the purpose of energy saving, the fan or water pump is usually controlled by frequency conversion according to the change of the terminal load on the demand side. In fan control, there are two methods: constant static pressure and variable static pressure. The constant static pressure method is to always maintain the pressure set point under the maximum design load, and the energy consumption of the fan is relatively high. Calculate the PID output at a fixed point to adjust the fan speed. This method has complex operation logic and unstable air pressure, making it difficult to implement and debug. In water pump control, pressure difference control and temperature difference control are commonly used. Differential pressure con...

AI Technical Summary

Problems solved by technology

Differential pressure control is similar to the constant static pressure method of fan control. It is necessary to maintain the maximum design to meet or meet the pressure setting of the most unfavorable loop, and the energy consumption of the water pump is high; the temperature difference control cannot meet the needs of each individual demand side end, and it is prone to occurrence Water imbalance

At present, the variable static pressure method is also proposed for water pump control, but there are still problems in the control of fan variable static pressure method with complex algorithms and difficult debugging

[0003] Regardless of whether it is fan control or water pump control, the variable static pressure method is to intelligently adjust the pressure set point of the air duct or water pipe according to the change of the terminal load on the demand side. It is generally recognized as the most energy-saving control method, but as mentioned above, using Traditional PID programming will have many problems such as complex algorithm, pressure oscillation, difficult debugging, instability of wind pressure and water pressure, etc.

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