Variable frequency energy-saving control method for refrigeration system

Abstract

The invention belongs to the technical field of energy conservation, and relates to a variable frequency energy-saving control method for a refrigeration system. The control method comprises the steps of: determining the mass flow of a refrigerant according to the change or change trend of cooling load, then determining consumed power of a compressor which satisfies the flow, predicting the minimum condensation pressure which ensures that the thermal load of a condenser satisfies the cooling load and the power change of the compressor through an established energy-saving control mathematical model, and gradually adjusting the power frequency of the compressor to ensure that the rotating speed of the compressor reaches a predicted value; and adjusting the opening degree of an expansion valve to ensure that the condensation pressure reaches to be lowest, realizing the minimum pressure difference operation between the condenser and an evaporator, and ensuring that the operation energy consumption of the refrigeration system is lowest. The method solves the optimizing control problem of the compressor, the expansion valve and a fan in the system, utilizes the energy-saving control mathematical model to perform joint regulation on controllable factors (such as the rotating speed of the compressor, the opening degree of the expansion valve, and the air volume of an outdoor unit) of the operation of the system, ensures that the refrigeration system operates at a best operating point, and realizes the further energy conservation of the refrigeration system based on the variable frequency regulation.

Description

technical field [0001] The invention belongs to the technical field of energy saving, and relates to a refrigeration system with a variable capacity or an air conditioning system with a variable capacity refrigeration circuit, in particular to a variable capacity adjustment matching the cooling (or heating) load and a maximum opening of the valve. Energy-saving operation control method. Background technique [0002] With the increasingly serious energy crisis worldwide, governments of various countries are actively promoting energy-saving and consumption-reducing technologies for sustainable economic development. The energy shortage problem has also become an important factor restricting the development of our country. With the increasingly widespread use of various refrigeration and air-conditioning equipment, the proportion of its energy consumption in the total energy consumption of the society is increasing rapidly. While pursuing comfort, energy and environmental prot...

AI Technical Summary

Problems solved by technology

Although the inverter air conditioner can adapt to the change of the cooling load to a certain extent by changing the speed, it still only takes the superheat of the evaporator as the control target, and it is actually difficult to maintain the system at the highest efficiency point.

On the other hand, although the electronic expansion valve technology has been widely used in the refrigeration and air-conditioning industry, its control strategy still has not got rid of the superheat feedback control mode, so it cannot fundamentally change the instability caused by the time-lag passive control method. and high energy consumption

Images