Double-evaporator air conditioning unit and control method thereof

Abstract

The invention provides a double-evaporator air conditioning unit. The double-evaporator air conditioning unit comprises an air duct air pipe A, an air duct air pipe B, a refrigerating system, a differential pressure sensor, a fan, an inlet main air pipe, an outlet main air pipe, a first air valve and a second air valve, wherein the inlet main air pipe and the outlet main air pipe are in communication with an air supply demand area; the refrigerating system comprises a first evaporator, a second evaporator, a first electromagnetic valve and a second electromagnetic valve; the first evaporator is arranged in the air duct air pipe A, and the second evaporator is arranged in the air duct air pipe B. The control method of the unit comprises the following steps that A, control parameters are set; B, refrigeration work is carried out according to an A-path refrigerating state; C, the A-path refrigerating state is switched to a B-path refrigerating state when switching conditions are met; D, the B-path refrigerating state is switched to the A-path refrigerating state when the switching conditions are met; and E, the standby evaporator is defrosted and the evaporation pressure the evaporator in operation is adjusted in the operation process of the unit. The unit and the control method thereof have the advantages of being low in cost and stable in air outlet temperature.

Description

technical field [0001] The invention relates to the technical field of air conditioning, in particular to a double evaporator air conditioning unit and a control method thereof. Background technique [0002] In places such as food preservation and grain storage, in order to ensure the freshness of food or grain and prolong the preservation time, it is necessary to use low-temperature refrigeration and air conditioning to achieve low-temperature air supply technology in the range of 0-5 degrees, and the current low-temperature air supply control in such places In terms of implementation, a low-temperature refrigeration system (the evaporation temperature of the low-temperature refrigeration system is usually lower than 0 degrees) is usually used to realize one-use and one-standby mode, that is, two sets of exactly the same low-temperature refrigeration systems are used to realize one-use and one-standby operation, so as to achieve one set When the evaporator of the low-temper...

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Problems solved by technology

[0004] 1) Two sets of exactly the same refrigeration system involve two sets of four major components of the refrigeration system, namely evaporator, condenser (including condensing fan), compressor, expansion valve, and refrigeration pipeline. The cost is high, and the customer The cost of purchasing two low-temperature air conditioners is basically the same;

[0005] 2) Since the components that originally belonged to two low-temperature air conditioners were installed in one low-temperature air conditioner, the air conditioner occupied a large volume and became more difficult to install and transport;

[0006] 3) This method is usually to use the heat exchange with nature to realize the defrosting of the evaporator after the ice blocking system becomes a backup system. This defrosting method is greatly affected by the ambient temperature. In the weather with low ambient temperature, The defrosting process is slow, and the low-temperature refrigeration system put into operation is in a low-temperature environment, and the frosting process is accelerated. In a low-temperature environment, the frost on the evaporator of the standby low-temperature refrigeration system has not completely melted, and the evaporator of the low-temperature refrigeration system in operation has frosted seriously. This eventually resulted in the inability of both cryogenic refrigeration systems to operate

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