Control device of multi-connected central air conditioning system and control method thereof

Abstract

The invention discloses a control device of a multi-connected central air conditioning system. The control device is provided with an outdoor unit and multiple indoor units, wherein an air pipe and a liquid pipe of the outdoor unit are connected with an air pipe branch and a liquid pipe branch of each indoor unit; an electronic expansion valve is arranged in the liquid pipe branch of each indoor unit; the control device is characterized by comprising a liquid pipe temperature sensor, a superheat degree detection module and a refrigeration opening regulation module, wherein the liquid pipe temperature sensor is used for detecting the liquid pipe temperature of each indoor unit; the superheat degree detection module is used for detecting the superheat degree; the refrigeration opening regulation module is used for regulating the opening of the electronic expansion valve in refrigeration, and comprises a first sub-module, a second sub-module and a third sub-module, wherein the first sub-module regulates the opening of the electronic expansion valve according to the first target temperature when the liquid pipe temperature is higher than or equal to the first target temperature; the second sub-module regulates the opening of the electronic expansion valve according to the second target temperature when the liquid pipe temperature is lower than or equal to the second target temperature; and the third sub-module regulates the opening of the electronic expansion valve according to the detected superheat degree when the liquid pipe temperature is higher than the second target temperature and lower than the first target temperature.

Description

technical field [0001] The invention relates to a multi-connected central air-conditioning control device and a control method thereof, in particular to the control of an indoor unit thereof. Background technique [0002] The multi-connected central air-conditioning system is an air-conditioning system composed of an outdoor unit connected to multiple indoor units, and is mainly installed indoors with a large space. In this multi-connected central air-conditioning system, since the cooling or heating capabilities of the indoor units can be adjusted independently, the temperature of each room where the indoor units are installed can be independently controlled as required. The cooling or heating capacity of the indoor unit is controlled by changing the opening of the electronic expansion valve. [0003] In the prior art, during cooling, the opening degree of the electronic expansion valve of the indoor unit is adjusted according to the degree of superheat, while during heati...

AI Technical Summary

Problems solved by technology

Especially for the indoor unit located at the end of the refrigeration cycle pipeline, due to the excessive resistance in the pipeline, the refrigerant flow rate will decrease, and the temperature of the gas pipe and liquid pipe will be relatively high, while the superheat will be relatively low.

At this time, if the opening of the electronic expansion valve of the indoor unit is only adjusted according to the degree of superheat, the electronic expansion valve of the indoor unit will not open, resulting in poor cooling effect of the indoor unit.

[0005] While heating, for the indoor unit at the end of the heating cycle pipeline, the temperature of the air pipe is also higher due to the increase of resistance in the pipeline or uneven distribution.

At this time, if the opening of the electronic expansion valve is only adjusted according to the temperature of the air pipe, the opening of the electronic expansion valve will be very large, and the heating effect will be relatively poor.

Images