Multi-unit system

Abstract

The invention discloses a multi-unit system. By replacing an original single air cooling heat exchanger with two air cooling heat exchangers, during low-temperature refrigeration, the multi-unit system can achieve the aim of the area of an air cooling condenser by powering off one of the air cooling heat exchangers, or reduce the area of the air cooling condenser, enlarge the area of an air cooling evaporator and reduce the risk of liquid-state refrigerant returning of the system by taking one of the air cooling heat exchangers as the condenser and the other air cooling heat exchanger as an evaporator; during high-temperature heating, the multi-unit system can take one of the air cooling heat exchangers as the evaporator and the other air cooling heat exchanger as the condenser to control and maintain system pressure and air return temperature within a reasonable range; during low-temperature heating and when the air cooling heat exchanger of an outdoor unit needs defrosting, the multi-unit system performs defrosting by taking one of the air cooling heat exchangers as the condenser and continues to perform heating by taking the other air cooling heat exchanger as the evaporator. Therefore, the requirements of units on continuous heat supply can be met, and further the comfort level of users can be guaranteed.

Description

technical field [0001] The present invention relates to the technical field of air conditioning, and more specifically, relates to a multi-connected system. Background technique [0002] In the existing multi-connected system, the air-cooled heat exchangers of the outdoor units are either used as evaporators or used as condensers. In low-temperature cooling, all the air-cooled heat exchangers of the outdoor unit are used as condensers, which may cause the condensation effect to be too good, and the evaporator cannot be completely evaporated, which will cause the system to return to liquid refrigerant, and in severe cases, the compressor will burn out; When heating, the exhaust temperature of the compressor is high, and the system pressure will also be high at this time, and the air-cooled heat exchanger of the outdoor unit is used as an evaporator, and the evaporation effect is too good, resulting in high return air temperature and high return air temperature. If the air-co...

AI Technical Summary

Problems solved by technology

In low-temperature cooling, all the air-cooled heat exchangers of the outdoor unit are used as condensers, which may cause the condensation effect to be too good, and the evaporator cannot be completely evaporated, which will cause the system to return to liquid refrigerant, and in severe cases, the compressor will burn out; When heating, the exhaust temperature of the compressor is high, and the system pressure will also be high at this time, and the air-cooled heat exchanger of the outdoor unit is used as an evaporator, and the evaporation effect is too good, resulting in high return air temperature and high return air temperature. If the air-cooled heat exchanger of the outdoor unit is used as the evaporator for low-temperature heating, the air-cooled heat exchanger of the outdoor unit is used as a condenser, and the heat exchange of the indoor unit The high-temperature and high-pressure refrigerant melts the frost when the air-cooled heat exchanger of the outdoor unit is condensed. However, the condensed refrigerant needs to evaporate and absorb heat in the heat exchanger of the indoor unit. In this way, if the indoor unit blows air, it will blow out It will be cold air, even if the indoor unit is not blown, it cannot continue to heat, resulting in the multi-connected system cannot continue to provide heating demand, thus affecting the user's comfort requirements

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