Multi-split air conditioner heat pump system, refrigeration control method thereof and heating control method thereof

Abstract

The invention discloses a multi-split air conditioner heat pump system, a refrigeration control method thereof and a heating control method thereof. The multi-split air conditioner heat pump system comprises a compressor (1), an oil separator (4), a four-way valve (5), a condenser (6), a gas-liquid separator (7), an outdoor unit main electronic expansion valve (8), an outdoor unit side stop valve (18) and an auxiliary electronic expansion valve (7), one end of the auxiliary electronic expansion valve (7) is connected between the four-way valve (5) and the condenser (6), the other end of the auxiliary electronic expansion valve (7) is connected between the outdoor unit main electronic expansion valve (8) and the outdoor unit side stop valve (18), a high-pressure switch (2) and a high-pressure sensor (3) are arranged on an output pipeline communicated with an output end of the compressor (1), and a low-pressure switch (11) and a low-pressure sensor (12) are arranged on an input pipeline connected with an input end of the compressor (1). The multi-split air conditioner heat pump system improves system running stability.

Description

technical field [0001] The invention relates to the technical field of air-conditioning equipment, in particular to a multi-connected air-conditioning heat pump system and a refrigeration control method and a heating control method thereof. Background technique [0002] Multi-connection is commonly known as "one-to-many", which means that one outdoor unit is connected to multiple indoor units through piping. The multi-split system has many advantages such as energy saving, comfort, and stable operation, and each room can be adjusted independently to meet the needs of different air-conditioning loads in different rooms. It is increasingly widely used in small and medium-sized buildings and some public buildings. [0003] At present, in the existing multi-connected air-conditioning heat pump system, under small load and small cooling conditions, due to the good condensation effect of the system, the condensation pressure is very low, and the output of the compressor is too la...

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Problems solved by technology

[0003] At present, in the existing multi-connected air-conditioning heat pump system, under the condition of small load and small cooling, due to the good condensation effect of the system, the condensation pressure is very low, and the output of the compressor is too large, which directly leads to the low evaporation pressure of the system

Due to the small high and low pressure difference of the system, frequent low temperature protection of the internal unit, and frequent start and stop of the compressor, a large amount of lubricating oil is discharged by the compressor and cannot be returned smoothly, which seriously affects the service life of the compressor.

[0004] The stability of the system operation is not high; under the condition of small load and high heat, due to the good evaporation effect, the evaporation pressure is high, and the output of the compressor is too large, which directly leads to a very high condensation pressure, which may even exceed the safety of the compressor in serious cases. Operating range, system operation stability is not high

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