CO2 transcritical parallel compression refrigeration system and control method

Abstract

The invention discloses a control method of a CO2 transcritical parallel compression refrigeration system. The system comprises a main path transcritical CO2 circulation device and a branch path near-critical CO2 circulation device. The main path transcritical CO2 circulation device comprises a main compressor, a gas cooler, a heat regenerator, a main path throttle valve, an evaporator and a gas-liquid separator which are circularly connected in sequence; a gas outlet of the gas-liquid separator is connected with a gas suction port of the main compressor; the branch path near-critical CO2 circulation device comprises a branch path throttle valve and an auxiliary compressor; and an outlet bypass path of the heat regenerator is connected with the gas suction port of the main compressor through the branch path throttle valve, the heat regenerator and the auxiliary compressor. According to the system, the optimization problem of the optimal exhaust pressure, the optimal intermediate pressure and the optimal volume flow ratio of a parallel compression system can be solved, and the problem that the system deviates from the working condition point with the optimal performance due to the change of the environment temperature in the actual operation process can be solved.

Description

【Technical field】 [0001] The invention belongs to the technical field of refrigeration and low temperature, in particular to a CO 2 Transcritical parallel compression refrigeration system and control method. 【Background technique】 [0002] With social development and scientific and technological progress, heat pump air conditioners have played an important role in people's production and life. Traditional CFCs, HCFCs, and HFCs refrigerants are widely used in the field of refrigeration and air conditioning because of their excellent thermodynamic properties, but the ODP and GWP of Freon refrigerants are high, making it a major development trend to replace Freon refrigerants with natural working fluids . [0003] CO 2 It has excellent heat transfer performance, is non-flammable, and non-toxic. The air-conditioning cycle works in a high-pressure area and has a low specific volume, which can reduce the volume of the equipment. In recent years, transcritical CO 2 The cycle h...

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Problems solved by technology

[0004] The object of the present invention is to provide a CO 2 The control method of the transcritical parallel compression refrigeration system is to solve the optimization problem of the optimal exhaust pressure, intermediate pressure and volume flow ratio of the parallel compression system, and in the actual operation process, due to the change of the ambient temperature, the system deviates from the optimal performance point of view

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