a transcritical co 2 Parallel compression system and its capacity ratio method

Abstract

The invention discloses a transcritical CO 2 Parallel compression system and its capacity ratio method, including two circuits, the main circuit and the auxiliary circuit, using the evaporation of the auxiliary circuit in the subcooling-evaporator to reduce the temperature at the outlet of the main circuit of the gas cooler to the temperature of the main circuit of the subcooling-evaporator Circuit outlet; the present invention includes three working modes according to the ambient temperature: in the normal operation mode, the ambient temperature is -20-0°C, and the frequency of the auxiliary circuit compressor is adjusted to ensure the efficient operation of the system; in the low-frequency operation mode, the ambient temperature is 0 ‑15°C, when the ambient temperature is high and the heating capacity is high, the frequency is reduced to save energy; in the overclocking mode, the ambient temperature is lower than ‑20°C, ensuring the heating capacity and operation stability of the system at extremely low ambient temperatures ; In the three modes, the return water temperature is 35-50°C, and the outlet water temperature is 50-70°C. During the start-up process, when the auxiliary circuit pressure is less than 5MPa, the low-frequency start-up mode of the auxiliary circuit compressor is carried out to ensure the stability of the auxiliary circuit start-up operation process.

Description

technical field [0001] The invention belongs to the technical field of heat pumps and relates to a transcritical CO 2 Parallel compression system and its capacity ratio method. Background technique [0002] A heat pump is a technology that transfers heat energy from a low level to a high level through a thermal cycle by consuming energy to do work such as mechanical energy, electrical energy, and thermal energy. Most of the traditional heat pumps used in heating systems use traditional working fluids such as R134a and R410a, which are poor in environmental protection and are facing phase-out. Instead, a heat pump system for heating using natural working fluid, CO 2 With its high thermal conductivity and constant pressure specific heat, smaller gas density, viscosity and surface tension, it is more suitable as a refrigerant. CO 2 As a refrigerant, it has good environmental protection performance. It is an inert gas and has no toxicity; its chemical structure is stable, it...

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide a transcritical CO 2 Parallel compression system and its capacity ratio method to ensure the existing transcritical CO 2 The performance of the parallel compression system can reach the optimal state at each ambient temperature, solving the frequency ratio problem of the main circuit and auxiliary circuit compressors under different ambient temperatures

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