By throttles, the high pressure is dropped down to evaporator pressure, and changed with the refrigerant temperature at the gas cooler, the regulation characteristics of the system are different from traditional system. 节流阀把高压侧压力节流到蒸发压力,同时控制高压侧压力并使其随气体冷却器出口温度的变化而变化,CO2制冷系统调节特性与传统制冷系统不同。