高低温试验箱制冷系统的基本组成 通常制冷系统以压缩机和膨胀阀为界，根据压力的不同，可以分为高压侧和低压侧两部分。结构简图一、高压侧（HIGH SIDE）大致相当于20个大气压的高温高压气体（300 psi of Hot High Pressure Gas）换算：1个标准大气压=14.7Psi=1.013bar=0.1013MPa 标准大气压（Standard atmospheric pressure）1、压缩机COMPRESSOR将低压气体压缩为高压气体。压缩机2、冷凝器（CONDENSER）冷凝器是一个用于将制冷刘所含热量释放、并将制冷剂由气态转变成液态的热交换器。将高温高压的气态制冷剂变成高压液态制剂。一种结构的冷凝器实物解剖图片式冷凝器结构示意图实物图3、贮液干燥器（RECEIVER DRIER）储存、缓冲、干燥和过滤。贮液干燥器结构图4、膨胀阀（EXPANSION VALVE）节流降压、控制过热度、调节流量、防止压缩机液击。一种热力膨胀阀解剖图P1+P4 = P2+P3P1 = Bulb Pressure (Opening Force)P2 = Evaporator Pressure (Closing Force)P3 = Superheat Spring Pressure (Closing Force)P4 = Liquid Pressure (Opening Force)一种电子膨胀阀解剖图一种电子膨胀阀外观The compressor and the electronic expansion valve (EEV) are integrated in a control loop. When the cold air requirement changes, the EEV takes on the task of precision adjustment by varying the degree of opening within a few seconds. If this precision control is no longer sufficient, the cooling capacity is adapted by way of the compressor speed. Due to the short control response times, the system always works in the optimum operating range, making it even more efficient.二、低压侧（LOW SIDE）17-30PSI of Low Pressure Gas1个标准大气压=14.7Psi=1.013bar=0.1013MPa5、蒸发器（EVAPORATOR）吸收空气中的热量（降温），干燥空气（降湿）。蒸发器