论文部分内容阅读
热力膨胀阀只能在一个较窄的工况和负荷范围下实现调节过热度的功能。现有一批在北美销售的屋顶机,设计运行工况范围较宽,在室外温度为-17.7℃～51.7℃下,机组都要求能运行。仿真结果表明,对这种运行工况的屋顶机组,用传统方法选出的热力膨胀阀未能在较多工况点充分发挥其控制过热度的作用。在考虑热力膨胀阀的振荡现象的基础上,对选型方法进行改进,并通过实验验证,证明在基于最小负荷比大于30%方法选出的热力膨胀阀能够在较多工况点控制空调机组的过热度,且避免了振荡现象的发生。
Thermal expansion valve only in a narrow operating conditions and load range to achieve the function of regulating the degree of superheat. The existing batch of rooftop machines sold in North America have a wide range of design operating conditions. The units are required to operate at an outdoor temperature of -17.7 ° C to 51.7 ° C. The simulation results show that for the rooftop unit operating in this operating condition, the thermal expansion valve selected by the traditional method fails to fully exert its function of controlling superheat at more operating points. On the basis of considering the oscillation phenomenon of the thermal expansion valve, the selection method is improved and verified by experiments. It is proved that the thermal expansion valve selected based on the minimum load ratio greater than 30% can control the air conditioning unit at more working conditions Overheating, and to avoid the oscillation phenomenon.