直膨式空调机组设计选型探讨
Discussion on design and selection of direct-expansion air conditioning unit
摘要：
根据设计实践分析了直膨式空调机组的特点及其适用性。不同于常规的水冷式空调机组，直膨式空调机组的制冷量与送风量需满足一定的匹配关系，机组合理的风冷比范围为170～200 m3/(kW·h）。当实际机组的送风量与设计风量有偏差时应对空调房间的状态参数进行校核。通过设计案例的数据对比，分析了室内空气设计参数、室外气象参数以及空调房间负荷特性对设计机组风冷比的影响，表明室内相对湿度对机组风冷比的影响比温度更为明显，而新风冷负荷是影响直膨式空调机组运行效果的关键因素。
Abstract：
Based on the design practice, analyses the characteristic and applicability of a direct-expansion air conditioning unit. Points out that it is different from the common water-cooled air conditioning unit. The supply air rate of the direct-expansion air conditioning unit must match its cooling capacity. The suitable range of air rate-cooling capacity ratio is 170 to 200 m3/(kW·h）. The air parameter in an air conditioned room should be checked if there is a great deviation between the actual air rate and design parameter. Based on the data comparison of a design case, analyses the effect of several factors on the design of air rate-cooling capacity ratio, such as indoor air design conditions, outdoor air design conditions and load characteristics of air conditioned room. It shows that the relative humidity of indoor air has a greater impact on the air rate-cooling capacity ratio than that of the indoor air temperature. And the cooling load of outdoor air is a key factor impacting on the operation effect of direct-expansion air conditioning units.
Keywords:direct-expansion air conditioning unit, air rate-cooling capacity ratio, design checking, influence factor, cooling load of outdoor air