For controlling indoor thermal environment, only indoor air temperature is usually considered when using conventional direct expansion (DX) based air conditioning (A/C) systems. Therefore, based on the previous experiences in developing novel A/C units to provide an enhanced moisture removal capacity, a novel constant speed DX A/C system with a two-sectioned cooling coil (TS-DXAC) has been proposed. In the proposed TS-DXAC system, to reduce its size, the two sections were arranged in parallel with their respective matching variable speed supply fans, and the mass flow rates for both refrigerant and air to each section could be adjusted. The total air flow rate of the system remained however constant, so as not to affect indoor air flow distribution and occupants’ thermal comfort. The inherent operational characteristics of a prototype experimental TS-DXAC system have been experimentally studied. The study results showed that the variations in the mass flow rates of refrigerant and air to the two sections would result in different combinations of the output total cooling capacity (TCC) and equipment sensible heat ratio (E SHR) from the prototype, and that the TCC – E SHR relationship was constrained within an irregular area. Furthermore, different inlet air temperatures and humidity levels would also influence its inherent operational characteristics as reflected by the changes in the positions and shapes of the irregular areas, with the latter influencing more on the operational characteristics.

为了控制室内热环境，在使用基于常规直接膨胀（DX）的空调（A / C）系统时，通常仅考虑室内空气温度。因此，基于开发新型A / C单元以提供增强的除湿能力的先前经验，已经提出了具有两段式冷却盘管（TS-DXAC）的新型恒速DX A / C系统。在建议的TS-DXAC系统中，为减小其尺寸，两个部分与它们各自匹配的变速供气风扇平行布置，并且可以调节制冷剂和空气到每个部分的质量流量。但是，系统的总空气流量保持恒定，以免影响室内空气流量分配和居住者的热舒适度。实验性研究了原型实验TS-DXAC系统的固有操作特性。研究结果表明，制冷剂和空气到这两个部分的质量流率的变化将导致原型的输出总制冷量（TCC）和设备显热比（E SHR）的不同组合，并且TCC – E SHR关系被限制在不规则区域内。此外，不同的进气温度和湿度水平也会影响其固有的运行特性，这由不规则区域的位置和形状的变化所反映，后者对运行特性的影响更大。研究结果表明，制冷剂和空气到这两个部分的质量流率的变化将导致原型的输出总制冷量（TCC）和设备显热比（E SHR）的不同组合，并且TCC – E SHR关系被限制在不规则区域内。此外，不同的进气温度和湿度水平也将影响其固有的运行特性，这由不规则区域的位置和形状的变化所反映，而后者对运行特性的影响更大。研究结果表明，制冷剂和空气到这两个部分的质量流率的变化将导致原型的输出总制冷量（TCC）和设备显热比（E SHR）的不同组合，并且TCC – E SHR关系被限制在不规则区域内。此外，不同的进气温度和湿度水平也将影响其固有的运行特性，这由不规则区域的位置和形状的变化所反映，而后者对运行特性的影响更大。并且TCC – E SHR关系被限制在不规则区域内。此外，不同的进气温度和湿度水平也将影响其固有的运行特性，这由不规则区域的位置和形状的变化所反映，而后者对运行特性的影响更大。并且TCC – E SHR关系被限制在不规则区域内。此外，不同的进气温度和湿度水平也将影响其固有的运行特性，这由不规则区域的位置和形状的变化所反映，而后者对运行特性的影响更大。