In small to medium‐scale buildings such as residences, direct expansion (DX) based air conditioning (A/C) systems are widely used for the control of indoor thermal environment. However, to simultaneously control indoor air temperature and humidity, additional equipment or costly measures are necessary. Therefore, in this paper, taking the advantages of multi‐evaporator technology, a novel DX based A/C system having a two‐sectioned evaporator or cooling coil (TS‐DXAC) was proposed, and its inherent operational characteristics were numerically studied through simulation. The evaporator in the TS‐DXAC system had two parallel‐ connected sections, a latent cooling coil section (LCC) and a sensible cooling coil section (SCC), operating at two different evaporating temperatures, with a constant total supply air flow rate passing through the entire two‐sectioned evaporator. The simulation results suggested that the TS‐DXAC system can achieve a wider combination of total cooling load (TCC) and equipment sensible heat ratio (E SHR), and a higher area ratio of LCC to SCC is beneficial to a larger variation range of TCC and E SHR.
Keywords direct expansion, two‐sectioned evaporator, simulation, variable dehumidification capacity