Development of a steady-state physical-based mathematical model for a direct expansion based enhanced dehumidification air conditioning system

Abstract

It is challenging and difficult for a conventional On-Off controlled single evaporator direct expansion (DX) air conditioning (A/C) system to deal with the variable latent load, unless complicated and costly supplementary measures to supply variable dehumidification ability are provided. Therefore, based on multi-evaporator air conditioning technology, a standalone DX based enhanced dehumidification air conditioning (EDAC) system with two evaporators was proposed to provide variable dehumidification ability. This paper reports on the development of a steady-state physical-based mathematical model for such an EDAC system. Firstly, a detailed description on the configuration of the EDAC system is presented, followed by reporting the development and experimental validation of the steady-state model for EDAC system. Thirdly, using the validated EDAC model, a follow-up detailed modeling study was carried out to both demonstrate that the EDAC system was able to provide variable dehumidification ability and optimize the sizing of the two evaporators used in the EDAC system. The modeling study results indicated that the EDAC system could produce variable dehumidification capacity. The modeling study results also suggested that a lower ratio of surface areas for the two evaporators in an EDAC system was beneficial to enlarging its variation ranges of both total cooling capacity (TCC) and equipment sensible heat ratio (E SHR).