Energy optimised control of the dehumidification process in HVAC systems

An energy optimised process of cooling and dehumidifying air with standard components which applies to heating, ventilation, and air conditioning (HVAC) is studied. The gaols of this study aim to decrease the unnecessary energy consumption during the cooling and reheating process and to reduce the mass stream of air that needs to be cooled. The findings prove that using the combination of a cooler with a controllable air bypass is the key to reach these goals. Modelling and control of either, the cooler and the bypass, are discussed including simulation and experimental results. Drawback is the more difficult control of the demanded supply air condition, in principal the quantities of air temperature and air humidity are coupled. Two approaches for decoupling by transformation of coordinates are introduced and a simple output feedback controller is proposed.