Controlling Temperature and Relative Humidity of Ventilation Air by using a Cooling Coil and Rotary Heat Exchangers

Furugaan Ibrahim, Surapong Chirarattananon, Pattana Rakkwamsuk, Pipat Chaiwiwatworakul, Surawut Chuangchote, Vu Duc Hien


Dedicated outdoor air systems (DOAS) are used to supply treated outdoor air to a cooled space. This paper focuses on a DOAS and its application in tropical climate. This DOAS is equipped with a desiccant coated Enthalpy Wheel (EW), a dehumidifying cooling coil (CC), and a sensible heat wheel (SW). A mathematical model was developed using the governing equations and validated with a TRNSYS simulation and experimental data with a coefficient of determination of 0.88 and 0.92, respectively. Simulations using the validated model showed that the DOAS configuration was applicable for the tested tropical climatic conditions. Further investigations showed that a maximum change in temperature with respect to rotational speed of SW achieved was 2.44°C, and maximum change in humidity ratio with respect to rotational speed of EW achieved was 0.38%. Also, CC showed a maximum change in temperature of 14.69°C and humidity ratio of 8.35% with respect to chilled water flow rate. Likewise, Air flow rate also showed change in temperature and humidity ratio of the supplied air.


Dedicated outdoor air system; Enthalpy wheel; Experiment; Sensible wheel; Simulation

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