Investigation of Thermal Comfort in a Space Conditioned by Liquid Desiccant Membrane Chilled Ceiling/ Displacement Ventilation System

Chilled ceilings combined with displacement ventilation (DV) have gained popularity due to their efficiency in terms of providing thermal comfort and high air quality, with minimal noise and good energy savings. Chilled ceilings can be replaced by liquid desiccant membrane systems integrated with DV system (LDMC-C/DV) to operate at lower ceiling temperatures and to directly dehumidify the indoor environment for improved performance. Thermal comfort is a major concern in any air conditioning system as it is directly related to the health of the occupants. Therefore, the effect of low ceiling temperatures in LDMC-C/DV environments on comfort needs to be investigated. For this purpose, a validated mathematical model of the dehumidifier panel will be integrated with a steady-state DV space model. The integrated model is used to represent the mass and energy balances inside the space and at the two sides of the dehumidifier panel. A parametric study will be carried out under different air supply conditions to predict the air conditions (temperature and relative humidity) in a space conditioned by the LDMC-C/DV system. Accordingly, the thermal comfort of the occupants inside the space is assessed based on the PMV value for different DV supply conditions and inlet desiccant solution temperatures. It was found that at low ceiling temperatures the relative humidty in the space rises but thermal comfort can still be realized under specified DV supply conditions.