Performance Evaluation of a New Liquid-to-Air Membrane Energy Exchanger Utilized in Liquid Desiccant Air Conditioning System
The electric energy demand for HVAC systems in the buildings sector accounts for nearly half of the electricity demand of this sector worldwide. Accordingly, liquid desiccant air conditioning systems have been studied extensively during the last two decades due to their positive effect in saving energy. In this study, a new internally cooled/heated liquid-to-air membrane energy exchanger (LAMEE) is proposed to be usedin Heat-Pump Liquid Desiccant(HPLD) systems. The new exchanger utilizes the thermal energy of evaporating/condensing refrigerant to control LD temperature inside the solution channels at desired points. The new module is numerically simulated using the aid of CFD software and the mathematical model is extended to simulate the whole HPLD system. Accordingly, the performance of new LAMEE is not analyzed as a standalone module, but it is analyzed in a fully coupled system. The proposed module and system attain better indoor air quality with higher energy efficiency. At design operating conditions of summer in Sharm El Sheikh City in Egypt, outstanding dehumidification capability is achieved with system coefficient of performance (COPsystem) as high as 6.38 and HP energy efficiency ratio (EER) as high as 14.88. Where fresh air at (30°C, 19 g/kg) is cooled and dehumidified to (20.18°C, 6.52 g/kg). Moreover, much higher dehumidification capacities are reachable by varying the key operating parameters at the expense of COP system.
Keywords - Cooling and Dehumidification, Heat Pump, Liquid Desiccant, New LAMEE, System Scale Analysis.