Performance optimization of heat pump driven liquid desiccant dehumidification systems

Heat pump driven liquid desiccant dehumidification (HPLD) devices, in which both the cooling capacity from an evaporator and heat from a condenser are utilized, have been developing rapidly in recent years. Because the amount of heat from the condenser is usually more than required for desiccant regeneration, the key to improve the performance of these systems involves effectively exhausting the extra heat. In this paper, two different methods for removing the extra heat are analyzed: adding an air-cooled assistant condenser in either the inlet or outlet of the regeneration air duct, and utilizing a water-cooled assistant condenser that uses cooled water from evaporation of the exhaust air. These handling processes were compared in terms of their HPLD performance under various operating conditions. Devices using an air-cooled or water-cooled assistant condenser showed better performance than a basic system without an assistant condenser. For systems with an air-cooled assistant condenser, the location of the condenser rarely affected the performance: COPsys was an average of about 18% higher than that of the basic system. The system with the water-cooled condenser performed the best out of all the investigated systems: COPsys was about 35% higher than that of the basic system.

► Introduces various heat pump driven liquid desiccant dehumidification (HPLD) systems. ► Effectively exhaust extra heat of condenser is key issue for performance improvement. ► Setting an assistant condenser shows a better energy performance than Basic Type. ► COPsys of HPLD with air-cooled assistant condenser is 18% higher than Basis system. ► COPsys of HPLD with water-cooled assistant condenser is 35% higher than Basis system.