Analysis of thermal effects in packed bed liquid desiccant dehumidifiers
Abstract An analysis of the performance of a packed bed liquid desiccant dehumidifier is presented. The enthalpy and material balance equations written over a differential height of the bed incorporate the effect of the heat of dilution of the desiccant liquid, the liquid—air interface temperature and the fraction of the evolved heat that is accounted for in the air stream. Numerical results obtained are discussed in terms of the physical and operating parameters of the system.
Performance studies for an experimental solar open-cycle liquid desiccant air dehumidification system
Abstract A nominal 10.5-kW (3-ton) open-cycle liquid desiccant dehumidification system has been designed, installed, and successfully operated at the Solar Energy Applications Laboratory, Colorado State University. Packed bed units were used to dry the air in the dehumidifier and to concentrate the desiccant in the regenerator. Liquid distribution in the regenerator was studied for two systems: a gravity tray distributor, and a spray nozzle system. Higher capacities (40–50% increase) and lower pressure drop (30–40% reduction) for the air flow were observed with the spray system. Cooling capacities of 3.5–14.0 kW (1.0–4.0 refrigeration tons) were achieved for both the regenerator and dehumidifier. Functional relationships correlating the independent variables to the rate of vaporization in the regenerator and rate of condensation in the dehumidifier were obtained by statistical analysis of the experimental data. These studies thus provide data and correlations useful for design guidance and performance analysis of similar open-cycle liquid desiccant cooling systems, particularly for the liquid/vapor contact units.
Active Hybrid Solar Cooling Systems
Systems that combine a desiccant dehumidification cycle with a second cycle that produces sensible cooling are discussed. The thermodynamic and possible economic advantages over simple cycles are outlined, and the literature that describes the behavior of such cycles is reviewed.