Vapour-compression and liquid-desiccant hybrid solar space-conditioning system for energy conservation

This paper presents some energy conservation and techno-economic assessment studies of a hybrid solar space-conditioning system consisting of conventional vapour-compression (V-C) and liquid-desiccant cycles. The liquid-desiccant cycle is used to bring the humidity within the comfort range by partially converting the latent heat load (LHL) into a sensible heat load and then meeting this load with a conventional V-C cycle. In a hybrid V-C system, the heat rejected from the condenser is used to partially regenerate the desiccant to improve the coefficient of performance (COP) of the system. Thermodynamic modelling of the hybrid V-C system with R-11 as the refrigerant and water-LiBr as the liquid desiccant has been carried out and the effect of operating parameters on the system COP and cooling capacity has been investigated. It is found that the hybrid V-C system is more promising under high latent heat load or higher ambient humidity conditions, and significant energy saving can be achieved over standard V-C cooling systems.