Abstract—Desiccant systems are widely regarded as energy-saving alternatives to vapour-compression air-conditioning for handling the latent load. In the present work an energy efficient liquid desiccant hybrid air conditioning system is proposed with a novel liquid desiccant calcium chloride regeneration system. This regeneration is obtained by spraying fine liquid desiccant, calcium chloride, droplets into hot moist air. The effect of spray regeneration conditions, ambient conditions and space cooling load sensible heat factor on the performance of the proposed system was investigated. A comparison between the proposed liquid desiccant air conditioning system and the traditional one was studied. It was found that the values of the injected droplet diameter size, spray angle, hot air temperature, and spray injection speed, had an important role in the evaporation process. At RSHF= 0.6, the proposed system achieves 72% energy savings compared to a traditional air conditioning system. Index Terms—Hybrid air conditioning system, liquid desiccant, calcium chloride, spray. I. INTRODUCTION Desiccants are substances known for their ability to absorb water vapour. Therefore, they can be used effectively not only to overcome the latent cooling load of air conditioning systems and improve the indoor quality but also to dehumidify air for any industrial applications. Recently, a number of hybrid air conditioning systems, in which desiccants (solid and liquid) were used to remove latent cooling load and conventional air conditioners were used to provide sensible cooling, have been suggested as alternative options to conventional vapour compression cooling systems. The aim of these systems was to conserve energy. These systems had different construction and methods of desiccant regeneration. Regeneration energy is equal to the heat necessary to raise the temperature of the desiccant to make its surface vapour pressure higher than the surrounding air, plus the heat necessary to vaporise the moisture that it contains. The regeneration of liquid desiccant can be driven by different methods; for example, solar energy [1]-[6], a heat pump [7], [8] electrical heaters [9], waste heat or other low-grade heat source [10], packed bed column [11]–[14], and multiple stage boiler (gas-fired) [15]. Researchers studied also the effect of different working parameters on liquid desiccant Manuscript received March 10, 2014; revised May 15, 2014. Y. A. F. El-Samadony is with Mechanical Power Engineering Department, Faculty of Engineering, and Tanta University, Egypt (e-mail: samadony25@yahoo.co.uk). B. M. Gibbs is with Energy and Resources Research Institute, Houldsworth Building, The University of Leeds, Leeds LS2 9JT, UK (e-mail: b.m.gibbs@leeds.ac.uk). regeneration process such as; liquid desiccant inlet temperature and concentration [3], [11], [14], [16], desiccant airflow rate [6], inlet air temperature and moisture content [3], [7], [8], and desiccant types [17]. Studak and Peterson [17] found that the best liquid for the anticipated application was found to be calcium chloride. Spray drying or spray evaporation is widely used for the drying of heat-sensitive foods, pharmaceuticals, fuel, and other substances mainly due to rapid solvent evaporation [18] – [24]. Calcium Chloride solution as a liquid desiccant was listed among liquids that can be sprayed [25]. El-Samadony et al., [26] simulated the spray evaporation of calcium chloride aqueous salt solution, into hot moist air using a three dimensional computational fluid dynamic software (CFX-10). Moreover, they validated the numerical results experimentally. They found a good agreement between the numerical and experimental results. Also, they found that the values of the injected droplet diameter size, spray angle, hot air temperature, and spray injection speed, had an important role in the evaporation process. As the injected droplet size decreases, the liquid desiccant outlet concentration increases. Therefore, the spray evaporation of a liquid desiccant can be used as a viable regenerator system In the present work a theoretical study of an energy efficient liquid desiccant hybrid air conditioning system is proposed with a novel liquid desiccant calcium chloride regeneration system. This regeneration is obtained by spraying fine liquid desiccant, calcium chloride, droplets into hot moist air. To conserve energy, the outlet hot air of a conventional vapour compression condensing unit is used. II. NUMERICAL WORK In the present work, the validated numerical program of EL-Samadony et al., [26] complete with its subroutine are used. A. Geometry and Physical Definition The geometry consists of a cylinder 86 cm in diameter and 200 cm in height, Fig. 1. The cylinder is fitted with a truncated cone, 50 cm in height, at its bottom. The truncated cone exit of 10 cm diameter, then attaches to the Calcium Chloride solution collection tank. Four 10 cm diameter tubes are connected to the cylinder wall, pointing upwards at a 45-degree angle in order to supply hot air. The geometry was assumed as one domain with four inlets (hot moist air) and two outlets. The first outlet is at the top of the cylinder for exhaust moist air and the second one is at the bottom of the truncated cone for the concentrated solution. The volume mesh spacing was defined as 4 cm for all the geometry. A new material Solid Calcium Chloride, liquid Calcium Energy Efficient Liquid Desiccant Hybrid Air Conditioning System Y.A. F. El-Samadony and B. M. Gibbs 211 International Journal of Modeling and Optimization, Vol. 4, No. 3, June 2014 DOI: 10.7763/IJMO.2014.V4.375