A Review of Exergectic Studies on Solar Collectors and Solar Cooling Technologies for Building Applications

The development of airconditioning systems that run on renewable energy sources will save electrical energy, which is mainly produced by the burning of fossil fuels. These systems will significantly reduce carbon emissions, and as a result environmental pollution and global warming effects of indoor climate control will be reduced. Among the various renewable energy sources, solar energy has proven to be the best option for airconditioning because the maximum load on an airconditioning system for cooling coincides with the period of greatest solar radiation input from the sun. Utilization of energy resources is related to sustainable development. To achieve sustainable development, increasing the energy efficiencies of processes utilizing sustainable energy resources plays an important role. Exergy, which is based on the second law of thermodynamics, is a useful tool to analyze energy systems, must be considered during their evaluation and modeling. Exergy analysis has been widely used in the modeling, simulation and performance evaluation of energy systems.This paper provides a comprehensive review of different solar refrigeration technologies with a focus on its exergecticstudies.Solar powered refrigeration basicallyconsists of two types, namely solar PV system, and solar thermal powered refrigeration system. The PVs work in combination with a conventional compressioncycle. Thermally powered refrigeration technologies are further classified into subcategories as follows: sorption cooling system (open systems or closed systems) and thermo-mechanical cooling system (ejector system). Solid and liquid desiccant cycles represent the open sorption system. Absorption and adsorption technologies represent the closed sorption system. These technologies can be designed and selected for its use according to the climatic conditions of the region, Coefficient of Performance(COP), its advantages and disadvantages, which have been discussed and considered in this study. The climatic condition of Saudi Arabia is also briefly presented, which will help in selection and proper utilization of these cooling technologies.