Thermodynamic modeling and exergy analysis of a solar adsorption cooling system with cooling tower in Mediterranean conditions

Thermally driven chillers offer a reliable and environmentally friendly alternative to conventional electrically powered chillers. Solar energy can be utilized in order to provide the necessary heat to these heat driven cooling cycles. This work examines the application of an adsorption chiller cooling system powered by solar energy under climatic conditions of eastern Mediterranean area. Athens and Nicosia the capitals of Greece and Cyprus respectively and Alexandria of Egypt are the three examined cities. A single stage, two bed adsorption chiller is selected for investigation. A lumped parameter model is used to simulate the performance of the cooling system. The maximum cooling capacity of the system is about 14.7 kW and is observed for Nicosia climatic conditions in July. Subsequently, the performance of the system is examined for various types of solar collectors under Athens climatic data. The utilization of hybrid photovoltaic-thermal (PV/T) collectors is studied and the production of electric power is calculated. The overall energy and exergy efficiencies are also calculated for the combined systems. Following the analysis of the adsorption chiller performance (cooling capacity, COP), the selective solar thermal collector is the optimum collector for the cooling system with maximum cooling capacity and COP around 16 kW and 0.51 respectively. The overall energy efficiency of the system is also maximized when the selective solar collector is utilized (21.7%). However the overall exergy efficiency is maximized when the un-glazed PV/T solar collector is used (11.35%). Finally, the effect of the cooling tower's cooling water outlet temperature on the adsorption chillers performance is investigated. (C) 2016 Elsevier Ltd. All rights reserved.