Appraisal of a building solar cooling plant. Building thermal behavior and absorption system performance assessment.

The current work dealt in its first part with the assessment of the thermal behavior of an office building located in the Center of Researches and Energy Technologies (CRTEn, Borj-Cedria, Tunisia). The second part focused on the evaluation of the performance of the solar absorption plant used for cooling. The simulations assessed the building in its existing structure and in its passive structure incorporating passive cooling techniques. The results showed relevant reduction of 44.8 % in cooling requirements; the maximum daily load decreased from 13.91 kW to 8.68 kW. As for the solar cooling system, it consists of linear parabolic trough solar collectors coupled to a 16 kW double effect Lithium Bromide absorption chiller. The performance of the solar system was evaluated and an improved system configuration was then studied; the integration of an auxiliary heater prior to the chiller as well as the increase of the aperture area guaranteed high driving temperatures and more suitable conditions to the absorption chiller. The modelling results of the improved configuration of the solar cooling system showed that the chiller operating time increased by 22% , the cooling power increased by 75.6 %, the solar COP reached 0.57 and the solar fraction averaged 87% .