Exergy analysis and optimization of a building air conditioning system in tropical climate

The space conditioning sector is one of the highest exergy consumers and least efficient from the point of view of primary-to-end-use matching. Exergy analysis can be considered as a reliable tool for analyzing and optimizing energy consumption related to building conditioning systems. The present study presents a comparative exergy analysis of the air conditioning system of the TOTAL S.A. offices located in Caracas, Venezuela to finally achieve a reduction of the global electric energy use of the considered building. Starting from the provided thermal cooling load, different possible cooling chains (primary-to-final energy conversion chain) are considered in order to locate the thermodynamically more efficient one from an exergetic point of view. The internal air handler unit, which provides for the cooled and dehumidified air to the building, is fed by the energy obtained from different possible converters of renewable energy primary sources. Specifically, solar and hybrid photovoltaic-thermal (PV/T) panels coupled with an absorption refrigeration machine and with an ejector refrigeration cycle are analyzed. The study that has been carried on leads to identify the most convenient matching between final use and primary sources allowing to substantially reduce the global non-renewable energy consumption of the considered building. Copyright © 2014 by ASME.