In order to optimize the energy utilization of an air conditioning system, a tri-generation system has been introduced. Energy in the form of heat is inserted to the prime mover of the system, and the total cooling demand of the building would be produced by utilizing a compression and an absorption water-cooled chiller. The prime mover can either be a micro-gas turbine (MGT), a gas turbine (CT), or a solid oxide fuel cell (SOFC). All the system components, such as the absorption chiller and the cooling tower have been modeled and analyzed through the energy and exergy approaches. Performance parameters of the system, such as energy utilization factor and second law efficiency, have been calculated in different operating conditions. The results would reveal the best operating conditions of the system and the most critical components would be highlighted. (C) 2013 Elsevier B.V. All rights reserved.