Energy and exergy comparison of a cascade air conditioning system using different cooling strategies

•A novel cascade air conditioning system using different cooling strategies is proposed.•Each system component is modeled through the energy and exergy approaches.•The performance parameters and the second law efficiency are calculated in different operating conditions.•Water is considered as a source of exergy and the systems water consumption is calculated.

A cascade air conditioning system consisting of a compression and an absorption chiller working in a parallel arrangement has been proposed. This system is powered up by a micro-gas turbine. Different cooling strategies are studied in order to recognize the best configuration. The system components have been modeled and analyzed through the energy and exergy approaches. The performance parameters of the systems and the second law efficiency have been calculated in different operating conditions. Water consumption of the systems has also been investigated, considering water as a source of exergy. The results revealed that a system with water-cooled chillers has the highest second law efficiency and water consumption. On the other hand, the water consumption of a system with an air-cooled absorption and a water-cooled compression chiller is about 50% less than that of the system with two water-cooled chillers while its second law efficiency is only about 10% less.