Performance evaluation of a mobile air conditioning unit: an exergetic approach

Abstract

This study considers a public bus (having a capacity of 99 passengers and a volume of 69 m(3)) along with its vapour compressed mobile air conditioning (MAC) unit (utilising R134a as a refrigerant) together as a low exergy (so-called LowEx) system. The LowEx analysis which has been mostly applied to buildings and conventional exergy analyses method are utilised together (coupled up analysis method) to assess the performance of this system for the first time to the best of the authors' knowledge. Based on the LowEx analysis total exergy efficiency and exergy flexibility factor are calculated to be 11.92% and 0.56 for the heating mode and 3.41% and 0.19 for the cooling mode respectively. Furthermore through on the conventional exergy analyses the highest exergy efficiency belongs to condenser with 93.08% in the cooling mode while it is 93.20% for the water heat exchanger in the heating mode respectively.