Climatic Effect on the Exergetic Performance of Conventional to Hybrid Evaporative Coolers With Varying Dead-State Temperatures in India

Abstract A comprehensive exergy, exergo-economic, and sustainability assessment of seven conventional to hybrid air-conditioning systems comprising direct and indirect evaporative coolers with direct expansion system and their several combinations integrated into an eight-story domestic building for five different cities corresponding to arid, semi-arid, humid subtropical, tropical wet and dry, and tropical wet climatic zones across India are investigated based on simulation output from energyplus. The exergetic performances are reported for varying dead state temperatures ranging from 5 °C to 40 °C, while the saturated humidity ratio and pressure at system outlet are two other dead state properties. The results reveal that the specific exergy of moist air and exergetic efficiency decreases with increasing dead state temperature and becomes least at a dead state temperature near American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) comfort temperature of 23 °C. In arid, semi-arid, and humid subtropical climates, the three-stage evaporative cooling system exhibits the lowest exergy destruction of 100 J/kg1 and the highest exergy efficiency of 90% at a dead state temperature of 40 °C. The two-stage direct evaporative-direct expansion cooling system exhibits superior exergy efficiency in tropical wet and dry and tropical wet zones. Furthermore, the Grassmann diagram based on the climate of Hyderabad indicates that the three-stage cooling system is energetically and exergetically optimum with exergy destruction of 28.86%.