Energy, economic, and environmental (3E) feasibility study of desiccant integrated multistage efficient indirect evaporative air conditioning system configurations in the subtropical climate

This paper presents the experimental-based performance evaluation of three different configurations of desiccant integrated direct/indirect evaporative cooling systems. These configurations include (1) Conventional desiccant cooling system with the direct evaporative cooler on process and regeneration sides (Configuration 1); (2) direct evaporative cooler on the process with indirect evaporative cooler (M-Cycle) on regeneration side (Configuration 2); and (3) indirect evaporative cooler (M-Cycle) on process and regeneration sides (Configuration 3). Each configuration is analyzed in terms of process air supply temperature, process air humidity ratio, thermal coefficient of performance (COP th ), and energy efficiency ratio (EER). Based on energy, economic and environmental (3E) analysis subjected to an ambient temperature range of 31–40 °C, 18 g/kg ambient humidity and regeneration temperature of 70 °C; Maximum average value COP th of 0.49, 0.8, 1.7 and EER 3, 4.12, 7 were achieved by configuration 1, 2 and 3, respectively. Present worth cost of configuration 3 for 10 h/day operating time is 13% less as compared to a conventional system with a payback period (PBP) of 6.5 years. As compared to configuration 1, the CO 2 emission is reduced by 32% and 38% for configuration 2 and configuration 3, respectively. Hence, the energetic, environmental, and economic evaluation revealed that configuration 3 is best amongst all three configurations in subtropical climate conditions.