Experimental investigations of a desiccant-coated M-cycle cooler as a step towards net zero air-conditioning

Abstract

Despite having the potential to be adopted as a solution towards net-zero emission-based air-conditioning systems, desiccant-evaporative cooling systems have limited applications due to the need to combine several systems to achieve the target conditions. This paper, therefore, undertakes an experimental analysis of a compact system that integrates solid desiccant dehumidification and M−cycle cooling in a single heat exchanger. The system then undergoes regeneration and cooling stages, where no air-conditioning occurs. It is observed that the system can achieve thermal comfort for almost all inlet conditions. Parametric analysis also shows that varying the inlet humidity ratio impacts the system output more than the inlet DBT. The overall cooling capacity of the system increases with greater channel velocity and peaks at around 30 % branching ratio. The concept of operational time (dehumidification stage) and downtime (regeneration and cooling stages) has also been investigated. The analysis shows that the operational time is more than the downtime for all cases except when channel velocity increases above 2.4 m/s. It is also observed that the operational time becomes double the downtime when the regeneration temperature exceeds 83 ℃. Therefore, the analyses practically demonstrate the combined reduction of sensible and latent loads through a simultaneous adsorption-evaporation phenomenon as a step towards a net zero emission-based air-conditioning system.