Transient analysis of an efficient solar assisted air-conditioning system forsubtropical climate with various solar thermal collectors

The air conditioning demand of the world is largely fulfilled by vapor compression systems; however, these
systems are also responsible for depleting ozone layer due to the nature of refrigerants. Desiccant cooling systems
integrated with solar thermal energy technologies could be an attractive alternative with some performance
enhancement techniques. In this study, transient seasonal performance investigation is performed for an innovative solar integrated desiccant cooling system that uses regenerative evaporative cooler known as solar assisted
desiccant integrated Maisotsenko cycle cooler for better cooling performance. Furthermore, transient annual
performance analysis of solar system for meeting thermal energy requirement for regenerating the desiccant
wheel in summer season and handling heating load of the building in winter season is also carried out with three
different solar thermal collector technologies for finding out more efficient technology. The key performance
indicators in this study are useful energy gain, solar source efficiency, auxiliary energy sharing, coefficient of
performance, and solar fraction. The results of the key performance parameters are reported as monthly average
values. The proposed integrated system resulted to be very efficient with a maximum COP value of 1.13 in April
when latent cooling loads are low and 0.78 in August when latent cooling loads are higher. The system’s
maximum cooling capacity is 24 kW in April corresponding to a sensible heat factor of 0.720. Furthermore, the
regeneration temperature requirements ranged from 50 ◦C to 78 ◦C, respectively that makes it favorable to use
low grade thermal energy through non concentrating solar thermal collectors. The regeneration thermal energy
requirement for desiccant wheel fluctuates throughout the year, maximizing in August due to higher dehumidification requirements. The study also revealed that the evacuated tube collector technology is most suitable
with average annual efficiency of around 36 %.