Characterization of semi-open liquid desiccant cycle energy efficiency in ventilation air treatment

Abstract

Efficient moisture removal from air without subcooling using liquid desiccants represents a major advancement in energy-efficient cooling, particularly through the separate sensible and latent cooling (SSLC) process. However, developing a high-performance, robust liquid desiccant dehumidification cycle remains challenging. Traditional open desiccant cycles rely on outdoor air to remove moisture from the desiccant solution in the regenerator, but this also extracts significant sensible heat, reducing overall efficiency. This study investigates a semi-open absorption cycle that eliminates the need for scavenging air, addressing a key inefficiency of conventional systems. An experimental system was tested under varying outdoor air conditions, demonstrating substantial performance improvements. The semi-open cycle significantly reduced sensible heat loss compared to traditional systems while maintaining strong moisture removal capabilities. Notably, it achieved a dehumidification coefficient of performance (COP) of up to 0.9, with peak latent cooling capacity observed at higher inlet air dew points. These findings underscore the semi-open cycle's potential for enhancing energy efficiency in dehumidification, particularly in regions with high latent loads.