On-site evaluation of indoor thermal comfort and energy performance of a liquid-desiccant assisted air-conditioning system in a high-latent-load building

Abstract

Indoor humidity control is increasingly important because indoor sensible heat ratio decreases to reduce building energy consumption. However, reference vapor compression cooling systems exhibit energy inefficiency and limitations in maintaining indoor thermal comfort. Therefore, this study proposes an alternative heat-pump-driven liquid-desiccant air-conditioning system, independently controlling air temperature and humidity. The reference and proposed systems are applied to a high-latent-load building to investigate their onsite indoor thermal comfort and energy performance empirically and simultaneously under various outdoor summer conditions. The reference system exhibits a thermal comfort satisfaction ratio of 97% only under limited hot and dry weather. Conversely, the thermal comfort satisfaction ratio sharply drops to 2% or less under humid weather. The proposed system consistently achieves a high thermal comfort satisfaction ratio exceeding 90% under various outdoor summer conditions. In empirical comparisons, the proposed system can maintain a thermally comfortable room for an hour while achieving energy savings exceeding 92.4% and 12.1% under warm and humid (rainy season) and hot and humid outdoor conditions, respectively. The proposed system is concluded to consistently maintain indoor thermal comfort while using energy efficiently, demonstrating its widespread applicability for general high-latent-load buildings characterized by low indoor sensible heat ratio values of 0.56 on average.