Experimental study on the performance of a novel superabsorbent polymer and activated carbon composite coated heat exchangers

Abstract

Desiccant coated heat exchangers have attracted great attention for their ability to handle both sensible and latent heat loads. However, widely used salt-embedded composite silica gels risk salt solution leakage. To alleviate this problem, a novel superabsorbent polymer (sodium polyacrylate) and activated carbon composite coated heat exchanger (C-DCHE) was developed and tested. Effects of air-side and water-side parameters on the performance of C-DCHE in terms of average dehumidification capacity (Davg) and thermal coefficient of performance (COPth) were investigated and compared to an activated carbon coated heat exchanger (A-DCHE). With the outdoor air of 38 °C&60% RH, Davg and COPth of C-DCHE can be up to 6.1 g kg−1 and 3.6, an improvement of 43% and 26% over A-DCHE, respectively. Besides, the performance of C-DCHE was compared with conventional and salt-embedded silica gels coated heat exchangers in recent publications. C-DCHE showed superior air supply comfort owing to a lower average outlet air humidity ratio and larger COPth under most conditions. Especially, at low regeneration temperatures of 40∼50 °C, its COPth can be 50%–220% higher. This paper provides a promising direction for salt-free composites in DCHE-based systems.