Experimental investigation on heat and mass transfer in heating tower solution regeneration using packing tower

Abstract

Heating towers which can take advantage of energy from air for heating supply is drawing more and more attention. However, the solution dilution problem exists in both open-type and closed-type heating towers, resulting an increasing risk of system freeze. This paper presents an alternative way for heating tower solution regeneration based on packed beds. A cross-flow regenerator equipped with PVC structured packing was established and glycol aqueous solution was selected as the circulating fluid. The effects of the inlet parameters on moisture removal rate, humidity effectiveness and thermal efficiency are experimentally investigated. Correlation expressions of heat and mass transfer coefficients are also proposed, which can be primary parameters for simulation and optimization. Besides, performance comparation between heating tower solution regeneration and liquid desiccant regeneration available in the literature is figured out. The results indicate that the impacts of inlet parameters show similar tendency with those in liquid desiccant regeneration. While the regeneration temperature required in heating tower is much lower than that in liquid desiccant regeneration, due to the lower required solution equivalent humidity ratio and regenerated air humidity ratio. That makes it possible to utilize low-grade energy.