Influence of Isotherm Shape over Desiccant Cooling Cycle Performance

• Published in: Heat transfer engineering Vol. 30; no. 4; pp. 302 - 308
• Main Authors: Nóbrega, Carlos E. L., Brum, Nísio C. L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Philadelphia, PA Taylor & Francis Group 01.03.2009; Taylor & Francis; Taylor & Francis Ltd
• Subjects: Adsorption; Applied sciences; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat transfer; Mathematical models; Miscellaneous; Moisture content; Numerical analysis; Partial differential equations; Sorbents; Temperature effects; Wheel; Cooling; Silica gel; Mathematical model; Performance; Dehumidifier; Desiccant
• DOI: 10.1080/01457630802381871
• ISSN: 0145-7632

The interest in desiccant cooling cycles has been continuously growing in the last years, driven by its simplicity and flexibility of arrangements, as well as the claim for environmentally sound acclimatization techniques. Accordingly, the present work aims at developing and solving a numerical model that is able to represent the conjugated heat and mass transfer within a desiccant material. A mathematical model is constructed based on a number of simplifying assumptions, so as to achieve a relative mathematical simplicity while retaining physical reasoning. Heat and mass balances are applied to elementary control volumes, resulting in a system of four partial differential equations that account for the temperature and humidity content within the air flow channel and the sorbent layer, respectively, as well as an algebraic equation, which stands for the adsorption isotherm. Three different desiccant materials are represented by a generalized adsorption isotherm, which is characterized by a single parameter. The model is solved using a fully implicit finite-volume discretization technique. The results showed that a balance between the properties of commercially available adsorptive materials is desirable if the coefficient of performance is to be maximized.