Research Article Mathematical Model for Design Parameter Analysis to Improve the Performance of a Desiccant Wheel A mathematical model for estimating the optimum design parameters of a desiccant wheel in order to reduce weight and size has been developed. Heat and mass transfer from both moist air and desiccant material were considered in this model. The design parameters were analyzed under the basic operating condition of simulation. Channel height, pitch, and length of the desiccant wheel were opti- mized, as well as other design parameters such as area ratio, aspect ratio, and por- osity. Keywords: Adsorption, Air conditioning, Desiccant wheel, Pressure drop, Regeneration Received: October 12, 2011; revised: February 21, 2012; accepted: March 09, 2012 DOI: 10.1002/ceat.201100536 1 Introduction Conventional air conditioning is based on a vapor compres- sion system utilizing HFC and HCFC which are harmful to the environment. Dai et al. [1] suggested that a desiccant cooling system is one of the best options to be used for air condition- ing as it deals with the latent load and simultaneously im- proves the indoor air quality by adsorbing moisture and pre- venting the contamination of air. A desiccant dehumidifier running in open cycle and characterized by no noise and low maintenance can be driven by solar energy or waste heat. Zhang et al. [2] developed a 1D coupled heat and mass transfer model considering the heat and mass transfer within the moist air. Based on this model, the effect of regeneration air velocity, process air velocity, and inlet temperature of re- generation air on the performance of a desiccant wheel was studied. Harshe et al. [3] presented a 2D steady-state model pertaining to a rotary desiccant wheel which included the mass and energy balance equations for the air streams and the desic- cant wheel. The model was capable of predicting steady-state behavior of a desiccant wheel for process, purge, and regenera- tion sections. Xuan and Radermacher [4] developed a 1D tran- sient model considering heat and mass transfer for moist air to investigate the performance of the wheel. Their simulation results revealed a significant effect of regeneration tempera- ture, air flow rate, and wheel speed on the performance of the wheel. Nia et al. [5] also presented a mathematical model con- sidering the heat and mass transfer within the moist air. A nu- merical method was used to determine the optimum rota- tional speed in order to improve the performance of an adiabatic rotary dehumidifier. Zhai et al. [6] developed 1D transient heat and mass transfer equations for a desiccant wheel considering the gas side resistance. Also, the effect of some practical issues related to wheel purge, residual water in the desiccant, and wheel supporting structure on the wheel performance were investigated. Bourdoukan et al. [7] provided a sensitivity analysis of the desiccant wheel dehumidification using the design of experiments and also studied the effect of operating parameters on the dehumidification rate of the wheel by experimental and numerical simulations. A 1D tran- sient desiccant wheel behavioral model considering the gas side resistance was developed with the capability to characterize the equipment under a wide range of operating conditions. The number of transfer unit (NTU) method was used to describe the model effectiveness [8, 9]. Chung et al. [10] developed an- other 1D transient model considering the gas side resistance. The performance of the desiccant cooling system was evaluated in terms of moisture removal capacity (MRC) and simulations were focused on the effect of the desiccant isotherm on opti- mal conditions of operating/design parameters. Antonellis et al. [11] applied a 1D transient gas side resistance model for de- veloping temperature and velocity profiles along the channels. Performance and optimization of the desiccant wheel were in- vestigated on the basis of an air angular sector and revolution speed. The above-mentioned models [2–11] do not consider the heat and mass transfer in the desiccant material and cannot re- flect the actual transfer process occurring in the desiccant Chem. Eng. Technol. 2012, 35, No. 00, 1–10 © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.cet-journal.com Avadhesh Yadav Vijay K. Bajpai National Institute of Technology, Department of Mechanical Engineering, Kurukshetra Haryana, India. – Correspondence: Dr. A. Yadav (avadheshyadava@gmail.com), National Institute of Technology, Department of Mechanical Engineering, Kurukshetra Haryana-136119, India. Desiccant wheel 1