Analysis of heat and mass transfer in porous sorbents used in rotary regenerators

Abstract A new dimensionless formulation, that locally accounts for heat conduction and mass diffusion in solid sorbent materials occurring in either enthalpy exchangers or desiccant wheels has been developed. Governing equations were fully normalized using classical dimensionless groups for heat and mass transfer. The model was validated using previously published results, including experimental data. The proposed equations are easily adaptable to incorporate additional features such as the influence of a supporting structure or the effects of flow entrance regions. Finally, results of a test-case are presented, indicating a possible optimization to wheel construction and compactness by reducing the felt thickness.

[1]  M. Kaviany.  Principles of heat transfer in porous media , 1991 .

[2]  W. Worek,et al.  Effect of adsorbent heat and mass transfer resistances on performace of an open-cycle adiabatic desiccant cooling system , 1988 .

[3]  John W. Mitchell,et al.  Design theory for rotary heat and mass exchangers—I. Wave analysis of rotary heat and mass exchangers with infinite transfer coefficients , 1985 .

[4]  A. London,et al.  Compact heat exchangers , 1960 .

[5]  John W. Mitchell,et al.  Analysis of regenerative enthalpy exchangers , 1990 .

[6]  Z. Lavan,et al.  Performance of Cross-Cooled Desiccant Dehumidifiers , 1983 .

[7]  Douglas M. Ruthven,et al.  Principles of Adsorption and Adsorption Processes , 1984 .

[8]  Chi-Chuan Wang,et al.  Heat and mass transfer for plate fin-and-tube heat exchangers, with and without hydrophilic coating , 1998 .

[9]  K. J. Sladek,et al.  Diffusion on Surfaces. II. Correlation of Diffusivities of Physically and Chemically Adsorbed Species , 1974 .

[10]  John W. Mitchell,et al.  Performance of Rotary Heat and Mass Exchangers , 1995 .

[11]  S. Kakaç,et al.  Heat Exchangers: Thermal Hydraulic Fundamentals and Design , 1985 .

[12]  P. Banks,et al.  Coupled heat and mass transfer in regenerators—prediction using an analogy with heat transfer , 1972 .

[13]  R. E. Treybal.  Mass-Transfer Operations , 1955 .

[14]  J. J. Jurinak,et al.  Effect of Matrix Properties on the Performance of a Counterflow Rotary Dehumidifier , 1984 .

[15]  K. J. Sladek,et al.  Diffusion on Surfaces. I. Effect of Concentration on the Diffusivity of Physically Adsorbed Gases , 1974 .

[16]  J. Bear.  Dynamics of Fluids in Porous Media , 1975 .

[17]  Z. Lavan,et al.  Performance Predictions for Adiabatic Desiccant Dehumidifiers Using Linear Solutions , 1980 .

[18]  P. J. Banks.  Prediction of Heat and Mass Regenerator Performance Using Nonlinear Analogy Method: Part 1—Basis , 1985 .

[19]  Roy B. Holmberg,et al.  Combined Heat and Mass Transfer in Regenerators with Hygroscopic Materials , 1979 .

[20]  D. Gidaspow,et al.  Nonlinear coupled heat and mass exchange in a cross-flow regenerator , 1974 .

[21]  Pradip Majumdar,et al.  Heat and mass transfer in composite desiccant pore structures for dehumidification , 1998 .

[22]  William M. Worek,et al.  Combined heat and mass transfer in a porous adsorbent , 1989 .

[23]  J. Niu,et al.  Heat transfer and friction coefficients in corrugated ducts confined by sinusoidal and arc curves , 2002 .

[24]  J. Niu,et al.  Effects of wall thickness on the heat and moisture transfers in desiccant wheels for air dehumidification and enthalpy recovery , 2002 .

[25]  J. Niu,et al.  Performance comparisons of desiccant wheels for air dehumidification and enthalpy recovery , 2002 .

[26]  R. Besant,et al.  Energy wheel effectiveness: part I—development of dimensionless groups , 1999 .

[27]  William M. Worek,et al.  NUMERICAL SIMULATION OF COMBINED HEAT AND MASS TRANSFER PROCESSES IN A ROTARY DEHUMIDIFIER , 1993 .

[28]  Carey J. Simonson,et al.  Heat and Moisture Transfer in Desiccant Coated Rotary Energy Exchangers: Part I. Numerical Model , 1997 .

[29]  John W. Mitchell,et al.  Design theory for rotary heat and mass exchangers—II. Effective n ess-number-of-transferunits method for rotary heat and mass exchangers , 1985 .

[30]  William M. Worek,et al.  Parametric study of an open-cycle adiabatic, solid, desiccant cooling system , 1988 .

[31]  D. Close,et al.  Coupled equilibrium heat and single adsorbate transfer in fluid flow through a porous medium — II Predictions for a silica-gel air-drier using characteristic charts , 1972 .