0
Research Papers

Statistical Investigation of Air Dehumidification Performance by Aqueous Lithium Bromide Desiccant in a Packed Column: A Thermodynamic Approach

[+] Author and Article Information
L. Omidvar Langroudi

Chemical Engineering Faculty,
Tarbiat Modares University,
Tehran 14155-143, Iran

H. Pahlavanzadeh

Chemical Engineering Faculty,
Tarbiat Modares University,
Tehran 14155-143, Iran
e-mail: pahlavzh@modares.ac.ir

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS. Manuscript received October 30, 2014; final manuscript received July 3, 2015; published online August 4, 2015. Assoc. Editor: Samuel Sami.

J. Thermal Sci. Eng. Appl 7(4), 041013 (Aug 04, 2015) (9 pages) Paper No: TSEA-14-1254; doi: 10.1115/1.4031082 History: Received October 30, 2014

Lithium bromide solution is used as a desiccant in air dehumidification systems. Liquid desiccant is a solution that facilitates the removal of humidity directly from the air. In this work, effectiveness of a LiBr based air dehumidifier was studied by correlating the vapor–liquid equilibrium data with a proposed thermodynamic model. For this, the nonelectrolyte Wilson nonrandom factor (N-Wilson-NRF) model and the Pitzer–Debye–Huckel formula were used to represent the contribution of the short and the long range ion–ion interactions. In particular, the proposed model assumed that the electrolyte solution is treated as a mixture of undissociated ion pairs and solvent molecules. The proposed equation of this study is valid for the temperature range of 20–35 °C and concentration range of 0.40–0.60 kg/kg. This relation was employed to estimate the equivalent humidity ratio, and then, the humidity ratio from the previous step was used to calculate the effectiveness of a LiBr based dehumidifier. The response surface methodology (RSM) was applied for the design and analysis of the dehumidification experiments. A quadratic model was implemented to predict the dehumidification effectiveness. This model studies the implications of four primary variables on the effectiveness of a dehumidification process. The optimal values to achieve the maximum effectiveness were found to be 32.5 °C for the air temperature, 0.0210 kg/kg for the air humidity ratio, 2.17 for the mass flow rate ratio, and finally, 0.50 kg/kg for the desiccant concentration. These values gave the dehumidification effectiveness of 0.544. The result of the model was in good agreement with the experimental value 0.542, thus verifying the accuracy of the proposed model.

FIGURES IN THIS ARTICLE
<>
Copyright © 2015 by ASME
Your Session has timed out. Please sign back in to continue.

References

Chen, X. Y. , Li, Z. , Jiang, Y. , and Qu, K. Y. , 2006, “Analytical Solution of Adiabatic Heat and Mass Transfer Process in Packed-Type Liquid Desiccant Equipment and Its Application,” Sol. Energy, 80(11), pp. 1509–1516. [CrossRef]
Ge, G. , Xiao, F. , and Niu, X. , 2011, “Control Strategies for a Liquid Desiccant Air-Conditioning System,” Energy Build., 43(1), pp. 1499–1507. [CrossRef]
Koronaki, I. P. , Christodoulaki, R. I. , Papaefthimiou, V. D. , and Rogdakis, E. D. , 2013, “Thermodynamic Analysis of a Counter Flow Adiabatic Dehumidifier With Different Liquid Desiccant Materials,” Appl. Therm. Eng., 50(1), pp. 361–373. [CrossRef]
Babakhani, D. , and Soleymani, M. , 2010, “Simplified Analysis of Heat and Mass Transfer Model in Liquid Desiccant Regeneration Process,” J. Taiwan Inst. Chem. Eng., 41(3), pp. 259–267. [CrossRef]
Daou, K. , Wang, R. Z. , and Xia, Z. Z. , 2006, “Desiccant Cooling Air Conditioning: A Review,” Renewable Sustainable Energy Rev., 10(2), pp. 55–77. [CrossRef]
Bassuoni, M. M. , 2014, “Experimental Performance Study of a Proposed Desiccant Based Air Conditioning System,” J. Adv. Res., 5(1), pp. 87–95. [CrossRef] [PubMed]
Lof, G. O. G. , 1955, “Cooling With Solar Energy,” World Symposium on Applied Solar Energy, Phoenix, AZ, pp. 171–189.
Liu, X. H. , Yi, X. Q. , and Jiang, Y. , 2011, “Mass Transfer Performance Comparison of Two Commonly Used Liquid Desiccants: LiBr and LiCl Aqueous Solutions,” Energy Convers. Manage., 52(1), pp. 180–190. [CrossRef]
Kinsara, A. A. , Elsayed, M. , and Al-Rabghi, O. M. , 1996, “Proposed Energy-Efficient Air-Conditioning System Using Liquid Desiccant,” Appl. Therm. Eng., 16(10), pp. 791–806. [CrossRef]
Conde, M. R. , 2004, “Properties of Aqueous Solutions of Lithium and Calcium Chloride: Formulations for Use in Air Conditioning Equipment Design,” Int. J. Therm. Sci., 43(4), pp. 367–382. [CrossRef]
Fumo, N. , and Goswami, D. Y. , 2002, “Study of an Aqueous Lithium Chloride Desiccant System: Air Dehumidification and Desiccant Regeneration,” Sol. Energy, 72(4), pp. 351–361. [CrossRef]
Gao, W. Z. , Liu, J. H. , Cheng, Y. P. , and Zhang, X. L. , 2012, “Experimental Investigation on the Heat and Mass Transfer Between Air and Liquid Desiccant in a Cross-Flow Dehumidifier,” Renewable Energy, 37(1), pp. 117–123. [CrossRef]
Ren, C. Q. , 2008, “Corrections to the Simple Effectiveness-NTU Method for Counterflow Cooling Towers and Packed Bed Liquid Desiccant–Air Contact Systems,” Int. J. Heat Mass Transfer, 51(1–2), pp. 237–245. [CrossRef]
Jain, S. , Dhar, P. L. , and Kaushik, S. C. , 2000, “Experimental Studies on the Dehumidifer and Regenerator of a Liquid Desiccant Cooling System,” Appl. Therm. Eng., 20(3), pp. 253–267. [CrossRef]
Gandhidasan, P. , 2004, “A Simplified Model for Air Dehumidification With Liquid Desiccant,” Sol. Energy, 76(4), pp. 409–416. [CrossRef]
Langroudi, L. O. , Palavanzadeh, H. , and Mousavi, S. M. , 2014, “Statistical Evaluation of a Liquid Desiccant Dehumidification System Using RSM and Theoretical Study Based on the Effectiveness NTU Model,” J. Ind. Eng. Chem., 20(5), pp. 2975–2983. [CrossRef]
Zhang, L. , Hihara, E. , Matsuoka, F. , and Dang, C. , 2010, “Experimental Analysis of Mass Transfer in Adiabatic Structured Packing Dehumidifier/Regenerator With Liquid Desiccant,” Int. J. Heat Mass Transfer, 53(13–14), pp. 2856–2863. [CrossRef]
Liu, X. H. , Qu, K. Y. , and Jiang, Y. , 2006, “Empirical Correlations to Predict the Performance of the Dehumidifier Using Liquid Desiccant in Heat and Mass Transfer,” Renewable Energy, 31(10), pp. 1627–1639. [CrossRef]
Pahlavanzadeh, H. , and Nooriasl, P. , 2012, “Experimental and Theoretical Study of Liquid Desiccant Dehumidification System by Using of Effectiveness Model,” ASME J. Therm. Sci. Eng. Appl., 4(1), p. 011008. [CrossRef]
Jafari, A. , Tynja la, T. , Mousavi, S. M. , and Sarkomaa, P. , 2008, “CFD Simulation and Evaluation of Controllable Parameters Effect on Thermomagnetic Convection in Ferrofluids Using Taguchi Technique,” Comput. Fluids, 37(10), pp.1344–1353. [CrossRef]
Patil, M. S. , Mathew, J. , Rajendrakumar, P. K. , and Karade, S. , 2010, “Experimental Studies Using Response Surface Methodology for Condition Monitoring of Ball Bearings,” ASME J. Tribol., 132(4), p. 044505. [CrossRef]
Boryta, D. A. , Maas, J. A. , and Grant, C. B. , 1975, “Vapor Pressure-Temperature-Concentration Relationship for the System Lithium Bromide and Water (40-70% Lithium Bromide),” J. Chem. Eng. Data, 20(3), pp. 316–319. [CrossRef]
Peters, R. , and Keller, J. U. , 1994, “Solvation Model for VLE in the System H,O-LiBr From 5 to 76 wt%,” Fluid Phase Equilib., 94(1), pp. 129–147. [CrossRef]
Haghtalab, A. , and Mazloumi, S. H. , 2009, “A Nonelectrolyte Local Composition Model and Its Application in the Correlation of the Mean Activity Coefficient of Aqueous Electrolyte Solutions,” Fluid Phase Equilib., 275(1), pp.70–77. [CrossRef]
Prausnitz, J. M. , Lichtenthaler, R. N. , and Azevedo, E. G. , 1999, Molecular Thermodynamics of Fluid-Phase Equilibria, 3rd ed., Prentice-Hall, Upper Saddle River, NJ.
Chen, C. C. , and Evans, L. B. , 1986, “A Local Composition Model for the Excess Gibbs Energy of Aqueous Electrolyte Systems,” AIChE J., 32(3), pp. 444–454. [CrossRef]
Zhao, E. , Yu, M. , Sauve, R. E. , and Khoshkbarchi, M. K. , 2000, “Extension of the Wilson Model to Electrolyte Solutions,” Fluid Phase Equilib., 173(2), pp. 161–175. [CrossRef]
Sadeghi, R. , 2005, “New Local Composition Model for Electrolyte Solutions,” Fluid Phase Equilib., 231(1), pp. 53–60. [CrossRef]
Pitzer, K. S. , 1980, “Electrolytes. From Dilute Solutions to Fused Salts,” J. Am. Chem. Soc., 102(9), pp. 2902–2906. [CrossRef]
Chen, C. C. , Britt, H. I. , Boston, J. F. , and Evans, L. B. , 1982, “Local Composition Model for Excess Gibbs Energy of Electrolyte Systems. Part I: Single Solvent, Single Completely Dissociated Electrolyte Systems,” AIChE J., 28(4), pp. 588–596. [CrossRef]
Montgomery, D. C. , 2001, Design and Analysis of Experiments, Wiley, New York.
Ray, S. , and Lalman, J. A. , 2011, “Using the Box–Benkhen Design (BBD) to Minimize the Diameter of Electrospun Titanium Dioxide Nanofibers,” Chem. Eng. J., 169(1--3), pp. 116–125. [CrossRef]
Khayet, M. , Cojocaru, C. , and Trznadel, G. Z. , 2008, “Response Surface Modelling and Optimization in Pervaporation,” J. Membr. Sci., 321(2), pp. 272–283. [CrossRef]
Ferreiraa, S. L. C. , Brunsb, R. E. , Ferreiraa, H. S. , Matosa, G. D. , Davida, J. M. , Brandãoa, G. C. , da Silvaa, E. G. P. , Portugala, L. A. , dos Reisc, P. S. , Souzaa, A. S. , and dos Santosc, W. N. L. , 2007, “Box-Behnken Design: An Alternative for the Optimization of Analytical Methods,” Anal. Chim. Acta, 597(2), pp. 179–186. [CrossRef] [PubMed]
Parsons, R. A. , 1997, ASHRAE Handbook of Fundamentals, American Society of Heating, Refrigeration and Air Conditioning Engineers, Atlanta, GA.
Lazarev, M. A. , and Sorochenko, V. R. , 1996, Properties of Aqueous Solution of Electrolytes, CRC Press, London.
Amani, T. , Nosrati, M. , Mousavi, S. M. , and Kermanshahi, R. K. , 2011, “Study of Syntrophic Anaerobic Digestion of Volatile Fatty Acids Using Enriched Cultures at Mesophilic Conditions,” Int. J. Environ. Sci. Technol., 8(1), pp. 83–96. [CrossRef]
Myers, R. H. , and Montgomery, D. C. , 1995, Response Surface Methodology: Process and Product Optimization Using Designed Experiments, Wiley, New York, Chap. 7.

Figures

Grahic Jump Location
Fig. 1

Schematic of the experimental setup [16]

Grahic Jump Location
Fig. 4

A comparison of the predicted and experimental values of equivalent humidity ratio (ωsat, kg/kg)

Grahic Jump Location
Fig. 5

Predicted dehumidification effectiveness versus the actual values for the dehumidification system with LiBr desiccant

Grahic Jump Location
Fig. 2

Mean activity coefficient of LiBr solution as a function of mass fraction at 25 °C

Grahic Jump Location
Fig. 3

The activity coefficient of H2O as a function of LiBr solution mass fraction at 25 °C

Grahic Jump Location
Fig. 6

Dehumidification effectiveness (ε) with respect to the air humidity ratio (ωa, kg/kg) and desiccant concentration (Xs, kg/kg) at Ta = 32.5 °C and R = 1.53. Images showing (a) contour plots and (b) response surface.

Grahic Jump Location
Fig. 7

Dehumidification effectiveness (ε) with respect to the desiccant concentration (Xs, kg/kg) and the mass flow rate ratio (R) at ωa = 0.0185 kg/kg and Ta = 32.5 °C. Images showing (a) contour plots and (b) response surface.

Grahic Jump Location
Fig. 8

Dehumidification effectiveness (ε) with respect to the mass flow rate ratio (R) and the air temperature (Ta, °C) at ωa = 0.0185 kg/kg and Xs = 0.48 kg/kg. Images showing (a) contour plots and (b) response surface.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In