DEHUMIDIFICATION PERFORMANCE INVESTIGATION OF RUN-AROUND MEMBRANE ENERGY EXCHANGER SYSTEM

Abstract

Liquid-to-air membrane energy exchanger is a novel membrane base energy exchanger, which allows both heat and moisture transfer between air and a salt solution. It uses semi-permeable membrane to eliminate entrainment of liquid desiccant as aerosols in air stream and allow simultaneous heat and moisture transfer between salt solution flow and airflow. The heat and mass transfer performance of a single liquid-to-air membrane energy exchanger is significantly dependent on two dimensionless parameters. They are the number of heat transfer units (NTU) and the ratio of heat capacity rates between solution flow and air flow (Cr*). The liquid-to-air membrane energy exchangers can also be applied in a run-around membrane energy exchanger system, which is mainly comprised of two liquid-to-air membrane energy exchangers and a closed loop of aqueous desiccant solution and used as a passive energy recovery system to recover the energy (both heat and moisture) from the exhaust air to precondition the supply air in air conditioning systems. In this study the dehumidification capacity of a run-around membrane energy exchanger is investigated numerically at different exhaust air temperatures and Cr* values. Increasing the exhaust air temperature or the Cr* would enhance the dehumidification capacity of the a run-around membrane energy exchanger system under Cr*≤1, but the improvement is limited. The dehumidification capacity at low Cr* is much lower than that under the optimal Cr* value (Cr*=3.2) where the maximum latent effectiveness is obtained.

Keywords

Dates

  • Submission Date2014-08-16
  • Revision Date2014-10-02
  • Acceptance Date2014-11-03
  • Online Date2014-11-08

DOI Reference

10.2298/TSCI140816129K

References

  1. Fan, Y., Ito, K., Energy Consumption Analysis Intended For Real Office Space With Energy Recovery Ventilator by Integrating BES and CFD Approaches, Building and Environment, 52 (2012), pp. 57-67 DOI: 10.1016/j.buildenv.2011.12.008
  2. Zhang, L.-Z., et al., Heat and moisture transfer in application scale parallel-plates enthalpy exchangers with novel membrane materials, Journal of Membrane Science, 325 (2008), pp. 672-682 DOI: 10.1016/j.memsci.2008.08.041
  3. Fehrm, M., et al., Exhaust air heat recovery in buildings, International Journal of Refrigeration, 25 (2002), 4, pp. 439-449 DOI: 10.1016/S0140-7007(01)00035-4
  4. Ignjatovic, M. G., et al., Influence of glazing types and ventilation principles in double skin facades on delivered heating and cooling energy during heating season in an office building, Thermal Science, 16 (2012), 2, pp. 461-469 DOI: 10.2298/TSCI120427183I
  5. Nguyen, A., et al., Experimental study of sensible heat recovery of heat pump during heating and ventilation, International Journal of Refrigeration, 28 (2005), 2, pp. 242-252 DOI: 10.1016/j.ijrefrig.2004.07.022
  6. Zhang, L.-Z., Energy performance of independent air dehumidification systems with energy recovery measures, Energy, 31 (2006), 8-9, pp. 1228-1242 DOI: 10.1016/j.energy.2005.05.027
  7. Zhang, L.-Z, Thermodynamic modelling of a novel air dehumidification system, Energy and Buildings, 37 (2005), 3, pp. 279-286 DOI: 10.1016/j.enbuild.2004.06.019
  8. Nasif, M., et al., Membrane heat exchanger in HVAC energy recovery systems, systems energy analysis, Energy and Buildings, 42 (2010), 10, pp. 1833-1840 DOI: 10.1016/j.enbuild.2010.05.020
  9. Zhang, L.-Z, Niu J. L., Energy requirements for conditioning fresh air and the long-term savings with a membrane-based energy recovery ventilator in Hong Kong, Energy, 26 (2002), 2, pp. 119-135 DOI: 10.1016/S0360-5442(00)00064-5
  10. Zhou, Y. P., et al., Performance of energy recovery ventilator with various weathers and temperature set-points, Energy and Buildings, 39 (2006), 12, pp. 1202-1210 DOI: 10.1016/j.enbuild.2006.12.010
  11. Sumarac, D. M., et al., Energy efficiency of residential buildings in Serbia, Thermal Science, 14 (2010), pp. 97-113 DOI: 10.2298/TSCI100430017S
  12. Zhang, L.-Z, Niu J. L., Performance comparisons of desiccant wheels for air dehumidification and enthalpy recovery, Applied Thermal Engineering, 22 (2002), 12, pp. 1347-1367 DOI: 10.1016/S1359-4311(02)00050-9
  13. Moghadamm, D. G., et al., Small-scale single-panel liquid-to-air membrane energy exchanger (LAMEE) test facility development, commissioning and evaluating the steady-state performance, Energy and Buildings, 66 (2013), pp. 424-436 DOI: 10.1016/j.enbuild.2013.07.017
  14. Ge, G., et al., Comparison of experimental data and a model for heat and mass transfer performance of a liquid-to-air membrane energy exchanger (LAMEE) when used for air dehumidification and salt solution regeneration, International Journal of Heat and Mass Transfer, 68 (2014), pp. 119-131 DOI: 10.1016/j.ijheatmasstransfer.2013.09.016
  15. Moghadamm, D. G., et al., Numerical model of a small-scale liquid-to-air membrane energy exchanger: Parametric study of membrane resistance and air side convective heat transfer coefficient, Applied Thermal Engineering, 61 (2013), 2-3, 245-258, DOI: 10.1016/j.applthermaleng.2013.07.017
  16. Namrav, R., et al., Transient characteristics of a liquid-to-air membrane energy exchanger (LAMEE) experimental data with correlations, International Journal of Heat and Mass Transfer, 55 (2012), 23-24, pp. 6682-6694. DOI: 10.1016/j.ijheatmasstransfer.2012.06.077
  17. Namrav, R., et al., Transient heat and moisture transfer characteristics of a liquid-to-air membrane energy exchanger (LAMEE) model verification and extrapolation, International Journal of Heat and Mass Transfer, 66 (2013), pp. 757-771, DOI: 10.1016/j.ijheatmasstransfer.2013.07.068
  18. Abdel-Salam, A. H., et al., Performance analysis of a membrane liquid desiccant air-conditioning system, Energy and Buildings, 62 (2013), pp. 559-569, DOI: 10.1016/j.enbuild.2013.03.028
  19. Ge, G., et al., Research and applications of liquid-to-air membrane energy exchangers in building HVAC systems at University of Saskatchewan: A review, Renewable and Sustainable Energy Reviews, 26 (2013), pp. 464-479 DOI: 10.1016/j.rser.2013.04.022
  20. Erb, B., et al., Experimental measurements of a run-around membrane energy exchanger with comparison to a numerical model, ASHRAE Transactions, 115 (2009), 2, pp. 689-705
  21. Seyed-Ahmadi, M., et al., Transient behavior of run-around heat and moisture exchanger system, Part I: Model formulation and verification, International Journal of Heat and Mass Transfer, 52 (2009), 25-26, pp. 6000-6011 DOI: 10.1016/j.ijheatmasstransfer.2009.07.012
  22. Seyed-Ahmadi, M., et al., Transient behavior of run-around heat and moisture exchanger system. Part II: Sensitivity studies for a range of initial conditions, International Journal of Heat and Mass Transfer, 52 (2009), pp. 6012-6020 DOI: 10.1016/j.ijheatmasstransfer.2009.06.037
  23. Mahmud, K., et al., Performance testing of a counter-cross-flow run-around membrane energy exchanger (RAMEE) system for HVAC applications, Energy and Buildings, 42 (2010), 7, pp. 1139-1147 DOI: 10.1016/j.enbuild.2010.02.005
  24. Hemingson, H. B., The impacts of outdoor air conditions and non-uniform exchanger channels on a run-around membrane energy exchanger, M.Sc. thesis, University of Saskatchewan, Saskatoon, SK, Canada, 2010
  25. Vali, A., et al., Numerical model and effectiveness correlations for a run-around heat recovery system with combined counter and cross flow exchangers, International Journal of Heat and Mass Transfer, 52 (2009), 25-26, pp. 5827-5840 DOI: 10.1016/j.ijheatmasstransfer.2009.07.020
  26. ANSI/ASHRAE Standard (American Society of Heating, Refrigerating, and Air-Conditioning Engineers) 90.1-2007, Energy Standard for Buildings Except for Low-rise Residential Buildings, Atlanta, US, 2007
  27. Moghadamm, D. G., et al., Evaluating the Steady-State Performance of a Small-Scale Single-Panel Liquid-to-Air Membrane Energy Exchanger (LAMEE) Under Summer AHRI Test Condition, Proceedings, 11th REHVA World Congress & 8th International Conference on IAQVEC, Prague, Czech Republic, 2013
  28. Rasouli, M., et al., Application of a run-around membrane energy exchanger in an office building HVAC system, ASHRAE Transactions, 117, (2011), pp. 686-703
  29. Rasouli, M., et al., Applicability and optimum control strategy of energy recovery ventilators in different climatic conditions, Energy and Buildings, 42, (2010), 9, pp. 1376-85 DOI: 10.1016/j.enbuild.2010.03.006
  30. Rasouli, M., Building Energy Simulation of A Run-Around Membrane Energy Exchanger (RAMEE), M.Sc. thesis, University of Saskatchewan, Saskatoon, SK, Canada, 2010.
  31. Simonson, C. J., et al., Determining the Performance of Energy Wheels: Part I-Experimental and Numerical Method, ASHRAE Transactions, (1999), pp. 105.
  32. Ge, G., et al., Analytical model based performance evaluation, sizing and coupling flow optimization of liquid desiccant run-around membrane energy exchanger systems, Energy and Buildings, 62 (2013), pp. 248-257 DOI: 10.1016/j.enbuild.2013.03.017
  33. Niu, J. L., et al., Membrane-based enthalpy exchanger: material consideration and clarification of moisture resistance, Journal of Membrane Science, 189 (2001), 2, pp. 179-191
  34. Zhang, L.-Z., An analytical solution to heat and mass transfer in hollow fiber membrane contactors for liquid desiccant air dehumidification, ASME Journal of Heat Transfer, 133 (2011), 9, pp. 1-8
  35. Welty, J. R., et al., Fundamentals of Momentum, Heat, and Mass Transfer, John Wiley & Sons Inc., New York, USA, 2001
  36. Zhang, L.-Z., et al., Conjugate heat and mass transfer in a hollow fiber membrane module for liquid desiccant air dehumidification: a free surface model approach, International Journal of
  37. Morrison, M. S., et al., Heat and mass transfer in air to air enthalpy heat exchangers, Proceedings, 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Matsushima, Japan, 2005
  38. ANSI/AHRI Standard 1060 (I-P). Performance Rating of Air-to-Air Heat Exchangers for Energy Recovery Ventilation Equipment, Arlington, VA, USA, 2011.
  39. Mahmud, K., Design and performance testing of counter-cross-flow run-around membrane energy exchanger system, M.Sc. thesis, University of Saskatchewan, Saskatoon, SK, Canada, 2009.