Energy Saving in Handling the Air-Conditioning Latent-Load Using a Liquid Desiccant Air Conditioner: Parametric Experimental Analysis

Authors: Mustafa Jaradat

Abstract:

Reasonable energy saving for dehumidification is feasible with the use of desiccants. Desiccants are able to lower the humidity content in the air irrespective of the dew point temperature. In this paper, a tube bundle liquid desiccant air conditioner was experimentally designed and evaluated using lithium chloride as a desiccant. Several experiments were conducted to evaluate the influence of the inlet parameters on the dehumidifier performance. The results show a reduction in the relative humidity in the range of 17 to 46%, and the change in the humidity ratio was between 1.5 to 4.7 g/kg, depending on the inlet conditions. A water removal rate in the range between 0.54 and 1.67 kg/h was observed. The effects of air relative humidity and the desiccant flow rate on the dehumidifier’s performance were investigated. It was found that the moisture removal rate remarkably increased with increasing desiccant flow rate and air inlet humidity ratio. The dehumidifier effectiveness increased sharply with increasing desiccant flow rate. Also, it was found that the dehumidifier effectiveness slightly decreased with air humidity ratio.

Keywords: Air conditioning, dehumidification, desiccant, lithium chloride, tube bundle.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.3462075

References:

[1] Kozubal, E., Woods, J., Burch, J., Boranian, A., Merrigan, T. (2011) Desiccant Enhanced Evaporative Air-Conditioning (DEVap): Evaluation of a New Concept in Ultra Efficient Air Conditioning. Technical Report TP-5500-49722, National Renewable Energy Laboratory, Golden, Colorado.
[2] M. Jaradat, R., Heinzen, U. Jordan, K. Vajen, “Initial Experiments of a Novel Liquid Desiccant Dehumidifier for Industrial and Comfort Air Conditioning Systems”, Proceeding of the 3rd International Conference Solar Air-Conditioning 2009, Palermo (IT), 30.09 - 02.10 2009.
[3] Kathabar Systems (2019). Available at https://www.kathabar.com/ desiccant-dehumidification. Accessed: 20 June 2019.
[4] V. Öberg and D. Y. Goswami, “Experimental Study of the Heat and Mass Transfer in a Packed Bed Liquid Desiccant Air Dehumidifier,” J. Sol. Energy Eng., vol. 120, no. 4, p. 289, 1998.
[5] Pesaran, Ahmad A. (1994). A review of desiccant dehumidification technology. Golden, Colo: National Renewable Energy Laboratory (NREL/TP-472-7010).
[6] X. H. Liu and Y. Jiang, “Coupled heat and mass transfer characteristic in packed bed dehumidifier/regenerator using liquid desiccant,” Energy Convers. Manag., vol. 49, no. 6, pp. 1357–1366, Jun. 2008.
[7] W. Kessling, E. Laevemann, and M. Peltzer, “Energy storage in open cycle liquid desiccant cooling systems,” Int. J. Refrig., vol. 21, no. 2, pp. 150–156, Mar. 1998.
[8] A. Lowenstein, S. Slayzak, and E. Kozubal, “A Zero Carryover Liquid-Desiccant Air Conditioner for Solar Applications,” in Solar Energy, Denver, Colorado, USA, 2006, vol. 2006, pp. 397–407.
[9] D. Cai, C. Qiu, J. Zhang, Y. Liu, X. Liang, and G. He, “Performance analysis of a novel heat pump type air conditioner coupled with a liquid dehumidification/humidification cycle,” Energy Convers. Manag., vol. 148, pp. 1291–1305, Sep. 2017.
[10] M. M. Bassuoni, “An experimental study of structured packing dehumidifier/regenerator operating with liquid desiccant,” Energy, vol. 36, no. 5, pp. 2628–2638, May 2011.
[11] M. M. Bassuoni, “Parametric study of a single cycle two-stage structured packing counter flow air dehumidifier using two feeding desiccant solution lines,” Energy Convers. Manag., vol. 75, pp. 175–183, Nov. 2013.
[12] M.-H. Kim, J.-Y. Park, and J.-W. Jeong, “Simplified model for packed-bed tower regenerator in a liquid desiccant system,” Appl. Therm. Eng., vol. 89, pp. 717–726, Oct. 2015.
[13] Z. Wang, X. Zhang, and Z. Li, “Investigation on the coupled heat and mass transfer process between extremely high humidity air and liquid desiccant in the counter-flow adiabatic packed tower,” Int. J. Heat Mass Transf., vol. 110, pp. 898–907, Jul. 2017.
[14] S. A. Abdul-Wahab, Y. H. Zurigat, and M. K. Abu-Arabi, “Predictions of moisture removal rate and dehumidification effectiveness for structured liquid desiccant air dehumidifier,” Energy, vol. 29, no. 1, pp. 19–34, Jan. 2004.M. Young, The Techincal Writers Handbook. Mill Valley, CA: University Science, 1989.
[15] A. Lowenstein, S. Slayzak, J. Ryan, and A. Pesaran, “Advanced Commercial Liquid-Desiccant Technology Development Study,” NREL/TP-550-24688, 12099, Nov. 1998.
[16] ASHRAE (1997). “1997 Handbook – Fundamentals, Chapter 6, Psychrometrics”, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, Georgia.
[17] Conde, Manuel R. (2004). Properties of aqueous solutions of lithium and calcium chlorides: formulations for use in air conditioning equipment design, International Journal of Thermal Sciences, vol. 43 (4), pp 367–382.