Analysis on a hybrid desiccant air-conditioning system

Hybrid desiccant-assisted preconditioner and split cooling coil system, which combines the merits of moisture removal by desiccant and cooling coil for sensible heat removal, is a potential alternative to conventional vapor compression cooling systems. In this paper, experiments on a hybrid desiccant air-conditioning system, which is actually an integration of a rotary solid desiccant dehumidification and a vapor compression air-conditioning unit, had been carried out. It is found that, compared with the conventional VC (vapor compression) system, the hybrid desiccant cooling system economizes 37.5% electricity powers when the process air temperature and relative humidity are maintained at 30 °C, and 55% respectively. The reason why the hybrid desiccant cooling system features better performance relative to the VC system lies in the improvement brought about in the performance of the evaporator in VC unit due to desiccant dehumidification. A thermodynamic model of the hybrid desiccant system with R-22 as the refrigerant has been developed and the impact of operating parameters on the sensible heat ratio of the evaporator and the electric power saving rate has been analyzed. It is found that a majority of evaporators can operate in the dry condition even if the regeneration temperature is lower (i.e. 80 °C).

[1]  Yunfei Dai,et al.  A simulation study of heat and mass transfer in a honeycombed rotary desiccant dehumidifier , 2003 .

[2]  Reinhard Radermacher,et al.  Performance Analysis Of a Combined Desiccant/Absorption Air-Conditioning System , 1999 .

[3]  Y. K. Yadav.  Vapour-compression and liquid-desiccant hybrid solar space-conditioning system for energy conservation , 1995 .

[4]  C. F. Kettleborough,et al.  A Review of Desiccant Cooling Systems , 1993 .

[5]  A. C Cleland,et al.  Computer subroutines for rapid evaluation of refrigerant thermodynamic properties , 1986 .

[6]  S. Touber,et al.  Distributed and non-steady-state modelling of an air cooler , 1991 .

[7]  Abdulghani A. Al-Farayedhi,et al.  Exergy analysis of a liquid-desiccant-based, hybrid air-conditioning system , 1998 .

[8]  Ruzhu Wang,et al.  Use of liquid desiccant cooling to improve the performance of vapor compression air conditioning , 2001 .

[9]  Kamel Ghali,et al.  Use of desiccant dehumidification to improve energy utilization in air‐conditioning systems in Beirut , 2003 .

[10]  S. C. Kaushik,et al.  Psychometric technoeconomic assessment and parametric studies of vapor-compression and solid/liquid desiccant hybrid solar space conditioning systems , 1991 .

[11]  C. K. Rice.  The effect of void fraction correlation and heat flux assumption on refrigerant charge inventory predictions , 1987 .

[12]  P. G. Jolly,et al.  A distributed model for prediction of the transient response of an evaporator , 1995 .

[13]  W. A. Beckman,et al.  Hybrid desiccant cooling systems in supermarket applications , 1985 .

[14]  J. R. Howell,et al.  Preliminary performance evaluation of a hybrid vapor-compression/liquid desiccant air conditioning system , 1987 .

[15]  Francesco Minichiello,et al.  HVAC dehumidification systems for thermal comfort: a critical review , 2005 .

[16]  N. Galanis,et al.  Prediction of the transient response of heat pumps , 1987 .

[17]  P. L. Dhar,et al.  Studies on solid desiccant based hybrid air-conditioning systems , 2001 .

[18]  Abdulghani A. Al-Farayedhi,et al.  Simulation of a hybrid liquid desiccant based air-conditioning system , 1997 .