Title: Comparison of air-cooled and water-cooled (hot-water and direct-fired) double effect LiBr-H₂O absorption systems: energy and exergy analyses

Authors: T. Avanessian; M. Ameri

Addresses: Faculty of Engineering, Department of Mechanical Engineering, Shahid Bahonar University, Kerman 7618868366, Iran; Energy and Environmental Engineering Research Center, Shahid Bahonar University, Kerman 7618868366, Iran ' Faculty of Engineering, Department of Mechanical Engineering, Shahid Bahonar University, Kerman 7618868366, Iran; Energy and Environmental Engineering Research Center, Shahid Bahonar University, Kerman 7618868366, Iran

Abstract: In this study, air-cooled and water-cooled cooling systems including hot-water and direct-fired double effect LiBr-H₂O absorption chillers are analysed and compared in different operating and climatic conditions according to the first and second laws of thermodynamics. Unlike most articles in literature, in this paper all components engaged in cooling generation have been considered to attain the total energy utilisation factor (EUF) and exergy efficiency for the cooling systems. Results show that the EUF and second law efficiency of the systems including direct-fired chillers are a little higher than the hot-water chillers. Comparison between similar water-cooled and air-cooled systems illustrates that although the EUF of water-cooled systems is considerably higher than that of air-cooled systems, the difference between their second law efficiency, especially in temperatures below 37°C, is very small. This fact attests to the potential of air-cooled systems to be used specially in moderate climatic conditions.

Keywords: LiBr-H2O absorption systems; lithium bromide; refrigeration; air-cooled chillers; water-cooled chillers; boilers; cooling towers; cooling systems; EUF; energy utilisation factor; second law efficiency; thermodynamics; hot water cooling; direct-fired cooling; energy analysis; exergy analysis; exergy efficiency.

DOI: 10.1504/IJEX.2015.069321

International Journal of Exergy, 2015 Vol.17 No.1, pp.110 - 133

Received: 27 Feb 2014
Accepted: 29 Apr 2014
Published online: 11 May 2015 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article