Exergy analysis of double effect vapor absorption refrigeration system

Abstract

SUMMARYEnergy and exergy analyses previously performed by the authors for a single effect absorption refrigeration system have been extended to double effect vapor absorption refrigeration system with the expectation of reducing energy supply as well as an interest in the diversification of the motive power employed by HVAC technologies. The total exergy destruction in the system as a percentage of the exergy input from a generator heating water over a range of operating temperatures is examined for a system operating on LiBr-H 2 O solution. The exergy destruction in each component, the coefficient of performance (COP) and the exergetic COP of the system are determined. It is shown that exergy destructions occur significantly in generators, absorbers, evaporator2 and heat exchangers while the exergy destructions in condenser1, evaporator1, throttling valves, and expansion valves are relatively smaller within the range of 1-5%. The results further indicate that with an increase in the generator1 temperature the COP and ECOP increase, but there is a significant reduction in total exergy destruction of the system for the same. On the other hand, the COP and ECOP decrease with an increase in the absorber1 temperature while the total exergy destruction of the system increases significantly with a small increase in the absorber1 temperature. The results show that the exergy method can be used as an effective criterion in designing an irreversible double effect absorption refrigeration system and may be a good tool for the determination of the optimum working conditions of such systems.

Exergy analysis of C2+ recovery plants refrigeration cycles

“…Analyzing a multi-component plant indicates the total plant irreversibility distribution among the plant components, pinpointing those contributing most to overall plant inefficiency (Kotas, 1995). There have been several studies on the exergy analysis of refrigeration systems (Vidal et al, 2006;Tozer and James, 1998;Nikolaidis and Probert, 1998;Talbi and Agnew, 2000;Zheng et al, 2001;Yumrutas et al, 2002;Stegou-Sagia and Paignigiannis, 2003;Ouadha et al, 2005;Wang et al, 2005;Remeljej and Hoadley, 2006;Mehrpooya et al, 2006a;Zhang and Lior, 2007;Bhattacharyya et al, 2007;Kabul et al, 2008;Khaliq and Kumar, 2008). The behavior of two stage compound compression-cycle, with flash intercooling, using refrigerant R22, investigated by the exergy method (Nikolaidis and Probert, 1998) and an exergy analysis carried out for an irreversible Brayton cycle by Zheng et al (2001).…”

“…Mehrpooya et al (2006a) illustrated simulation and exergy-method analysis of Bhattacharyya et al (2007). Methodology for thermal design of novel combined refrigeration/power binary fluid systems carry out by Zhang and Lior (2007) and Khaliq and Kumar (2008) presented Exergy analysis of double effect vapor absorption refrigeration system. Kabul et al (2008) described performance and exergetic analysis of vapor compression refrigeration system with an internal heat exchanger using a hydrocarbon, isobutene (R600a).…”

Energy and exergy analysis of a double absorption heat transformer operating with water/lithium bromide

“…The authors concluded that the condenser and evaporator heat loads and exergy losses are less than those in the generator and absorber. Double effect absorption cooling systems operating with the water-lithium bromide mixture have been studied by Khaliq and Kumar [15] and by Gomri and Hakimi [16]. They found the irreversibilities in each one of the components of the systems and concluded that the method can be utilized to optimize the design of absorption refrigeration systems.…”

Performance analysis of an industrial waste heat-based trigeneration system

“…Determining exergy efficiency for an overall system and/or the individual components making up the system constituents a major part of the exergy analysis. A comprehensive analysis of a thermodynamic system includes both energy and exergy analysis in order to obtain a more complete picture of system behavior [11].…”