A comparative study of the performance characteristics of double-effect absorption refrigeration systems

Abstract

Three classes of double-effect lithium bromide-water absorption refrigeration systems (series, parallel and reverse parallel) with identical refrigeration capacities are studied and compared thermodynamically. In order to simulate the performances of the systems, a new set of computationally efficient formulations is used for thermodynamic properties of Li-Br solutions at equilibrium. The simulation results are used to examine the influence of various operating parameters on the first and second law performance characteristics of the systems. In addition, the dependences are investigated of system performance on the effectivenesses of the solution heat exchangers, the pressure drops between the evaporator and the absorber and between the low-pressure generator and the condenser, and the low-grade heat externally supplied to the low-pressure generator. The results reveal the advantages and disadvantages of different configurations of double-effect lithium bromide-water absorption refrigeration systems, and are expected to be useful in the design and control of such systems.

Performance comparison between a conventional vapor compression and compression-absorption single-stage and double-stage systems used for refrigeration

“…Effective interpolation techniques were used in the calculation of thermodynamic properties to obtain a maximum accuracy. The enthalpy values of the water-lithium bromide mixture were calculated by Kaita [13].…”

“…The flow exergy can be defined as: Table 7 shows the equations for the exergy analysis of the compression-absorption doublestage system taking into account the consideration made in the mathematical model section plus those added in this section. The entropy values of the water-lithium bromide mixture were calculated by Kaita [13]. Table 7.…”

“…Arun et al [12] presented the performace analysis of a double-effect in series LiBr/H 2 O absortion system in wich all the vapour generated at the high pressure generator is fully condensed at the low pressure generator. Garousi et al [13] carried out first and second law analyses for series, parallel and reverse parallel double-effect absorption refrigeration cycles and compared the results. The COP and exergetic efficiency for the parallel and reverse parallel systems were similar and higher than those of the series system.…”

Use of low grade heat sources in combined ejector–double effect absorption refrigeration systems

“…Detailed discussion of these investigations is presented elsewhere by the authors Garousi Farshi et al 31,32 A combination of ejector and double-effect absorption refrigeration cycle is proposed by Kuhlenschmidt. 33 However, it is expected that the COP of this system will not be higher than that of a single-effect absorption system, as some of the refrigerant vapor generated is discharged directly to the absorber (as the motive fluid) without producing a cooling effect.…”

“…31,32 The combined ejector-double effect absorption refrigeration cycle is shown in Figure 2. In this configuration four pressure levels are involved.…”