An advanced GAX cycle for waste heat recovery WGAX cycle

The objectives of this paper are to develop an advanced generator absorber heat exchanger cycle (WGAX) to reduce the generator exit temperature as low as possible using waste heat sources, and to compare it with the standard GAX cycle (SGAX). This paper performed parametric analysis to study the eff ects of the waste heat source temperature (T-w) and the outlet temperature of a gas fired desorber (GFD), T-g, on the cycle performance. Three differe nt WGAX cycles (type A, type B and type C) were compared from the viewpoint of performance improvement. It was found that the effect of the waste heat source temperature (T-w) on coefficient of performance (COP)s was negligib le for a given GFD outlet temperature in the WGAX cycles. The GFD outlet te mperature could be reduced down to 172 degrees C with a higher COPbeta of W GAX cycle than the COP of the SGAX cycle. Therefore, the corrosion problem in the SGAX cycle at a higher T-g than 200 degrees C will be solved by adop ting the WGAX cycles with a comparable COP. Type A had a merit from the vie wpoint of the GAX effect while Type B had a merit from the viewpoint of exe rgy loss effect. In the WGAX cycles developed in this study, the GAX effect was dominant for a lower temperature than 181 degrees C while the effect o f exergy loss was dominant for a higher temperature than 181 degrees C. It is found that the solution heated desorber should be placed below the GAXD to improve the cycle performance in the WGAX cycles. It is strongly recomme nded that there be a subcooling effect in the weak solution for cycle perfo rmance enhancement in the WGAX systems. (C) 1999 Elsevier Science Ltd. All rights reserved.