Abstract
The objectives of this paper are to develop an advanced GAX 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 effects of the waste heat source temperature(Tw=135°~200°C) and the outlet temperature(Tg =170°C ~200°C) of the gas fired desorber (GFD) on the cycle performance. Two different WGAX cycles, Type A and Type B were introduced, and compared from the viewpoint of cycle performance. It was found that the effect of the waste heat source temperature on COPs was negligible for a given GFD outlet temperature. The GFD outlet temperature could be reduced down to 170°C with a higher COP of WGAX cycle than that of SGAX. The corrosion problem which may occur at high temperature in GFD of the SGAX cycle would be solved by adopting the WGAX cycles with a comparable COP. In the WGAX cycle, Type A has a merit from the viewpoint of larger absorber/generator (GAX) heat exchange while Type B has a merit from the viewpoint of smaller exergy loss. In the current cycle modeling, the effect of the GAX heat exchange was dominant for a lower temperature than 181°C while the effect of the exergy loss was dominant for a higher temperature than 181°C. It is strongly recommended that there should be a subcooling effect to improve the cycle COP in the WGAX systems.
