Energy and Exergy Analysis of Combined Ejector - Absorption Heat Transformer
Résumé
In order to upgrade industrial waste heat at low temperature to higher process temperatures, an optimized
ejection absorption heat transformer is studied as an effective means for upgrading waste heat at low
temperature with relatively adequate performance compared to conventional single stage heat absorbers. By
the use of the ejector, the absorber pressure becomes higher than the evaporator pressure and thus the
cycle works with a triple pressure level. The ejector has a double function; it enables the pressure at the
evaporator to remain low, and upgrades the heat quality obtained in the absorber by mixing the refrigerant
vapor with the solution. Under the same operating conditions, system's COP and ECOP are compared
between an AHT with ejector and without ejector. Major conclusions are that the circulation ratio is reduced
and the system's dimensions can be reduced. The latter show potential for overall cost reductions.