Abstract: Apparatus and process are disclosed for increasing the efficiency of thermally actuated absorption process such as absorption compression and absorption heat pumping. The improvement allows greater temperature overlap between generator and absorber, ambient responsive performance, significantly lower need for rectification, multiple temperature level refrigeration, and hybrid operation. Referring to FIG. 2, the useful result is obtained by routing the sorbent from the externally cooled absorber (10) to a sub-ambient absorber (2) and further cooling and diluting the sorbent by means of the evaporator (28). The sorbent is concentrated in the absorber-heated generators (14 and 18) and the externally heated generator (22).