  We consider absorption refrigerators consisting of simultaneously operating
Carnot-type heat engine and refrigerator. Their maximum efficiency at given
power (MEGP) is given by the product of MEGPs for the internal engine and
refrigerator. The only subtlety of the derivation lies in the fact that the
maximum cooling power of the absorption refrigerator is not limited just by the
maximum power of the internal refrigerator but, due to the first law, also by
that of the internal engine. As a specific example, we consider the
simultaneous absorption refrigerators composed of low-dissipation (LD) heat
engines and refrigerators, for which the expressions for MEGPs are known. The
derived expression for maximum efficiency implies bounds on the MEGP of LD
absorption refrigerators. It also implies that a slight decrease in power of
the absorption refrigerator from its maximum value results in a large nonlinear
increase in efficiency observed in heat engines whenever the ratio of maximum
powers of the internal engine and the refrigerator does not diverge. Otherwise,
the increase in efficiency is linear as observed in LD refrigerators. Thus, in
all practical situations, the efficiency of LD absorption refrigerators
significantly increases when their cooling power is slightly decreased from its
maximum.
