1. A system for cooling, comprising:one or more computing structures, each structure comprising:
one or more cooled servers; and
an intra-structure cooler configured to selectively provide coolant to the one or more cooled servers;
one or more heat rejection units configured to cool coolant;
one or more heat exchangers configured to selectively transfer heat from the coolant in the intra-structure cooler to coolant in the one or more heat rejection units; and
a controller configured to adjust cooling of the coolant in accordance with ambient temperature information, to decrease cooling of the coolant if an input coolant temperature falls below a first coolant threshold temperature by an output to disengage one or more heat exchangers, and to turn on additional servers if the input coolant temperature is below the first cool and threshold and all heat exchangers have been disengaged.