A chiller for supplying chilled fluid for cooling a room includes two distinct power inputs. A critical power input is configured to supply power to a controller and to a pump in a chilled-fluid loop that circulates a cool working fluid through an air handler 34 to cool the air in the air handler. A non-critical power input is configured to supply power to a compressor and, possibly, other elements of a refrigeration loop that includes an evaporator, the compressor, and a condenser to provide refrigeration via an evaporation/condensation cycle. When power is lost to the non-critical power input, the critical power input can continue to independently power the circulation of the working fluid through the chilled-fluid loop to continue to provide a level of cooling in the air handler.