Patent ID: 7770806

Claim:
An apparatus for maintaining a substantially constant temperature within a space within an enclosure, the apparatus comprising: a variable-capacity temperature changing system for changing the temperature within the space by at least one of adding heat to or removing heat from the space; a temperature sensor positioned and configured to sense a present temperature within at least one of the space or air drawn from the space; an input device configured to receive an input temperature set point from an operator of the temperature changing system; a controller that is in communication with the input device and in control of the variable-capacity temperature changing system, wherein the controller is configured to automatically continuously gradually change the capacity of the variable-capacity temperature changing system so that the temperature within the space asymptotically approaches the input temperature set point, and wherein the controller comprises: a first control means for changing the capacity of the variable-capacity temperature changing system over a range of present temperatures within the space, wherein the first control means provides a maximum capacity at a first end of the range, a minimum capacity at a second end of the range, and at least two gradually differing intermediate capacities between the ends of the range, and a second control means for automatically moving the range, wherein the second control means moves the range less frequently than the first control means changes the capacity.