Method and apparatus for controlling comfort conditions including setback

Abstract

Method and apparatus are disclosed for controlling and selectively setting back the comfort condition, such as temperature, within a conditioned zone utilizing a system which includes both preferred and back-up conditioning means, the former exhibiting more favorable energy consumption characteristics than the latter. The system is operable in both a normal mode, and in an economy mode during which the comfort condition is permitted to degrade toward an economy level during a setback period of predetermined duration. Selective operation of the preferred and back-up conditioning means is effected in order to minimize energy consumption during both modes and especially during the time that the comfort condition is restored to the normal level from the economy level. In a preferred embodiment, the preferred conditioning means comprise an electrically operated heat pump of the vapor compression type and the back-up conditioning means comprise electrical resistance-type heating means. A second aspect of the present invention involves the provision of a system which includes a refrigeration system for cooling a conditioned zone in conjunction with economizer means for supplying cool ambient air to the conditioned zone during those times when it is available and wherein operation thereof is effected in both normal and economy cooling modes so as to minimize the overall energy consumption of the system.