A Survey of Discontinuous Temperature Control Methods for Electric Space Heating and Cooling Processes I-The Survey

The historical background of electric space heating and cooling, and automatic temperature control, is summarized, and developments since world war II outlined. The advantages of discontinuous control systems are traced from recent investigations into the control of temperature in electric space heating, and the gap between nonlinear control theory and the discontinuous control of electric space heating and cooling is outlined. The representation of the controlled process by block diagram is discussed in detail. The choice of the temperature transducer for use as a primary feedback element is examined. The suitability of nonlinear elements for line voltage control is discussed. The snap-acting switch is treated as a discontinuous control element. A control equation is quoted combining the primary feedback element, the control element, and the process. The action of this control equation is illustrated.