The conceptual sketch below shows a model of a closed loop control for heat in a room. Prepare a block diagram for this closed loop control. Label each block on the block diagram with the name of the corresponding component or components on the sketch. To simplify, assume the furnace delivers the net heat being the difference between what the furnace produces and the heat lost from the room, Q_Net = Q - Q_L. The thermostat operates by comparing T_SP (the thermostat’s set point) to TM (the measured room temperature) and sending that signal to the furnace. The furnace is “on” if that difference is positive, and vice versa.

Thermostat Room Net Heat, QNet Furnace, Q