A ---------------> B _ /\ / \ / \ / \ / \ / \ / \ / |_ C
Point B: Temperature climbs to 5 degrees
Point C: Temperature drops back to 0 degrees
Well, the set point is.... 0 degrees. And this is the reference temperature for the entire system. When the cycle travels from point A to point B, the temperature raises to 5 degrees. There is a switch in the thermostat which will close at this point and start the compressor coils. These will cool the system, taking it from point B to point C, where the system has returned to the set point and because of negative feedback, will cause the thermostat to open the switch and turn off the coils.
"But tell me, now the heck does your body know when to stop drinking water, or eating food? Ingestion is a delayed process....."
In the human body we call them satiety mechanisms. In simple terms satiety is a means for the human body to make a guess as to the amount consumed. We all need these satiety mechanisms because of the structure of the human digestive system. Digestion is not an immediate process. Surely you know about not swimming for at least an hour after eating, and that digestion can take eight hours or longer....