larry wrote:
wrote:
Uncle Monster wrote:

... The heat is just enough to trick the thermostat, not to warm the
refrigerator compartment.
How would that accomplish the goal?

The slight heat produced by the heater is enough to raise the temperature
around the thermostat to trick it into running the compressor for a longer
period of time. It's not necessary to increase the temperature of the whole
refrigerated box, just the temperature around the thermostat.

That doesn't make sense to me...

It's like the timer with a 10K resistor clipped under a
regular wall thermostat to do an over-night "setback".
Thermostat thinks it's getting warmer and turns off the
furnace when the room isn't warmer.

But that makes the room colder at night. How do we keep the fridge
a constant 40 F and the freezer frozen in a 40 F room?

If the freezer stays 0 F in a 60 F room while the 40 F fridge box
is gaining Q Btu/h from the room, cooling the room to 50 will reduce
the fridge gain to Q/2, so the compressor will run half the time.

But the required freezer run time will only go down by 50/60, so
we need to add enough heat to the fridge box (vs the thermostat box)
to raise the run time back up to 50/60 of the 60 F room run time, no?

The fridge box won't absorb any heat at all from a 40 F room, but
the freezer still needs 40/60 of the 60 F room run time to stay 0 F.

Nick