I have a question about air conditioning and the probable modes of failure.
I recently installed a Nest thermostat in my home. I've noticed that it seems to prefer to have the air conditioner's compressor on for multiple short durations instead of one long period. This got me thinking...
1) This is going to kill the starter capacitor of the air conditioner more quickly than normal.
2) I wonder why they made the control system like this... It MAY extend the life of the compressor.
Here's my thought process:
The AC compressor is effectively a non-linear constant-Q source (i.e. you pump energy into it (by compressing the freon) at a rate (which is technically a function of the temperature differences involved) and it heats up until the energy coming in (from the compression) equals the energy going out (by the blower)).
If you were to run this continuously, the compressor itself would get really, really hot, always running at its maximum temperature (i.e. the crossover point between the efficiency-drop of the compressor at the high temperature vs the convection-cooling of the compressor). If you work it in smaller increments, you can keep the temperature down of the compressor.
The starter capacitor is an annoying $100 capacitor... but the compressor dying can effectively total the AC.
So: how much of the wear on the compressor is due to over-heating? Is this actually going to make an appreciable difference, or is Nest just unnecessarily eating my starter capacitor?