Additionally, over-drying is bad for clothes.
That we agree on. I'm just saying if you have an accurate sensing method for when the cloths are actually 'dry enough' then worrying about having more precise temperature control, say a thermostat switch Vs a full P&ID controller, I don't see any benefit in the added complexity and expense. And what drying temperature to operate at Vs the 'best' time duration to dry seems to be a pretty constant product (total BTU consumed per drying cycle needed to dry the cloths to the 'dry enough' state) in my thinking.
The whole waste heat recovery thing is a different additional animal and is not what I was talking about. Certainly any method of heat recover and recycling will pay off because it would allow the 'dry enough' time to happen faster vs using no waste heat recovery/recycling. If there is other external uses for the waste heat instead of recycling via a air intake heat exchanger, then the possible savings are external, but still real and useful, but doesn't effect what control algorithm the dryer should use.
Bottom line I was trying to make is if one can indeed actually measure accurately when the load has reached a 'dry enough' state then that is the key process variable to used in a closed loop control algorithm.
Under drying the cloths load is a failure of control objective, over drying of cloths is needless waste of energy and hard on the cloths, I suspect we can agree on that?
Lefty