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Day 3

A project log for Solar filament drier

How to keep filament dry while being too poor to afford electricity.

lion-mclionheadlion mclionhead 02/01/2022 at 04:250 Comments

Communication finally improved enough to get a full 24 hours of data.  The fan was only on when inside temp was above outside temp.  The temperature crossings show clear acceleration up when the fan turned on & acceleration down when the fan turned off.  An important distinction is the temperature is not the temperature of the filament but the container.  The filament is hotter than the container because it's black & massive.  The fan transfers heat from the filament to the sensor, with the expected inflections in temperature.

The feedback was tuned to keep the inside dewpoint right at the outside dewpoint as the temperature rose.

The rise in dewpoint in the morning should be faster & the fall in dewpoint in the evening should be slower with the fan actively controlled, but the temperature crossings aren't the ideal times.  More water would be extracted if the fan came on earlier & shut down earlier.

A sensor that detects solar input might be the answer.  The thresholds would be quite unstable as the sensor moved around.

There could be a derivative of inside temperature. If inside temperature rises a certain amount, turn on fan.  If inside temperature falls a certain amount, turn off fan.  If inside temperature is above outside temperature or inside dewpoint is above outside dewpoint, always run fan.  In this case, clouds caused a few drops in temperature during the day.  This would have stopped the fan prematurely.

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