In my haste to get the bench testing started, I didn't pay attention to the optimum location of the thermistor. I mistaken the evaporator expansion port as the factory thermistor. I would soon notice the frequent cycling. For resistive heating short cycling is not a problem due to conservation of energy, but not the case with compressor refrigeration.
There is a fine balance between selecting a narrow dead band for tight temperature regulation but in sacrifice of efficiency - energy consumption. For refrigeration for domestic use, temperature regulation is far less important. Also the store food with high thermal mass would see less temperature fluctuations than the sensor.
I would soon realize this is a much better location for the thermistor
this dual 12Vdc power panel comes in handy with 2 prototype test in progress - the bathroom skylight ventilation fan and the Ink Bird digital thermostat for the refrigerator
Speaking of the bathroom skylight ventilation fan, after over a day of test, I begin to feel the CFM, noise level, and most important, power consumption is actually quite close to a sweet spot.
now the digital temperature controller sensor is in agreement with the digital thermometer to within 1 degree C most of the time
I set the dead band to 1.5 C and with the proper sensor location the cycling time is much better. The nice thing is all these variables are within my control to fine tune them. At this point, I see no reason not to proceed with the project.
While babysitting the bench testing I have some time to pay close attention to the refrigerator. I identified a few areas for improvement to increase energy efficiency which I will address later.
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