Data has arrived! The persimmons are ripening and the experiments are taking place. The first series of tests were using different heater power levels, 150W, 300W and 600W. Note that most commercial dehydrators of this size use around 1kw, but they also heat the food more than I would like, which kind of cooks it and changes the nature of it.
I will first apologize for my lack of scientific rigor. The amount of fruit was not kept consistent between tests because my supplies vary and it just takes so much time to do a batch. There were long periods of no measurements due to me being asleep. Also, I did not measure the temperature, which is an important parameter. Having said that, here is the result of the first three tests.
One cool thing to point out is that the 600W test was drying 999g of fruit. After just 2.7 hours it was down to 672g. That means I evaporated 327g of water in just 2.7 hours. That's almost a full can of beer. In total it evaporated 749g, or about 75% of the mass, in 10.3 hours. I suspect it got to a good level of dryness earlier, but I lack data points due to being asleep.
So how about energy use:
- 600W for 10.3h = 6.18kWh
- 300W for 25h = 7.5kWh
- 150W for 36h = 5.4kWh (It looks like it would take about 36 hours to get to the same dryness)
Considering time required, the clear winner is the 600W version.