[clayrichardson]

Thank you for the feedback, this is awesome!

There is always more to read up on and calculate :)

EDIT: The current dehumidifier does accumulate ice on the evaporator coils, depending on the ambient conditions. Once enough ice has accumulated, the compressor turns off and the ice melts into the collection tray. I'm assuming we have to depose the ice out of the dry atmosphere at BRC, since the dew point is below the freezing point of water. Is this not the case?

[FiatLuxDave]

If you aren't trying to make ice, then the energy which goes into making ice is waste. This cuts your efficiency. So, in that case, you do need to include the enthalpy of fusion in your calculations, just be aware that portion is waste. In fact it is doubly wasteful, because the ice reduces the thermal transfer rate and having to stop the compressor means your duty factor is lowered (less water per hour for same size machine).

There are ways to prevent this, although I'm not sure if they would work for your project. Adding salt is a classic, so you can supercool your water while remaining liquid. That's probably not great for drinking water, even with RO. If you can use the melting of the ice as a source of cooling, you can recycle the enthalpy of fusion. It really is a waste and you don't need to pay it. One way to do this is to use the melting ice to lower the heat rejection temperature of your compressor.

However, it may not be worth adding complexity just to cut your energy costs by 15%.

[intron]

Would it make sense to use a reversing valve and use the hot fluid to melt the collected ice?

Agreed that it'd be better not to freeze the water at all, but that might be difficult at low dew points.