Quote:
Originally Posted by jeff5may
The brine solution has an affinity for water. The latent heat of condensation is substituted for the energy required for the salt to dissolve. The water isn't condensing into the solution, it is being absorbed. The process allows the solution to not have to be cooler than room temperature to grab moisture from the air. It is also less energy demanding than a phase change system.
If employed by the OP, the desiccant system would not replace the mini split, it would complement operation by attacking the latent load. It could feed off of the outdoor unit waste heat, though. Direct contact not recommend (salt water and aluminum or copper could prove deadly to the heat pump), but a simple helical wrap around the compressor discharge pipe would make a good preheat exchanger.
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You still have to add heat to regenerate the desiccant, and that amount of heat is equal to the amount of energy needed to drive the desired amount of phase change. With that you likely then have left over heat that you have to get rid of. The total energy added is greater than the latent load, unless you are running the desiccant with a vapor pressure differential that helps drive recharge. Yes you can make the energy additions more efficient ("free" energy from the sun or waste heat) or use "free" energy dumps (night time radiant cooling) however the total energy required is still higher than the latent load you are removing.
Using a chilled waterfall system the only heat you are adding to the system is a small amount of pumping energy. Excess water gathered by the system only has to be drained away.
So if this is more efficient why doesn't FEMA and the military use it? #1 evaporation collected water is clean. #2 it is operating outside they don't need to bring the brine water back down to indoor temperatures.