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Peltier dehumidifier Answered

Hello. I'm experimenting with peltier dehumidifier. First I know its least efficient dehumidifier but I have one and I'm trying to experiment with it to increase efficiency. We have many smart people here, maybe you guys can help me to understand one thing. On peltier dehumidifier air is pulled through cold side in to the hot side and warm "less humid" air coming our from other side. Why not to pull hot air from the hot side and reroute it to cold sink because that would create bigger temperature difference on the cold side and would increase condensation and warmer air has more moisture as well. Please correct me if I'm wrong because I dont understand why these dehumidifiers are made this way. Thank you


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1 year ago

Thanks for your great answer. I guess I'll leave peltier alone :))


Best Answer 1 year ago

Sadly our current laws of physics won't allow for this to work better.
The idea sounds logical but not once you consider if you heat humid air it actually is less humid in an airstream plus the peltier lelement woul waste just more nergy this way.

If you want to make a crappy base more efficient then work on making it better by eliminating what you can ;)
The element should be controlled PID-PWM control.
The temp of th cold side should be kept at a temp best for condensation but not freezing.
Ideally with the temp sensor placed in a suitably sized heatsink.
The hot side has its own heatsink, preferably a fan forced heat pipe salvage from and old computer or graphics card as they allow for the best possible heat transfer - this gives you a massive efficiency boost.
With no freezing on the cold side the condensating water will just drip off into a holding tank.
A finely finned heatsink as used on old CPU's works great here especially the round type.
With the fan placed in a plastic tube that goes over the heatsink, small holes or slots or holes in the fin area will get the most air through the heatsink.
Using another heatpipe here is tempting but requires to fully insulate from the peltier element to actual heatsink at the end of the pipe!
Otherwise you risk freezing over the pipe and element which would drastically reduce efficiency.
Using seperate airstreams is fine and no need to divert them onto the other side of the element.
It really has no benefit to cool a peltier element from its own cold side ;)