35W 220VAC Peltier Thermoelectric Dehumidifier Stainless Tube
How A Thermo-Electric Dehumidifier Works
Thermo-electric dehumidifiers (sometimes called Peltier or Peltier
effect dehumidifiers) use the thermoelectric effect (more
specifically the Peltier effect) to convert electricity into a
temperature difference across a Peltier module. This created
temperature difference is what facilitates dehumidification. Before
we look at the parts and processes involved in the operation of
thermo-electric dehumidifiers, let’s first discuss the science
behind how they work. That science is the thermoelectric effect.
Thermo-Electric Dehumidifier Parts
A thermo-electric dehumidifier is made using very few parts. It
1. The Peltier module
2. Two heat sinks – a smaller cold side heat sink and a larger
(about twice as large as the cold side) hot side heat sink
3. A fan – on most thermo-electric dehumidifiers under $100 this is
nothing more than a small 12V computer style fan
4. Various switches and buttons
The Peltier module is sandwiched between the two heat sinks. As we
discussed above, one side of the Peltier module gets cold and the
other side gets hot when electricity is run through it. The cold
side of the module is in direct contact with one heat sink. The hot
side of the module is in direct contact with the other heat sink.
The cold side heat sink is on the side of the dehumidifier where
warm humid air enters – the front of the dehumidifier. The hot side
heat sink is on the back side of the dehumidifier. Behind the hot
side heat sink is the small brushless fan that pulls air through
the whole assembly.
So we have, in order from the front of the dehumidifier where air
enters to the back of the dehumidifier where air exhausts through
- The cold side heat sink
- The Peltier module
- The hot side heat sink
- The fan
It’s important to realize that the fan pulls the air around this
whole assembly of parts toward the back of the dehumidifier. There
the air exhausts through the top of the dehumidifier.
Warm humid air enters the dehumidifier through the front grille.
It’s being pulled into the dehumidifier by the fan at the back of
the dehumidifier. This warm humid air first comes into contact with
the front of the cold side heat sink. Here is where
dehumidification occurs. Just like warm air condenses onto the cold
evaporator coils of a compressor based dehumidifier, the warm air
that enters the thermo-electric dehumidifier condenses onto its
cold side heat sink. The cold side heat sink has a smooth finish
with a angled finned design to allow for the condensate to easily
drip down into the condensate collection reservoir below it.
Keep in mind that the same air is still being pulled into the back
of the dehumidifier. The air essentially travels around this front
cold side heat sink and the whole Peltier module/ heat sink
assembly to the back of the dehumidifier. Here the air is pulled
past the hot side heat sink. The air exhausts out of the
dehumidifier as warmer (because of the hot side heat sink) dryer
(because of the cold side heat sink) air.
Now that you know how thermo-electric dehumidifiers work it’s time
to look at how they compare to their compressor based and desiccant