35W 220VAC Peltier Thermoelectric Dehumidifier / Peltier Condenser

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 consists of

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 top:

• 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.

The Process

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 counterparts.