Thermoelectric cooling is a new technology that has the potential to revolutionize the way things are kept cold, whether it is food, wine, beer or cigars.  In fact, it is a completely different approach to refrigeration from standard compressors.  

How Compressor Coolers Work

Compressors are the heart of refrigerators and air conditioners.  A compressor works thanks to special chemical refrigerants that are able to turn from a liquid to a gas at fairly low temperatures. When it expands into a gas, the refrigerant is able to absorb heat.

When attached to a thermostat, compressors cycle on and off to keep temperatures within the desired range by applying pressure to the refrigerant so it turns back into a liquid, thus allowing all the heat the refrigerant had been carrying to be released into the air.  With the refrigerant as a cold liquid again, it's ready to head back inside to pick up more heat and continue cooling.

How Thermoelectric Coolers Work

TEC diagram

As their name suggests, thermoelectric cooling systems rely on electricity flowing through two different types of conductors – such as different types of metal like copper or zinc. When DC voltage is applied and direct current runs from one conductor to the other, there's a change in temperature where the two conductors join. When this small thermoelectric effect is multiplied by creating junctions between two ceramic plates, a cooling effect strong enough to keep appliances and computers cool is created.

TEC diagram

One plate is the "cool side" while the other is the "hot side." The cold side goes inside an ice-free cooler or wine refrigerator, while the hot side is connected to metal fins that act as a heat sink to help dissipate excess heat on the outside of the appliance.

Thermoelectric cooling (TEC) is also known as solid-state cooling, because there is no liquid refrigerant running through the machine. Instead, solid metal is used to transfer thermal energy.

Products Which Typically Use Thermoelectric Power

  • Small refrigerators and wine coolers
  • Electric portable picnic, beverage, and car coolers
  • Portable and personal air conditioning and other small cooling appliances
  • Cooled seating
  • Cooled coverings such as blankets

The Benefits of Thermoelectric Cooling

In general, TEC works best in small spaces, particularly for electronic devices where there simply isn't enough space to put a compressor-based cooler. In a small size cooler, these systems are also quite efficient and may use less electricity than a compressor-based unit of the same size. Thermoelectric cooling also allows for very fine temperature control, to within 0.1 degree under certain conditions.

Solid state cooling units have no moving parts, so they are far less likely to break than a traditional compressor, which requires several fans and lengthy coils through which refrigerant must pass.

TEC’s use no refrigerant, which are known to damage the ozone layer if they leak from a faulty machine. These refrigerants also make proper disposal difficult. 

TEC is also silent. Unlike a compressor, which vibrates when running and can be quite loud when it cycles on, the simple electric current required to run a TEC makes no sound at all, unless a fan is present to improve air circulation.

The Drawbacks of Thermoelectric Cooling

TEC units quickly become costly when used in large spaces. This is because more ceramic plates are needed to cover a larger area, and in turn require higher input voltage to operate. In other words, the more ceramic plates needed, the more electricity needed to run the machine.  Slightly larger compressors, on the other hand, do not use that much more electricity than a smaller one. 

TEC is entirely dependent on the ambient temperature for its ability to cool. Unlike a compressor system, which can maintain sub-freezing temperatures in certain applications, a thermoelectric device can only bring down the temperature to a certain point below room temperature. This may not be a problem indoors if you have central heating and air conditioning to limit extremes in temperatures, but the temperature difference can be a big deal in RVs or camping applications. While thermoelectric cooling does offer fine temperature control, it's crucial to understand that this is only within the range allowed by the outside temperature on any given day.

Thermoelectric coolers also don't dehumidify the air around them. The ceramic plates simply transfer heat away from one area and into another, leaving the moisture content of the air intact. This is wonderful when dehumidifying may not be a desired result; for example, cigar humidors which should stay quite moist as they cool.  Since TEC doesn't have any influence over the humidity levels in a humidor, it is much easier to keep humidity levels steady without having to constantly add moisture to keep up with a compressor's dehumidification. In cold climates a thermoelectric cooler can also be run in reverse, which will allow it to operate as a heater to maintain the perfect temperatures for cigars all year round.

This is very different from compressor cooling, in which cold evaporators lower the dew point of the air and cause moisture to condense. These water droplets are carried outside and left to drip away in a compressor air conditioner, effectively lowering the moisture content of the air in the home.  This is very desired for a refrigerator to keep food dry to help keep rot at bay.

Which is Better – Condenser Cooler or Thermoelectric Cooler?

Choose a thermostatic cooler if...

  • ✓ You're very concerned about the environment
  • ✓ You plan to keep it in a room with steady temperatures year round
  • ✓ You are aging wine and wish to reduce vibrations that can stir up sediment
  • ✓ You want exact control over the interior temperature

Choose a compressor cooler if...

  • ✓ You live in a climate with temperature extremes
  • ✓ You want to be able to chill carbonated beverages to be extra-cold
  • ✓ You aren't bothered by the sound of your regular refrigerator
  • ✓ You need an extra-large storage capacity

Thermoelectric cooling is a fascinating technology, and it definitely has its place when it comes to wine coolers and humidors. When shopping be sure to carefully compare options and keep in mind the most important features for the perfect appliance.