How Thermoelectric Generators TEG work (Seebeck Effect) is outlined below. We have been manufacturing TEG Power Generators for the last 20 years. Interest in this field has exploded in the last 5 years. We are here to help explain the nuances of the technology as there is very limited information on the web.
Thermoelectric modules work on two different principals
1. Peltier Effect: This effect introduces power to the module with a resultant cooling of one side and heating of the other. These types of modules are low amp (typically in the 6 amp range, running at 12V) and are designed for low temperature exposure of no more than 70°C to 80°C hot side. Higher temperature exposures will cause the module to either break apart, couples joints to melt and are not good power generators!
2. Seebeck Effect: This effect creates a temperature differential across the module by heating one side of the module and cooling the opposite (heat removal side). These modules have been specifically designed to operate at temperatures in the 320°C (BiTe). 360°C Hybrid modules (Combination of BiTe and PbTe) designed to take advantage of hot side temperatures in the 260°C to 340°C range, PbTe designed for 450°C to 600°C (842°F to 1112°F) of which we have 2 selections (PbTe only and PbTe/TAGS) and finally CMO Oxide modules (from 600°C to 850°C) (1112°F – 1562°F) hot side. To see our selection click on Shop.
Correct terminology is essential to any technology. A Seebeck Module is a power generator (power from a heat differential) DT and a Peltier Module is a cooling module (supplying DC power to get a differential) hot side and cold side. You can use a Peltier module as a generator but will not be able to produce much power because the materials used to bond the device together are low temperature and the module will be destroyed if exposed to high temperatures. To produce meaningful power you will need to expose the hot side to temperatures in the 300°F to 700°F range or more! If you want to produce milli watts this is less necessary. The cold side should be designed to remove maximum heat ( Liquid moving in a liquid sink is the best) as it passes from the hot side through the module or modules to the cold side. Sub zero if possible on the cold side. The colder the cold side is the more power is produced. In fact with the same DT a module will produce slightly more power given the equivalent DT but a lower cold side. This is because as a semiconductor is cooled it’s internal resistance decreases.
Two critical factors dictate power output
1. The amount of heat flux that can successfully be moved through the module (HEAT FLOW). The greater the amount of heat the more power can be produced. Example: If the heat source is a candle the amount of power that can be produced is limited. If you have a 100,000 BTU wood stove you can produce significant power enough to charge a 12 or 24V battery system if you can tap the direct heat inside the stove. For an explanation go to (What’s News)
2. (DT) Delta Temperature – the temperature of the hot side less temperature of the cold side.
Great effort must be placed on both the heat input design and especially the heat removal design (Cold Side). The better the TEG Generator System construction is at moving heat from the hot side to the cold side and dissipating that heat once it arrives to the cold side, the more power will be generated. Unlike solar PV, which use large surfaces to generate power, Thermoelectric Seebeck Effect modules are designed for very high power densities. On the order of 50 times greater than Solar PV! Thermoelectric Seebeck Generators using moving liquid on the cold side perform significantly better than any other method of cooling and produce significantly more net additional power than a pump consumes (based on system size). So, to move the best possible heat would require the best thermally conductive materials such as Aluminum and Copper in the construction of the Thermoelectric Generator system.
The best designed Thermoelectric Generator System.
Want to see one working with outputs to show multimeter recordings from our unit click here https://www.youtube.com/watch?v=3-prKCGwV5M
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To finalize we will include an example:
If you want to produce a 100 watt TEG thermoelectric generator. The TEG size is based on a DT of 100° C (Hot side – Cold side)
- Need at least 2000 watts of heat on the hot side going thru the modules given a 5% efficiency conversion.
- Require to dissipate 1900 watts of heat on the cold side continuously as only 100 watts is being converted to power.
- How critical is DT. The same 100 watt TEG. If DT temperature is increase to 150°C your output would increase to roughly 140 watts. If DT increased again to 200°C your power output would increase again to roughly 180 watts.