What Is a Thermoelectric Generator? How a TEG Turns Heat Into Electricity
- PiggyPower
- 22 hours ago
- 3 min read
A thermoelectric generator, usually shortened to TEG, is a solid-state device that converts a temperature difference directly into electrical power. There is no turbine, piston, alternator, or spinning shaft inside the thermoelectric element. Heat flows from a hotter side toward a colder side, and the thermoelectric material produces a DC voltage through the Seebeck effect.
The Seebeck effect in plain English
Thermoelectric materials respond to a temperature gradient. When one side of a module is hotter than the other, charge carriers move in a way that creates an electrical potential. Connect a suitable load and current can flow. The larger and better-controlled the temperature difference, the more electrical output the system can generally produce within the module's safe operating range.
Why a TEG needs a hot side and a cold side
Heating the module is only half the job. If the cold side heats up until both sides are nearly the same temperature, electrical output falls. A working generator therefore needs both heat input and heat rejection. Depending on the design, the cold side may use air cooling, a heat sink, liquid cooling, or another thermal path.
Why water cooling can make a thermoelectric generator more useful
Water can carry a large amount of heat away from the cold side while keeping the generator compact. In a system such as PiggyPower, that moving water also creates another opportunity. Instead of treating the rejected heat as useless waste, the hot water can be sent toward storage, a heat exchanger, or space heating. That is one reason water-cooled TEG systems are interesting for off-grid and combined heat and power projects.
What can a thermoelectric generator run?
The answer depends on the generator's actual output under load. Small systems may be useful for LEDs, USB devices, sensors, radios, or charging a battery bank slowly. Larger multi-module systems can support higher-power DC loads and more meaningful battery charging. A TEG should be evaluated by real wattage at stated hot-side and cold-side temperatures, not by a voltage number alone.
Where thermoelectric generation makes the most sense
TEGs are especially attractive where heat already exists or where a fuel source is already being burned for another reason. Examples include wood stoves, controlled burners, hot surfaces, engines, industrial waste heat, remote equipment, camping systems, emergency power, and small combined heat and power experiments. Their biggest advantage is that they can make electricity without a mechanical generator inside the thermoelectric device.
TEG efficiency is only part of the story
Thermoelectric conversion is not usually the highest-efficiency way to turn premium fuel into electricity if electricity is the only thing you want. The economics change when the heat source is already available, the system needs reliability with no moving parts in the thermoelectric element, or the rejected heat can still be used. In those situations, total useful energy can matter more than electrical efficiency by itself.
How PiggyPower uses thermoelectric generation
PiggyPower Cells use controlled heat on the hot side and active water cooling on the cold side. The electrical output is conditioned for practical use, while the cooling loop can carry useful heat into hot-water storage or HeatBanks for space heating. The Cell line ranges from compact low-power systems through larger multi-module generators for higher output projects.
The short answer
A thermoelectric generator is a heat-to-electricity device. Keep one side hot, keep the other side colder, stay within the hardware's temperature limits, and a properly designed TEG system can produce continuous DC power as long as that temperature difference is maintained.
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