Thermoelectric device wraps around hot pipes to generate electricity

Thermoelectric device wraps ar...
The flexible form-fitting thermoelectric generator laid flat (top), and wrapped around a hot pipe
The flexible form-fitting thermoelectric generator laid flat (top), and wrapped around a hot pipe
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The flexible form-fitting thermoelectric generator laid flat (top), and wrapped around a hot pipe
The flexible form-fitting thermoelectric generator laid flat (top), and wrapped around a hot pipe

We've already heard about hoses that get wrapped around existing hot water pipes, using heat radiated from the pipe to heat water inside the hose. A new wrap-around device, however, uses that same pipe-heat to generate electricity.

Created via a collaboration between Pennsylvania State University and the National Renewable Energy Laboratory, the experimental thermoelectric device is made up of multiple flat, square modules known as couples.

More precisely, it consists of 12 rectangular strips of six couples each, with a flexible metal foil substrate electrically connecting those strips to one another. Unlike previously developed flat, rigid setups, this design allows the 72-couple device to be wrapped around hot water pipes – or other types of pipes that get hot – in a home, factory, or anyplace else.

As is the case with other thermoelectric devices, an electrical current is generated as electrons move from the warmed inner side of each couple to its cooler outer side – the greater the temperature difference between the two sides, the stronger the current. The electricity can be channeled into a grid, or used to charge a battery.

When applied to a hot gas flue pipe, the prototype is claimed to have exhibited the highest-ever reported output power and device power density from a single thermoelectric generator. In more detail, a 3-inch (76-mm)-squared version of the device utilized a 570 ºC (1,026 ºF) temperature difference to deliver a total power output of 56.6 watts.

"Think about an industrial power plant with pipes hundreds of feet long," said Penn State's Prof. Shashank Priya. "If you can wrap these devices around an area that large, you could generate kilowatts of energy from wasted heat that’s normally just being thrown away. You could convert discarded heat into something useful."

A paper on the research was recently published in the journal ACS Applied Materials & Interfaces.

Source: Penn State

If they generate more value in captured energy, than they cost to purchase and implement without a 5 year ROI, then great, take my money.

Otherwise, it's just another stepping stone to a more practical device far down the road at best.
Would work great on the exhaust of an ICE/ hybrid car
Why not insulate the pipes and save on the energy being lost in the first place? This sounds like an inefficient way of producing energy.
History Nut
Like all "proof of concept" ideas/developments, this is just a first step in a long journey. Industrial applications would seem to be the best initial use. Further development may lead to practical consumer uses. I like to say we should always think in terms of energy rather than gallons of fuel or other sources. Finding ways to use energy that is otherwise wasted is key to lowering costs overall and greater efficiency in use of our fuels.
Douglas Rogers
Very handy for an off-grid wood stove!
It's still an inefficient heat->electricity converter. If you've got waste heat at a significant temperature difference, insulate the pipes and send the heat to a turbine or Stirling engine or other efficient converter. If the temperature difference isn't significant, such as warm dishwater, you're not going to generate worthwhile amounts of power. Thermoelectric generators have niche applications, so improvements are good, but forget about marketing this as a 'power your house from waste heat' product.
This already applied on a small scale by the ECO fans placed on top of my wood stove. If this could be applied to the inside and outside of house insulation using the temperature difference there in a cost effective manner it might be another component of a solar/ wind powered home.
Malcolm Henry
Even if this development is a step to further development it proves that waste heat is a resource that can be utilized. As for least of efficiency one only has to look at any IC motor to see a very low efficiency against heat energy that needs to be got rid of through the radiator. To me the IC motor is the most inefficient piece of equipment ever developed. As for comments concerning the use of insulating pipes etc , if one has ever worked with industrial boilers and heating systems the metal cladding still gets hot and any surface that gets hot is wasting heat/energy. If one thinks of all the surfaces that gets hot from solar heating of iron roofs through to artificial heating it is a source of power generation. The larger the heated area the greater the power generation. The only restriction well be the cost verse the return that's going to be the limiting factor. More surface more effieciency.