Navitron Renewable Energy and Sustainability Forum

General Renewable Topics => Inventions, Ideas, Innovation, Bodges etc => Topic started by: sleepybubble on March 15, 2009, 07:27:24 PM

Title: Combining devices
Post by: sleepybubble on March 15, 2009, 07:27:24 PM
Was wondering around the house aimlessly having completed suffiecient DIY tasks for the day and the following occurred to me.
I did some basic googling and realised that with TEG's in their current level of infancy there is not much merit in it but...
Would it be possible to build such a thing as a combined immersion heater/TEG... on some days it could be providing heat via electricity and on other days it could be extracting heat and producing electricity.

Just a thought.

Title: Re: Combining devices
Post by: Ivan on March 21, 2009, 12:11:38 AM
TEGs are very low efficiency - in practice, probably no better than 2%, although in theory they could go to 5%. If they went much higher, they'd start to break the rules of thermodynamics (at least, with small dTs). So they'd cool your cylinder quite a lot to produce a mediocre amount of electricity. They could be used as a heat-dump for solar systems, but you'd be unlikely to make back the 40W or so used to circulate the water, so even then, not much use.