Heat and light

[openspaceman]

For those that have ecofans on their stoves here's a step up

 

http://he-energy.gmbh/en/seebeck_eng.html

 

It actually knits in quite well with solar PV for off grid as it would provide light and IT if you use a laptop and LED lighting and at this time of year the PV gives very little.

 

I was following Caterpillar's  development of a truck which had no alternator but derived 5kW of electricity from heat passing through the exhaust using Seebeck TEGs but that has gone quiet. TEGs seem to be an order of magnitude mere expensive than PV  for a given installed capacity.

 

 

[Squaredy]

46 minutes ago, openspaceman said:

For those that have ecofans on their stoves here's a step up

 

http://he-energy.gmbh/en/seebeck_eng.html

 

It actually knits in quite well with solar PV for off grid as it would provide light and IT if you use a laptop and LED lighting and at this time of year the PV gives very little.

 

I was following Caterpillar's  development of a truck which had no alternator but derived 5kW of electricity from heat passing through the exhaust using Seebeck TEGs but that has gone quiet. TEGs seem to be an order of magnitude mere expensive than PV  for a given installed capacity.

 

 

Interesting but is it practical?  

 

My fan only worked for a year or so - big fat waste of £60 that turned out to be.  Looking at other AT threads they seem very flaky.  Is that the case with all these electricity from heat devices?

[openspaceman]

30 minutes ago, Squaredy said:

Interesting but is it practical?  

As I said Caterpillar failed to get it to market yet.

 

My ex colleague went on to work on solid oxide fuel cells  in conjunction with gas turbines  and told me they were months away from the market producing electricity at 70% c thermal conversion efficiency, RollsRoyce made him redundant last week and the business was sold to LG in Korea.

 

30 minutes ago, Squaredy said:

 

My fan only worked for a year or so - big fat waste of £60 that turned out to be.  Looking at other AT threads they seem very flaky.  Is that the case with all these electricity from heat devices?

My £25 one is still going fine after 3 years, not sure it distributes much heat though. The thing is the little Peltier effect devices they use were developed for cooling as they have a big market for cooling electronics (and beer ;-)) thus they became available cheaply. The problem is they break down at 200C, so if you get them too hot...

 

Dedicated heat to electricity ones use much the same effect but named  after the bloke who described it, Seebeck, and presumably survive higher temperatures, but probably much more expensive.

 

These semiconductor TEGS   convert about 5% of the heat passing through from hot to cold side into electricity, metal to metal ones less than 1% but withstand much higher temperatures.

[Squaredy]

10 minutes ago, openspaceman said:

As I said Caterpillar failed to get it to market yet.

 

My ex colleague went on to work on solid oxide fuel cells  in conjunction with gas turbines  and told me they were months away from the market producing electricity at 70% c thermal conversion efficiency, RollsRoyce made him redundant last week and the business was sold to LG in Korea.

 

My £25 one is still going fine after 3 years, not sure it distributes much heat though. The thing is the little Peltier effect devices they use were developed for cooling as they have a big market for cooling electronics (and beer ;-)) thus they became available cheaply. The problem is they break down at 200C, so if you get them too hot...

 

Dedicated heat to electricity ones use much the same effect but named  after the bloke who described it, Seebeck, and presumably survive higher temperatures, but probably much more expensive.

 

These semiconductor TEGS   convert about 5% of the heat passing through from hot to cold side into electricity, metal to metal ones less than 1% but withstand much higher temperatures.

Sounds like I have cooked mine then.  As you say it doesn't seem to achieve much anyway - when mine did work I wasn't aware of any noticeable improvement in hot air getting into the room.

[openspaceman]

19 minutes ago, Squaredy said:

Sounds like I have cooked mine then.  As you say it doesn't seem to achieve much anyway - when mine did work I wasn't aware of any noticeable improvement in hot air getting into the room.

They are cheap enough to replace

 

https://www.aliexpress.com/w/wholesale-peltier-teg-module.html

 

The important part is the bimetal strip on the bottom, this decouples the fan heat input from the stove by lifting one side as it heats, creating a small air gap.