Stirling Engines.

[classic33]

Yes, it was something like that. How does it work?

See https://en.m.wikipedia.org/wiki/Crookes_radiometer

 

[nickyboy]

Temperature differentials are very common throughout the world such as between surfaces in direct sunlight and in shade. It seems that Stirling Engines have been proposed as a means of generating power from these differentials which seems to make sense

I presume that Stirling Engines are just too expensive to build on an industrial scale to make the power generation economic

 

[mad despot]

I wonder why they don't use them at power stations - couldn't the heat that's wasted through cooling towers be used to drive Stirling engine generators?

 

[derrick]

Made a light and heat pad for it.

View: https://www.youtube.com/watch?v=YNBx96cdrjA&feature=youtu.be

 

[Dave7]

I hope so. I've seen traditional bicycle horns for sale at £10 on the web, they're identical to the ones sold by Poundland.

How much are they in Poundland?

 

[Soltydog]

See https://en.m.wikipedia.org/wiki/Crookes_radiometer

They were popular in the 70s when I was a kid & my dad had one. I was told (can't remember who by) that it was light that caused it to spin not heat, apparently the dark side absorbed the light whilst the white reflected it, close but no cigar

& on a side note (might be of interest to @raleighnut ), whilst in Aldi today they had stove fans available, marked at £22.99, went through till at £21.99. We've had a stove for nearly 15 years since moving to our current house & looked at them a few times, but today finally bought one It does seem to direct some more heat into the room, but not sure if the room temperature will be noticeably warmer ? https://www.aldi.co.uk/workzone-woo...VC7DtCh0sxQPxEAQYASABEgIOv_D_BwE&gclsrc=aw.ds

 

[Yellow Fang]

Temperature differentials are very common throughout the world such as between surfaces in direct sunlight and in shade. It seems that Stirling Engines have been proposed as a means of generating power from these differentials which seems to make sense

I presume that Stirling Engines are just too expensive to build on an industrial scale to make the power generation economic

I think it's largely because they tend to be rather inefficient. A heat engine's maximum theoretical efficiency is determined by the ratio between the hot temperature and the cold temperature. The heat source is normally not that hot compared to ambient temperature. If you had a heat source that was 60°C and air temperature was 10°C then the maximum theoretical efficiency would be (Th-Tc)/Th = 50K/(60K + 273K) = 15%. In reality it would be a lot less, particularly as the heat source is applied externally and has to conduct across the barrier.