Fenders. Or maybe mudguards.

On Tue, 16 Feb 2021 22:20:25 -0500, Frank Krygowski
wrote:

On 2/16/2021 4:23 PM, Jeff Liebermann wrote:
On Tue, 16 Feb 2021 13:41:47 -0500, Frank Krygowski
wrote:
Regarding home heat: We have a fireplace. Normally fireplaces heat the
room they're in, but cool the rest of the house by drawing in cold
outside air to replace hot air going up the chimney. Long ago I
fabricated an outside air intake and installed glass fireplace doors so
the warm air stays in. But it works best with the blower grate - which
requires electricity.

Hmm. Another application for a Stirling engine.

Too complexicated. Think about a self powered fan (peltier junction):
https://www.google.com/search?q=self+powered+fireplace+fan&tbm=isch
I built my own, which somewhat resembles those in the photos. Be
careful to not get the peltier device too hot. The first one I built
died when the solder melted.

I rather like using two fans, like this:
https://www.youtube.com/watch?app=desktop&v=kgfAAA4Uajc
One fan keeps the top of the heat sink cool thus creating the
temperature difference for the peltier junction. The larger fan blows
the hot air into the room.

Peltier? Meh. That's black magic at work.

It's not magic:
https://en.wikipedia.org/wiki/Thermoelectric_generator
The big gotcha is lousy efficiency. I did an insulated box, heater,
and Peltier module test, which yielded about 3% thermal efficiency.

Give me nice, understandable
thermodynamics! ;-)
https://warpfivefans.com/
https://www.stirlingengine.co.uk/d.a...VULCANSTOVEFAN

Nice. However, I see some problems. The Warp Five Sterling Engine
powered fans are priced from $250 to $432 plus taxes and shipping.
https://warpfivefans.com/stove-fans-stirling-engines/
The Kontax stove fan is $180.

The typical Peltier Junction powered fan on eBay is $7 from China or
$40 to $60 and up from US vendors.
https://www.ebay.com/sch/i.html?_nkw=wood+stove+fan&LH_TitleDesc=0&LH_PrefL oc=1
Or, do it thyself:
"DIY $2 Woodstove Fan EASY 2 minutes"
https://www.youtube.com/watch?v=OLn7bGzxJGs
More of the same:
https://www.youtube.com/results?search_query=wood+stove+fan

Building one does require some thermal calculations, which I didn't
bother doing and ended up melting the solder in the Peltier Junction
device. I've built several so far. My favorite was replacing the
upper heat sink with an aluminum plate and a cat food can filled with
water. I could adjust the rpm by adding or draining water. Spilling
water is not an option. Also, take some time to balance the fan.
Having a hot fan "walk" off the top of my woodburner was rather
dangerous.

eBay Peltier thermoelectric modules:
https://www.ebay.com/sch/i.html?_nkw=Peltier+Thermoelectric
At those prices, you could easily build one for tinkering without the
need to drill a Sterling size hole in your bank account.


--
Jeff Liebermann
PO Box 272 http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann AE6KS 831-336-2558