SparWeb;
He's pretty good at details and generally answers emails and posts.
Having played around with this tin can and using heat from a few different sources, I think I'm going to stay away from any liquid addition to the sand.
In fact I'm working on cooking the sand as dry as possible, since I'm leaning towards as close to a closed loop system as possible, along with a pressure gauge & relief valve of some sort.
Back when I had my Mercedes 5cyl 300TD I got around to "remembering" how to build a tube-in-tube system and found that the cooling system worked great to pre-heat the Bio-D. I of course added a few extra temp probes (Both digital and analog) Analog cause I'm nostalgic for swing needles
![Grin ;D](https://www.fieldlines.com/Smileys/default/grin.gif)
as I was curious about the returning fuel's temps.
I also remember the disaster here when a steam boiler failed and launched itself killing two onsite and two people who had just started a new job 60+ meters away.
The video liked below gives a very good recreation of what happens.
https://www.youtube.com/watch?v=3Bs6W19cLcYI know from reading a bunch of your posts and answers to other posts, you understand
THE DANGERS when doing these sort of tests and I know JW is a steam guru, BUT anyone else reading these needs to watch the video so they are aware of how quickly
things can get deadly ![Embarrassed :-[](https://www.fieldlines.com/Smileys/default/embarrassed.gif)
.
I'm also remembering surface contact is vital to extracting the stored energy in an efficient way. OF course all this Mechanical engineering math gets my brain to hurting again and I need to take libation breaks often
![Cool 8)](https://www.fieldlines.com/Smileys/default/cool.gif)
. I still have an old 1M satellite dish that I may setup as a sorta of heliostat to gain a few extra temps.
I've also done some of handed testing of capturing waste heat from our gas dryer by using a few soldered together tins to pump a little warmer air into the house , I borrowed a few surplussed air monitors to make sure there wasn't any nasty un-burned hydrocarbons trying to give me a headache.
I do like the use of tin cans, as they are free, can take a pretty high heat and solder together nicely too. Using the surface area of them I can do these trails pretty cheaply. Also when I ran out of solder I tested a few connections using the Flex-Tape, that worked surprisingly well for a short term test.
Sorry for the disjointed reply;
It's been a busy week
![Shocked :o](https://www.fieldlines.com/Smileys/default/shocked.gif)
Bruce S