Direct Fluid Heating possible?

[boss]

Howdy
My name in Brian Rodgers
I live with my family in northern New Mexico. We're going to build something Rocketstove oriented.

I've been making biodiesel since 2005.

We built our own axial flux wind turbine
I'm wondering if it would work well enough to heat fluid directly with the Rocketstove? From what I've been reading heat exchangers have their own set of problems due to the excessive heat on the coils.
I'm contemplating what I can use the heat for. Sometimes it would be handy to boil WVO (waste Veggie oil) Also we have five or six 55 drums of glycerol which needs distilling to remove the methanol
Has anyone used a Rocketstove as the heat source for a still?
I like the idea that it uses small sticks and gets a great deal of heat output. I don't know because I never built a Rocketstove, but I assume it is simple to turn off the heat when the fluid is to temperature?
Brian
outfitnm.com My alt energy sustainable lifestyle website. No ads, not selling anything.

[canyon]

I built a rocket still for ethanol in particular but it also works for hot h20 heating. External heat exchangers are good for hot h20. I built a tube shell version (stainless steel) and used a series of tee's/crosses with dampers to change exhaust stream flows and bypass. I highly recommend building a basic "out of the book" unit first to get some ideas on how it works before doing any real fabrication. You can heat a shop, dwelling, or greenhouse nicely with a mass bench. The mass bench is great to dump the heat and capture it when your other means of heat exchange are up to temp. Plus with pipes in the bench you can harvest some of that for preheating etc. Anyway, as you get more specific in your needs and start looking at details I'll share what I've learned. Please share your experience too!

[boss]

Thanks for the info. After reading here I concur: it will be prudent to build a basic unit first. A buddy is going to do a rocketstove workshop here at my shop at the end of this month.
outfitnm.com/wp-content/uploads/Shop-turbine-Oct-2010.JPG
In an attempt to learn as much as possible beforehand, well here I am.
Brian

[randy]

Heating liquid with a rocket stove is exactly how I found this forum.
I have a different dilemma.
I live in S Florida, and I am looking for an economical DIY solution to Air Conditioning, so we can wean ourselves from the grid, and be more self sufficient, in the event the shtf.
My thoughts are to store heat from solar in eutectic salts, and use that heat to drive an ammonia gas driven air conditioning unit, similar to how RV frigs work.
The rocket stove might be an economical way to supplement the heat storage.
The other part of my plan will involve a super insulated earthbag house filled with rice hulls, giving us an R-45 or 50.
In this way, I think I can reduce my AC requirements from the typical 36-60,000 btu/hr to maybe 5-12k btu/hr.
Doe anyone know of any type of plans available?
So far, all I've found was the Yurt under the floor rocket heater by Fisherman's Daughter, where she wrapped a copper coil around the outside of the barrel.
It seems to me that you would want a coil inside the drum, for maximum heat transfer. You may also want that to be filled with a special fluid, like antifreeze.

[Donkey]

Randy..
Yer cooling needs might be better met, at least mostly accomplished with a thermal mass wall (read cob) in the north side, down in the shade. You might want to insulate in the south against the heat and thermal mass in the north to bleed it off.

To coils in the barrel: yeah, it can work, maybe a little too well. Pipes there should NEVER be smaller than 3/4 inch and ALWAYS include safety valves.
Personally, I'd put the coils in the mass storage, a couple/few feet down from the barrel.

[boss]

To coils in the barrel: yeah, it can work, maybe a little too well. Pipes there should NEVER be smaller than 3/4 inch and ALWAYS include safety valves.
Personally, I'd put the coils in the mass storage, a couple/few feet down from the barrel.

Sounds like POP (pipe on pipe) heat exchanger.
I also like the notion of mixed media walls. I may be rebuilding our house this Summer. I really want to be around rock again. The last time I built with rock I put it on the south side, but I lost the house in a divorce before I got a chance to see how it worked.

My situation is much in the air right now, I still need to keep ideas in mind for a number of possibilities.

NASA scientists call for curbing methane gas, black carbon
www.thestatecolumn.com/science/nasa-scientists-call-for-curbing-methane-gas-black-carbon/
Perhaps you all have seen this story... For me it is a testament for Rocketstove technology

[endrunner]

I have been wrestling w the heat to cool problem for years. do you plan to build your own ammonia system? Commercial ones start gigantic, even smallish ones start at 30k. Building your own can be tricky. Even the large refrigerator ones are tricky. They can work at the plant but by the time they are shipped anywhere they no longer work. Also i think trying to drive cooling with low heat like in the salts may be a show stopper.

Most cooling systems need higher quality heat. I read every related patent for the last 30 years. It is not an easy problem. I only found one solution that really had promise in taking low level heat and making cool air. Unfortunately the guy would not license it, and is not developing it. Bummer. I had a way to maybe do something like it, but ran out of time to finish experiments, maybe this summer.

[Donkey]

I've often wondered if there was a low tech solution to this.
Could heat pipe technology be adapted to work?
These little passive coolers are used in the Al/Can highway to help keep it frozen.

[Deleted]

Posted by Donkey on Yesterday at 10:26pm

Could heat pipe technology be adapted to work?

Yes, no problem.
A working range of a water heat pipe starts at the freezing point.
Purified water in clean metal with a smooth surface will freeze at -48°C.
The upper range of a water heat pipe is only limited by the pressure it can withstand.
400 ºC / 752 ºF are possible, depending on the thickness of the tube and the material
it could be even more.
The cold end hast to be above the hot end.
The temperature differenze between hot and cold end is very small.
For copper pipes only a few °C.
If the heat at the cold end is removed fast enough to keep it within the working range
the hot end will stay within too, even if the environment of the hot end is much hotter.

DIY one is simple.
Many years ago I have created a 8mm heat pipe of material from a DIY-shop for less than 3$. It could keep a 100W CPU 8°C cooler than a commercial one for more than 150$.
Even a 150W CPU could be keept in a save range with a single 8mm pipe.

The amount of heat that can be moved will be increased with the diameter of the pipe
and deppends also on the amount that can be removed at the cold end.