semi-new distiller need help with cooling system

[bitoric]

Hi guys long time lurker first time poster.
Last year i had a very small still running for a while inside my garage and i was using a water hose to bring water into my condenser and another hose to syphon it outside where it drained away.. needless to say a huge waste of water and money for water, that coupled with the small size of my still made it too costly to get any decent amount of liquor. so this year ive got all the stuff i need, and built a decent size pot still but to cool it i want to make a recirculating system, i have a basic plan:
I have an old above ground pool pump for a 14x4 foot pool so it pumps quick.
i was thinking i could dig up the yard behind my shop and bury some pvc pipe in a big u or w shape and have it pump through the pipes underground cooling the water then back into my condenser making it much cheaper to run only costing me the minimal electricity to pump the water and the propane fr the burner.
So my question is has anyone done this before? if so how deep did you bury the pipes and how much length of pipe was needed?
if you havent done this before i would still appreciate any input or ideas on the subject, i want to have this running in the next week or two but i cant start my mash until i know i can run my still without any cooling issues

[Od1tspyd3r]

Bitoric, do a search for swamp cooler or recirculating cooling. The efort you would expend on cutting the trenches for the pipe could be used to build a swamp cooler, with the pump and gravity doing most of the work.
What kind setup you runnin? And what kind of condenser.

[bitoric]

ill be running a 35 gallon drum with a copper coil at 1" thick from a 20 gallon stock pot built still.
i want to use the ground which is always cool at low to med depths to keep the water in the drum cool enough to condense the alcohol
as far as a plug in recirculating cooling system they arent cheap and it would cost less for me to buy some pvc, mod my pool pump and pull out the tiller and a shovel.
the work isnt the issue just trying to figure out at what depth the ground will maintain cool enough temps for this, and how much feet of pvc pipe id need.
and my issue with the swamp cooler idea is that it wont work on rainy days(id rather be distilling on rainy days and fishing on sunny ones).
also it evaporates water at a high rate making it inefficient as far as water usage is concerned

[bitoric]

well i found the info on the depth i would need to lay the pipe.
on average 4-6 feet deep the ground maintains a temp of 50-55 degrees.( i see what you meant by the work in digging the trenches 4 feet is alot of dirt)
now the question i have is how much length of pipe would i need to run?

[Od1tspyd3r]

Found this might help, http://www.engineeringtoolbox.com/pipe- ... _1734.html" onclick="window.open(this.href);return false;" rel="nofollow
Butbif my math is right to get little more thab a half gallon with 4" thats 12 feet.

[shadylane]

bitoric
Just a thought.
The 35 gallons of hot water from the condenser has energy that you paid for.
Figure out how to reuse it or make the condenser more efficient or both.
Then worry about how to dissipate the rest of the heat.

\

[bitoric]

I have a water heater so i have hotwater on tap s as to the suggestion to use it for something that would still be taking away and adding water back i need to find a way to use the same water with some method for cooling the water, maybe ill buy a small pool and set it up near the shop in the shade and fit the pump to the condensing barrel when i do a run... the larger source of water might be enough?
anyone have any better suggestions that wouldnt cost me more than $100?

[superdaveva]

I have what's known as a cube, 250 gal tank with cage around it. I keep it under the down spout and water my garden with it. I use a small pump to recirculat the water and an old radiater and fan to keep it cool. You can get them cubs for about 50 bucks.

[Od1tspyd3r]

Im running a similar setup, smaller albeit. 6 gal pot with 20 gal condenser and a full run only gets the condenser hot at the top. Have you made a run with you current setup.

[Grey_Meadow]

bitoric, Your biggest problem is the Thermal Conductivity of PVC pipe. k = Watts / (meter x degree C)
copper k= 400; Steel k = 50; Stainless Steel k = 16
PVC k=.19
using a heat loss calculator on http://www.engineersedge.com" onclick="window.open(this.href);return false;" rel="nofollow (http://www.engineersedge.com/heat_trans ... _12921.htm" onclick="window.open(this.href);return false;" rel="nofollow)
using 1" PVC Sch 40 pipe, I calculated the heat loss at 58 Watts / meter. Assuming you are inputing 1500 Watts into your boiler you will need 30 meters of buried pipe to keep the water from heating up. Most people us a relatively large volume of water and just recirculate the same water. Doing some basic calculations I would use cooling tank of about 4-5 times the size of you boiler. So if you have a 5 gallon boiler, use a 20 gallon cooling tank. If that isn't enough add a junk yard car radiator to the system.

Try the recirculation system in an open tank before you dig up you backyard.

Grey

.

[S-Cackalacky]

Grey-Meadow makes a good point about the heat exchange rate for PVC - copper would be a very expensive solution for the method you're proposing. I believe you're way over thinking the whole cooling thing. If the condenser your using isn't capable of maintaining temp over the course of a run, either get a bigger cooling water reservoir, or replace water in the existing reservoir over the course of the run. To replace water, you need to add cool water to the bottom of the reservoir and remove water (hot) from the top of the reservoir. You could do this with a second reservoir and a pond pump ($20 from ebay). Or, you could use a piece of vinyl tubing to the bottom of the reservoir with a funnel attached at the top and just pour cool water into the funnel when you think you need to cool it down. You would also need an overflow near the top to take off the hot water - run it into a bucket to be used later. Or, you could even run a garden hose to the bottom of the reservoir with an overflow to a drain or to your lawn and just run some fresh cool water into the reservoir as needed.

There are many inexpensive and simpler ways to do it without having to dig up your yard.

[dstaines]

Your biggest problem is the Thermal Conductivity of PVC pipe. k = Watts / (meter x degree C)
.

That's definitely true, and I wouldn't recommend PVC pipe for this application. What you're proposing to build, if you didn't already know, is called a Ground Source Heat Pump. I've looked a little into making something similar to what you're proposing for maintaining steady temps in a wine "cellar" cabinet, but they are used commonly to cool (and heat!) houses, on a much bigger scale than what you or I care about. What the pros use on the whole-home installs is HDPE tubing, 3/4 diameter or so, in long looping coils laid along the bottom of a 4-6 foot trench. The thermal conductivity of HDPE is not a lot better than PVC, but the walls of the tubing are quite thin and it works just fine.

You can probably get away with smaller diameter stuff, and you don't need to buy it from a professional installer. Go to any irrigation supply store and ask them for a roll of half-inch diameter drip tubing. Make sure its the kind without built in emitters. I know a shop that has 1000' rolls for $55 which should be way more than you need. Wherever you go will also likely have all kinds of fittings that you can use to make it connect to your system.

If you pull this off, PM me! I'd love to see someone make it work on a hobbyist scale.

[bitoric]

first off od1tspyder i have not made a run with it yet.
i have got a pool from my friend and am planning to use it to recirculate the water.
now as for the future i intend to still go with the underground recirculating system eventually and will pm dstaines in the future when i can find the time to get it done. also thanks very much dstaines for the hdpe suggestion that would be a much easier method.
thanks guys for all the responses and input it helps alot

[SoMo]

Dude you are over thinking a very simple setup, there's been folks do the underground pex etc it doesn't work as efficiently as you think. A 10$ trash can and a 6$ pond pump some vinyl or garden hose and you're done. How much are you going to spend digging meters of ditch 5 ft deep? Gonna be throwing money away,think it thru you can build a lot for a few dollars and some reading. Good luck.