Old Question with a new twist???

[zorad]

I've seen the question before about the well head and would like to
revisit it. I have a small lathe and CNC mill and have built one of
the Stirling engines Jerry Howell offers and tried a design of my
own that, although quite asthetically appealing, never ran. So, I
get the principle, but not on an engineering level. My idea isn't
to revolutionize the energy industry but to possibly take small
advantage of a previous catastrophe. The catastrophe occured when
we drilled 6 wells before hitting water on our twenty acres. Only
one of the 5 empty wells is lined but it's 500 feet deep and, like I
mentioned, I have 20 acres so space isn't an issue. Having done
some very basic, and probably inaccurate math I've calculated that
with a 33 degree celcius temperature difference I could get upwards
of 11 cubic feet of expansion. This is ideal in that it would be
with displacing all of the air in the well which is 55 degrees F to
an outside air temp of -5 degrees F. Like I said it is ideal in
that it doesn't get that cold too often but it does occasionally. I
know you never get 100% temp change and I'm sure there are a bunch
of other factors I don't even know about. In the summer it gets
upwards of 100 but you could create a mini greenhouse cover that
raised it upwards of 120 I'm guessing. So, here's my thought.
I put a plate on top of the wellhead that has a hole in the middle
and smaller holes around that hole. It is 6 inches in diameter and
fitted to the inside of the well liner. Attached to the inside of
the center hole is a piece of PVC pipe 500 feet long with holes cut
in it. I'm not sure of the pipe diameter as I'm not an engineer and
don't know the ideal way to build this. Around the PVC pipe is a
bladder that is 500 feet long and 5.75" in diameter. The idea here
is air forced into the PVC pipe files the bladder displacing the air
in the well out the top. The PVC pipe and slightly smaller diaphram
ensure the top doesn't fill first and block the air coming up and
out the smaller holes. On the inlet hole the PVC pipe is connected
to a reversible air pump. Now I put a 90 on it and attach 500 feet
of 6" PVC laying on the ground. Inside it I do the same thing I did
to the well with the plate, PVC pipe, and diaphram. In this way I
can use the air pump and bladders to displace the air from one side
laying on the ground to the other side in the well and vice versa.
I'd time it to be 90 degrees out like the small model I have.
According to my math; it's 25 degree F outside right now and the
internet says my well is about 55 degrees F. That means I'd get a
5.5 cubic feet of contraction and expansion assuming I moved 100% of
the air (not the case)and got 100% temperature change (not the
case). If the rest of my math is right the PSI change is only .89
but with the large air volume I can spread it across a larger piston
and it would generate 629 lbs of pressure on a 2 and 1/2 foot piston
moving it with a 1 foot throw. Even if these numbers are right I
know I can't get a complete temperature change from 25 to 55 so the
numbers are still off and I lose some to driving the air motor,
computer mechanism that would control it, and friction. Also I'm
wondering about using the air bladders. As I'm using air for the
bladders would it be a problem or perhaps act like a regenerator? I
know it won't power the world but wouldn't it be cool to drive by
that empty well and smile as it made at least some energy instead of
driving by remembering the $5k I spent on just one empty well? So,
my questions are; given that I already have the 500' empty well
could this work to create any energy and is there someone who can do
the math with accuracy and determine at what temperature difference
it should run, how much power.....

I'd also like to know if the concept will work sufficiently to just
run itself as I have an idea along these lines on a useful purpose
for it.

thanks,

Mark

[stan.hornbaker]

Your message indicates some innovative thinking as to a way to get some return from a dry hole. I'm not sure of the structural ability of a 500 ft. vertical piece of PVC pipe suspended vertically to carry its own weight. The cost the 1,000 feet plus the bladders etc would be expensive and the cycling of the air from one to the other would be so slow as to make any output from the system very un-economical in my considered opinion.

As to the Stirling engine you designed and can't get to run. I assume this is an LTD pancake engine with circular displacer and cylinder on the bottom and a flywheel, output cylinder and piston on top, with a connecting rod and a displacer rod.
Drill and tap a #4-40 hole in an inconspicuous place on the top plate to take a #4-40 flat head machine screw to close and seal the hole. With the hole open the engine must run freely when spun by hand and when closed turn slowly but not stalled or with great difficulty. These tests insure that the engine is almost but not perfectly air tight.
Jan Ridders of the Holland makes exquisite Stirling engines and will supply drawing of many of them via email request. Look for his listing at

[bptdude___2569]

Yeah, he just gave you priceless specifics about tweaking your engine.

About the well thing, though...

I actually gasped when I read the part about the 500 foot bladder, even a 500 foot piece of PVC might be tricky!

The sad truth is, you are very not likely to get a functional Stirling powered by the relatively small temperature differences from the hot and cold sinks, even when reversed.

But, I do love the hands-on innovation and Yankee ingenuity you have shown! *huge smiles*

So, here is my best suggestion.

1. # heat pump, go look it up, and think if you could make this work. basically you use it by taking permanent construction costs to do away with operating costs. if you had a larger cooling hookup, that cost you more to build, cooling into the ground, your cooling operating costs would be much lower, and you may have enormous amounts to play with.

2. # something more fun just for you!

In the heat of the summer, the bottom of the hole will stay cool, only as much as you put heat into it, and the surrounding ground absorbs the heat. In this respect, you might want to use well number six, the one with the water in it.

If you ran 500 feet of flexable PVC tubing down and ran an air pump feeding it from the top, the return air would be cooled. The input to the airpump comes from the house. This would be a large quiet air pump, if you could find something like that. You would be replacing conventional air conditioning with this. If the cost were about the same to setup, because you found a huge old air pump you fixed up, then you will have only the electricity cost of the pump itself for a cooling bill, to cool what could be a huge area.


In the winter, it would be interesting to see if cold air, like fozen air from the unheated barn, were pumped down the well, the barn would be heated to about 50 degrees.

Ideas for you, good luck....

- Joe

[stan.hornbaker]

Well casing is 6" D. with an area of 28.27 SqIn or 14 SqIn for each duct up/down to circulate air. That will take a sizable blower/air pump to cool an average house. High air velocities poor heat exchange noisy blower, etc. would make this most unattractive.

Far better to use the wet well as a heat sink for a conventional heat pump A/C system.