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Old 11-26-10, 09:12 AM   #381
pachai
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This assembly was just a test project - wanted to see if I can
get to 2'. Then I want to try to drill with water jet at the
bottom of the hole. If I can do that at 2', I might be able
to do it at 20'. (If I can get to 20' :-) The hole I dug before
is about 1 foot away.

I did not use water, did not need to clean the pipe yet.
The fitting at the top is a 3/4" tee, so I can attach a hose to it.
HD sells a female hose thread (reverse bib?) that fits on a 3/4" pipe,
so I can flush it.
I was thinking of using hose quick-disconnects.

In this configuration, I can't be flushing while drilling.
If I found a way to put a pulley or sprocket on the pipe,
I could drive it from the side, so I could connect the hoses
from the top while drilling.

(I forgot to post a picture, but I have a motor
that I won - the builder says it's big enough for about 36VDC,
for a scooter or such. I want to use it alternately on
different projects - like snowblower, drilling rig, etc.
My home PC is incommunicado today :-)

One drawback I observed, and I am sure it is a problem...
is Pipe threads are not ordinary threads. They are designed
to tighten once. The first 10 minutes of drilling was the
impact gun making sure all the fittings were really tight.
The way plumbers disassemble these....is with a sledge hammer
and a small anvil. The fittings are cast, and so they shatter.
Home Depot fittings may shatter more easily :-)


Last edited by pachai; 11-26-10 at 09:18 AM..
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Old 11-26-10, 12:48 PM   #382
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Quote:
Originally Posted by pachai View Post
One drawback I observed, and I am sure it is a problem... is Pipe threads are not ordinary threads...The way plumbers disassemble these....is with a sledge hammer
and a small anvil.
pachai,

Water pipe wasn't meant for drilling holes in the earth, bit it's cheap and can get the job done.

I was using 3/4 inch pipe, and I used axle grease on the pipe thread joints so I could get them apart more easily. I certainly got to know how to use a pipe wrench, and that really big pipe wrenches are really good pipe wrenches. If you're going to do some serious digging, aluminum pipe wrenches would save wear & tear on your arms. Harbor Freight has sales on these from time to time. I know that compared to the real thing, plumbing pipe and connectors are not the best... however they do work and I tightened and un-tightened them more times than I care to recall.

If you continue to use water pipe, one problem I found that you may encounter, was that most pipe threads are not exactly 'on-axis' (though some are better than others). This created a problem that when the drill string was assembled out of multiple segments, the off-axis condition could multiply and I had to deal with a very un-straight drilling string, flopping about in the hole.

So, I started sorting my segments by assembling short segments together and rolling them on a flat surface to check for off-axis wobble. I found a few pipes and connectors that were pretty straight and I would take them to the plumbing store and use them to sort more pipes and coupling there in the store, on the floor. It really helped. I found that some stores had pipes and connectors with better on-axis quality than other stores, but none were perfect. The on-axis condition was unrelated to the price of the pipe or the country of origin.

I also found that the threads on one end of a pipe segment were often nearly perfect and that the threads on the other end were usually much more off-axis. I considered cutting the off-axis threads off, and making a jig that would hold a pipe connector perfectly on-axis, onto the cut end, and welding the connector on. But I was able to get pipe that while it wasn't perfect, was good enough and so I continued drilling...

This on-axis thing doesn't really affect regular plumbing. The stores are unaware of it.

Regards,

-AC_Hacker

Last edited by AC_Hacker; 11-29-10 at 10:16 AM..
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Old 11-28-10, 01:01 AM   #383
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For grease, I used a petroleum-based lubricant that I
had used to grease the fill tube in the toilet.

I needed to buy it on short notice, so I bought
the kind they sell in the all-night drug store.

It's baby scented...not Vaseline, but house brand,

And it can be submitted to my Health Flexible Spending account. :-)
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Old 12-03-10, 07:44 PM   #384
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Default Beginning Loop Testing...

Today I decided to hook up a pump to the ground loop that was previously put in.

I have several diferent pumps laying about, so I decided to start with the smallest, cheapest one to see what the performance was like.

The pump is actually sold as an aquarium pump. it draws 35 watts and has a magnetically-driven impellor. I've misplaced the specifications for the volume and head curves of the pump.

I made an adapter to connect the 1/2 inch MPT output of the pump to a 3/4 barbed connector and connected the pump to the input of the loop field. The pump went into the bottom of a barrel and the output from the loop field went into the barrel also.

When I plugged the pump in, I wasn't really sure if it would even have enough power to circulate the water at all through the loop field. I was also very corious what the temperature of the loop field would be.

I tested regular tap water and it was stabilizing at 49F to 50F.

The loop flow from the aquarium pump was really pathetic, I measured the time it took to fill a gallon jug, and it took 3 minutes to fill it up.

After the water in the loop had flowed (slowly) for maybe 45 minutes I took another reading and it was a 51 degrees. I had expected it to be higher, but I'm more interested in what actually is.

The test I ran two summers ago yielded this graph:


... The black line, labeled "chill" was temperature if the barrel I was cooling... like the incoming water in the loop field. The light blue line, labeled "COP*10", that is bouncing all over the place like a drunken flea is the momentary, calculated COP. If I imagine a trend-line through the COP line (by thinking like a sober flea), it looks like it will be about COP = 4 when the incoming water temperature is about 50F. Not as good as I had hoped for, but good enough to keep on with the testing...

I Googled about for "how to purge a ground source loop field" and up popped this little ruby.

This document is calling for specific pieces of equipment, but the basic proceedure is there for me.

I noticed small bits of debris drifting in during the hour or so that I ran the pump. The proceedure calls for a linear velocity of at least 2 feet per second to flush out debris. I haven't calculated the velocity of the water driveling through the pipe, but it was way, way below 2 FPS.

Next step, hook up the next larger pump and continue flushing debris & purging air.

Last edited by AC_Hacker; 12-03-10 at 11:24 PM..
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Old 12-04-10, 12:17 AM   #385
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Default Loop Testing (part 2)

I broke out my quarter horse sump pump that I bought recently for flushing my tankless water heater.

The hook-up was so much easier than it was for my aquarium pump, that I don't even know why I bothered with the little pump.

Once I shook all the air bubbles out of the pump it started working pretty good, with much better water flow than before.

I could see that air pockets were being purged by the better flow rate. I also noticed that the more air I purged, the better the flow rate.

I filled up a gallon jug with the outlet pipe from the loop field, and timed it with the second hand of my watch. It took almost exactly 30 seconds to fill the jug (much better than the three minutes from the aquarium pump).

Next task was to calculate the linear flow rate to see how that stacked up against the recommended minimum 2 linear feet per second (2 FPS) flow rate.

I measured the ID of the pipe to be .815 inch

From this I calculated the area of the pipe to be .5217 square inch.

Next I multiplied the area by 24 inches per second (2 FPS) to get 12.52 cubic inches per second.

Then multiplied by 60 seconds per minute to get 751.2 cubic inches per minute.

Then divided by 231 inches per gallon to get 3.25 gallons per minute.

But I measured my fill rate to be only 2 gallons per minute, so I'm getting close, but I'm still short, according to the recommendations in the procedure.

I fiddled around a bit with the tube and found that if I put my thumb briefly over the end of the tube and quickly let go, I could expel a bit more air, but that there was still more to expel.

So this is all telling me that the suggested 2 FPS minimum is really a reasonable and true number.

It also is telling me that I need a bigger pump for purging.

But through all of this, I am not seeing any more debris in the bottom of the barrel, so even the aquarium pump, as wimpy as it is, was enough to get those debris bits out.

The sump pump has been running for about four hours now. I made a level marker so I can tell if I lose any water.

I need to resuscitate my original homemade heat pump and hook the cold side up to the loop and hook the hot side up to a measured amount of water so that I can get some idea of the effectiveness of this thing.

The loop water temperature is measuring 51F. Outside the air temp is 36F.

Delta T is 15F.

I guess there's some satisfaction in that.

Regards,

-AC_Hacker
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Old 12-04-10, 05:13 AM   #386
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Quote:
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Today I decided to hook up a pump to the ground loop that was previously put in.
I must have missed something in the thread... did you abandon your setup to use something else?
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Old 12-05-10, 09:48 AM   #387
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Quote:
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I must have missed something in the thread... did you abandon your setup to use something else?
Bathroom & kitchen remodel, it is mentioned in the thread.
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Old 12-05-10, 11:47 AM   #388
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Default Loop Testing (part 3)

I have been experiencing a slow drop in the level of water that is being circulated in the loop.

I wasn't sure if it was because I was too casual in my measurements, or if I had a slow leak in the system that I had not caught.

A slow leak was certainly possible in the 720 feet of HDPE, which featured more than 112 hand-welded joints, done with homemade thrift store sourced components. I did test all the welds before burying the pipe, but accidents can happen.

So last night, I was very careful when I measured the water level, and I noted the exact time of the measurement. I also noticed that ever since I installed the quarter horse sump pump, a very thin stream of occasional bubbles had been coming from the loop output (where the output tube goes into the barrel, I put on some transparent tubing, and the end is beneath the surface of the water, making thin bubble streams easy to spot). This held out another explanation as to why the water level was slowly dropping... because air was being slowly purged from the system, in the form of a thin bubble stream.

If I had a more robust pump, The purging would most likely have been done in the first hour.

So this morning I went down to look at the water tank again and I saw no more evidence of the bubble stream, so it looks like the purging process is complete.

I also carefully checked the level of water in the barrel, and there was no perceivable change in level over a 15 hours period. If I don't see any change in level over the next few days, I'll call it a perfect loop.

Regards,

-AC_Hacker
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Old 12-07-10, 01:26 PM   #389
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Default Loop Testing (part 4)

I just went down to the cellar and measured the level of the water in the barrel where the sump pump has been churning away for the last four days. I am happy to report that there has been no change in the level of the water that is circulating through the loop field. I was expecting at least a tiny drop in level from evaporation, but I can't see any change whatsoever.

So the loop-field is holding perfectly, and all 112(plus) welded joints are functioning exactly as I had planned.

Looking back, it is good that I tested all joints, because I did find two joints that were leakers, and I was able to replace/repair them before I installed them in the boreholes.

So, while I did all of my research, and was very careful when I worked, and did test everything as I went along, it is extraordinarily gratifying that the whole loop field is working perfectly.

Regards,

-AC_Hacker

Last edited by AC_Hacker; 12-07-10 at 01:28 PM..
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Old 12-07-10, 01:34 PM   #390
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Mad congrats on the leak free loop field!

How about hooking It up to your sanyo for temporary use?

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