Start now!
 

dremd,

Start now, the digging part is what takes so much time.

Call some local installers and ask what the preferred local configuration is. Is it slinkys in ditches or is it boreholes? How much earth exchanger do you need to take care of your house?

You can buy or modify or build the heat pump part during the cold months.

Start now & take lots of pictures to share with us.

Good luck!

Best Regards,

-AC_Hacker

Probably going to just rent/ borrow a Bulldozer and dig the trenches quick fast and in a hurry.

Slinkys is preferred in my location + situation.
I've got 7 Acres to spread out on; may put a few in the bottom of the pond as well; but over the last 5 years it has been pretty dry (we now get about 1/2 of the rain the we historically have).

I probably will go with just a standard A/C. I only use heat about 30 nights and maybe 10 days a year I'd like a Heat pump; but I do not feel that the extra cost/ complexity is worth while.

I did a test with an old (free) window unit and a pair of 55 gallon drums; appeared to work well; but my compressor seized before I could get any real testing done.

Thanks for the inspiration!

I don't know if you mentioned this before, AC_Hacker, but can you explain why you didn't go for an open-loop system? Bad drainage/soil composition, municipal water only, or a really deep (read: energy intensive) well?

Why not open loop?
 

Green_Masheen,

The short answer is that I live on a 50' x 100' city lot and my options are limited by available space.

I'm hitting wet sand at 17 feet but I don't think that there's enough flow to do open loop.

I could have rented a small back hoe and dug trenches and put in a slinky configuration. It would have gone faster.

The way I'm doing it with boreholes is more work, but I'm half done now with my loop field. The rest of the holes should take me less time, I've learned how to do it better and quicker.

I've also built and improved and discovered new tools to make things go easier. More about this later.

Hope this helps...

Best Regards,

-AC_Hacker

This is a great thread. I live a few miles south in the mid Willamette Valley, so I'm wondering if you're calculations (220 ft/ton of capacity) are applicable in my area. We're in the foothills of the coastal range, so there may be more rock, etc. Perhaps I could do a number of short wells too. Is there any minimum well depth required for the total depth to remain the same (ie, could I do 40 five foot wells?).
Thanks

Toward a more perfect union...
 

My flexi-joint on the electric auger was not holding up so well to all the punishment I have been putting it to.

The shock-mount connectors are working just fine at absorbing jolts and off-axis loading, but I'm watching the fourth set of these suckers fail.


So I tried a Ford/GM steering doughnut replacement part, set up the way it was designed and it worked just fine for about three glorious, high-stress minutes before failing.


So my solution was to use stainless bolts to bolt straight through the doughnut and add some rubber washers atop the flanges capped with big washers, and adjust the nyloc-nuts to 'barely snug'. Under off-axis loading, this allows the bolts and rubber washers to flex just a bit, but under full torque load, the stainless steel bolts carry the full load.


After about five hours of high stress digging, the new system is working perfectly.

Problem solved.

-AC_Hacker

I just hope that shock loading isn't going straight to your gear motor now.

Shock Load...
 

Daox,

Not to worry, the drill pipe acts as a torsion rod and acts as a buffer against damaging shocks.

Regards,

-AC_Hacker

Drilling Report Aug 31, 2009...
 

Yesterday I finished up hole number 11 of 16.

I thought I'd summarize what I have learned so far about this process. I'd be very surprised if anyone experienced soil conditions exactly like mine. I'd be much more surprised if no one had any of the experiences I have had.

So I offer the following information in the hopes that at least some of my experience can be useful to those who might want to try to make their own loop field.

Here is a diagram of the soil conditions I have encountered in every hole I have dug:


TOP 2 FEET - sand/clay/organic bits
The top two feet I initially started with a shovel and a pointed steel rod, to loosen things up. At first, just tossed the dirt on the ground near the hole, not realizing just how much was going to come out of the hole (and also not realizing that it would all have to go back into the hole). On subsequent holes, I used a 55 gallon barrel to hold the dirt while I was digging. This makes is very much easier to get the dirt back in the hole.

In my experience, roots are a problem in the top 2 feet but really not much of a problem any deeper. I started using the Shop Vac on the second hole to remove debris, and it really helped in dealing with roots, as once the dirt was vacuumed away from the root, it became very apparent exactly where to cut to remove the root.


I tried hacking out the roots with a sharpened cold chisel welded to a section of water pipe, but it didn't work nearly as well as going in with a reciprocating saw.

The top two feet were very easy to get through, the soil was sand and clay, but there was so much organic matter mixed in that the soil was 'light' and easily penetrated.

2 FEET TO 6 FEET - clay to clay/sand
This was the toughest layer to get through. The clay was pretty dry and hard. Initially I tried just a hand auger. It was slow, exhausting work. Using a pointed iron digging bar to loosen things up a bit, ahead of the hand auger helped, but it was tough work.


I tried various diggers and bits on my electric auger, with better results, but only 1/4 horse power, it could only push a three inch bit (see photo above) about a half a foot into the clay, after which I'd have to bash away with the pointed steel bar and vacuum out the debris, and back to the electric auger, etc, etc, etc. On every hole, there was a particular layer of clay at about 4 feet deep which was very tough and it took at least an hour of drilling and bashing and vacuuming to advance six inches.

So I got my hands on a 5.5 HP post hole auger and drilled out the remaining holes to the depth of the auger bit, about 36 inches. I also had Howard-the-machinist make me an adapter so I could put on an extension and drill deeper.


To my disappointment, the post hole digger didn't exhibit the advantage of power I had expected. I tried putting water in the hole a couple of days before drilling, but when I hit the tough layer of clay, it wasn't just tough but it was tough and slippery.

I tried a smaller diameter post hole auger bit and that did help in some cases, but not all.

It seemed that the ultimate approach was drilling, bashing with the pointed iron bar and vacuuming, and repeat, and repeat.

I did make an improvement to the electric auger which has helped, and that is I added an electric wench to the drill stand. A 120 volt wench would have cost me about $100 + bucks, but I got a 12 volt model on sale for $50. I had a spare 12 volt deep discharge battery laying around and a battery charger, so it was pretty easy. The real reason I added the auger is that the manual wench had open gears and I came very close to getting my fingers in the gears more than once. I have been playing guitar most of my life, and I have grown very fond of my fingers.


Also, the last time the finger tips nearly went into the gears, I did a hasty calculation of what it would cost to take a trip to the emergency room, and compared that to the $50 for the wench, an I found myself driving to the store to get the wench.


[* Drilling Report Aug 31, 2009 Part Two to come... *]

Regards,

-AC_Hacker

http://ecorenovator.org/forum/attach...int-flange.jpg

You said you'd go into more detail about this. Would you mind? :)

The Swivel Story...
 

Daox,

Sure, the water swivel is used to transfer water (or drilling mud) down a rotating drilling pipe. The purpose of this is to lubricate and cool the drill bit, and to flush cuttings up and out of the hole.

They can be purchased on ebay currently at this link:

water well swivel, great deals on Business Industrial on eBay!

I've been trying to reduce cost on this project at every step, so I made my own.

I don't currently have a lathe, so I tried to find off the shelf parts to do the trick. I made two different kinds, here's the best...

Against all advice I decided to use 3/4 inch drill pipe. I now realize that for really serious drilling 3/4 is too narrow and constrictive to transfer the amount of water required to drill deep. However, for depths such as I'm undertaking, it works just fine.

Here's a drawing:


I forgot to label the holes that are drilled in staggered positions (for strength) on opposite sides of the pipe.

Here's a photo of the drilling in process:


...so you'll want to stagger the holes and both holes should have a combined area a bit bigger than the ID of your drill pipe.

Now the trick is to find a shell and a bearing that require minimum machining to fit up properly.

Here's what I came up with:


The white shell and screw-on end caps are from Ace Hardware and are called a 'PVC 1 1/4 inch compression T'. Throw the rubber compression thingies away, you won't need them.

Here was the real breakthrough: The bearings are not measured in millimeters as bearings usually are, but are inch bearings. Get one that has an ID of 1 inch. The bearing OD must be specified to be the same as or just slightly smaller than the ID of the compression T. I found one (sorry, I forget the exact OD of the bearing) that was a perfect snug fit inside the PVC plastic compression fitting.

The 3/4 pipe OD will have to be skimmed down a few thousandths to be a proper press-on fit to the inside of the sealed bearing. This will take off the tops of the threads, but not enough to affect strength.


I stuck some bread dough about an inch down into the top end pipe and filled it up with J.B. Weld to form a plug so the water wouldn't get out.

If you want to use the rotary mud drilling technique, your rotating motor doesn't do much of the work, the water and mud become the real tool.

If you need to drill through sand/clay, mud drilling progress is really fast. However, the mud does obscure the soil you're going through. I really learned a lot about the soil characteristics, sand characteristics & soil moisture zones etc, by digging dry.

Hope this helps...

Regards,

-AC_Hacker

Drilling Report Aug 31, 2009 Part Two
 

(continuation...)

After I have managed to get through the layer of clay at 4 feet, the soil composition becomes a mixture of brown sand and clay, with the percentage of sand increasing as I go deeper. Here the electric auger works just fine, and has saved me loads of hard manual work.

I've tried lots of different bit designs on the electric auger, but the one that works the best is the bit from a manual post hole auger bit.


I make a temporary mark on the electric auger's vertical tube to keep track of drilling progress and let the auger do the work. I have found that after it has dug about 4 inches, the auger bucket is full, so I use the shop vac down the hole to vacuum out the debris and then drill down another 4 inches, etc.

Sometimes when working in this mode, the auger is turning but stops progressing, so I have found that rocking the auger stand back and forth seems to concentrate the force on an edge of the auger blade, and the auger digs on down again.

I can usually get from 5 feet to 8 feet pretty fast, maybe an hour's time.

6 FEET TO 9 FEET
At about eight feet, I start seeing black sand grains mixed in with the brown sand, so I know that the wet black sand layer is not far away.

After every five or ten buckets, I try removing the auger from the hole and try using the shop vac alone. If it works poorly, I continue with the auger, if it works well, I switch methods and use the shop vac alone. I put the 45 degree tip on and rotate the PVC pipe back and forth. This way the pipe acts both as a drill and as a debris remover, in one operation. The shop vac method is easy, fast and much safer than the electric auger.

I have used two shop vacs, one is from Lowe's and is rated at 4 HP. The other is a Rigid rated at 5.5 HP. Using a shop vac for drilling a borehole into the earth is at the very least 'cruel and unusual punishment'. As I said before, I estimated that the dirt removed from each 17 foot deep hole weighs about a half ton of dirt and rocks. The Rigid is up to the task, the Lowe's shop vac is not. This is not necessarily an endorsement for Rigid shop vacs, rather advice on choosing the right tool for the job.

I have found that the 2 inch PVC pipe works best. It sucks up great volumes of dirt and a surprising amount of stones get drawn up as well. I finally wised up and added a larger-radius PVC 90 degree turn (NOTE: large radius turns have less friction loss than sharp 90 degree elbows) to the top of the PVC pipe, and use a 2 inch rubber plumbing adapter to connect the shop vac hose to the PVC.


I use the hose clamp on the shop vac side, and use the rubber side loose on the PVC side. When the shop vac is running, the suction keeps it all together very well. The surprise benefit is that the 90 degree bend gives me a handle for rotating the pipe. And best of all, no more vacuum-hose kinks.

Blockage of the suction line is a very common occurrence. It usually occurs from stones, but can be a glop of wet sand, a leaf fallen into the hole and wet sand can do it to.


At first I thought blockage was a setback, but now I see that every blockage removed is just that much more material that is not in the hole any more.

The rubber slip-fit mentioned above, allows me to quickly disconnect the shop vac from the PVC to determine the location of blockage. I can tell when things get blocked because the shop vac will increase its RPMs dramatically. If the RPMs reduce to normal when the slip-fit is separated, it means that the vertical pipe (see photo on left above) or the PVC 90 degree bend is plugged (see photo on right above), usually but not always at the tip.

If the shop vac is still reving very high, it means that the hose is blocked or a stone has gotten lodged near the opening of the vac unit.

I have become so attuned to this process, that I can tell if the blockage is a round stone completely blocking things, or a flat stone causing a partial blockage.

9 TO 12 FEET
In my situation, more black sand means less clay and very fast removal, but it also means more and larger stones, which present unique problems.

William_Hackerson suggested that we needed some kind of down-the-hole claw to remove rocks. Here's what I came up with:


Here's another shot with a carpenter's tape for scale, along with a rock I hauled out of the hole using the claw:


If part of the claw looks like a wrecking bar, there's a very good reason.

(* Drilling Report Aug 31, 2009 Part Three ... coming soon)

Best Regards,

AC_Hacker

Hey there AC_Hacker, loving this thread! Just wondering... what ever became of the heat pump you were going to show us? Did i miss something? I'm on the edge of my seat, don't leave us hangin!

Thanks for all the info so far, looks like you've done a ton of work on this.

Thanks for all the great info!

Converting the Air Conditioner to a Heat Pump
 

CDIG,

I don't mean to leave you hanging...

The loop field is taking me longer to complete than I had estimated. My plan was to complete the loop field, then dress the water lines into the basement and then go to work on the conversion.

But I tell you what, let me know when you (or anyone else who is reading this) have the air conditioner and the heat exchangers ready to go, and I'll break what I am doing and go into the full glory of the AC-to-Heat_Pump conversion process. It's really pretty interesting and easier than you might think.

Your AC might cost from $10 to $50 depending on your luck. Your heat exchangers might be anywhere from $10 (if you scrounge copper tubing and make your own) to $40 and up (if you buy them on ebay, etc). If you make your own, don't forget to braze rather than solder (NOT EVEN SILVER SOLDER). Solder won't hold up to the vibration.

You don't want to break into your AC system until you have everything ready to re-assemble, braze, pump down and charge. The longer the system stays open, the more water from the air gets into the compressor oil. You don't want that to happen.

In return, all I ask is that you post your results to this blog, so that others can learn from your experiences, as you are learning from mine.

Deal?

Best Regards,

AC_Hacker

Drilling Report Aug 31, 2009 Part Three
 

As stated in previous entries, clay is really tough to get through. But I have had some success as of late.

I got to thinking about my earlier efforts in using a water drill or water and/or mud drill and remembered how easily it cut through the clay layer. So I designed and built another very agressive water bit to be used just to get through the clay, thinking that then I'd go back to the shop vac for sand & gravel removal.

So here's the bit I welded up. I took the photo with one hand while I held the bit with the other hand, because the bit was still too hot to touch.


I had considered tempering the cutting edges, but figured that the bit will see only limited use so I decided to use as is.

Here's a pic of the business end of the bit so you can see how I left the end open for water flow.


And here's a shot of the business end with water running through it.


As you can imagine from a dirt's eye view, with this thing coming at you, rotating away, and water blasting out all the clay and sand debris, the clay just doesn't stand a ghost of a chance.

What had formerly taken me an hour or two of arduous hacking and vacuuming, took maybe 5 minutes of watching the auger do all the work.

If I were in a situation of digging a loop field in ground that was all sand and clay, I wouldn't hesitate to use a rotating water bit. I would also not use water as I did today, but I woud use drilling mud, because it prevents fluid loss through the sand, and it inhibits cave-in of sand.

Here's a link to the stuff I used before:

QuiK-Gel, 50lb. Bag, 200 mesh Wyoming sodium bentonite, drilling mud : Mud - Directional Drilling : Atlantic Supply

I was having the problems of fluid loss, and cave in and the mud cured both of those problems. But the problem of rocks it just couldn't help. It also obscured the soil characteristics so that I really couldn't tell what was going on.

You might overlook the need for a husky flow of water or mud down the drill pipe. With rotary mud drilling, the fluid becomes at least as much of the tool as the metal and motor. So you'll want to minimize friction losses and get a pump that will really gush. For my pruposes, I used a 1.5 HP electric pump that worked pretty well. I measured it's flow rate against that of city water andd found it was 2x the volume. Worked great. Mud and sand and bits of gravel are really hard on pumps, so get one called a "trash pump":

trash pump - Google Search

...or get a really, really good guarantee.

So if you're going to go the route of mud/rotary drilling, you'll want to set up some kind of recirculating system so that debris settles out of the fluid that is forced to the top and will send the liquid mud forcibly back down the drill pipe.

Here are some links regarding rotary mud drilling:

Mud Rotary Drilling

Mud Rotary

There's plenty more on the web, but the gigantic size of what the professionals use is not always easy to reduce to DIY scale.

There are some church groups who have done some reasonable work on small scale drilling. Some videos also on youtube:

YouTube - well drilling

Some are crafty, some are crap, mine them for ideas.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%

So for me, getting through the clay, I figured I'd be going through about 2 cubic feet of clay per hole, and decided to just use water and just let the clay wash up onto the ground.

After I made it through the clay, I used the shop vac again in "wet mode": and sucked out the water and as much of the mud as I could. It took 2 or 3 vac loads per hole, but it sure beat bashing away relentlessly with a sharp iron rod.

It was a bit sticky for the first few feet going through clay/sand, but again better than clay bashing.

I'm working on the last four holes simultaneously, gas augered them all, used the water bit on them all and am now electric augering down to black sand where I can start in with the shop vac.

One thing that I learned previously that I need to include is that there is wet drilling and there is dry drilling and as I have found, each has it's benefits and its drawbacks.

The spiral auger bits like you might find on post hole diggers are fine for dry drilling, but all of those radiating "fins" can really work against you if you want to drill wet. If you have mud and water in the hole and a spiral bit, the bit can become stuck in the ground, due to all those horizontal surfaces.

I found out the hard way at the beginning of last winter, when I got a nice new $100 spiral bit stuck 8 feet down in a cold, muddy hole. I tried to pry it out of the ground with a hydrolic engine hoist and very heavy chain fastened real close to the hydrolic cylinder.

There was straining and groaning of the hoist and then a peace-shattering bang as some substantial steel failed in shear.

That new auger bit is still 8 feet down in the ground, and on cold winter nights, I can still hear it calling my name...


Best Regards,

-AC_Hacker

Sorry for my enthusiasm AC... I'm no where near ready to start converting an a/c unit into a heat pump. I guess I'm just eager to find out of this is something that I can actually build. I'm currently doing research and collecting/shopping for materials for a solar furnace for my garage... haven't had alot of time though, got other renovations in the works right now that take priority.

I've got friends who've gotten Geothermal installed in their house, they love it but it did come with a 15-20k price tag, which is why your project intrigues me so much. That and I have 4 old a/c unit laying around that I'm itching to tear apart now! I can understand that you're busy with the digging stage, so I'll be patient.

Thanks again for sharing all your work this. I'll be sure to share anything I learn and employ here.

lol, thats a great bit of story telling there. I love it!

Also, I'm very glad to see you got a bit that can get you through that tough clay! So, you should have the rest of those holes done in no time, right? :)

Response To cdig...
 

cdig,

OK, I know just how tough it is to wait for info, so I'm posting some links that ought to go a long way toward satisfying your burning curiosity.


Here is one of the most informative sources of refrigeration hacking I have ever come across:

Phase Change Building Guide - XtremeSystems Forums

It has been considerably expanded since I first discovered it.

I'd advise you to read the whole thing, and when you are through, go back and read the whole thing again. This is an absolute gold mine.

Make note of the tools required, and start nailing down access to the stuff you're gonna need. You may have friends or relatives who have some of these tools to lend or give or sell cheap.

Sometimes Chinese tools can get you by:

Harbor Freight Tools

(* hint: don't even consider the 'Air Vacuum Pump', not good enough *)

Ebay is a good source of refrigeration servicing equipment. Here's a good starting point:

eBay ? HVAC Tools, HVAC Meter and HVAC Gauge items on eBay.com. Find IT on eBay.

Also, sadly, due to the horrible economic situation, there are HVAC techs who are forced to pawn their working tools. So check out the pawn shops, but don't go there until you have studied ebay, to familiarize yourself with what the going prices are. The pawn shop owners do this as a matter of course. Prepared yourself for some lively bargaining.

Do they have garage and estate sales where you live? Another good source.

And lastly, I'd advise you to read well the section on brazing. Then get some copper tubing and a MAPS tourch (Propane will work, only slower) and some silver brazing rod, some brazing flux, and start practicing. The infra-red energy of brazing isn't so good for your eyes, so don't neglect eye protection. An old welder told me that even plastic-lens sun glasses will offer protection, but you should double check that.

Regarding brazing, the tools and materials aren't so expensive and you can get some practice right away. I tried all kinds of brazing rod for this and didn't have any luck until I tried 40% silver rod. The silver content makes it flow really nicely. This stuff isn't cheap but you can get "job packs" with about 5 or 6 sticks.

The temperature at which the brazing rod flows well isn't very far away from the temperature at which copper slumps, so there is some skill there that you will have to develop. You'll want to have this skill on tap and well-developed before you hack into your AC unit. Resign yourself to the prospect that you may have a half dozen failures before you learn how to get one really pretty brazed joint.

You may even want to tackle a homemade brazed tub-in-tube heat exchanger.

Be patient, be persistent, you can do this.

Hope this helps...


Best Regards,

-AC_Hacker

Response to Daox...
 

You aren't nearly as happy about the clay situation as I am!

Yes, here in Western Oregon we have two seasons, wet season and dry season. This weekend it is raining, it's the annual prelude to the wet season. I know that I don't have a lot of time left to work on the loop field this year, may 30 days if I'm really lucky. Working with homemade electric tools in the rain is not what one should do if a long life is desired.

After the last of the boreholes, there's still the trenching (with rented trencher) and final polyethelyene welding to go.

It's still possible that I can get it all done this year. I will be working toward that possibility.

Best Regards,

-AC_Hacker

I'll share my experience with refrigeration relating to a research project I did about refrigerating CPUs for higher performance.

Before doing anything else, research. It is very important if you want to assemble the device properly and have it work correctly on the first try. In particular, the TXV, as simple as it may seem, is one of the most difficult parts to understand. Make friends with a refrigeration engineer if you can. (In my case, the "fridge girl" I became friends with really helped me buy stuff, and not just by helping me select the right parts, as you'll see later.)

Then obtain the tools needed for refrigeration work. Some of the most common essentials are: a gauge set, vacuum pump, multimeter with thermal probe, MAPP or acetylene torch, and refrigerant can tap (if using refrigerant cans without nipples).

The gauge set is the most frequently used tool in refrigeration work. It mostly comes in 2 varieties - 2 valve and 4 valve. It is cheaper to convert a 2 valve gauge set into a 4 valve by adding a splitter and valves, although professionals may find that too clumsy. It's fine for DIY work, though. Expect to pay about $50 for a good entry level gauge set.

A vacuum pump is used to remove air and moisture from refrigeration plumbing. (Air and especially moisture can cause internal corrosion.) As previously mentioned, "jet" vacuum pumps are used for vacuum packing and are more or less worthless for refrigeration. I made my own vacuum pump from an old freezer compressor by replacing the oil with vacuum pump oil.

Unless you're going to use all flare connections (which have their own problems), you'll need a torch to "weld" (really more like high temperature soldering) the connections together. You'll need at least MAPP since propane does not get hot enough to make reliable connections. Acetylene is even hotter but much more expensive and overkill for our uses. You'll need welding rods made just for refrigeration since regular plumbing solder will crack and leak under pressure cycling. It will take a lot of practice to get it right. In my experience, the temperature is about right once the pipe starts glowing red.

Then you'll need parts and supplies. A cheap way to obtain many refrigeration parts is to buy an old refrigerator, freezer, A/C, or dehumidifier from Craigslist. (In my area, I have seen a listing for an old dehumidifier for $10. I'm going to make it into a small heat pump clothes dryer if it is still available.) You'll need to locate a refrigeration parts store in your area to buy service nipples, fittings, pipe, and some other parts and tools. Some stores are reluctant to sell to individuals (which makes no sense since they're losing a potential customer), so be prepared to locate another store to actually buy stuff. (I had a real problem buying a TXV for my CPU cooling project since only one store in my area had the right one available and they did not want to sell to me. The solution was to have my friend buy the part, which I then buy from her. Apparently, they could not resist selling supplies to a pretty customer!)

When it's time to start assembly, the parts to install last are the filter drier and (if prefilled with oil) the compressor. They will be degraded by exposure to air, so make all the other connections, then start pulling a vacuum after finishing the last connection ASAP. If you're reusing an old compressor, tape shut the pipes immediately after removing it and/or change the oil in it. If you're changing the oil, do not add the new oil until after the vacuum is pulled and then purged and leak tested with an inert gas. (Helium for inflating balloons works well, as does CO2 or nitrogen.)

If the first vacuum and leak check is fine, continue by releasing the pressure and pulling another vacuum for about 3-4 hours. Then purge with an inert gas to about 5 PSI of pressure and start another vacuum of about 3-4 hours. Repeat the purge and vacuum process again, then fill the system with refrigerant up to about 40PSI. Then start the system and continue filling until the sight glass fills up (if there is one) or until subcooling or superheat reaches the proper range.

reply to NiHaoMike
 

NiHaoMike,

Great info...

Can you say a bit more about using a freezer compressor as a vacuum pump?

What kind of vacuum levels were you able to pull?

I like the idea of a DIY vacuum pump!

Regards,

-AC_Hacker

Sam's Laser FAQ - Vacuum Technology for Home-Built Gas Lasers
I don't have a gauge that can precisely measure the vacuum level, but it pulls as low as the gauge set will measure. I estimate 1 Torr or so since it is a rotary compressor.

I have an old well on my property that we just recently decomissioned in favor of town water. In the geo_thermal manual you provided at the beginning of this thread there's a section on 'standing column well ground heat exchanger' ... thoughts?

How deep would the well have to be in order to work? The ground water is pretty high around here, so I don't think the well is very deep, but if I can use it instead of drilling a bunch of holes in my yard, why not right?

reply to cdig...
 

The easiest & cheapest way is usually the best way.

However, in my explorations of alternative energy strategies, I am continually confronted by just what a tremendous amount of energy I use habitually without being aware of it. The alternative energy strategies usually involve using energy densities much lower than what is available with fossil fuels.

I got a taste of this when I hooked up my first experimental 400 watt heat pump to a 10 foot ground loop to see how much heat I could extract. Short story is that the loop froze solid in about 25 minutes.

There was heat in that loop, but my little 400 watt compressor was drawing the heat out at a much faster rate than the 10 foot loop could supply it. The ground gives up its heat, but gives up its heat very slowly.

In a few days, I should have the last of my loops completed and I'll have 240 feet of loop for the heat pump to draw heat from. I'm pretty confidant that my little heat pump won't be able to extract heat as fast as the ground can supply it.

cdig, I'm not sure where you live, but some things you'll need to know are:

1. What is the average ground temperature where you live? If you have a state office of energy, they should be able to tell you this. It will be aprox. the temperature at about 25 feet down. The baverage ground temp where I live (Western Oregon) is around 55 degrees F. However, the measurements I have gotten at the bottom of my holes is 53 degrees.

2. What are the heating degree days where you live throughout the year? This is a number that is used to calculate of how much heat will be required in your area.

3. What is the heat load of your house? You can get some computer programs that can give you a pretty close approximation of this for free.

Try something here:

home heat load calculator - Google Search

...here's one that might work for you:

Heat Load Calculator / Refined Home Renovation

You can also figure it pretty close from your heating bill. Look at the bill from the coldest month, convert it to BTUs per hour for that month. and maybe multiply the BTU per hour by 50% to account for energy use peaks.

Last winter, where I live, we had a really cold spell, and for that two week period, I turned off my gas heat and used only electric heaters which had watt meters (Kill-a-Watt) on each one, and I kept detailed records every 4 to 6 hours, so I know with a very high degree of confidence what my energy use baseline is.

4. What is the rate of energy transfer I can expect from my source? In your case, the well you're talking about. If you look through this blog (http://ecorenovator.org/forum/projec....html#post2787), I site a test that you can do on your own well to determine what the rate of heat out will be.

So you can experimentally determine the heat you can get from your well, divide that into your calculated or measured peak heat load and see what percentage of your heat you'll be able to get from your well.

If it is over 100%, you are indeed in fat city!

If it's somewhat less than 100%, you can use your well as an adjunct to your existing heating setup and save some money.

If it's pretty tiny, like for instance only 5%, then you know that if you had 20 such wells, you'd be back in fat city.

I did exactly this procedure, and my calculations came out to 15.4 holes, so I'm going for 16.

I'm also going for a lot more insulation.

Hope this all helps...

Best Regards,

-AC_Hacker

Equipment Failure
 

Last Thursday, I had made great progress having finished the fifteenth hole.

I also suffered a setback when the pully which is at the top of my drill set-up failed.


I was trying to extract an auger from the hole #16 and the forces generated by the 2000 pound winch easily deformed it.


I wasn't terribly surprised as the pully was actually made for reeling in clothes line. I had estimated correctly that it was a good match for the manual winch, but the power winch was just too much for the light assembly.

So I bought a winch-grade pully and rebuilt the pully-carrier, this time with much stouter steel.


Problem resolved.

So now, with the show...



Regards,

-AC_Hacker

Wow, 15 holes. You're getting close now. :)

Hole #16 Prior to Filling...
 

* * LOOP SPACERS * *

There's one important detail I forgot to post earlier, so I'm apending it to this post...

I read that the performance of the boreholes is improved by keeping the 'down-the-hole' and 'returning' pipes separated as much as possible. There is a commercial product that is available that does an excellent job I am sure. But I made my own out of thin-wall irrigation tubing I had laying around and some bicycle tubes cut into strips. The local bike store most likely has a barrel filled with dead inner tubes, just waiting for you to come get some.

I put the spacers on the loop pipe at intervals of 3 to 5 feet.

In the beginning of this project, I bought 100 feet of thinwall 1/2 inch irrigation tube for $10. I soon realized that it would be crushed by the weight of the earth, so I didn't use it, and I had 'munged it up' enough that I couldn't take it back either. But it did turn out to be very useful for tubing spacers.

In the picture at the top are some spacers I cut from the plastic tubing. Since the holes varied in size, I cut a large number all at once, but varying in length from 4 to 7 inches, to fit various situations.


The photo on the bottom shows some strips of bike tires I cut into strips to use for tying the spacer-tubes onto the poly pipe loops.

I looped the tire strip around the poly pipe as shown in the photo below:


The photo above show how I passed the tire strip ends through the small tube.

And tied the free ends around the other leg of the poly pipe loop as shown in the photo below.


The photo above shows the spacerin place, doing its job of keeping the poly loop pipes spread apart. One nice thing about the thinwalled irrigation pipe is that if I mis-calculated the width of the borehole and put in a spacer that was too big, the thin-walled tubing would collapse a bit.

Toward the end of this phase of the project, I developed an alternate method which may be more appealing, and that was to make a wire hook out of coat hanger wire to be used with rubber bands cut from a fat tire bike tube. I tried a mountain bike sized tube for making rubber bands, even cutting them at a diagonal, and they were just a little bit short. I didn't try it, but I think that a 'fat-tire' innertube would be just right.

Upper picture shows the hook, with an orange ribbon attached to aid visibility, the tube spacer, and a diagonal-cut rubber band.


As shown in the bottom pic,the rubber band would be slipped over one leg of the loop, then the wire hook would be pushed through the spacer tube, hooking the rubber band. Then the hooked rubber band end would be pulled through the tube and slipped over the remaining leg of the loop. Several of these would be put over the loop, then slid into place at desired intervals.

I tried this method toward the end of the hole drilling phase, and it was just about as fast as the tying method, using cut strips, and I could see that with a bit of practice, the new method would go faster than tying.


Regards

-AC_Hacker

WOW man
MAD props!

EDIT:
Just saw you notes above about VAC pump.
If you are going for cheap http://www.harborfreight.com/cpi/cta...emnumber=96677 is impossible to beat; you will need a big air compressor to run it; but if you are doing this , once per year you could borrow one . . . mine pegs my automotive HVAC A/C gauge every time.

I also own http://www.harborfreight.com/cpi/cta...emnumber=66466
Works well also (I use if for My bio-diesel pickup tank). If you want you can take advantage of Harbor Freight tools lax return policy and "rent" one if you are careful not to scratch/ get it dirty.

Alright! Congrats on getting all the holes done! :D

Next is trenching?

Vacuum Requirements for HVAC work...
 

dremd,

> WOW man
> MAD props!

Thanks, it was a ton of work (actually 8 tons of work)!

The manifold gauges get non-linear near the end of their scale which is very unfortunate, because we really need to know what is happening at that end to be successful.

I found a very useful link to vacuum equivalents here:


...probably a good idea to bookmark AND print it out and tape it to the inside of your HVAC tool box (I have one in mine).


The venturi-type vacuum pump you linkled to (HF #96677) is able to hit 28.3" of mercury at sea level. So this would be 'Inches Mercury Gauge' on the chart. Notice that this is around 94.8% vacuum. For HVAC work, we need to pull down to at least 80 microns (99.995% vacuum) and hold it there for a while to let all the moisture that may be in the system turn into vapor and get sucked out by the vacuum pump. It's true that the venturi-type vacuum pump may peg your manifold gauge, but the extra vacuum is where the de-moisturization magic happens.

The micron gauges use the principle that heat dissapates very poorly in a total vacuum. The gauge has a tiny heater and a tiny thermocouple together in the space that is getting vacuumed. While there is air, etc in that space, the heat dissipates well. As a vacuum is approached, the heat dissipates progressively less well, and the temperature rises. The thermocouple measures this heat rise and turns that data into vacuum readings.

The other pump you linked to (HF #66466), the Two Stage 3 CFM Air Vacuum Pump would work just fine.


Might want to keep your eye peeled for a good micron gauge to show up on ebay. I bit the bullet and bought one new.


Best Regards,

-AC_Hacker

Next is Trenching...
 

Thanks for the congats, yes, next is trenching. I'm trying to co-ordinate the trencher with a friend who is replacing water main pipe at his place... save us both some money.

I'm also re-testing for leaks on all the U-tubes.


And I will repeat the thermal transfer test I did previously, this time with HDPE pipe I'm actually using and hole depths I'm actually using.


Regards,

-AC_Hacker

Reply to NiHaoMike...
 

NiHaoMike,

Thanks for the link to the laser/vacuum page. Lots of very good info there.

However, in the section on using refrigeration compressors, it stated:
So, in my opinion, for the purposes of experimentation, a refrig/freezer/de-humidifier compressor would be just fine to test out the technology.

But the purpose of this thread is enable you to build your own highly reliable, very economical Ground Source Heat Pump for your home. A properly built heat pump should last decades. And since refrigeration reliability is very much dependant on purging your system of any water, for the final version of your heat pump, you might want to get pretty serious about the vacuum thing (known good vacuum pump, known good micrometer vacuum gauge, strict adherence to proper procedure, no short-cuts).

As I have gone through this saga of learning all I can about GSHP technology and coming to grips with all the sub-technologies associated with it, my standard of comparison is a $35,000 GSHP system with a COP of 3.5. If I can approach that performance for a tiny fraction of the cost (I'm still shooting for a final cost of under $1000), then I have completely succeeded.

Regards,

-AC_Hacker

I make no claims to the accuracy of my test equipment, nor the performance of my vac pumps; but.

Harbor freight venturi vac pump
http://gallery.me.com/dremd/100071/V...12529717130001

Harbor freight 2 stage vac pump
http://gallery.me.com/dremd/100071/I...12529728370001

Not trying to make any point here; but that's my quasi scientific test results.

dremde, I'm not at all trying to disrespect your gauges. I'm sure your equipment is just fine.

The problem is that the gauges like the kind in your photos (Bourdon type) generally have their maximum sensitivity and accuracy at mid-scale readings and are the least sensitive and accurate at the extremes. In HVAC work, some very important stuff happens at the deeper levels of vacuum. This is why the micron gauge was invented.

The specs for the Harbor Freight venturi-type gauge suggests maximum vacuum it can pull to be around a 98.4% vacuum, and for the rotary vacuum pump it is 99.995% vacuum.


The Bourdon type gauge is just not physically able to distinguish between 98.4% vacuum and 99.995% vacuum. But it is at the 99.99% end that the water flashes to vapor and is pumped out.

The issue here is the inherent limitation in the design of the Bourdon Gauge.

Here are some links regarding the micron gauge and deep vacuum in HVAC:

pulling a vacuum - HVAC-Talk: Heating, Air & Refrigeration Discussion

Pulling A Good Vacuum Equals $$$ For The Contractor - How To - Air Conditioning, Heating & Refrigeration NEWS

why use a micron gauge - Google Search

Best Regards,

-AC_HAcker

I actually used an incandescent lamp to warm various parts of the plumbing during the second and third vacuum pull. I actually have a sight glass with moisture indicator, which indicated that it was dry on the first vacuum pull, without using the lamp. Therefore, the pump I used was sufficient for my application, but then again, it is not particularly demanding since I can use a lamp to help remove the last traces of moisture. Setting up a heat pump on a cold day, on the other hand, would demand a very good pump system. That's where an ion pump or diffusion pump comes into play.

Has anyone thought about building a precision vacuum gauge? Take two pieces of glass tubing, fill one with vacuum pump oil, and cap off the end so there's no trapped air. Then take a piece of vacuum hose, connect one end to the glass tube filled with oil, fill it with oil as well, and connect the other end to the other glass tube. Mount it on a stand in a U configuration and connect the remaining open end to the vacuum pump. If the density of the oil is known, the vacuum level can be calculated by measuring the difference in level in the tubes and translating it into pressure.

Trenches are all dug...
 

With a favorable weather forecast, I decided to work like a demon while time and weather are on my side.

I went in with my friend Bruce-the-Pirate to rent a trenching machine. We visited the local power tool rental establishment to see what they had.


We selected a Ditch Witch which was probably second choice, but it did have the advantage of being 'maneuverable'. It turns out that this type of machine has no real steering, it just goes backwards in a generally straight line and digs as it goes. Changing direction is not easy and consists of grabbing this horribly heavy machine and using all of your strength and moving it a few degrees, then repeat until properly positioned.

But once positioned, the controls are all hydrolic and the engine is fairly powerful and it sure beats digging by hand.


Here's William_Hackerson at the controls. He'd had a bad day at his regular job but grudgingly admitted that running the trencher made him forget his bad day at work. Maybe not so different from being at war makes a country forget the serious social and economic issues it faces.

So the trenches went in and great care was used to not damage any of the polyethylene loop pipes.

The pic at the top shows how the trencher was run up close, but not touching the pipe...


...the pic on the bottom shows digging the trench next to the loop pipe.

By the way, I asked the man who ran the tool rental store what they had in the way of hole diggers. He asked how deep, I said maybe 20 feet, he asked how many and I said maybe twenty or so, he threw up his hands and said no, there was nothing like that, and went on describing how it could not be done.

I told him that I had already dug sixteen holes that were each seventeen feet deep, with a shop vac!

I didn't have my camera, but this was the look on his face:


Best Regards,

-AC_Hacker

Vacuum on the Cheap - Refrigeration Compressors
So it looks like it is possible to build a good vacuum pump from refrigeration compressors. Just get two and not just one. The modern high efficiency ones should work even better since they have tighter tolerances for higher efficiencies.

NiHaoMike, good info here.

And just in case anyone might miss it, your link also contained this link to a PDF with detailed but dated instructions to build your own vacuum pump:

http://www.belljar.net/fbleeconversion.pdf

And here is a link to HVAC vacuum pumps on ebay:

vacuum pump, great deals on on eBay!

Additionally, here is a link to vacuum pumps at Harbor Freight:

Harbor Freight Tools

Harbor Freight used to carry a 1.5 cfm pump which was cheaper than any in the above link, and would work fine, though more slowly.

And here's a discussion from an HVAC blog about how you can't/can/can't/can
build a vacuum pump from a refrig compressor:

Compressor ID for DIY vacuum pump - Refrigeration-Engineer.com forums

One of the posts (#14) is worth re-quoting:
So, for HVAC work, it looks like 1 Torr is not quite low enough.

If you're going to build your own vacuum pump (or buy used), it would be advisable to get your hands on a micron gauge so you know for sure what kind of vacuum you are actually pulling.

Best Regards,

-AC_HAcker

P.S.:


The loop-field is 50% in and tested. Working like a demon to try to beat the rain.

After this project, I don't care if I never see a shovel again!

Welding vs. Barbs...
 

Earlier in the blog ("mini-hack") I showed how to make heat fusion (AKA: plastic welding) tools.

So far while installing the loop field, I've had some situations where I thought I'd have to resort to barb connections rather than welded pipe. I got some brass barbs and installed them up and tested them.

I can now report that when comparing welded connections to barbed connections,

Welding is cheaper
Welding is easier
Welding is more durable
Welding is faster
Welding is more likely to yield a leak-free connection

The choice is pretty clear.

Regards,

-AC_Hacker