The Homemade Heat Pump Manifesto - Page 11

AC_Hacker · 10-01-09, 12:10 PM

Quote:

Originally Posted by GvilleRenovator

That is GREAT!

Did you bury any one wire temp sensors?

That would have been an excellent idea, I thought about it often, but I really don't have a sufficcient understandiing of '1-Wire' technology at this time.

It would have been a very good idea to have a sensor on the 'IN' and 'OUT' of each loop and a sensor on the 'IN' and 'OUT' of the total loop field.

Also it would have been a good idea to have put a vertical string of sensors, say every two feet, on one or more loops.

I actually have a package with four 1-Wire temp sensors in my desk drawer. I'm schemeing to make a 15 to 17 foot plastic pipe with sensors, all filled with plastic to make it water proof, and burying it somewhere in the middle of the loop field.

Do you have a handle on 1-Wire good enough that you could explain it to me?

Regards,

-AC_Hacker

AC_Hacker · 10-01-09, 01:26 PM

Here's a diagram of my Loop Field...

...as you can see, I planned for more loops than I actually put in.

If I need to, I can add more loops in the future. There's even room in the front yard for maybe 6 additional loops. During the summer, I measured the pavement of the street in front of my house, and it was 145 degrees F on the hottest day. Some serious heat under that street, and with my name on it too!

I arrayed the boreholes as I did to get them as close as possible, like how honey bees arrange their cells. It allowed me to pack more holes in the space I have, but it really made trenching more difficult. If I had more space to work with, I would definitely put them in a grid pattern.

The hook-up sequence was arrived at because I wasn't sure how much pressure would be reduced by stringing all the loops in series. As I have it, I can cut in after the 8th loop and re-connect the field as two branches, each with 8 loops.

It's much simpler with one loop, but if I can't get the flow rate I want, I may change it in the future.

[EDIT (2015-04-22) the idea to leave the possibility off future change turned out to be very important. My total loop field pipe length was 720 feet, way too long for 3/4" pipe and required almost 1/4HP pump. I subsequently cut the loop in the middle which gave me two loops and it cut my pump power requirement by a factor of 4! (1/16HP), because I was able to get the same flow quantity at half velocity, and flow resistance increases (& decreases) by the square of velocity.]

Here's the loop field after trenching, before connecting all the loops:

I found that it really pays to run the trencher as close as possible to the plastic pipe, without hitting the plastic. Making corrections for a wide space (I had many) has been very time consuming.

Also the trencher threw the dirt up just over the edge of the trench and quite a bit fell back into the trench. The trusty Rigid shop vac was the perfect tool for clearing out the trenches and reclaiming those precious extra inches.

Here's Rhonda-the-Grandma, demonstrating good trench-vacuuming technique:

As I stated previously, I though I'd need to use barbed connecctors in the trenches, but later realized that I could pull the pipe up tight, weld the connection, working just inside the trench and then push the pipe in and cover it while holding it down with anything heavy (like large stones or my foot).

Here's a pic of the welding jig as I used it in the trench. I put a cinder block under it to hold it up. By tightening the hose clamps on one side of the jig and leaving them a bit slack on the other side, I was able to free up a hand which I'd then use to hold the fusion paddle.

After each weld, I'd let it rest for about 5 minutes, then I'd fill it up with water and gradually introduce air pressure to 90 psi. This should be done gradually, because if you hit the water filled tube fast, it gets the water moving pretty quick which can exert much more than 90 psi on the branch under pressure. I didn't do it, but I'm pretty sure that it would be possible to rupture a water-filled branch by pressurizing it too fast. I think this is referred to as "Water Hammer". I tested every weld, every time. Leaks were very easy to spot, water was spraying out of the few bad welds. Using a water bath method and looking for air bubbles to find leaks was out of the question.

Here is a pic showing two welds:

The top weld is a nice looking weld, the bottom one was done in a hurry and looks pretty crappy.

However, when I filled them with water and pressurized them, they both held just fine.

That's what really counts.

Best Regards,

-AC_Hacker

(* more to follow *)

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

GvilleRenovator · 10-01-09, 04:39 PM

Quote:

Originally Posted by AC_Hacker

Do you have a handle on 1-Wire good enough that you could explain it to me?

I WISH I had a clue. Searching for answers currently.
I agree on your idea for a string of sensors. Since my untested plan is to have loops 40 - 60 (or more) feet deep I was thinking 10 - 15 foot spacing.
I just ordered my Logomatic and several 1 wire temperature sensors. I will post my findings/experimenting on your DIY Data Logger thread.

Hugh Jim Bissel · 10-03-09, 09:40 AM

Looking awesome!

Quote:

Originally Posted by AC_Hacker

It would have been a very good idea to have a sensor on the 'IN' and 'OUT' of each loop and a sensor on the 'IN' and 'OUT' of the total loop field.

Also it would have been a good idea to have put a vertical string of sensors, say every two feet, on one or more loops.

Since you're running your loops in series you wouldn't need more than a send and a return temperature which you could read at the inside unit. If your loops were in parallel having a send and return on each parallel leg would allow you to verify each leg was providing equally.

Having more sensors than that (ie send and return on each well in series and/or every 2 feet) would be cool to have to see HOW it is working, but would be unneeded for anything except additional info. The main send/return temp change (and actual water temperature) is the big thing.

Looking forward to seeing it in action!

Daox · 10-03-09, 07:30 AM

Sounds like a good idea, but some of your pictures aren't showing.

AC_Hacker · 10-03-09, 10:41 AM

Quote:

Originally Posted by Daox

Sounds like a good idea, but some of your pictures aren't showing.

Daox,

Which pix are not working?

I will fix.

Regards,

-AC_Hacker

Daox · 10-03-09, 11:13 AM

The ones in the link you posted. The second, third and fourth pictures I get red Xs.

apppended loop spacer tube details

Nikolai · 10-06-09, 03:23 AM

Hello to everyone,
this is my first post here although I follow this idea and similar forums.

Regarding isolation, do not forget to underground pipes draws heat from the earth at a depth below about 1.5 m, while all that is shallower than that is above the "frost line".

This means that theoretically you should insulate pipes to a depth of 1.5 m, but in practice I think that is enough to isolate less, likely to 1m depth max. Of course, all parts of the pipes that come from the soil should be well insulated, and separated each one of other.

For this purpose, Styrofoam or similar can be used ...

GvilleRenovator · 10-06-09, 11:31 AM

Welcome Nikolai!

Quote:

Originally Posted by Nikolai

Regarding isolation, do not forget to underground pipes draws heat from the earth at a depth below about 1.5 m, while all that is shallower than that is above the "frost line".

YAY no frost line in Florida!

I did plan on doing my best to keep everything 3 feet deep or more though.

AC_Hacker · 10-07-09, 07:42 PM

Quote:

Originally Posted by GvilleRenovator

YAY no frost line in Florida!

I did plan on doing my best to keep everything 3 feet deep or more though.

GvilleRenovator,

So, if you're in Florida, you're most likely looking to use your GSHP for cooling, right?

I'm in a more northerly location (W. Oregon) so heating is my primary aim. I plan to put in a radiant floor heating system because having that large area is very favorable for heast pump... A radiant floor wouldn't work for cooling, because water will condense on the floor and you'd have to contend with wet slippery floors all summer.

However, I recently read that the Germans are doing cooling by pumping cold water through the ceiling. The temperature of the water in the ceiling is regulated to be just below the dew point, so condensation doesn't happen. Apparently, having a very large heat absorber in the ceiling gives a greater cooling comfort level without needing to reduce the temperature of the air as much as is usually done.

Also, what is the situation regarding drilling & trenching? Do you have clay soil? Sandy soil? Big rocks? How many feet of borehole or how many feet of trench is required to get a Ton (12,000 BTU/hr) of HVAC?

Best Regards,

-AC_Hacker

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10-01-09, 01:26 PM	#2
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	Loop Field Hook-Up... (Part #1) Here's a diagram of my Loop Field... ...as you can see, I planned for more loops than I actually put in. If I need to, I can add more loops in the future. There's even room in the front yard for maybe 6 additional loops. During the summer, I measured the pavement of the street in front of my house, and it was 145 degrees F on the hottest day. Some serious heat under that street, and with my name on it too! I arrayed the boreholes as I did to get them as close as possible, like how honey bees arrange their cells. It allowed me to pack more holes in the space I have, but it really made trenching more difficult. If I had more space to work with, I would definitely put them in a grid pattern. The hook-up sequence was arrived at because I wasn't sure how much pressure would be reduced by stringing all the loops in series. As I have it, I can cut in after the 8th loop and re-connect the field as two branches, each with 8 loops. It's much simpler with one loop, but if I can't get the flow rate I want, I may change it in the future. [EDIT (2015-04-22) the idea to leave the possibility off future change turned out to be very important. My total loop field pipe length was 720 feet, way too long for 3/4" pipe and required almost 1/4HP pump. I subsequently cut the loop in the middle which gave me two loops and it cut my pump power requirement by a factor of 4! (1/16HP), because I was able to get the same flow quantity at half velocity, and flow resistance increases (& decreases) by the square of velocity.] Here's the loop field after trenching, before connecting all the loops: I found that it really pays to run the trencher as close as possible to the plastic pipe, without hitting the plastic. Making corrections for a wide space (I had many) has been very time consuming. Also the trencher threw the dirt up just over the edge of the trench and quite a bit fell back into the trench. The trusty Rigid shop vac was the perfect tool for clearing out the trenches and reclaiming those precious extra inches. Here's Rhonda-the-Grandma, demonstrating good trench-vacuuming technique: As I stated previously, I though I'd need to use barbed connecctors in the trenches, but later realized that I could pull the pipe up tight, weld the connection, working just inside the trench and then push the pipe in and cover it while holding it down with anything heavy (like large stones or my foot). Here's a pic of the welding jig as I used it in the trench. I put a cinder block under it to hold it up. By tightening the hose clamps on one side of the jig and leaving them a bit slack on the other side, I was able to free up a hand which I'd then use to hold the fusion paddle. After each weld, I'd let it rest for about 5 minutes, then I'd fill it up with water and gradually introduce air pressure to 90 psi. This should be done gradually, because if you hit the water filled tube fast, it gets the water moving pretty quick which can exert much more than 90 psi on the branch under pressure. I didn't do it, but I'm pretty sure that it would be possible to rupture a water-filled branch by pressurizing it too fast. I think this is referred to as "Water Hammer". I tested every weld, every time. Leaks were very easy to spot, water was spraying out of the few bad welds. Using a water bath method and looking for air bubbles to find leaks was out of the question. Here is a pic showing two welds: The top weld is a nice looking weld, the bottom one was done in a hurry and looks pretty crappy. However, when I filled them with water and pressurized them, they both held just fine. That's what really counts. Best Regards, -AC_Hacker (* more to follow ) %%%%%%%%%%%%%%%%%%%%%%%%%% Attached Thumbnails Last edited by AC_Hacker; 04-22-15 at 10:45 AM..*

10-03-09, 07:30 AM	#5
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Sounds like a good idea, but some of your pictures aren't showing. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-03-09, 11:13 AM	#7
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	The ones in the link you posted. The second, third and fourth pictures I get red Xs. apppended loop spacer tube details __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

10-06-09, 03:23 AM	#8
Nikolai Lurking Renovator Join Date: Oct 2009 Posts: 4 Thanks: 0 Thanked 0 Times in 0 Posts	Hello to everyone, this is my first post here although I follow this idea and similar forums. Regarding isolation, do not forget to underground pipes draws heat from the earth at a depth below about 1.5 m, while all that is shallower than that is above the "frost line". This means that theoretically you should insulate pipes to a depth of 1.5 m, but in practice I think that is enough to isolate less, likely to 1m depth max. Of course, all parts of the pipes that come from the soil should be well insulated, and separated each one of other. For this purpose, Styrofoam or similar can be used ... Attached Thumbnails