01-05-11, 02:03 PM | #1 |
Renovator-in-planning
Join Date: Oct 2010
Location: Northern NJ
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Partial DIY GSHP?
I'd like to bounce something off the group.
I am having an addition built on my house. (Digging started on Tuesday :-) The builder asked me what kind of heat/cooling I want. Well, GSHP, of course! I have been pricing GSHP, and everyone around here says, there is not enough room for horizontal loops. (even the one person who seemed quite knowledgable and thought at first it could be done :-) So, they say, we drill. That's expensive. Bedrock is only about 15' down. We talked about perhaps a Domestic water well with Pump and dump, etc. (It would be fun to get DWW and have 30% tax credit :-) But even with the tax breaks, this is very expensive. I got two quotes for over $60,000. I'm still waiting for another one, but it likely will be more not less. I have also been following the HomeMade GSHP Manifesto thread, and have even built a drilling rig, but winter and bulldozer came before I finished my own tests on it. What tests I did showed me that it would be a fun project, but I could not possibly do it on the builder's tight time schedule. He doesn't seem too interested in helping me. (but his worksite manager has a green streak, did not have a chance to talk to him :-) In a parrallel project, my friend has added RF microcontrollers to my boiler and all my steam radiators, which should make the house more comfortable, and should save 20% on my gas bill. (I am a beta site) So I thought, maybe I'll use steam for the addition, (which should need heat in about 1 month or 2)... (I can do that, I did for one radiator previously). and work on DIY GSHP. in the spring/summer/fall/winter etc. Ideas that have occured to me include -borrow money and "do it right" (another forum had this idea) -Have the GSHP installer "start" do the parts that need to be done before the walls go up, and "finish" after the refinance -Buy a commercial GSHP and install myself, and pray that I can put in the Redundant Array of Independent Ground Loops myself Note, I am convinced that some of my heat can come from Solar Thermal and GSHP...and I have ideas for cooling the loop water also. So if my ground loop is shorter than "specified" for a GSHP, I am not so worried. (BTW, if I went horizontal, I think I can get at least 140' of trenches without much hassle). -Buy a used GSHP on ebay for $600/ton and DIY install as above -Convert my old Air Conditioners (EER 9 - 10) - A few good ideas were shown on this forum. -Have the builder install the wall penetrations at the time of pouring cement, and even stub out the pipes 5' so that I don't have to dig near the house when I go to make the ground loop. - He and I discuessed putting in a dry well (misnomer), so I thought I could use that as a manifold vault. I could have him stub out 6 pipes into the dry well, and then do my drilling from there. (BTW, my friend who is using my house as a beta site, said, just spray water on the coils of my existing A/C. Not as easy as it sounds, but do-able). One concern I have is whether a "homeowner-assembled" heat pump would impact home value positively or negatively. And of course, into the whole mix goes my "free time" which is really. (It will get bigger in a year or two, as my kid gets old enough to help... :-) BTW, I signed a contract under 1BOG.org to get solar panels on the roofs that face 120' and 210', so it's only the 300' face remains, 18' pitch. I am thinking I will have a 2'x20' skylight on the 210' face, and make my own solar collector under it - INSIDE the thermal envelope I would be grateful for your comments, good bad or otherwise. I hope it doesn't sound like a repeat question...at the very least, it is a revision of an old question. Thanks for your patience Seth, in NORTHERN NJ Last edited by pachai; 01-05-11 at 02:13 PM.. |
01-06-11, 05:32 PM | #2 | |||
Supreme EcoRenovator
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Location: Portland, OR
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Quote:
And of course, if your heat loss can be reduced, so can the size of your heat pump and those electric bills. Best part is you will be able to reduce the size of your loop field. The rules-of-thumb for estimating the size of your heat pump and the size of your loop field are based on the square footage of your house. You should go the max ('do it right' as you put it) and then have a professional analyze the heat load, and use that as your starting point. So there's a great manual that was posted on the manifesto thread, and it is loaded with techniques to retain the heat you have paid for. I strongly reccomend it. I don't know if you mentioned where it is you live, because that could influence your decision as to the best choice. GSHP is not the hands-down winner in all cases. If you live in a very mild climate, you'd be better off with mini-splits. Their COP is getting really high. If you live in a harsh climate, Ground Source is the way to go. Quote:
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If you're considering some serious DIY options, buying a minisplit to heat some of or most of the house will buy you time. The intrusion hole is not too big, and you could sell it or keep it in place as a backup. Something else to consider is the wife part. Trying to DIY something as fundamental as heat can be very trying. -AC_Hacker Last edited by AC_Hacker; 01-06-11 at 06:17 PM.. |
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01-06-11, 06:19 PM | #3 |
Renovator-in-planning
Join Date: Oct 2010
Location: Northern NJ
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AC Hacker,
Thanks for your additional thoughts. You are right, I meant "Integrate-it-yourself" not build-from-scratch. I am in Northern NJ, where Outside temp is 21' now. I am paying attention to the the thermal envelope. The current house has cellulose. I replaced all the 1st floor windows - not 3pane, but good ones. This week, a door was added between foyer and mudroom, and a window upstairs that was installed wrong was replaced. (that's eligible for 30% back :-) My friend is getting a demo of a thermal imaging camera, commercial grade. He thinks that's even more effective than a blower test. Meanwhile, the contractor found the old oil tank. I thought it had been removed, but now I see the fine print says it was decommissioned. Oh Well, NOW it has been removed. He may have to stop work for the EPA et al to come out here, in which case I can do a few more test drilling, (but now I am 10' below grade:-) The Contractor asked the Excavator man if he would be interested in helping me with the loops, and he was interested. I mean Intere$ted. I need to review the Heat Loss/Gain info I have on my house. My assumption is that my current boiler might work as a backup. In fact, we could wire it as a backup heat source for the ground loop. Not very efficient, but emergency heat in the winter is....good to have. (A/C failure in the summer is not usually an emergency.) Thanks Seth |
01-06-11, 07:11 PM | #4 | |
Master EcoRenovator
Join Date: Mar 2009
Location: Western Wisconsin.
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Quote:
I agree that insulation should be your prime focus, if you can afford to lay tubes for a ground source heat pump then do it, but if your choice is to lay ground source heat pump tubes or add 4" of foam to your foundation walls then I say insulate and seal as you can never have to much insulation. |
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