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dmaceld
Veteran Member
Posts:1465
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| 16 Nov 2010 03:39 PM |
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Posted By Chris05 on 16 Nov 2010 11:31 AM
If I do an attached garage it would be a 3 car, cause I do love my toys:
Garage Slab 32X24X6" ....don't know the exact cost, but I would guess it won't be cheap......
Is one of your toys a Caterpillar crawler that you plan to park in the garage? If not, you don't a 6" slab. 3 1/2", nominal 4", will do just fine. |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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Chris05
New Member
Posts:18
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| 16 Nov 2010 04:07 PM |
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Toys = Hydraulic Vehicle lift. Min requirement is 4 1/4 http://www.rotarylift.com/uploadedFiles/FAQ1.pdf That's the actual unit I am pricing - http://www.rotarylift.com/templateProduct.aspx?id=732 I have a hobby of tinkering with vehicles to make them go faster, on E85 of course  If I go this route, I will likely have to scratch out the basement (under) the garage idea that kicker has..... |
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Dana1
Senior Member
Posts:6991
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| 16 Nov 2010 05:38 PM |
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Posted By kicker_92 on 16 Nov 2010 03:15 PM
Posted By Dana1 on 16 Nov 2010 01:48 PM
in a high-R structrure you can''t skimp on window quality or and designing for the right balance of solar gain against cooling cost. Don't skimp on under-slab insulation either. The Urbana PassiveHouse has under-slab R values nearly identical to the wall-R. (R56 slab, R60 walls.) An uninsulated slab would DOMINATE the heat loss of an otherwise decent high-R design in Missoula/Hamilton. Your sub-soil temps are considerably lower than in Urbana IL: http://mb-soft.com/solar/soilmap.gif
Best analogy I can think of: It'd be like designing a styrofoam coffee cup with a metal bottom.
That's about right. Of course whether the metal bottom is a good idea or not depends on whether you're setting it on an ice cube (like alpine MT or MN dirt) vs something about the same temp as you'd like (such as MS, AL or GA dirt). With subsoil temps in the ~65F range (give or take a few) earth-coupling the building to the subsoil can have sometimes have real benefits, winter and summer. But as the total-R goes higher, the site-particulars will usually call for at least SOME insulation between the thermal mass of the local subsoil and the building. The Saft PassiveHouse in cooling-dominated Lafayette Louisiana where the deep subsoil is about 68-70F has ~R35 walls (done with half pound foam + 1" rigid iso), R21 (XPS) basement walls, and with ~R17 (XPS) under the slab, a very DIFFERENT ratio than used in much cooler climates & cooler subsoil. See: http://www.greenbuildingadvisor.com/blogs/dept/green-building-news/following-passive-house-deep-south So, would this be more like a foam lemonade cup with a steel bottom resting on a cardboard coaster?  |
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FBBP
Veteran Member
Posts:1215
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| 19 Nov 2010 10:37 AM |
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R valves versus air exchange. Does it really make sense to super insulate a building when healthy living requires at least a few air exchanges. Yes we can design/build a house that you can heat with a candle but in order to exhaust indoor polutants you still need to bring in minus 30 air in Calgary (and I suspect Montana). Passive heating can not make up the heat loss of this incoming air on a cold and frosty morning. Those of you that are into Net Zero, how do you deal with this?? |
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dmaceld
Veteran Member
Posts:1465
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| 19 Nov 2010 11:01 AM |
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Posted By FBBP on 19 Nov 2010 10:37 AM
R valves versus air exchange. Does it really make sense to super insulate a building when healthy living requires at least a few air exchanges. Yes we can design/build a house that you can heat with a candle but in order to exhaust indoor polutants you still need to bring in minus 30 air in Calgary (and I suspect Montana). Passive heating can not make up the heat loss of this incoming air on a cold and frosty morning. Those of you that are into Net Zero, how do you deal with this??
That's why the ventilation is done with a Heat Recovery Ventilator or an Energy Recovery Ventilator. Upwards of 95% of the heat in the exhaust air is returned to the incoming air. |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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kicker_92
New Member
Posts:65
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| 19 Nov 2010 11:57 AM |
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Posted By dmaceld on 19 Nov 2010 11:01 AM
That's why the ventilation is done with a Heat Recovery Ventilator or an Energy Recovery Ventilator. Upwards of 95% of the heat in the exhaust air is returned to the incoming air.
Are your refering to a 95% energy recovery, or 95% apparent sensible effectivness? |
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Dana1
Senior Member
Posts:6991
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| 19 Nov 2010 12:02 PM |
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What damceld said.
HRV has been used successfully in the Canadian midwest on superinsulated buildings for more than 30 years now. Indeed the PassiveHouse Institute was founded by Harold Orr, designer of the (successful) Saskatchewan House experiment back in the 1970s utilizing very high-R and heat recovery ventilation. If anything the Saskatchewan house was over-designed & overbuilt, and a house with similar performance could be designed & built using the PassiveHouse design methodology for probably half the cost of the original.
See:
http://www.buildingscience.com/documents/insights/bsi-025-the-passivhaus-passive-house-standard
http://www.buildingscience.com/documents/insights/bsi-026-passivhaus-becomes-active-further-commentary-on-passivhaus
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kicker_92
New Member
Posts:65
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| 19 Nov 2010 12:02 PM |
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Posted By Chris05 on 16 Nov 2010 04:07 PM
Toys = Hydraulic Vehicle lift. Min requirement is 4 1/4 http://www.rotarylift.com/uploadedFiles/FAQ1.pdf
That's the actual unit I am pricing - http://www.rotarylift.com/templateProduct.aspx?id=732
I have a hobby of tinkering with vehicles to make them go faster, on E85 of course
If I go this route, I will likely have to scratch out the basement (under) the garage idea that kicker has..... For any suspended concrete slabs, the key person is a good structural engineer. Find someone that deals with commercial concrete construction who is willing to tackle a small side project. Point loads from a vehicle hoist are a key conversation to have. Anything can be done, but the loads will determine the slab thickness, and amount of rebar used. We wanted a 26ft clear span underneath the garage with no posts, and managed to get it with only a 12" thick floor and some creative solutions. Again, for concrete designs that are more than just a box, a good structural engineer is worth their weight in gold. |
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TexasICF
Advanced Member
Posts:622
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| 19 Nov 2010 12:23 PM |
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Dana1, Thanks for the building science links -- very interesting material. Regards. |
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FBBP
Veteran Member
Posts:1215
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| 19 Nov 2010 03:41 PM |
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19 My thought and experience with HRV. (anyone with "fact" please feel free to jump in. • as a rule we want to see 20ºF between any exchanger to get effiecient transfer. Even if "all" the heat is scrubbed of the outgoing air, the very best you could hope for is your entering air to be around 50ºf. • at -30 there is not nearly enough btu in the out going stream to heat the incoming therefore the electrical elements kick in. Not real good if you are running batteries and a windjamber. • at around 0º F the moist exhaust air condensates and freezes in the exchanger causing the unit to go into defrost mode. Again electric heat. Do they work. Sure but are they effiecent? |
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Dana1
Senior Member
Posts:6991
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| 19 Nov 2010 05:13 PM |
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Posted By FBBP on 19 Nov 2010 03:41 PM
19
My thought and experience with HRV. (anyone with "fact" please feel free to jump in.
• as a rule we want to see 20ºF between any exchanger to get effiecient transfer. Even if "all" the heat is scrubbed of the outgoing air, the very best you could hope for is your entering air to be around 50ºf.
• at -30 there is not nearly enough btu in the out going stream to heat the incoming therefore the electrical elements kick in. Not real good if you are running batteries and a windjamber.
• at around 0º F the moist exhaust air condensates and freezes in the exchanger causing the unit to go into defrost mode. Again electric heat.
Do they work. Sure but are they effiecent?
???? On most ERVs & HRVs the electrical elements are for preventing ice-up on the outgoing air stream, not to pre-heat the incoming air. It's duty cycle is high when it's -30F outside because the outgoing air has too MANY BTUs (in the form of water vapor), not because it has too little. The BTU content of the air at any fixed temp & humidity is the same. But those raw BTUs from condensing then freezing that water DO end up in the incoming air stream. Electrical pre-heat is a comfort-option, but one that could be disabled/defeated for off-grid operation. If you're running during extreme cold it's more efficient all the way around to run the ERV at the minimum required for decent indoor air quality. For any off-grid application you have to weigh the (quite high) cost of your electricity for even running the blowers of an ERV against the cost of additional heating fuel by using non-powered means of ventilation. Simply building the place to randomly leak air isn't exactly a ventilation scheme- it's asking for condensation & frost issues in some layer where you can't see or repair it easily. For on-grid apps the cost of the defrost or pre-heat will generally be quite low overall, even if at the way-below-zero extremes it can be something of a wash. Most people in the US & Canada live in places where the December-February temperature averages are above 0F, and the efficiency is quite good, and the frost control runs at a low duty cycle relative to the overall ventilator's cycle. (See: http://www.greenheck.com/library/articles/75 ) Except in perma-frost regions preheating the incoming air to the HRV with earth tubes further reduces defrost power. Also, your 20F delta-T between incoming & outgoing air would only occur during the extremes of cold, high flow ( or with old school versions of HRVs). Low flow/high surface area counterflow heat exchangers don't need anything like a 20F delta for efficient sensible-heat transfer, and the temp differentials between exit & incoming air streams are quite modest over a wide range of operating temps. But the BTU content of the humid outgoing air compared to the dry incoming air in winter can be dramatically different, even with a sub-5F delta-T when the outdoor dew point is -20F or lower.
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adi43d
New Member
Posts:87
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| 19 Nov 2010 05:21 PM |
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not all the HRV have electric defrost systems. there are HRVs out there which perform the defrost thru recirculation of indoor air and for example venmar ECO series consumes only 40 watts. there seems to be a consensus in the building science comunity that HRV and ERV do actually work. you will not recover all the energy that you spent to heat the exhaust air but you'll get some of it back. how fast you'll recover your money spent on the HRV?I don't know...but I'm sure you'll get your money back during the life of the HRV.
adi |
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| http://torontonetzerohouse.blogspot.com/ |
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dmaceld
Veteran Member
Posts:1465
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| 19 Nov 2010 09:18 PM |
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Posted By FBBP on 19 Nov 2010 03:41 PM
Do they work. Sure but are they effiecent?
More efficient than air exchanges created by air leaks, where 100% of the energy in the exhaust air is lost to the outdoors, and your heating system has to supply all the energy to bring the incoming air up to room temp. One of the new rules in building, "Build it tight, ventilate it right." |
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| Even a retired engineer can build a house successfully w/ GBT help! |
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Dana1
Senior Member
Posts:6991
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| 24 Nov 2010 12:30 PM |
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Posted By dmaceld on 19 Nov 2010 09:18 PM
Posted By FBBP on 19 Nov 2010 03:41 PM
Do they work. Sure but are they effiecent?
More efficient than air exchanges created by air leaks, where 100% of the energy in the exhaust air is lost to the outdoors, and your heating system has to supply all the energy to bring the incoming air up to room temp. One of the new rules in building, "Build it tight, ventilate it right."
For every rule there are exceptions. FBBP is off-grid, getting his electrical power from a Windjammer (of limited capacity almost by definition), in a VERY cold environment that requires a high duty cycle on the defrost. Build tight, sure, but an exhaust-only ventilation approach with a dedicated inlet point (earth-tempered with earth tubes, perhaps) probably makes more sense than HRV for him. For us grid-attached folks living in only moderately cold climates HRV makes more sense. |
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FBBP
Veteran Member
Posts:1215
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| 24 Nov 2010 05:36 PM |
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Much better. While I'm not quite ready to move in, my present system is exhaust tubes under intake tubes encased in concrete to a point approx. 100ft. from the house (buried +/- eight feet). Intake pillar will be two level to take cooler air in summer and warmer air (glass enclosure) in the winter. When the air enters the house it is routed through a reheat coil to a high velocity unit. This brings me back to my original question. Does it really make sense to to super insulate (and yes we all believe in air tight envelopes) a building when when we are required to meet air change rules. Let say we are changing the air 1.25 times per hour and the outside air is at -21ºC like it has been here the past week. It would seem that insulation in excess of R40 doesn't do much good. People rate ICF'S differently but assuming you have 2.5" of foam on each side of the concrete what's the advantage of increasing it? The air handler is going to by pass the insulation and the air still has to be heated. For me, I have chosen to go with the standard ICF and put the rest of the money into solar water heat to mass storage. I'm not sure this is the right answer or the right answer all the time but would be interested in here other points of view. |
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matteo
New Member
Posts:56
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| 25 Nov 2010 08:37 AM |
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I checked out the MCNZ home, it is impressive! I like it a lot. I don't think I could do a complete "net zero" house yet, as the price of Solar is still really high.
I know there is the 30% fed, but Montana lacks on the state level, as far as rebates go. I checked the DSIRE website, and I wasn't impressed.
Hi, me too,i check it before and im amaze for house they have but i like so expensive at all..... |
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philemup
New Member
Posts:1
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| 28 Feb 2011 11:50 PM |
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Posted By Chris05 on 16 Nov 2010 11:31 AM
I don't know if I am going to go Quad-Lock anything anymore.
They are Canadian based which would not support the economic growth of the US, directly. (nothing against Canada)
That would ultimately weigh on my conscience, considering the current unemployment rate.
I also don't know if I could deal with 20+ inches of foam panels on the exterior, which would limit my exterior choices, to pretty much stucco, unless I am missing something.
FYI Quad-Lock also manufacture in Atlanta - and all their wall configurations have fastening points in the tie feet so you can finish it with just about anything.
Just done training - building two houses with the R45 configuration at the moment - very impressed. http://www.quadlock.com/green_building/building_shell_superinsulation.htm |
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renangle
Basic Member
Posts:304
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| 01 Mar 2011 03:23 PM |
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philemup,
I must ask...why in the world would you seek out a post that is 9 pages back and essentially dead and then say you don't really support them because they are Canadian owned, then only to say you are impressed by the product manufacured in the US?
I realize its you 1st post, but come on man...this makes no sense in the least! Oh the humanity! |
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