Solar-Heated Radiant Concrete Floor Slab Kit Build Legalett: Slab on Grade Super-Insulated ICF Forms
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- Опубліковано 22 тра 2019
- Read All About It! www.ecohome.net/guides/3368/s... & www.ecohome.net/guides/3203/a... There are many advantages to air-heated radiant floors over hydronic radiant floors, but none greater than the ability to inject solar-heated air into the thermal battery which is the concrete slab floor. Solar air-heating panels are a growing trend in green building, with one notable shortfall - the heat that is generated is difficult to store or control. Many people take advantage of the relatively simple and affordable nature of air-heated panels (compared to photovoltaic panels) to harness the energy of the sun to heat garages and workshops, but solar air-heating has yet to be a viable and reliable option for well-balanced home heating. Until now ….
When looking for a heat-storage solution that would allow us to incorporate solar-air heating panels into our design in a sensible way, we approached Legalett, a manufacturer of super insulated slab-on-grade engineered ICF form kits and air-heated radiant floors, to see if high performance air-heating solar panels could feed air directly into their existing in-floor duct work. They welcomed the challenge and engineered the system that will be the main heat source of our new (as close as we can get it to ) Zero Energy home.
Legalett's existing radiant floor heating process consists of a closed-loop network of 4-inch tubes running through the concrete with a heater box embedded directly in the floor. In this case, added to that system are 6-inch tubes (seen in video) that will feed air to air solar panels on the south wall of the house. Air heated by those solar panels in winter when the sun's angle is lower will be fed into the floor heating radiant system, which will reduce the energy demand on the heater coil. Conversely and cleverly, in summer if the heat isn't needed in the house the heat is diverted to an air/water heat exchanger for heating the hot water tank instead. What this adds up to is Energy savings; ideal for Passive Solar Homes, ZNE, PNE, LEED & Passive House projects... See lots more at www.ecohome.net , North America's Favorite Green Building Information Resource or watch our video on hydronic radiant floor heating • The merits of radiant ...
#SolarRadiantHeatedFloor #SolarRadiantHeating #SlabonGrade #Home #Kit #DIY #USA #Canada #ICF #AirHeated
This should of happened 60 or more years ago! Great work! Even if you added electric backup It would have been a boon to home owners and the Earth... Maria Telkes is smiling.
This is a cool system. Solar heated air distributed through thermal mass floor then releasing heat into the house for 12 or 15 hours.
I built a 8 x 3 foot electric coil floor heater with foam insulation and layers of concrete board topped with tiles. It silently and gently heats my bedroom. I am planning to build similar one in the living room.
I also built a series of pop can and downspout solar air heater which really do work with high insulation.
Dude this is super cool stuff....
I love your drive to try new things!! I'm super interested to see you post logging data on how the house performs! I'm a bit sceptical only because fluid is so much more efficient at heat transfer than air. But your pipes are larger than hydronic pipes so I'm sure that makes up the difference in ability to distribute heat. Thanks for sharing your project, can't wait to see more posts on this project!
Hi Mark,
Thanks so much for the encouragement! It will take a full winter to really get some performance numbers, but the estimates based on how much heat is generated by surface area of panel along with the projected heat load of the building and an estimate of climate conditions mean we are hoping to see somewhere in the area of 60-70% of the heat provided by the solar panels. We have no real estimate on the production of hot water yet but we look forward to seeing some of that data from Legalett as the system is tested.
As for the air tubes instead of water, I linked an article above for Ian but I’ll stick it here too, it’s our page on air heated floors that explains the advantages.
www.ecohome.net/guides/3203/air-heated-radiant-floors/
Your skepticism is understandable, and your assumptions are correct - by volume, water holds more heat than air, but in the case of hydronic vs air-heated radiant floors, Pex tubes are a half inch diameter while the air tubes are 6 inches in diameter. So there is a greater surface area for transferring heat. One Legalett floor heater will meet code requirements for heat for about 1700 square feet of a single-story house, though some make-up heat is required with HRVs. For larger houses they just put in additional heater boxes.
The thing about air-heated floors, is that while a hydronic floor will provide the necessary amount of heat to a house (and sometimes a lot more), there are far more hot and cold spots with hydronic. So this delivers a more balanced heat throughout the house. And from a long-term maintenance point of view, the heater box itself is hardwired, so the heating unit inside the box can be unplugged by the homeowner and taken our for maintenance.
The house itself is currently being built, it's a pre-fab dense-packed cellulose wall system, so we will keep updating the ecohome.net website as it progresses. Again, thanks so much for such an encouraging post!
@@TheEcoHomeNetwork have you collected and processed the data at this point? I'll check your site but a note here would be welcome either way.
I am in the beginning phases of building a new home. Did you ever get data for this project. The front range in Colorado is not nearly as cold as Canada. I could not find anything on your website.
@@TheEcoHomeNetwork any update?
So neat.
Very cool.
Great system. No water = no leaks.
Would like to know more on the solar - air part.
I love the idea and the simplicity of the slab which I'm planning to do for a 2 story garage/home 24 x 40 (side walls should be around 20 feets high). But I'm also worried about wind effect, specialy sliding or overturning? because i feel like the slab isn't really attached to anything... any thoughts or special care you did under that slab? And how is the energy effiency and comfort so far? thank you very much for sharing your experiences and ideas :)
I am dying for an update on this PLEASE!!!!!!
What's the plan for condensation within the horizontal runs of pipe when hot air from the solar panel hits the cold wall of the pipe against the slab? Also, the amount of bends and the small diameter of pipe will cause huge restrictions in air velocity and overall system efficiency.
In the future, I'd suggest looking into Ground to Air Heat Transfer systems (GAHT) from high efficiency greenhouses. They increase efficiency by effectively digging a basement, insulating the walls, then back filling to bury the heat transfer system in an insulated thermal mass. The piping is perforated to allow condensation to drain into the soil, and must be installed above the site water table.
It's a really neat idea for a residential build, but I don't think it's going to perform the way it is intended.
no update ;(
It is a closed system. So there shouldnt be any condensation if the moisture content is low to begin with.
Great idea! How would you apply this concept to container homes?
I’ve seen DC element heated water directly from PV panels, not tied to the grid heat a concrete floor which was very effective.
Doesn't your insulation need to extend beyond the outer walls to prevent frost from working under the slab?
Would this work for a slab “foundation” which is a requirement for a mobile home pad here in the northeastern US (Adk/NE states region of USA) and help to keep the pipes from freezing rather than using electric tape on the pipes under a mobile home, if we were to block in underneath the mobile and create a crawl space?
Would this work for an outdoor heated patio 40 x 71 in Northeastern. MN
Can this be adapted to a small workshop that is under 500 sq. ft.? I definitely like the idea of solar heating. I am also considering solar with batteries for electricity for this building. Please advise. Building location is near Washington , DC. It's not that cold there.
How long does it take to heat floor compared to the hydro radiant?
Would it be possible to cool this house by blowing cool air from earth-tubes ( tubes 3 ft underground that draws air in that is warmed or cooled to about 50° F - 10° C). The floor would be cool to feet in summer but I would prefer a cool floor in summer.
Use the heater in the winter and in the summer just turn heater off and connect piping to a geothermal loops buried in the ground for a cool 60F
Can you use this system with basements
Is there a follow-up?
Approximately what's the cost of this system?
Fyi, read about a system similar to this in a Wisconsin barn detailed in a Mother Earth News issue from about 1970!
Read about Passive Solar homes in Colorado from 700AD ! www.ecohome.net/guides/1428/passive-house-and-passive-solar-what-these-buzz-words-really-mean/
will wood lice eat into the icf slab
Yaayyy
i think electrical heating of the sub floor slab would be better idea.
What happens when a car or truck enters the garage and steps where the tubes are...? At that point there's only 3 inch concrete???
Correct, and the system is designed and engineered to take that load if it's specified for a garage. Like an aircraft frame which is full of rounded holes, you don't necessarily need mass for strength if it's well engineered - and in our experience this system works really well - There are millions of sqft of insulated and heated floor slabs sat on this forming system in the US, Canada & Europe, and the company are Passive House members that's why we decided to try it!
Average slab is 3.5-4". You run 2-3" pipes and now you have to double your slab cost. No thanks. Radiant heating with water is a much better, time tested method. I'm actually quite impressed someone spent this much time making a much worse system.
I dont understand how this can be built without footers. That wouldnt pass inspection around here.
What happens when there is snow on the panels in the winter months, and the low sun angle also?
The solar panels are wall mounted, so no snow and oriented for winter sun.
You know that you can solar heat liquids, right?
That was a stuped idea, hope it works for you :)
i don't really understand how this is better than a hydronic radiant system.
Hey Ian,
Having done many hydronic radiant floors in the past I was a hard sell at first, but now having done both systems I can honestly say I like this better from an installation point of view, but the advantages go beyond that. You can read more about how air-heated floors work here - www.ecohome.net/guides/3203/air-heated-radiant-floors/ but the short story is - it comes with zones designed, installation directions and a cut list for pipes, so your standard carpentry crew can pull this off no problem without subbing the work out to plumbers.
You don't have to worry about damaging a tube during install like with hydronic, it also distributes heat more evenly than hydronic floors. All the heat is contained within the floor, and by insulating the tubes close to the heater box you eliminate the boiler room affect that is typical with hydronic systems where the mechanical room is the hottest room in the house.
As for performance, there is less latent heat in air than liquid, so when the thermostat shuts the system off it doesn’t' overshoot the desired temperature the way a hydronic radiant floor often does. Also, with an electric system the whole thing in contained in the floor, so it's quiet and it doesn't take up much space. We built this house in Quebec so it's heated by electricity, but it can also be done with gas boilers and a liquid coil as well. In either case you save a lot of space in the mechanical room so it’s a great option for slab on grade and smaller homes.
Simple. It's not. In no shape or form is this better. It's a complete waste of time. Waters capacity to carry heat and evenly distribute, is unmatched. Not to mentioned the added cost to your slab since you need to increase the thickness with this.
@@shawnd567 You have not lived with a floor like this, I have, for 17 years, it is amazing. The slab is guaranteed for the life of the building. Legalett knows what they are doing. No pumps, no leaks, only a very quiet fan inside the floor. Mine is under my dryer. And the savings from having such a thermal mass are significant. In addition, in the summer the floor is cold. People think I have AC, but I don't. At 30+ outside my feet can stay cool, the dogs lie flat out on the cold floor. I love it and it is free.
@@leoniebelcher1680 Hi Leonie, In what region is your home located?
Leonie Belcher I would like to know where you live? I’m wondering if this will work in Montana weather!
Dommage que tu continu de donné de la fausse info pour poussé le raft de Legalett.pas besoin d'enlever la glaise ou sol pour l'installation d'une dalle structurale ou radier.de plus dans votre première maison vous avez fait la preuve qu'un chauffage radant dans la masse de béton n'étais pas nécessaire! Peut etre un peu trop en conflit d'intérêt Mike !!!
I cannot believe this is actually taking flight in any shape or form. Air is a terrible media to carry heat. Water is much more effective and will always lead to better results. The "pros" list they have is laughable as they're adding things you can address in a radiant floor in 5 seconds. Also, a standard slab is 3.5-4". Absolutely no way you're putting 2" PVC without destroying the integrity of the floor. So now your concrete bill just doubled. Boilers/tankless water heaters can power hydronic floors and are extremely cheap/common. Good luck replacing whatever gimmick heating product they've come up with.
I have a Legalett floor and have had since 2003 and I love it. The concrete is very thick, not a standard slab, and is an extremely efficient thermal mass. The hot air is recirculated inside the spider web of pipes, it does not enter the building. I heat with electricity and it is very much cheaper than heating with fossil fuels. The heat is soft and even. I will build another.
I am certain its a conspiracy and all these satisfied people are actors
What a dumb idea .