I am brand new to this forum..question: if simplicity is the goal for solar heating with radiant and solar and harvesting low temps is more efficient, here is my question:
  
    In a new Sip walled timber framed home, can i just SIMPLY apply loops of pex tubing under a metal roofing system(between furring 2X strips) on top of the osb roof Sip and then circulate this glycol fluid to the underside of my hardwood floors with SIMPLE staples from the basement side of the sub floor AND have a successful harvesting of 75-85 degree solar water temps?????... It would be a  cheap, SIMPLE solution and able to provide low temp fluid to floors when sun was shining on PV operated fluid pump.....perhaps even use to pre-heat Domestic hotwater....what say you????   PS: would Osb layer of roof Sips need protection from condensation??? if so, what to do???  thanks...Steve Masse  in the Lowell, Mass area of the USA..Thanks guys...

Check out http://www.dawnsolar.com/gallery.html They pretty much do as you describe. Unfortunately, if you check out the ratings of their system on http://www.solar-rating.org/, you will see that the efficiency isn't very good.

In general, I think you have a good idea. I just don't know if it will work in our area (I am in Douglas, MA).

Good luck regardless of the path you choose.

Ed

In the New England snow belt you'd need to keep the roof pitch high enough to reliably shed snow to get any significant winter time boost out of it, but you'd get a decent amount in the shoulder seasons. You can get more out of it during the heating season by putting it under eave-sheltered siding (an approach also used by DawnSolar) rather than on a pitched roof.

Unglazed solar collectors have pretty crummy cold-day characteristics, but even in eastern MA the average afternoon temps in January are in the low 30s F, which means you can get 10-20% efficiency out of it making 80-100F water. In the fall & spring with 45-50F afternoons that efficiency doubles, but output more than doubles due to the higher intensity of the incident radiation. But glazing it will triple or quadruple the average output when you need it the most.

I live in vt and plan to put a steel roof on this year and have found a company that sells steel perlins that allow you to snap the pex tubing in. I contacted them they have one customer that has install in vt but has not tested yet. Any one out there that has tried this in cold climate states.  This is the add from e-bay it is a metal perlin with a snap in pex area they install reflective product between the roof deck and steel roof

Liberty Solar Roof Purlin
Creates Hidden Roof Solar Collector

LESS THAN $2/square foot!!
This do - it - yourself solar collector for hot water can collect up to 90,000 BTU per day!

Contractors Welcome!

The Liberty Solar Purlin is used to collect the sun’s energy in the form of hot water suitable for domestic hot water, space heating, or to power a solar chiller for air conditioning. The purlin is the same size as a 2x4 wood purlin and can be structurally integrated into the building. Because a re-roof or new roof installation often uses 2x4 wood purlins, you can replace the wood purlins with the new solar purlins (1.5” x 3.5”) and use them to heat your hot water.

The System:
We recommend placing foil-faced insulation down before screwing the solar purlin to rafters or to an existing roof or deck. This reflects the heat into the 1.5” air space to be captured in PEX tubing that snaps into the solar purlin. The flexible pex tubing snaps into the rounded slot in the top of the solar purlin for optimum heat transfer from the metal solar purlin to the water. The roofing is then screwed onto the purlin in the wide area designed for attaching the roofing or decking. When the roof is warmed by the sun, the solar purlin transfers the heat to the pex tubing carrying water or glycol (in areas where freezing temperatures occur). The one square foot can collect from 150 - 300 btu/day. 

The Advantage:

In utilizing the energy from the sun by collecting it and turning it into useable energy, the most efficient process is to collect the heat (thermal energy) from the sun. Even using our high efficiency heat tube systems, the cost is high and payback will be 5 - 10 years for many applications. Here at Liberty we have been researching and designing new machines for many years. From our very first downspout machine to the many machines that have followed we have always sought to bring COST EFFECTIVE solutions that can be readily used by contractors and installers of systems.

In our quest to provide the most cost effective solar system, we have a new machine that can be used to capture the heat absorbed by an entire roof system. Even in our northern Pennsylvania, we know that roofs collect a lot of heat. In the summer, roofers start early in the morning, and if they are laying asphalt shingles, they need to be off the roof by noon or the shingles get so hot that they can burn their hands or ruin the surface of the shingles.

Until now, home owners and contractors had no choice... they had to install the roof and then later add a costly solar system. Now we have a new machine that can make any roof a solar collector with very minimal cost on a new roofing job. It can be used on steel, steel r-panel, standing seam, tile, and even asphalt shingles. Our roll-former can make a solar roof purlin that allows pex tubing to be quickly be put in place.

The heat that is captured on sunny days can assist in heating water, heating a building with radiant in-floor heat, or even cooling a building with a cooling tower to take the energy collected and drive an air conditioning unit.

Here is what you get with our system. This system is designed for a 10 x 30' of roof area.

Included in the above price is:

140' of our patent pending solar purlin profile ($1.60/linear foot)
300' of 1/2" Pex tubing to snap into the solar purlin as you can see in the pictures.
400 sq. ft of reflective foil insulation (seen underneath the solar purlin.

What you will need to complete the collector is:

Installation of the solar collector is easy.

1. Staple the foil insulation to your decking, rafters, or old roofing.
2. Nail your 2x4's around the perimeter of your solar area.
3. Screw your solar purlins in rows like normal purlins in parallel lines horizontally.
4. Snap the pex tubing into the solar purlin leaving room to go from the roof area towards your source and destination.
5. Screw the metal roofing down, marking lines so you don't screw through the pex tubing.

Once your collector is in place you can hook a pump to pump domestic water, swimming pool water, etc. through it.
This system is save, hidden from view, keeps your attic are cooler.

For larger systems you can email us at [email protected] or call us at 814 326-4121 for custom sizes.