Author Topic: Solar Barrier Fabric- seems to help a bit with reducing energy use in desert smr  (Read 742 times)

0 Members and 1 Guest are viewing this topic.

jlsoaz

  • Jr. Member
  • **
  • Posts: 61
I know I have mentioned this before in other contexts, but I'm not sure if I've mentioned it here:

For more than 10 years I've been using this fabric to mitigate some of the summertime harshness of a large skylight:

http://solarthermalfabrics.com

My location is Southern Arizona, USA.  It seems too be a relatively low-cost solution that for me has been a keeper, so passing the point along.  I've also recently tried using it in a garden and so far the results seem not bad.  I am talking about using the reflective fabric mainly in the summer.  There is also an absorptive fabric that should help with winter heating, but I have not had as much success with that.

DamonHD

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3578
  • Country: gb
    • Earth Notes
We use solar reflective curtains/blinds to keep strong sunlight and thus heat out of the house on the two warm days per year in London that are our summer, eg as mentioned here:

http://www.earth.org.uk/manage-the-heat-Maltese-style.html

Rgds

Damon
« Last Edit: July 03, 2017, 01:05:21 AM by DamonHD »

MattM

  • Sr. Member
  • ****
  • Posts: 385
Shouldn't the two be combined.  One side reflecting, the opposite absorbing.  The fabric needs to be insulative considering it's the downside of extreme temperature deltas.

Mary B

  • Hero Member
  • *****
  • Posts: 719
My bedroom window faces south and being on the second floor right under the roof it gets very hot quick. I bought a roll of reflectix insulation and made a 4 layer window cover that is incorporated into a window shade setup so it is not visible inside the house. Pretty simple and cuts the temps in my bedroom by 10 degrees. I can't roll it up but it is velcroed on so easy to remove if I want light in that room.

jlsoaz

  • Jr. Member
  • **
  • Posts: 61
My bedroom window faces south and being on the second floor right under the roof it gets very hot quick. I bought a roll of reflectix insulation and made a 4 layer window cover that is incorporated into a window shade setup so it is not visible inside the house. Pretty simple and cuts the temps in my bedroom by 10 degrees. I can't roll it up but it is velcroed on so easy to remove if I want light in that room.

Right on.  I guess my own situation sounds like it was similar to yours.  I didn't mention this on the original post, but the reason I like this particular material is that it allows a lot of visible light through, but still seems to do an excellent job of keeping the heat down.  That particular room in my house went from being unbearable to being basically the best room in the house (home is partially underground, so natural light is at somewhat a premium).  Still, if I did get a completely reflective material that did not do much or any visible light through, it would probably do an even better job of keeping the heat out.
« Last Edit: July 03, 2017, 01:28:08 PM by jlsoaz »

jlsoaz

  • Jr. Member
  • **
  • Posts: 61
Shouldn't the two be combined.  One side reflecting, the opposite absorbing.  The fabric needs to be insulative considering it's the downside of extreme temperature deltas.

I am chagrined to say I hadn't thought of it, but maybe you're right, maybe they could or should be combined.  I'll say I've never used the reflective one on the inside.  I have bought and tried the absorbing (absorptive?) one on the inside only, but haven't so far been able to make much use of it during the colder months.

george65

  • Sr. Member
  • ****
  • Posts: 288
  • Country: au

I'm at a loss to see how that solar fabric does anything normal shade cloth could not.
I read through the link but I just don't see what the big deal is?

Every summer for about the last 10 years I hang some thick shade cloth off the eaves of my house on the side that gets the afternoon sun and On the back verandah. This stops the sun coming in the back glass doors and also heating up the dark patio tiles which can still be too hot to walk on bare footed 2 hours after the sun has gone down.
The cloth hanging off the eaves makes a Huge difference and I frequently go out and hose it which traps the water and has a great cooling effect.
One other side benefit I never initially though of was hail protection. We always got 1-2 damaging hailstorms here a year and it usualy comes in a hell of a storm where the hail comes more horizontal than vertical.  the Shade cloth acts like the nest in an indoor cricket pitch and stops the hail in it's tracks well before it hits the windows or walls or bounces off the tiles.

As far as the heating goes, you could get black builders plastic and put that inside your windows or lay that on the floor. I'll guarantee it's loads cheaper than the stuff they are peddling.  I think more effective though would be another trick of mine and that is an inline fan and ducting back through the manhole into the house.  there is a lot of surface area on a roof and the the enclosed space makes for a lot of hot air.  I simply pull it down from the crown of the roof and pump it into the house.  I have thermostats top and bottom so when the temp in the roof is cooler than the temp in the house, it shuts off till it heats up again.  Often on a sunny day I just run the fan slowly all the time till about 3pm when the heating effect is lost.

I have also been using the black builders plastic for over 20 years since I first came here as a pool cover. I welded 2 pieces together with a soldering iron to give me the requires width which is far stronger than anyone whom hasn't done it would ever suspect, myself especially the first time.
 I keep that over the pool all winter and into the summer. It just floats on the water surface.  I run the pump and the salt water clorinator maybe an hour a week when and if I think of it and when it rains heave, I pump the water off the top of the plastic which stops the pool water chemistry being diluted.  When I pull the cover back when the summer comes, there is like a light layer of dust on the bottom the Kreepy Krualy has no trouble cleaning up, do the levels and it's ready to go.  I keep the cover on during the lead up and fall off and the pool is like a bath. You cannot leave the plastic on in the middle of summer if you want to use the pool ( it's great from stopping evaporation) because even though my pool is large at 75KL, it just gets too hot to be comfortable after about 3 days of hot weather and sunshine.  I once had the pool up to 46 oc after being away for a couple of weeks during a bout of hot weather. Was amazing to have that much water that hot just from sunshine and a bit of black plastic.

It just amazes me that these environmental ideas always amount to a much more expensive way of accomplishing the same result that can be had easily with existing products that cost a fraction of the price and a bit of DIY out the box thinking. 

DamonHD

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3578
  • Country: gb
    • Earth Notes
When trying to keep cool, if the fabric is INSIDE the window/home, then it is important to get as much light out again as light, and not let it be absorbed and turned into heat and get trapped in the house.

In that case reflective or at least bright white beats simply shading.

Rgds

Damon

MattM

  • Sr. Member
  • ****
  • Posts: 385
My first home purchase had an addition on the back where my bedroom was, sitting on the second floor.  (The front door was at that second story, because it was built on a slope.)  My room had windows on three sides that literally spanned most of the walls.  But the previous owners had installed heavy fabric curtains over all the windows that were so thick they deadened outside noise.  As long as they were closed I couldn't tell what the weather outside was like.  Opening any one of them brought me closer to God's creation.  Soundproof curtains are great.  I wish my current house had them now.

Mary B

  • Hero Member
  • *****
  • Posts: 719
That is where the reflectix really works well. It is silver and reflects light well. SInce this is in my bedroom that is a bonus because I keep vampire hours LOL

When trying to keep cool, if the fabric is INSIDE the window/home, then it is important to get as much light out again as light, and not let it be absorbed and turned into heat and get trapped in the house.

In that case reflective or at least bright white beats simply shading.

Rgds

Damon

DamonHD

  • Administrator
  • SuperHero Member
  • *****
  • Posts: 3578
  • Country: gb
    • Earth Notes
BTW, I forgot to add, our solar reflective blinds (that double as blackout blinds) are cheap too, and hang on existing curtain hooks.

Rgds

Damon

george65

  • Sr. Member
  • ****
  • Posts: 288
  • Country: au
When trying to keep cool, if the fabric is INSIDE the window/home, then it is important to get as much light out again as light, and not let it be absorbed and turned into heat and get trapped in the house.

In that case reflective or at least bright white beats simply shading.

Rgds

Damon

I see the value here. My thought has been better to keep the heat out than in.  That's why I have hooks on the eaves that I attach the Shade cloth to. On my home the eaves are 18" from the walls so there is a good air gap. The shade cloth being a dark green does get warm/ hot itself but still keeps the walls of the house tens of degrees cooler than if the sun is beating down on them. When hosed, it has a huge cooling effect.

I would still think myself that keeping the light and heat out would be much easier and more efficient than allow it in and trying to bounce it out again but that's just a guess.

The house I'm going to should get the main sun on just one end of the place. It has an amount of natural Shade cloth there atm in the form of hedges.  There is hedge near the house and another taller hedge about 3m away on the other side of the path.  I'll look at it when summer comes but I might get some roll out blinds installed  to cover the gap where the sun will hit the house direct for some hours at least.  This place is not aesthetically pleasing to start with so I have not been more concerned with function over form. The new place however will also be used for my business and well as being a show home  that aesthetics will be linked to the value so I'll have to pay a lot more attention to presentation as well as practicality.

This is a brick home (That's going to be a pain in the arse to change wiring etc) so will hold the heat it gets. Not sure of the insulation, time will tell but still better to keep the heat off all together I would think.  I'm also going to change the colour of the place from the green it is now to a nice, boring, cool off white. Roof is also green but a light shade so probably of no consequence.  I am going to see what the roof temps get to with the idea of putting some thermostatically controlled exhaust fans in there to suck out the hot air and create an airflow to again try and keep temps down in the first place rather than just rely on insulation to repel them.

There may be an amount of sun that falls on the front of the place but I think that will be limited.  There is a landmark massive tree in the front yard that would protect a lot of the front of the place and a decently wide verandah that should keep the sun off the walls anyway.
The shed where I plan to spend a lot of time is unfortunately Un insulated however there is a good size hedge beside it that will provide a lot of shade and the panels I plan to put on the roof will take away direct sun impact there.  I will probably insulate the roof anyhow because I want to put a heater in there for winter and the roof is not sealed being corrugated so I know where my heat will be going.

Just because I have the ability to pump insane amounts of heat in there for free does not mean I don't want to make some attempt at efficiency!  :0)