SunTex Solar Screen project

[Xringer]

Climatological Data

It's been getting pretty hot these days, and the SunTex screens have just about paid for themselfs.
Even when it's in the 80s & 90s, (deg F) we are using the AC less, because the Den isn't getting so over-heated..

These screens were a great investment!

[Xringer]

It's that time of the year again. Summer seems to be coming back!

Woburn May Weather 2012 - AccuWeather Forecast for MA 01801

It's still pretty cool in the early morning, but the solar gain in the den has exceeded
my wife's comfort level a few times already. (76F).

So, the Solar Screens are back up. It takes me 4 minutes to install them.
We can already notice the difference in room temperature. (Where's my jacket)?

[Piwoslaw]

I put up bug screens on some of the windows for the summer. They are a grey color (so they reflect more than black) and thought I'd check how much sun they block. I used a window on the southwest side with more than enough solar exposure. This is a double window and the screen is on one side, so this allows a relatively fair test. The windows also have light colored roller blinds (see this post), so I checked their effect too.
I measured the temperature of the window sill and the blinds' surface (when down). The indoor temperature was around 21°C (70°F), outdoor 27°C (81°F).

temperature °C (°F)	screen	no screen
window sill with blinds up	24.5 (76.1)	26.5 (79.7)
window sill with blinds down	22.0 (71.6)	21.9 (71.4)
roller blind surface	27.8 (82)	31.3 (88.3)

So, in direct sunlight the bug screens reduce the amount of heat entering the room by about 2-3°C.

[Xringer]

That's pretty good. 2-3°C isn't a lot, but it can make a big difference when the room would normally be at 22-23 °C.


Since my Solar Screens are black, with a tight mesh,

They must absorb 80% of incoming solar radiation. Then re-radiate the energy as IR heat.
My guess is, the IR radiation can't penetrate the double pane windows very well.
The Andersen windows must be reflecting some of the IR right back into the Solar Screen. (Making it even hotter).

Now that there is an extra layer of insulation inside the windows,
http://ecorenovator.org/forum/conser...-storms-2.html
It's hard to feel much solar energy inside the room..

Our problem now, is the old 42" Plasma TV.. It's providing heating that
adds to the filtered solar gain!
There is a clock/thermometer on that west wall, right above the TV..
It's warmed by the sun on the west side and the TV on east side! (1 meter under it).
Sitting on the sofa watching TV in the evening, I can see it's 27 °C across the room.
But, where I'm sitting, it feels like 22-23 °C.. Which is nice!

Once the summer gets really into full swing, The Sanyo #2 will make short work of any extra heat in the room.

This will be our first full summer with Sanyo #2 installed.
With the Solar Screens and the inside thermal blocks (plastic sheet barriers & insulated curtains),
I expect to see very effective ASHP cooling, using very little power..

[creeky]

I look forward to your posted #s on power use.

[Xringer]

We got the Solar Screens installed in early June 2011.. Here's the bill since last year..



But, it's going not going to be real useful, since we installed a 24,000 BTUh
Sanyo in the room on 10-10-2011.

http://ecorenovator.org/forum/geothe...-2011-a-2.html

This summer, we turn on both units when we need some cooling..

The Den has never been used so much this past winter and this summer.
My guess is our 42" Plasma (400 watts) has never been on for so many hours.
It's gotten 3 years of use during the last 9 months!

[Dana Lynn]

Now those screens have been up for a time, how well do they blocking heat?

[Xringer]

We are still very happy with their performance. It hasn't been crazy hot this year,
but combined with the humidity it's been AC weather. See the last 28 day plots pics.

It's only 32 square feet of windows, but if
"the Solar Constant can be stated as 442 British thermal Units (Btu) per square foot per hour"
that's a theoretical worse case of 14,144 BTHh coming into the den..
Which is okay during the winter months. But during the summer,
our solar screens are stopping about 85% of that energy from ever getting to the outside pane of glass.
These screens are one of the best eco-investment we've made.. And, they still look like brand new.

The only problem we've had is when we put them up too early. Because when it gets cool
on some spring days, we would like that solar gain!

[Xringer]

Above, I said.. "They must absorb 80% of incoming solar radiation. Then re-radiate the energy as IR heat."


Maybe I was right.?. Today, I saw some neat info on solar space heating, using FG screen as the absorber element.
Solar Air Collector Performance Testing for DIY Collectors

[AC_Hacker]

Xringer,

The title of your thread is SunTex Solar Screen...

Did you know that you can get this stuff from garden supply stores at a much lower cost? They sell it as shade cloth and is comes in various quantities, various percentages of light blocking, and even various colors (even basic black).

Here's a link to one source, it's straw colored and 90% block.

It comes out to 37 cents per square foot.

How does that compare to the SunTek stuff?

Here's 70% black for 33 cents per S.F.

Here's Black 40% for 12 cents per S.F.

Here's one that is probably 60% for 1.1 cents per S.F. (sounds like error, but there is the ad)

-AC