Radiant barrier paint additive for exterior walls - Page 2

AC_Hacker · 08-03-14, 03:17 PM

Quote:

Originally Posted by gtojohn

I ran few tests today. We had a lot of scattered clouds so conditions we less than optimal. However...Its not looking good. I have 4 equal sized pieces of ship lap. 1 original satin green, 2 green with ceramics, 3 aluminum radiant barrier base coat (somebody said this works) and 4 aluminum radiant barrier paint for proof of performance.
Siding was laid out together facing up in direct sun through out the day . There was an air gap underneath to simulate a hollow wall. I checked the temps off and on throughout the day with a IR thermometer with a fresh 9volt. Temps for 1-3 averaged within 1 degree of each other, 135f surface and 111f on the backside. 4 was up to 101f on the surface and a few degrees over ambient on the back. I might try the difference with the siding upright like its on the wall in case there's any difference. A gloss finish might help reflect more heat.

Wow, thanks for the test!

Looks like aluminum barrier paint is very effective.

Do you have any ceramic left?? Might be interesting to see if that stuff + aluminum paint improved the aluminum reflectivity.

Best,

-AC

Daox · 08-04-14, 10:18 AM

Do you have any pictures of your test setup? This is something I'd be interested in writing up for the blog.

gtojohn · 08-05-14, 12:47 AM

I'll snap a few pictures for you. Weather is forecast for full sun the next few days. I do have most of the powder left. I was thinking about testing a gloss finish and or green base with a clear coat with ceramic added. I really wish I could make this work, maybe a radiant barrier with green tint... I was impressed by how well the silver paint works unfortunately it might look out of place on my siding!

gtojohn · 08-07-14, 11:16 PM

gtojohn · 08-07-14, 11:48 PM

I took a lot of reading over the last several days. Surface temps varied some, the satin was always a few degrees cooler than the 2 ceramic boards. The aluminum painted board well showed well under but...that seems to have been more because of its reflectivity and its effect on my thermometer. Most ir guns compernsate for .98 emissivity and most aluminums rate under .2 .Making this more obvious was when I measured the unpainted back sides of the same siding samples. The satin averaged 7 degrees cooler than the other 3 samples. The back side of the 3 samples coated with radiant barriers and ceramics were the same regardless of coating. An over simplified account for temperature readings after 4 hrs of full sun would be...Satin finished green surface 134f, back side 114f. Ceramic beaded samples 141f, back 121f. Aluminum radiant barrier paint sample surface 104f (not reading correctly), back side 121F. The ceramic bead additive makes the surface rough and gives it a matte finish. I believe that is the cause of the addition heat gain. Based on these results I'd like to test a gloss finish for any reduction on temps.

gtojohn · 08-08-14, 12:07 AM

One more thing, about ceramic...I took a piece of green ceramic tile, left it with the siding samples. Same surface temps as the the warmest 3, back side measurement same 141F as the surface 141F. It has no magical heat reflective properties, and no great insulative value. At least with the wood siding there was a 20F difference between front and back.

AC_Hacker · 08-08-14, 03:23 PM

You might want to check out my Space Blanket Test.

-AC

Ormston · 08-09-14, 03:24 AM

I did an experiment with the ceramic balls you add to paint around 6 years ago.
At the time I was working for a company that had a thermal imaging camera so used that for testing.
I constructed a wooden box with a light pendant inside as a heat source and painted 2 sides with white paint and the other 2 with the same white paint and ceramic beads added.

The sides with ceramic beads added were showing hotter on the thermal imaging camera so I gave up and binned them.

Steve

AC_Hacker · 08-09-14, 10:40 AM

Quote:

Originally Posted by Ormston

The sides with ceramic beads added were showing hotter on the thermal imaging camera so I gave up and binned them.

Maybe we should reverse out expectations and use these little reflective spheres to coat solar heat collector surfaces, since they seem to be failing so completely.

-AC

Mikesolar · 08-09-14, 11:47 AM

The ceramic is acting just how a brick on the house does. It will hold the heat and release it slower so, while it is not so good for cooling the house, it would help in heating the house. They say my double brick (no insulation) house has an R value of 8 at best yet it costs less to heat than most houses with R22 or greater batt insulation. Mass is good.

08-04-14, 10:18 AM	#12
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Do you have any pictures of your test setup? This is something I'd be interested in writing up for the blog. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

08-08-14, 03:23 PM	#17
AC_Hacker Supreme EcoRenovator Join Date: Mar 2009 Location: Portland, OR Posts: 4,004 Thanks: 303 Thanked 723 Times in 534 Posts	You might want to check out my Space Blanket Test. -AC __________________ I'm not an HVAC technician. In fact, I'm barely even a hacker...

08-05-14, 12:47 AM	#13
gtojohn Journeyman EcoRenovator Join Date: Jul 2014 Location: Austin, TX Posts: 314 Thanks: 39 Thanked 50 Times in 45 Posts	I'll snap a few pictures for you. Weather is forecast for full sun the next few days. I do have most of the powder left. I was thinking about testing a gloss finish and or green base with a clear coat with ceramic added. I really wish I could make this work, maybe a radiant barrier with green tint... I was impressed by how well the silver paint works unfortunately it might look out of place on my siding!

08-07-14, 11:16 PM	#14
gtojohn Journeyman EcoRenovator Join Date: Jul 2014 Location: Austin, TX Posts: 314 Thanks: 39 Thanked 50 Times in 45 Posts

08-07-14, 11:48 PM	#15
gtojohn Journeyman EcoRenovator Join Date: Jul 2014 Location: Austin, TX Posts: 314 Thanks: 39 Thanked 50 Times in 45 Posts	I took a lot of reading over the last several days. Surface temps varied some, the satin was always a few degrees cooler than the 2 ceramic boards. The aluminum painted board well showed well under but...that seems to have been more because of its reflectivity and its effect on my thermometer. Most ir guns compernsate for .98 emissivity and most aluminums rate under .2 .Making this more obvious was when I measured the unpainted back sides of the same siding samples. The satin averaged 7 degrees cooler than the other 3 samples. The back side of the 3 samples coated with radiant barriers and ceramics were the same regardless of coating. An over simplified account for temperature readings after 4 hrs of full sun would be...Satin finished green surface 134f, back side 114f. Ceramic beaded samples 141f, back 121f. Aluminum radiant barrier paint sample surface 104f (not reading correctly), back side 121F. The ceramic bead additive makes the surface rough and gives it a matte finish. I believe that is the cause of the addition heat gain. Based on these results I'd like to test a gloss finish for any reduction on temps.

08-08-14, 12:07 AM	#16
gtojohn Journeyman EcoRenovator Join Date: Jul 2014 Location: Austin, TX Posts: 314 Thanks: 39 Thanked 50 Times in 45 Posts	One more thing, about ceramic...I took a piece of green ceramic tile, left it with the siding samples. Same surface temps as the the warmest 3, back side measurement same 141F as the surface 141F. It has no magical heat reflective properties, and no great insulative value. At least with the wood siding there was a 20F difference between front and back.

08-09-14, 03:24 AM	#18
Ormston Apprentice EcoRenovator Join Date: Mar 2013 Location: UK Posts: 131 Thanks: 13 Thanked 35 Times in 32 Posts	I did an experiment with the ceramic balls you add to paint around 6 years ago. At the time I was working for a company that had a thermal imaging camera so used that for testing. I constructed a wooden box with a light pendant inside as a heat source and painted 2 sides with white paint and the other 2 with the same white paint and ceramic beads added. The sides with ceramic beads added were showing hotter on the thermal imaging camera so I gave up and binned them. Steve

08-09-14, 11:47 AM	#20
Mikesolar Master EcoRenovator Join Date: Aug 2012 Location: Toronto Posts: 958 Thanks: 40 Thanked 158 Times in 150 Posts	The ceramic is acting just how a brick on the house does. It will hold the heat and release it slower so, while it is not so good for cooling the house, it would help in heating the house. They say my double brick (no insulation) house has an R value of 8 at best yet it costs less to heat than most houses with R22 or greater batt insulation. Mass is good.