Is there any hard data out there or any personal experience about reduced cooling load as a result of solar panels installed on a south facing roof? So far I have found 1 study showing a 5 degree…Continue
"Photocatalytic materials often have titanium oxide or other substances in them as part of the trigger to break down materials when hit with the UV in the sunlight. Adding to paint - is generally an ineffective ensure the proper application of…"
"I agree. I want to buy the nano material that radiates heat into space and there is a professor who came up with photocatalytic paint that prevents mold and moss on white roofs. I would like a white product that can be painted onto asphalt shingles…"
"Radiant barriers - especially paints and foils... have been tested many times by various labs and shown to be less than cost effective. Then simply good old fashion insulation and air sealing.
As for new special radiant materials.... indeed…"
good point re: PV benefit of load shifting re: waste heat.
I was referring to the whole cooling system, which is removing heat from a building. If the building shell and cooling system are not very efficient, then PV systems are…"
"We have a radiant barrier that stops roof heat in summer and opens and lets roof heat radiate onto the ceiling and attic ducts on sunny days in winter. Automatically, with no electronics and cheaply. We want to get it made in the USA.
It solves this…"
"I had noted, and show with graphs that there was some cooling because of the shading of panels. But it was small compared to the reduction as a result of insulation - more insulation and not just code minimum.
The original posters was from the…"
"re: hard data, I recall seeing at least one study that showed some cooling from PV shade on roof. Suggest you contact David Sailor's groups at AZ State U. re: their project:
Impacts of Photovoltaic panels on urban climates and…"
"Generally when PV modules are added to a roof, the installers are supposed to ensure that AT LEAST fifteen years remain on the roofs life span (more likely they'd look for 20 years).
It would be difficult to do an adequate job that a roofer…"
"In Alabama the duct work is usually in the hot attic. So it is not just the drywall temperature. IMO ducts should only be allowed inside the thermal envelope.
When solar pool panels are removed from an asphalt shingle roof the roof looks almost…"
"PV modules are going to be in full sunlight (if possible), worrying about the heat on panels is secondary to the good sunlight and secure mounting on the roof.
The original post is now nearly three years ago, at the time he was…"
"Basic principles to always follow:
Keep the solar PV panels as cool as possible.
Insulate the roof as much as possible R 40? or better, with venting above the insulation, not through it, if at all possible to keep heat in winter and…"
"The radiation "effectiveness" doesn't change with temp... its the heat flow that changes with the delta-T.
Q = U x A x T where Q is the heat flow (either direction), U=1/R with R being the insulation R value…"
I get what you are saying, but that makes R-13 batt insulation and an inch of styrofoam thermal bridges also - it's all just a matter of degree. And room temp is effected by surface temps. The closer to the interior air temp…"
"ALL building materials are thermal bridges which allow for the flow of heat in either direction. Concrete foundations will act as a thermal bridge and provide a good path for heat loss (or gain) unless the interior floor and space is isolated…"
"Not sure the drywall being a thermal bridge pertains in this discussion - it is on the inside of a bunch of insulation and serves to add a bit of continuous R-value and provides airtightness. What are the readings you are getting on the attic…"
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