In a practical context, it's not only increasing the roof insulation; it's reducing the
alpha of the roof to a value about 0.20 from a previous value as high as 0.9 for
dark brown asphalt singles. If you did not reduce the solar absorbtance in the
model you missed the boat.
This is also a bone of contention with 'green roof' advocates. Yes they do save
energy, but they will never have a solar absorbtance as low as 0.20 or even 0.10
for silvered roofs.
John Ross
Daniel Solís wrote:
__._,_.___Hi E+,
I simulated a house with DesignBuilder in a very hot and dry climate.
I insuated the roof with EPS polyestyrene. No matter how much
insulation I used, the results were almost the same.
In DB forum I got the answer that no matter the climate, the
temperature and HVAC consuption is entirely driven by internal gain
and so there is no difference insulating the roof.
It's all the opposite I have read in the state of the art. Even, in
that specific city I got the weather file from, there is a government
support for people to insulate their roofs because they have a lot of
measurements proving an HVAC reduction of 15-20%.
Since DB uses E+ as core program, I'm asking you directly what's
happening,
Thanks,
Daniel
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___