RE: [EnergyPlus_Support] Heat gain through blinds.

Thank you very much for your response Dr Hitchcock,
As you suggested I tried placing the blinds outside the window. I have observed an decrease in HVAC energy consumption by ~10-15 % on June 21 and ~30% on March 21 when compared to the interior blinds.
But as we change the slat angle by closing the external blinds from 0 to 45 angle shows that the HVAC energy drops by only 1.2-3.8%. Closing the exterior blinds from 45 to 90 degree angle shows that the HVAC energy drops by only 1%. Thus there seems to be no effect of closing the blinds on the HVAC Energy consumption due to the heat gained or lost.
I would like to know if there is any possible explanation to this. .?
I would like to know if my inputs are correct for the outputs that I wish to have.

I am attaching the Idf file in the files section. The name of the file would be 2008-07-09 Conventional-45 External.

Thank you

----- Original Message ----
From: Rob Hitchcock <RJHitchcock@lbl.gov>
To: EnergyPlus_Support@yahoogroups.com
Sent: Tuesday, July 8, 2008 6:46:31 PM
Subject: Re: [EnergyPlus_Support] Heat gain through blinds.

Interior venetian blinds can help control daylight illuminance and visual glare levels in a space. But, they will not necessarily reduce heat gains since the solar and thermal gains have already penetrated the glazing before encountering the blinds. The blinds will warm up and transfer that heat to the space. EnergyPlus accounts for all of these interactions.

Try placing the blinds on the outside of your windows as a test.

Rob
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gv.deepak wrote:

Hello everyone,

I am involved in simulating Interior venetian blinds on 6'X6' window
in a 11'X15'office building in Gainesville, Florida. I have been
simulating the blinds for getting energy consumption and Illuminance
values for the Office room. The simulations are performed for three
design days i.e March 21, June 21 and December 21. The simulations are
performed for different slat angles varying from 0 to 90 degrees.

According to common observation as the slat angle of the blinds
closes the Illuminance values decreases along with the heat gained
from outside. Thus the expected results would be to have a constant
decrease in the HVAC energy consumption due to decrease in the heat
gain in March and June and decrease in HVAC Energy consumption due to
decrease in heat loss in December.
But according to the results I obtained from the simulations, I
observe that the HVAC Energy consumption does not decrease due to
closing of the blinds.

Does Energy plus recognize heat gain/heat loss through windows ?
Does the HVAC take into consideration the Heat gained/ Lost from windows ?

Thank you.