I have not read the new findings, however, it is not really that important to made the solar information current in the EPlus weather file for general use.
TMY is typical information for the last 30 years compiled/selected into averaged one hour period data. There is a warning that it is not to be used for wind power, solar power simulation. IWEC is specially compiled to satisfy the annual energy consumption model.
This is why Mr. Ooi is looking for and doing some measurements himself. However, after looking at the 10 second interval values for Global Horizontal, etc. he is convinced that the room temperature, etc. will not be affected very much. However, the lighting in the room will follow the fast variation of the sky illuminating conditions.
Mr. Ooi has not finalized on how he is going to measure all these different components. I suggest to him that it is no use looking at the whole sky. He should only quantify components through the windows, while he is carrying out subjective tests on comfort conditions.
If your interest is in lighting, etc. more detailed solar information would be required.
For annual energy calculation, the current IWEC weather file data is sufficient.
I am not against updating the sky luminance distribution model in EPlus. However, I do not see how to improve it without having more input data.
Date: Wed, 3 Feb 2010 11:01:59 -0500
Subject: Re: [EnergyPlus_Support] sky luminance
Of course, because there are not enough studies to quantify the sky type recognization, it is not easy to convert new models into code now.
if EPlus code changed the model of its reference, its prediction may be unreliable if without prior validation of new models. In that page, EPlus cited the reference where the model appears, it is probably that EPlus follows the approach of its reference. Hope to check it out and make it clear.
On Wed, Feb 3, 2010 at 8:51 AM, Linda Lawrie <linda@fortlawrie.
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