Daylight harvesting on a floor of building model in eQUEST

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This is a very peculiar behaviour in this model.

After looking at the .inp, I couldn't see anything immediately that was the cause.

I noticed that the model with daylighting had significantly higher autosized system cooling capacities than the model with no daylighting. This was on all floors, not just the floor with daylighting. You may want to try specifying the cooling capacity of each system in the daylighting model, with the autosized capacities from the non-daylighting model.

It could also be related to the windows - many of the windows on the third floor are specified using the "Simplified" specification method. I don't fully understand why, but I've been told that eQuest doesn't properly handle the angle of incidence of solar radiation to the window when they are "Simplified", and so it may not be giving you the correct solar gains in those third floor spaces. What this means is that when you turn on the daylighting calculation, it may be giving you too much solar gains in those spaces when it does the daylight calculation, resulting in higher cooling loads. You might try a window from the glass library and see if that makes a difference.

One other comment, Ashok, that isn't related to this problem, but I wanted to let you know - when you use the VRF curves provided by Daikin and import them into the eQuest, one of the heating curves doesn't import properly - the line is too long and eQuest truncates the exponent.

The curve "VRV Heating EIR-F-EWB/ODB AC" imports with coefficient number 4 as 7.145853, but it should be 0.07145853 in the model. Again, not a problem for you since you aren't using that particular curve, but could be a problem down the line. :)

I would need more specifics on the weather files to be able to tell whether they are the cause for the change. Julien's comment says that the runs were done using the 2014 ISHRAE and 2013 ISHRAE weather files for Jaipur. As far as I know, there have been only two versions of ISHRAE weather files - the first set in 2009 and a second set in 2014. I helped in recalculating the solar radiation for the first set, and was responsible for producing the second set. The solar in the first set were calculated "blind", but for the second set I had a more refined approach and was also able to calibrate the results against satellite-derived solar from NREL. Therefore, I'm more comfortable with the solar on the second (2014) set. I'm not sure what was meant by the 2013 ISHRAE weather file.