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Erik, You are right on with all three of your points. For reference, we discontinued use of Type109 in Trnsys17 in favor of option 2 (Type15), which is correct from an energy perspective even though it isn't a smooth curve. In gernal think that a control strategy that relies only on the instantaneous DNI as its input might run into trouble not only in simulation but also in the real world; clouds pass in front of the sun rapidly sometimes. While I won't pretend that the "spiky" profile that Type15 generates is totally realistic, I think it is a fairly accurate representation of DNI. Bear in mind that Type15 is trying to reconstruct a minute by minute radiation profile based only on 1 number and to do so correctly for all possible climate types. You might consider a control strategy that uses the output of Type15 but put through a running-average component so that your control decisions are based on a somewhat more stable (smoother) profile. Best, David On 11/11/2011 00:32, Erik Boschek wrote:
-- *************************** David BRADLEY Principal Thermal Energy Systems Specialists, LLC 22 North Carroll Street - suite 370 Madison, WI 53703 USA P:+1.608.274.2577 F:+1.608.278.1475 d.bradley@tess-inc.com http://www.tess-inc.com http://www.trnsys.com |