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Younness, I think it might be Type93, a component that takes an input and holds it for one or more time steps (in fact by however many time steps the user indicated using a parameter) and then "releases" the input as an output. It can help to stabilize a simulation that has convergence problems by building back in some of the time delays that get "simplified out" when we write mathematical models of physical processes. For example, in building models and thermal storage models, we assume that mixing of an inlet air or water stream into the zone or tank node occurs instantaneously and that thermostats sense the change instantaneously. In reality, the mixing and sensing both take some finite time. Adding the Type93 "input delay" is an effective way of building the finite time for mixing back in. You should take a lot of care in using it because it is quite easy to stick them all over a simulation and force the system to converge when in fact there are other problems that should be addressed. I would recommend only using the Type if you are using a small timestep such as 1 or 5 minutes. Kind regards, David On 11/16/2011 09:18, youness EL FOUIH wrote: Dear all, -- *************************** 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 |