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Dear Ahmadu, It looks as if your simulation is going in the right direction but as though there are a lot of small errors. I don't have the *.bui file for your building so I cannot run the simulation. However, in taking a look at some components, here is what I noticed: - the equation for the return temperature from the building is incorrect. It is Tout = Tin+(Qload/4190*mdot) and should be Tout = Tin+(Qload/(4.190*mdot)). The cooling load output of Type56 is in kJ/h. - the pump in that same loop has a rated flow rate of 100 kg/h, which is unrealistically small. This pump sets the maximum rate of flow to the load to 100 kg/h and will result in a VERY large temperature increase. In fact, the same is true of all the pumps in the system. If you aren't sure about pump sizes, try to get an idea of what kind of temperature rise you want across a given branch of the system and determine the flow rate that would obtain such a temperature rise. - there is no thermal capacitance on your absorption chiller's cooling water loop. I think you need to put a tank in that loop. - as in a previous email that I sent to the list today, make sure that your tanks are large enough to hold more than one timestep of fluid in them. - your time step should be on the order of 1 to 5 minutes, not an hour. TRNSYS can only make one control decision per timestep and systems that can only change their behavior once per hour rarely converge. - on both of your Type4 tanks, go to the output tab and enter "4" in the field that asks how many nodes there are in the tank besides the top and bottom nodes. There is an inconsistency in your tanks as to how many nodes they are modeling. I am afraid that this is not an exhaustive list. I would recommend that you back up to the point where you have just the building giving loads to the equation labeled "Equa." Give a constant flow of water to that equation and make sure that you are seeing somewhere between a 5 and 10C temperature rise in the water at the peak load. Next, add pump "Type3b-5" and control the flow through "Equa." Add one component at a time and each time you add a new now, attach a type65 to it and plot some output or other to make sure that you fully understand the results that you are seeing. Kind regards, David On 10/29/2012 08:09, Talib Ahmadu
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 |