David,
I did not take the time to run the project but there are two
issues that need to be resolved.
The first is the 1-hour time step; I would guess that part of the problem is non convergence due to the long time step. The pump on the hot water side of the absorption chiller has a flow rate of 58000 kg/h and the tank is 5m3. That means that in each time step, the tank volume turns over a bit more than 11 times. The flow rate on the collector loop is 20000 kg/h causing another 4 turnovers in each time step. I would start by reducing the time step to about 5 minutes.
The other issue is that you have two devices in the collector loop that are both trying to set the flow rate in that loop. Type110 is being controlled by an on/off differential controller but your collector is also set up in Pump Control Specification mode 2 (an input), which means that the collector model is modulating its own flow in order to deliver a specified outlet temperature.
kind regards,
David
Hi, I'm trying to simulate a system with a single effect absorption chiller (project file attached) however I keep getting an error saying pump mass balance failed, is there a way of calculating the correct mass balance. Any help gratefully appreciated. Thanks David
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-- *************************** David BRADLEY Principal Thermal Energy Systems Specialists, LLC 3 North Pinckney Street - suite 202 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