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Brian, In your example of a tank and an auxiliary heater you are correct that the first component appearing in the input file determines the flow for both. The order of components in the input file is determined by the order in which they were placed on the assembly panel in the Studio. However, you can modify the order by opening the control cards (where you set the simulation start and stop times) and then by clicking on the "component order" tab. Click and drag components around the list to change their order. TRNSYS typically uses the "successive substitution" method to solve the system of components. The outputs of one component are substituted into the inputs for the components to which that output is connected. Each component takes its current set of inputs and computes its outputs, passing them back to the TRNSYS kernel (brains) to see whether they have changed from the previous iteration. Once everything stops changing from iteration to iteration the kernel decides that convergence has been reached and advances to the next timestep. Your example changes somewhat if you put a pump into the system. Pumps and fans in TRNSYS control the downstream flow. The output flow rate from a pump or a fan is the rated flow rate multiplied by the control signal (usually; there are some components that do not conform to this method). The flow rate from the pump or fan is then passed to the downstream components and should get passed all the way around the flow loop such that there is a mass balance. Most pump and fan models issue a warning as to how much of the simulation their mass balance failed. kind regards, David On 02/17/2016 21:07, Brian Raichle
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-- *************************** 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 |