Re: [TRNSYS-users] Type60 tank problem

[David BRADLEY <d.bradley@tess-inc.com>]

Brian,
  Technically, there is nothing wrong with the way that you implemented your inputs to Type60. The negative flow rate error is showing up because of the order in which the components are called (they are called in the same order in which they appear in the input file). For reference, your input connections are:

pump (Unit 6 - Type114) --> Flow Rate at Outlet 2 (Unit 4 - Type60)
pipe (Unit15 - Type32b) --> Flow Rate at Inlet 2 (Unit 4 - Type60)

At one of the iterations in the first timestep (before convergence has been reached) the pump changes state and the tank gets called before the pipe component does so as a result, the flow rate out of the pump has changed but the flow rate out of the pipe hasn't yet when the tank model is called.

The fix is pretty simple: you can just revise your connections as follows:

pipe (Unit15 - Type32b) --> Flow Rate at Outlet 2 (Unit 4 - Type60)
pipe (Unit15 - Type32b) --> Flow Rate at Inlet 2 (Unit 4 - Type60)

best,
 David

On 2/17/2013 22:25, Brian Raichle wrote:

Hello,
I'm using a Type60c tank in a simple direct solar water heating model. I get the "negative flow" error. The input/outputs are defined as:
inlet 1 flow: mains flow             outlet 1 flow: -2
inlet 2 flow: solar pump flow      outlet 2 flow: solar pump flow
Not sure where else to look.  Any thoughts?
Thanks,
Brian

--
Brian Raichle
Department of Technology and Environmental Design
Appalachian State University

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