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bramvdh91 / modelica-ibpsa

Modelica libraries that are used and/or developed within IEA EBC Annex 60
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Variables in PDETime_massFlow #46

Closed marcusfuchs closed 8 years ago

marcusfuchs commented 8 years ago

Some of the variables in PDETime_massFlow could be renamed.

E.g. in my opinion v_a sounds like velocity at port_a. Instead this and similar variables are used as 

  Boolean v_a "Is the fluid flowing from a to b?";
  Boolean v_b "Is the fluid flowing from b to a?";
  Boolean v_0 "Is the fluid standing still?";

I suggest using e.g. variable names like isDesignFlow and isZeroFlow instead. Also, the velocity u is currently calculated for the normalized distance between 0 and 1. I think having velocity relate to the real pipe length would be better understandable for the user. My experience was that I first struggled to find out that currently u is in normalized units per second, not meter per second.

If that is ok with others, I'll make a suggestion for redesigning this and push it later. At least for me, this may make further work on the models a bit easier.

bramvdh91 commented 8 years ago

@marcusfuchs Okay for me! However, maybe it's not needed to put too much time into this if we would decide to go towards a simpler model such as in issue37_newDelayMod.

marcusfuchs commented 8 years ago

That's a good point. I will have a look at it anyway to better understand the current implementation. E.g. I would have thought that going from normalized velocity u back to real velocity v should not have significants effects on the results, but it seems like this still influences tau noticeably, so we may want to stick with u.

marcusfuchs commented 8 years ago

As there are currently more important issues, I'll close this for now. Once we have decided on whether to keep this implementation or go with Bram's suggestion of 2 tau values we may or may not re-open this issue.