Parametric runs showing inconsistent results

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Background:
We are developing a baseline model with three modeled alternatives to the baseline. We created a baseline, then copied and modified that model for each of the three alternatives. After all four models are complete, we re-open the baseline model, select Tools>Parametric Runs and set up the three alternatives as parametric runs "Based On Separate Building Descriptions" to link the alternatives to the baseline. In each case, the run is based on the baseline run. The simulations run fine, and we get results in our "* - Parms.csv" file.

Issue:
Since our alternatives are complete models, we will run them and test and debug them extensively before linking everything together in parametric runs in order to get comparative reports. We have discovered an issue where the results reported in the "* - Parms.csv" does NOT match the results of running the model independently of the parametric run. The "* - Parms.csv" file clearly shows that under "Case Description" each alternative is "0+Run 1", "0+Run 2", etc. Sometimes this inconsistency is small, but on other models it turns out to be large enough that it can't be ignored.

Questions:
Has anyone else observed this issue? Is there a fix or a workaround?

Thanks in advance,

Doug Laney

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Joined: 2011-09-30
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Doug,

I have encountered situations where a parametric run changes more than I initially thought it would. It seems to be similar to how making a selection about a system type determines the defaults on later screens. The example that comes to mind is changing a boiler to a condensing boiler and then lowering the supply water temperature so that the boiler will actually condense. I entered these as two separate parametric runs. When I was working on the second parametric run I saw that the supply water temperature was already changed! So there may be more changes in your parametric runs than you realize.

________________________________
Keith Swartz, P.E., LEED AP

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Joined: 2011-09-30
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