Correction of Errors in Inside Movable Insulation

[RKStrand]

Pull request overview

• Fixes Inside Movable Insulation causing increased heat loss #10865

Description of the purpose of this PR

Some testing with inside movable insulation uncovered results that did not seem to make sense. Comparing results between a case where an extra layer of insulation was added to the inside of a construction to a case where inside movable insulation added that layer on the base construction definition all year showed very large differences in district heating and cooling results (over 100% and close to 60% differences, respectively). A similar comparison with outside movable insulation showed reasonably small difference of only a few percent. The problem was traced back to an incorrect application of the inside movable insulation to the inside heat balances. For example, solar radiation was being added at the interface between the inside movable insulation, but inside movable insulation is assumed to be non-transparent. After correcting this issue, the difference between the case of adding insulation as the inside layer of the base construction definition and the case of using movable insulation dropped to less than 1% for both heating and cooling. A comparison of surface temperatures between these two cases also showed excellent agreement with the average difference for an annual simulation of around 0.005C. Corrections to the engineering reference and a new unit test were also included in this work. No difference are anticipated in the existing test files and the user provided files that demonstrated the error now provide the results quoted above.

Pull Request Author

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Reviewer

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• If new idf included, locally check the err file and other outputs

[RKStrand]

Here is a before and after comparison of heating and cooling loads before and after the fix. Note that the user posted district heating and cooling results, but the concept is the same.

[RKStrand]

Percentages listed above are the differences between heating and cooling between the construction change and the additional of inside movable insulation.

[github-actions]

⚠️ Regressions detected on macos-14 for commit 6ff4e82

Regression Summary

• EIO: 3
• ESO Big Diffs: 3
• MTR Big Diffs: 3
• Table Big Diffs: 3
• Table String Diffs: 3

• View Results
• Download Regressions

[github-actions]

⚠️ Regressions detected on ubuntu-24.04 for commit 6ff4e82

Regression Summary

• EIO: 3
• ESO Big Diffs: 3
• MTR Big Diffs: 3
• Table Big Diffs: 3
• Table String Diffs: 3

• View Results
• Download Regressions