Bugfix for autosizing when detailed performance capacity fractions are provided #1862
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These two cases run the same home with different heat pump detailed performance inputs (capacity fractions), using autosizing. The design temperature is 6.6F but the capacities at 5F after hvac sizing are very different, which is caused by this issue. This PR fixed it and now gave numbers very close to expectations. |
| hpxml_bldg.heat_pumps[0].cooling_detailed_performance_data.find { |dp| dp.outdoor_temperature == HVAC::AirSourceCoolRatedODB && dp.capacity_description == HPXML::CapacityDescriptionMaximum }.capacity_fraction_of_nominal = 1.1 | ||
| XMLHelper.write_file(hpxml.to_doc, @tmp_hpxml_path) | ||
| _model, _hpxml, hpxml_bldg = _test_measure(args_hash) | ||
| assert_equal(hpxml_bldg.heat_pumps[0].heating_capacity, htg_cap_orig) |
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The unit test here verifies that the autosized rated capacity is the same as original, regardless of maximum speed capacity fractions of nominal at rated temperatures. The fractions will be applied later when pop up the capacities in detailed performance data points.
…o detailed_performance_autosizing_bugfix
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@yzhou601 I see that there are no CI diffs, but I was thinking that |
This issue only shows up when the maximum speed capacity fraction at rated temperature is over 1.0. For that test file we configured it to be 1.0 at maximum speed, 47F (for ducted system, it is close to 1.0, in default: https://github.com/NREL/OpenStudio-HPXML/blob/master/HPXMLtoOpenStudio/resources/hvac.rb#L1899). Besides, the test file uses HERS sizing methodology, where the loads override the sized capacity. See my unit test, it reveals the issue and gets fixed with the changes in this PR. |
FYI, the defect test file uses MaxLoad sizing methodology and is a ductless minisplit so this issue is captured |
Pull Request Description
The autosizing to convert design condition load to rated condition capacity (47F) is based on the 47F maximum capacity fraction, which is not correct. It should apply the nominal capacity fraction (which is 1.0).
cc @jonwinkler
Checklist
Not all may apply:
EPvalidator.xml) has been updatedopenstudio tasks.rb update_hpxmls)HPXMLtoOpenStudio/tests/test*.rband/orworkflow/tests/test*.rb)openstudio tasks.rb update_measureshas been run