E+ Coincidental Load > Noncoincidental

asked 2021-10-19 10:22:46 -0500

updated 2021-10-19 23:03:06 -0500

I'm looking to output (coincidental) building block load envelope components using an E+ model.

The issue is that the coincidental block heating load (from the Facility Component Load Summary report) is (significantly) higher than the sum of the non-coincidental zone heating load peaks (pulled from the Zone Component Load Summaries), which should not be the case.

Has anyone had this issue? Any solution?

Another anomaly is that the “Time of Peak Load” is blank in the Facility Summary.

The attached image shows the Facility Summary, with the right-most two columns showing the sum from Zone Summaries.

The building is modeled in v8.8 with district heating/cooling, ideal loads air systems, 0 internal loads, annual heating design day object entered for SizingPeriod:DesignDay, and all options in the SimulationControl object set to “yes”.

image description

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Does the same issue occur with the latest version of EnergyPlus (currently 9.6.0)?

JasonGlazer's avatar JasonGlazer  ( 2021-10-20 06:54:12 -0500 )edit

We are not using 9.6.0 currently, but in 9.4.0 the "Grand Total" peak heating load is -488,300 (major change from the -644,338 in 8.8, seen in the image); the "Fenestration Conduction" component is now at -266,728 and accounts for the majority of the change. Wondering what changed in the calculation for the Facility Component Load Summary outputs between the two versions? I don't have a quick way to sum the Zone Component Load Summary Outputs from the 9.4 output yet, but the 9.4 coincidental load is only 2% less than the 8.8 noncoincidental heating load.

Brittany Carl Moser's avatar Brittany Carl Moser  ( 2021-10-20 16:17:18 -0500 )edit

There have been bugs fixed over time related to these reports so I would encourage you to use the latest version of EnergyPlus.

JasonGlazer's avatar JasonGlazer  ( 2021-10-20 16:20:21 -0500 )edit

Good to know. Have there been bug fixes since v8.8, and since v9.4, for the Zone Component Load Summary calculations, as well? Thank you.

Brittany Carl Moser's avatar Brittany Carl Moser  ( 2021-10-20 16:39:42 -0500 )edit