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How to get the OpenStudio Results to correctly show Interior Lighting Power Densities?

asked 2016-05-09 17:27:50 -0600

updated 2016-05-10 00:42:38 -0600

Is there a way to get the OpenStudio (1.11) Results report under "Interior Lighting Summary" to correctly display the Lighting Power Densities without rezoning? I have noticed that it only shows the correct LPDs for thermal zones that are made up of one space type. If there is a zone with multiple space types, it will break the zone out into how many spaces are in it and incorrectly calculate the LPD for the space. This seems to be because the formula used in the report to calculate the LPD takes the space total power and divides it by the zone area. In my screenshot below there are two zones, with areas of 1,364.36 ft ² for L1 CORRIDORELECPUMPSTAIR and 1,130.91 ft² for L1 LOBBYSTAIRELEVATOR. Dividing any of the "zone" Total Power listed by the actual zone area gets the Lighting Power Density shown, which is incorrect. The report should only show 2 zones with LPDs of 1.5 W/ft². This is causing a LEED reviewer to believe that I have entered my baseline building lighting loads incorrectly.

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The only other question I have found that is related is this one:

kramerica's avatar kramerica  ( 2016-05-09 17:28:30 -0600 )edit

@kramerica as you mention this is probably a mistake in the measure's calculation. @David Goldwasser should be able to fix this. In the meantime, I suggest using the Zone Summary table from the EnergyPlus Results.

MatthewSteen's avatar MatthewSteen  ( 2016-05-10 10:34:44 -0600 )edit

Except that section of the measure doesn't do it's own calculation, just queries the sql:

ericringold's avatar ericringold  ( 2016-05-10 11:57:35 -0600 )edit

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answered 2016-05-10 19:28:36 -0600

It lists all the individual lighting load instances. As @Eric Ringold mentioned, it is pulled from the E+ report, although it does convert W/m^2 to W/ft^2.

@kramerica, it sounds like you may want a zone total LPD, which we don't currently report. We do report a zone total vs. listing instances for plug loads, which didn't have an equivalent table in the EnergyPlus html file.

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The reporting issue is part of how EnergyPlus creates its reports, like @Eric Ringold mentioned. @David Goldwasser, yes, I would like to find a way to easily alter my inputs for space types or individual spaces so that the report will show the total zone LPD. The only way I can think of would be to break these zones into multiple zones with only one space type per zone.

kramerica's avatar kramerica  ( 2016-05-11 10:34:12 -0600 )edit

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Asked: 2016-05-09 17:27:50 -0600

Seen: 375 times

Last updated: May 10 '16