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importEPW - directNormalRadiation outputting values in lux instead of W/m2 #463

Closed patternarch closed 5 years ago

patternarch commented 5 years ago

Looks like V 0.0.67 NOV_20_2018 version of ImportEPW has Radiation and Illuminance flipped in the outputs. Radiation is in lux and Illuminance is in W/m2. Also directNormalRadiation is reporting diffuse and diffuseHorizontalRadiation is reporting direct components.

chriswmackey commented 5 years ago

@patternarch ,

This is definitely an issue that is specific to your EPW since a bug this large would have been noticed by myself or any of the other hundreds of active community members on our forum. Here's a screenshot just for more proof: image

We can help you figure out what is wrong with your EPW if you upload it to a post on our forum but, because this is not a bug in ladybug, I am closing out this issue for now.

patternarch commented 5 years ago

@chriswmackey This consistently issue is for every TMY3 weather file We have run every weather file to test this. TMY and TMY2 along with some international locations are correct. I think further exploration is warranted. Thanks for looking into this! Try the USA_AZ_Phoenix-Sky.Harbor.Intl.AP.722780_TMY3.epw for instance.

mostaphaRoudsari commented 5 years ago

@patternarch, is it happening for weather files from DOE website or OneClimate? Can you send the exact link to the weather file. Thanks.

patternarch commented 5 years ago

@chriswmackey Also even in the example you show the direct normal radiation is outputting in lux rather than W/m2.

patternarch commented 5 years ago

@mostaphaRoudsari the climate files come from DOE

chriswmackey commented 5 years ago

@patternarch ,

If that is the case, then you'll have to explain what you are expecting these results to be since these make sense to me: image

patternarch commented 5 years ago

Okay, looks like I was wrong on the TMY3 files. I thought I was connected to that one. However, I was connected to a TMY format. See screenshot. Radiation is looking correct but Illuminance has problems. Thanks for your patience. I should have put a screen shot in the first time! TMY problem

mostaphaRoudsari commented 5 years ago

@patternarch, values >= 999900 are missing values. TMY files are older and it is common that they are missing data. See here: https://bigladdersoftware.com/epx/docs/8-3/auxiliary-programs/energyplus-weather-file-epw-data-dictionary.html#field-diffuse-horizontal-illuminance

There is not much we can do about this. @chriswmackey what are your thoughts?

chriswmackey commented 5 years ago

Glad that we have come to an agreement that it is an EPW-specific issue and, yes, I agree that there isn't anything that we should change with ladybug legacy to estimate these missing illuminance values.

However, there are luminous efficacy models within the new ladybug-core Python library that would allow you to estimate the illuminance from the radiation and dewpoint values in the EPW. I have posted an example file to hydra with a component that uses these libraries to estimate illuminance. If you post this question about missing illuminance to the forum where I know several people will benefit from seeing the answer, I will give a more detailed explanation and the links to the luminous efficacy model resources.

mostaphaRoudsari commented 5 years ago

Thank you @chriswmackey! @patternarch I'm going to close this issue as the original question has been resolved. Please post any follow up questions on the forum as suggested by Chris.