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Which advanced surface properties are important?

asked 2015-12-02 13:29:05 -0500

What advanced surface properties are important for users to be able to adjust? EnergyPlus has the concept of hierarchical defaults for many things (like heat balance algorithm). Which levels of the hierarchy are most important (e.g. do you more often change the heat balance algorithm for the entire model, for a particular construction, or for a specific surface)? We are planning on adding support for a few new advanced surface properties in OpenStudio, please feel free to comment on this document.

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answered 2015-12-02 13:52:19 -0500

updated 2015-12-02 13:55:59 -0500

I'm somewhat disappointed to see SurfaceProperty:ConvectionCoefficients in the 'not planned' section. Per this issue, EnergyPlus seems to not be getting these quite right for radiant ceiling panels. The ability to apply these coefficients to, e.g., surfaces with internal source constructions (as opposed to SurfaceProperty:ConvectionCoefficients:MultipleSurface, which is only by surface type), seems like a good input hierarchy level.

Out of curiosity, to what extent are UserVoice suggestions making it into your new features planning? There doesn't seem to be a lot of activity when it comes to updates of the 'status' of suggestions. We're making and voting on suggestions; is anyone listening!?

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This is good feedback, thanks! I do wonder if the user issue you referenced could also have been solved by using a different algorithm? It seems that the adaptive methods could have been applied to all surfaces and just specify a particular algorithm for the right surface type (e.g. Floor Heat Ceiling Cool Stable Horizontal Equation Source). Maybe someone from the E+ team could weigh in?

As for user voice, we are listening but that is just one source of input. This request came in from a different avenue and was already green-lighted but I wanted to get user input on it before we start.

macumber's avatar macumber  ( 2015-12-02 16:12:32 -0500 )edit

I wonder as well. The little bit of digging I've done into my radiant ceiling panel models indicated that the default adaptive convection choices seemed OK, but I didn't get so far as to experiment with changing them, mostly because it was going to be a pain to do from OpenStudio! Thanks for the clarity regarding uservoice, I know you guys get a lot of input from lots of parties, and definitely appreciate your responsiveness.

ericringold's avatar ericringold  ( 2015-12-02 16:39:55 -0500 )edit

@Neal Kruis these surface properties are a good example of a place where there is too much control. There are 44 algorithms available in SurfaceProperty:ConvectionCoefficients. It's neat that you can have this much control but 99% of users just want EnergyPlus to do the right thing. You shouldn't need to know that you have to go adjust surface convection coefficients when you have radiant heating/cooling, the defaults should do this for you. We could address this at the OpenStudio level but I think it is really something that should be in EnergyPlus.

macumber's avatar macumber  ( 2015-12-03 09:10:09 -0500 )edit

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Asked: 2015-12-02 13:29:05 -0500

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Last updated: Dec 02 '15