units in EP output table coming out of OS

asked 2018-03-20 16:36:56 -0600

Matt Koch gravatar image

updated 2018-03-21 04:16:05 -0600

Using only the Set Output Table to IP Units EnergyPlus measure in OpenStudio, part of the EnergyPlus output lists the following results for two separate and unrelated models.

image description

image description

In either case, the individual capacity is on the order of 10 to 20 ton. Yet, as shown in the fourth column of these tables, the capacities are reported as 10s of thousands of ton! There is actually an earlier Table (DX Cooling Coils under Equipment Summary, that also shows these large tonnages).

In contrast, another Table (Coil:Cooling:DX:TwoSpeed under Component Sizing Summary) shows more plausible numbers, e.g. 6.7 ton (or ) for RTU-CC-0 or 15.66 ton for RTU-CC-5. This does not seem to be a simple ton vs. BTU/h conversion problem either, as, for example, 15.66 ton is 187,920 BTU/h vs. 52,601.02 "ton" in the table above.

However, 52,601.02 "W" would convert to 14.957 ton, which is close to the 15.66 ton - give or take whatever EnergyPlus might do?

Does anyone have an explanation for what the unit of the fourth column really is? And if it is "W" indeed, why do I only get 14.957 ton and not 15.66 ton?

What are that chances that other units might be compromised as well?

edit retag flag offensive close merge delete


Edited to make the images clickable (by wrapping the image inside a link to the same image: eg [![image desc](link)](link))

Julien Marrec gravatar image Julien Marrec  ( 2018-03-21 04:16:57 -0600 )edit

It'd be great if you could tell us what E+ version you're using exactly, and share your model. If you don't want to share your model, please run it in SI units too and compare the SI report (which has to be right) to the IP one to see if you can recreate the numbers. If this is a bug, then it'll belong on Github instead, but let's not jump the gun.

Julien Marrec gravatar image Julien Marrec  ( 2018-03-21 04:20:21 -0600 )edit