EnergyPlus chiller load is much lower than measured data [closed]

asked 2024-10-15 15:17:22 -0600

173 ●4 ●6

updated 2024-10-21 11:06:10 -0600

Hello,

I have been calibrating an EnergyPlus model for a very old mid-rise multi-family building. My approach involves modifying the DOE Prototype Mid-rise Apartment Building Model and calibrating it against site-measured data.

While the simulation results show a reasonable match for the whole building load compared with the measured data, the chiller electrical load is much lower than the measured data except between 10 AM and 5 PM. I have adopted the empirical chiller data provided by EnergyPlus, which corresponds to the same model as the on-site chiller. Below figure shows the model calibration results.

image description

My objective is to achieve an acceptable chiller CVRMSE against the measured data.

I would appreciate any thoughts or comments you might have to resolve this issue.

Thank you!

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Closed for the following reason the question is answered, right answer was accepted by Yapan
close date 2024-10-22 10:07:19.105933

Comments

@Yapan It looks like the model is under-predicting night-time cooling by ~30 kW, but the model is only under-predicting night-time whole-building by ~10 kW. Do you have other meters of measured end uses to understand what could cause this discrepancy?

Aaron Boranian ( 2024-10-18 11:05:40 -0600 )edit

Hi @Yapan, the "E+ Facility" includes the chiller, I expect? The same in the real building? Seems strange. As Aaron asked, are there any other meters available in the real building? The integral below the E+ chiller curve (i.e. energy use in the interval studied) would seem to be maybe half that of the measurement? This makes the fair agreement for "overall" really quite strange). FWIW, simply to maybe jog an idea. Best, Achim

AGeissler ( 2024-10-21 02:27:51 -0600 )edit

@AGeissler @aaron-boranian, Thank you so much for your comments. Yes, the EnergyPlus facility does include chiller electrical load. I was wondering whether the on-site chiller operation diverges from the empirical data provided by EnergyPlus. My model uses the "ElectricEIRChiller Carrier 30RB130 447.7 kW/2.8 COP" from the EnergyPlus data. I will double check the measured data, will post here later. Thanks again!

Yapan ( 2024-10-21 10:42:19 -0600 )edit

The building data does look close and the chiller data matches at peak, so that's a good sign. It looks like there are missing nighttime loads. For example, infiltration, lighting, equipment, outdoor air, operating schedules, etc.