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Re: [EnergyPlus_Support] DOE-2 and EnergyPlus calculated different cooling loads for the same building
I think you'll have to upload the files because attachments don't fly through the support group emails. I know one big difference between the two simulation engines is the link between the loads calculation and hvac simulation routines. In EnergyPlus, this is an iterative process, while in DOE2, the loads are calculated first and then this becomes an input to the hvac simulation. The load calculated in DOE2 may be substantially different from EnergyPlus. If you are just using purchased air, this may not be as much of a problem, because the load is calculated, and that amount of cooling/heating is automatically provided by the system. If E+ has to simulate a system, however, this will be more prominent.
Edwin
----- Original Message ----
From: Simge Andolsun <simgeandolsun@xxxxxxxxx>
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sent: Friday, December 7, 2007 6:59:20 PM
Subject: [EnergyPlus_Support] DOE-2 and EnergyPlus calculated different cooling loads for the same building
Please find the attached EnergyPlus(1) and DOE-2(2) files. These two files are supposed to be the DOE-2 and EnergyPlus simulations of the same building. Thus, they are supposed to exhibit the same cooling energy consumptions. The cooling energy consumptions, however, differ. Please find the attached line graph (3) that shows the cooling energy consumption of the building with respect to EnergyPlus and DOE-2 simulations on the peak cooling day (3rd of July). The DOE-2 output exhibited twice of EneryPlus results. Please also find the attached line graphs (4) that show the temperature fluctuations in the interior zones of DOE-2 and EnergyPlus spaces. When compared to EnergyPlus simulation, there was a time-lag in the temperature fluctuations of the DOE-2 interior space. This made us consider FLOOR-WEIGHT factor in DOE-2 as a probable reason. We tried different floor-weight values. This however did not help much. Moreover, the cooling energy
graphs (3) showed a very similar
behavior although the values were very different. This suggested that there might be a single definite reason for the difference in cooling loads calculated by the two programs. With your experience on EnergyPlus, which input would you recommend us to check as the probable reason for the difference in results?
Thanks in advance for your reply,
ps: If I should upload the attached files, please let me know.
Simge Andolsun
Graduate Research Assistant
Texas A&M University
Energy Systems Laboratory
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