Hi all,
Is it possible to use EnergyPlus to model a walk-in cooler or freezer? I have tried but regardless of the temperature setpoint I choose for the freezer, the modeled temperature does not want to drop below about 42 F.
Also, has anyone made a model of a cooler that accurately estimates electricity loads? I was able to model a cooler with a 45 F setpoint but I was way under the electricity consumption estimates I found for coolers/freezers on the web. I think my problem was the large amount of electrical usage for non-compressor loads ? defrost cycle, evaporator fan, condenser fan, etc.
Kurt Creamer
Kurt,
We had this problem before in the mid-80s simulating an ice rink at a Rec Center. This was published in an ASHRAE Transactions paper. We basically got around the issue by fudging the "U x A x Delta-T"...in this case fiddling with either the U or the A to adjust for the Delta-T. Results worked well against metered data.
Jeff S. Haberl, Ph.D.,P.E., FASHRAE
Hi Kurt,
We model a refrigerated warehouse using ESPr and
TRNSYS. We did not try Energy+.
The main reason was to evaluate the effect of the
thermal mass stored against the incoming product that was warmer.
when we compare our result to those of the
refrigeration contractor there was a big
difference. Half of their calculated load
And compare to actual energy consumption, it was close.
So if you use energy+ be shure to include thermal mass.
Martin Roy, ing. PA LEED
eQUEST has the refrigeration module that can model this
http://doe2.com/equest/index.html
We have used this version of eQUEST on restaurants (small QUICK -SERVICE))
Jorge E. Torres Coto
If you are modeling a refrigerated you can also use ENERGYPRO, though you
have to buy the software.
Jorge E. Torres Coto
I have successfully modeled walk-in freezers for the upcoming Title 24 supermarket refrigeration code in E+. I used the explicit method which requires compressor racks. If you are using compressor rack objects make sure that you are choosing the right compressor and that the compressors can meet the load. The .err file will give a warning if the system cannot meet the refrigeration loads.
FYI, The dataset folder in the E+ folder has several compressor curves.
Haider.
Sent from my mobile device.