Julien,
· There is a mix of open and closed cases
· Compressors are external to the cases and condenser is outdoors
· Waste heat is being captured from one of the systems
· The other stores have a different mix of cases and it is not practical to measure comparable portions
James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653
From: Julien Marrec [mailto:julien.marrec@xxxxxxxxx]
Sent: Wednesday, January 22, 2014 6:11 PM
To: Jim Dirkes
Cc: EnergyPlus_Support@xxxxxxxxxxxxxxx; bldg-sim@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: [Bldg-sim] Claiming refrigerated casework savings for a LEED project
Hi Jim,
Just to clarify, are those open or closed refrigerated units? (Is there a door?)
How many are we talking about? (kW or tons)
Are the compressors integrated within the unit (heat rejection within the conditioned area) or do you have condensers outside? If you do, are you also reusing waste heat to produce either hot water or heating?
When you say you have data from other stores but they are not identical, what do you mean? Isn't there a unit that is similar (or exactly the same) to those previously installed (reading your email I believe the replacements have already been made in your studied building) where you could strap a pulse meter for example for at least a couple of weeks?
Best,
--
Julien Marrec, EBCP, BPI MFBA
Ingénieur en efficacité énergétique du bâtiment
T: +33 6 95 14 42 13
www.julienmarrec.com
DoYouBuzz : www.doyoubuzz.com/julien-marrec_1
LinkedIn (fr) : www.linkedin.com/in/julienmarrec/fr
LinkedIn (en) : www.linkedin.com/in/julienmarrec
2014/1/22 Jim Dirkes <jim@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Dear Forum,
I am modeling a supermarket which has made effort to install refrigerated casework that is more efficient than “normal” in three ways:
• Casework lighting is LED instead of fluorescent
• Evaporator fans use ECM motors and are demonstrably more efficient
• The compressors have higher COP
I did not realize that claiming savings from a “process” load also requires substantiation of the Baseline energy for the process load via comparison to several similar facilities or a published paper. I wish I knew that months ago!
We have data from three other supermarkets owned by the same company, but these other examples are not identical. So far, all I can say is that:
a) Manufacturer literature claims that LEDs used in their casework use ~ 65% less energy than fluorescent lights
b) ECM fans use about 35% less energy in a manufacturer power comparison table
c) The COP is better (I do not have detailed data yet)
This strikes me as a fairly weak argument, so I am asking you for suggestions or published data to strengthen the argument.
p.s., My last alternative is to ignore the process energy savings and make it the same for both models. I think the savings are substantial, however, and would rather find a way to claim them!
"Attack me … rather than the path I follow and which I point to anyone who asks me where I think it lies. If I know the way home and am walking along it drunkenly, is it any less the right way because I am staggering side to side?" Leo Tolstoy
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