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!
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"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
Jim,
For the lights I would do a quick calculation of the Wattages of equal
illumination lighting. Whatever the case manufacturer would use in
their BASELINE models. I'm sure the LEDs are an upgrade, so just base
the savings on the wattages and the hours of operation. That one should
be easy.
You could basically do the same thing with the COP. As long as it is
for the entire system, you can use a reasonable load and just multiply
it out. I'd try that anyway. You might get shot down, but then you can
always come back with different.
I'm not so sure about the ECM fans. Where is the savings? If they are
variable speed, then there are some studies on variable speed fans
versus constant speed fans, but they should be application specific /
load profile specific. I have seen ECM fan coil fans that save
approximately nothing.
I believe that utilities give rebates and incentives for refrigeration
upgrades like these. Maybe the local utility does that. Maybe PG&E
does that. If so, they may be able to steer you to a paper.
Good luck!
Robert Wichert P.Eng. LEED AP BD&C
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
The LEED for Retail New Construction and Major Renovations reference guide under EAc1 outlines a baseline refrigeration system. We have used this for Austin Energy Green Build in the past. It does a pretty good job but is a little vague on some of your issues. The Energy Trust of Oregon has a version as well: http://energytrust.org/library/forms/NBE_PG_TechGuidelines.pdf.
Tim
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
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
Great information, Tim! I?ll check them out.
James V Dirkes II, PE, BEMP, LEED AP
Jim,
The 2013 version of ASHRAE Standard 90.1 added requirements for refrigerated casework. I suggest you identify where your project exceeds those requirements and make the case to USGBC that what is in 90.1 should be the baseline. Good luck.
Michael Rosenberg, CEM, LEED AP
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
Another good insight. Thank you!
James V Dirkes II, PE, BEMP, LEED AP
Jim,
There is a similar baseline description of commercial refrigeration systems in Alliant Energy?s Technical Guide Book 2012. Start on page 124 of http://www.alliantenergy.com/wcm/groups/wcm_internet/@int/documents/document/mdaw/mdiz/~edisp/023759.pdf.
Info for anti-condensate door heater controls starts on page 119.
Info for LED lighting in refrigeration cases starts on page 48.
The State of Illinois also publishes deemed savings values for various upgrades in their Technical Reference Manual (TRM). See Section 4.6 for refrigeration. http://www.ilsag.info/il_trm_version_2.html
ComEd incentives for refrigeration upgrades are listed in https://www.comed.com/Documents/business-savings/SIFYB_PY6_Refrigeration.pdf.
Some of the measures in the above references are specifically for upgrading existing equipment, not new construction, so read the fine print carefully.
I hope this helps!
Sincerely,
Keith Swartz, PE, BEMP, LEED AP
I am starting to think GBCI doesn't have a chance (to disagree), but I will have to read these references first :).
Thanks so much!
The Building Performance Team
Look at addendum AR as well.
Michael Rosenberg, CEM, LEED AP
Jim,
In case you don?t have 90.1-2013, Addendum g to 90.1-2010 is the one that added energy requirements for refrigeration cases (see attached, I believe the addenda are free downloads).
As someone who has gone through the exceptional calculation method for process loads with LEED, I would recommend using this guidance as your baseline if you show a significant improvement with your design because establishing a baseline for process loads can be challenging (read: lots of extra time spent).
Scott P. West, P.E., LEED AP BD+C, BEAP, BEMP
Jim,
I have not modeled casework in a while but I recall the frustration over defining the baseline and claiming savings. The LEED 2009 for Retail rating system literature addressed several of these parameters and maybe version 4 does too. When available, it is best to cite their own literature back to them.
Good luck,
Paul Riemer, PE, LEED AP BD+C
Jim,
In case you don't have 90.1-2013, Addendum g to 90.1-2010 is the one that added energy requirements for refrigeration cases (see attached, I believe the addenda are free downloads).
As someone who has gone through the exceptional calculation method for process loads with LEED, I would recommend using this guidance as your baseline if you show a significant improvement with your design because establishing a baseline for process loads can be challenging (read: lots of extra time spent).
Scott P. West, P.E., LEED AP BD+C, BEAP, BEMP