Large Process Loads and Baseline Systems

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Hey all,

I'm about to begin a LEED energy model for a warehouse project that contains a very large process load. It will be a major renovation project. The building will be broken out as 50,000 sq ft office and 300,000 sq ft warehouse. The anticipated HVAC systems on the project are package rooftop units with DX cooling/gas heating for both the office and warehouse areas. The warehouse space requires cooling and heating.

Two issues that come to light:

1. Large Process Load

a. Anticipated process load will consume roughly 40-60% of the buildings annual energy consumption. The Exceptional calculation method has been considered. However, the process being done at this facility is extraordinary and there is not a "baseline" to compare savings off of.

2. Baseline System

a. Based on the size of the warehouse, System 7 will be modeled. This system is a packaged rooftop VAV with reheat with chilled water and hot water boiler system. Based on previous experience and preliminary modeling results, the baseline system will be more energy efficient than the package rooftop units with DX cooling/gas heating. There's been a suggestion by our team to request a LEED Interpretation and to possible change the baseline system to also packaged rooftop units with DX cooling/gas heating as that is typically designed for warehouse type facilities.

Based on these two issues, I am having a hard time foreseeing this project being able to hit the minimum 5% savings requirement on major renovations. I searched the LEED Interpretations database but didn't find one that dealt with a project that had both these issues.

Any suggestions?

William Mak, LEED AP BD+C

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Hi William,
We did a Leed warehouse herre in Canada but it
was version NC 1.0, your 2.2 version.
In that case process energy has to be remove for comparaison with baseline.
We aslo can reclaim up to 2 credit in process
energy i.e. heat recovery from refrigeration.
If it is Leed 2009 than you have to include
process energy in baseline and proposed.

Hope this help

Martin Roy, ing. PA LEED

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Yes the project is a LEED 2009 project.

William Mak, LEED AP BD+C

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Percent Energy Savings is not an indicator of good building design. See
http://bepan.info/articles
2 - VCT - Mechanical-Design and Percent-Energy-Savings

Varkie Thomas's picture
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Hi William,

The "large process load" issue has been discussed extensively. Basically,
the process loads are not allowed to be omitted from baseline and proposed
design models. For your case, without touching the process loads, you
probably have little chance to claim energy credit even you are allowed to
modify the baseline. The possible solution will be the Process loads itself.
See whether you are able to claim savings due to the introducition of high
efficient equipments. Bear in mind, reduction of energy use in process loads
is allowed as long as it is well documented with a comparison between market
standard equipments (baseline) and energy-efficient ones (proposed design).
By searching this forum or online, you will be able to find more info on
this subject.

Regards,

Cheney

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I guess that's the only possible route we can take. What possible options do we have if we cannot document a market standard equipment design? Their process is very unique and there are only a couple firms that do the process this firm does.

I agree, even if we can get the baseline system variance to be approved, it will insignificant since the process load takes up the majority of the energy consumption.

William Mak, LEED AP BD+C

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Joined: 2011-09-30
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