Forum discussion
CS-2009 EAp2: Minimum Energy Performance
In Title 24 we are allowed to exempt the low level nighttime lights and exits signs around exterior doors from the energy model as typical lighting exemptions. For the purposes of LEED are we required to include this lighting - ASHRAE 90.1-2007 specifically mentions luminaire source efficacy for exit signs (9.4.3).
Since we are allowed to use Title 24 do we get to follow their exemption policies, or do we need to include this low-level lighting?
Thanks
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
October 21, 2010 - 9:45 am
LEED requires that all energy uses be included in the models. It does not matter whether the referenced standard exempts certain components from the compliance requirements. 90.1 also exempts certain lighting systems but they must still be modeled and included for LEED projects.
It simply comes down to an issue of compliance vs savings. LEED requires you to determine savings, not just demonstrate compliance. If the referenced standard does not contain a baseline then the models should be identical, in other words, the baseline should be the same as the proposed.
Prudence Ferreira
PrincipalIntegral Impact
88 thumbs up
October 23, 2010 - 4:43 pm
Thanks Marcus,
Another question. We are working on modeling our process loads - particularly the medical equipment. In the reference guide it states that process energy includes "lighting exempt from the lighting power allowance (e.g. lighting integral to medical equipment)" I assume this would mean that we do not actually have to model the medical equipment itself in the process energy. Is this a correct interpretation? If not, do you know of any defaults that we could use, or a default for "lighting integral to medical equipment?"
Thanks,
Thanks,
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
October 25, 2010 - 9:53 am
You must model all energy uses within and associated with the project. Nothing is exempted from this requirement for LEED.
The lighting in medical equipment is just an example of exempted lighting which is an example of process energy. This example is from 90.1. I do not know a default for something this specific. To get the information you should obtain the specific equipment cut sheets and determine energy use.
Prudence Ferreira
PrincipalIntegral Impact
88 thumbs up
October 25, 2010 - 1:25 pm
Marcus,
Our issue is that we do not yet have tenants, so we cannot specify equipment. It could potentially be a significant amount of energy, but we will not know for several months yet who will actually be using the space. I will try to research other medical office buildings and see what they modeled for medical process energy.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5907 thumbs up
October 25, 2010 - 2:18 pm
The ASHRAE 90.1-2007 User's Manual contains a table with acceptable receptacle power densities. For Health/Institutional it is 1.0 Watts/square foot; for Office it is 0.75 W/sf.
Another good source of information on plug load data is COMNET - http://www.comnet.org/