Currently I am working on laboratory building and pursuing points for EAc1 Optimize Energy Performance. During the design phase, my team and mechanical consultant made an attempt at energy modeling and came out with a similar result. However, when the energy modeler for NYSERDA funding did theirs, it came much less than what we had anticipated. After several discussions, we found out that NYSERDA modeler didn’t count for possible saving for low infiltration rate because ASHRAE 90.1 2007 Appendix G does not allow performance credit for infiltration reduction. So if we want to purse obtaining additional points for ‘infiltration reduction’, I would probably need to do ‘exceptional calculation method’.
I was wondering if anybody have any experience on this one and offer some advice. One possible steps we discussed were;
1) Establish the baseline leakage to be modeled in the baseline simulation, based on typical construction practice, field studies, etc.
2) Measure actual leakage of completed building (use blower door or some other technique).
3) Develop and document approach (including simulation assumptions) to estimate energy savings. In a lab building there is significant mechanical ventilation 24/7, so we’d need to think through how to translate infiltration reduction into energy savings in this setting. In general, infiltration is often turned off/minimized in the simulation when mechanical ventilation is on, which obviously reduces / cancels out any savings that may be realized due to air tightening of a lab building.
But this just seems too much and not sure if we would obtain points doing this. Also this credit falls under ‘design’ submission, so testing part just doesn’t make sense to me.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
February 18, 2011 - 9:11 am
Air infiltration reductions are not an allowable energy saving strategy for LEED projects. The problem is that 90.1 does not establish a quantifiable baseline. Without this baseline the USGBC and the LEED reviewers have not allowed savings in this area.
Studies show that air infiltration in commercial buildings has a much higher effect on energy use than commonly assumed. The UK has an air infiltration requirement in their building code. See this web site for a good set of links on the issue - http://www.infiltec.com/inf-larg.htm
The 90.1 committee has a task force working on this issue but it has proven to be quite complex. It seems too much in your situation because it probably is.