FAQs about EAp2 :

Our project has a large process load—75%. Despite our efforts to make an efficient HVAC design, the cost savings are minimal. What can we do to earn this prerequisite and be eligible for LEED certification? Is there any flexibility in how we model the p

Can SHGC be higher in the proposed than in the baseline model?

Our process load is higher than 25%. Do we have to justify that?

Do I need to justify the electrical and fuel rates I am using in my model?

Our local code references ASHRAE 90.1-2010. Should I use that for my documentation, or 90.1-2007?

Can I claim exterior lighting savings for canopy lighting even though a baseline model cannot include shading elements?

The project is built on a site with existing exterior lighting installed. How should this be accounted for?

Can mezzanines open to floors below be excluded from the energy model?

How do I provide a zip code for an international location?

For a project outside the U.S., how do I determine the climate zone?

For a project outside the U.S., how do I determine the Target Finder score?

Do hotel rooms need automatic light shut-off control?

How commonly are the 90.1 mandatory compliance forms submitted as part of EAp2/EAc1?

The Section 9 space-by-space method does not include residential space types. What should I use?

Can the Passive House Planning Package (PHPP) be used to energy model for LEED?

Is it acceptable to model a split-type AC with inverter technology compressor as a heat pump, like modeling VRF?

Can the Trace 700 'LEED Energy Performance Summary Report' by uploaded to LEED Online in lieu of the Section 1.4 tables spreadsheet?

A portion of our building envelope is historic. Can we exclude it from our model?

Which baseline HVAC system do I use if my building has no heating or air conditioning?

For an existing building, do I need to rotate the model?

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Forum discussion

NC-2009 EAp2:Minimum Energy Performance

Existing System with New Chiller Plant

Our project is an existing 36,000 sf museum with a planned 18,000 sf addition. The existing portion is served by a dual-duct HVAC system with a boiler and chiller plant. The boilers and chillers will be replaced as part of the LEED scope of work, but the airside equipment will remain. The addition will be served by a new multizone system, also connected to the new boiler/chiller plant. Based on 90.1 and reviewing LEED User, the baseline energy model would include the existing dual-duct system for the existing building and System 3 - PSZ for the addition. But it seems ambiguous how to model the heating and cooling plant serving the dual duct system in the baseline model. Two strategies have occurred to me: 1. In the baseline, model a central plant that mirrors the proposed plant but with minimum efficiencies and mandatory controlsfrom section 6 only - 2. In the baseline, model a central plant based on Appendix G requirements for boilers and chillers - i.e. two natural draft boilers, one screw chiller, etc Has anyone dealt with a similar situation or have an opinion about those two approaches?

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Wed, 02/22/2012 - 16:18

None of the above. I would recommend #3 below. Model the whole building baseline as a system 5 from Table G3.1.1A. Since you are only keeping the airside equipment and not a complete system, I would default to the Appendix G defined baseline. The 90.1-2007 User's Manual indicates that if there is a complete existing HVAC system it should be modeled identically in both models. It does not address a situation where part of the system will be retained. To base the baseline in any other way creates a very awkward hybrid that would be difficult to justify.

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