I am working on a 9 storey office building (8 levels of office and 1 basement level). The building has a total floor area of 9,400m2. The space heating and cooling will be provided by means of a VRF system and the primary ventilation, which will consist of DX AHU's will provided tempered fresh air at 18 degrees C. The ventilation system will provide 100% outside air sized on minimum fresh air requirements. Therefore the heating, Ventilation and Air conditioning will all be provided using electricity. With this is mind my question is which Baseline System should we use and which fuel types should we use. ?
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
March 8, 2017 - 11:39 am
All electric and more than 5 stories is a System #8. See Table G3.1.1A.
Ciaran McCabe
DirectorPassive Dynamics Sustainability Consultants
12 thumbs up
March 8, 2017 - 12:29 pm
Thanks Marcus for your reply. If we were to change to an AHU which provides heating via natural gas (fossil fuel) while keeping the VRF system would this change the the Baseline System selection ?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
March 8, 2017 - 12:57 pm
That sounds like a hybrid system so it changes to a System #7.
Ciaran McCabe
DirectorPassive Dynamics Sustainability Consultants
12 thumbs up
March 10, 2017 - 12:00 pm
That's great Marcus. If the service hot water was generated using gas and the space heating, cooling and ventilation was electricity would this be defined as hybrid. Or is service hot water irrelevant when picking the most appropriate baseline system.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
March 10, 2017 - 1:01 pm
Only the space heating fuel matters in the selection of the Baseline system.
Ciaran McCabe
DirectorPassive Dynamics Sustainability Consultants
12 thumbs up
March 13, 2017 - 10:16 am
Am I correct in saying that even if we had one radiator that was heated from fossil fuel in the building and everything else was electric heating - in this instance it would be still be considered hybrid system.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
March 13, 2017 - 10:46 am
Potentially yes. You would also check to see if any of the G3.1.1 exceptions would apply.
Ciaran McCabe
DirectorPassive Dynamics Sustainability Consultants
12 thumbs up
March 13, 2017 - 12:20 pm
Also using System #7 I feel we are being unfairly punished because our baseline system will use gas as the fuel type (System 7) and our proposed system will use electricity for the space heating and gas for the ventilation air heating. Gas is a lot cheaper than electricity therefore any saving we try and produce are diminished by the difference in fuel costs Gas Vs Elec. We have heat recovery built into all our air handling loads therefore the dominant heating fuel will be electricity. Can I obtain further clarity on this matter.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
March 13, 2017 - 1:05 pm
No one said the system is always fair (just like life in general).
You have a very clear hybrid system. The entire building is partially heated with gas. Check out LEED Interpretation #10285.
Wayne Mc Fall
Senior Mechanical EngineerMetec Consulting Engineers
2 thumbs up
September 4, 2020 - 4:25 am
Hi Marcus,
Would gas fired kitchen cooking equiment have any effect on an all electric system bearing in mind that no space heating or cooling in the building will be served by gas systems. Is the fact that cooking is a process load, it would not form part of the baseline system selection decision? In this case, would I be right in saying, we are all electric and more than 5 stories, so System #8 would still be chosen?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5912 thumbs up
September 4, 2020 - 10:30 am
Yes, gas cooking would not affect HVAC system selection.