To Whom It May Concern:
I'm looking for guidance on how unit heaters, radiant panels and electric heaters that are in the proposed design are modeled in the baseline building. Keeping in mind that as this is a LEED Canada building and as per the LEED Canada 2009 Supplementary Energy Modeling Guide, if the proposed building has zones with no mechanical cooling, then there is also no cooling in the baseline building.
The building I'm modeling is an indoor soccer field house with associated support spaces (locker rooms, washrooms, spectator areas, offices, underground parkade). The building falls under System 7: VAV - Chiller - Boiler (Area > 150,000 sq. ft + NG boiler). As many areas receive transfer air from the field house (e.g. locker rooms), I have only included areas that are directly conditioned in the proposed building in the System 7 Baseline. Is this approach correct?
As per G.3.1.1, there is meant to be a System 7 modeled for each floor of the building. In the basement there is a parkade and a number of mechanical/storage rooms that have hydronic unit heaters. The Parkade has a MUA unit and exhaust fan system which falls under an exception as the fan only operates a few hours per day based on CO levels and is thus modeled as System 3. It doesn't make sense to me that the mechanical/storage rooms that only have unit heaters should be modeled as a System 7. So how should they be accounted for? Similary, the third floor contains the main mechanical room which is conditioned via unit heaters in the proposed design, so again it does not make sense to me to model as a System 7.
Furthermore, there are numerous spaces that are not directly conditioned via the primary air system and have local electric heaters (stairwells) and hydronic radiant panels (locker rooms with transfer air from field house). What would be the best approach to model these areas?
My initial guess would be to model the electric heaters in the Baseline the same as the Proposed (same capacities). Similarly, for the radiant panels. However as the unit heaters have a fan component, I'm not sure about the correct approach to model these in the baseline.
Any guidance is greatly appreciated.
Don
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
November 4, 2014 - 10:14 am
The indirectly conditioned spaces must be included as part of your system 7.
Apply Addendum dn for heating only systems. You can model a system 9 or 10 from ASHRAE 90.1-2010 in the heating only spaces. Sounds like this would take care of your system 7 on a couple of the floors. There are limits to the space types which can apply this addendum, for example the locker rooms would not qualify.
Dónal O'Connor
November 4, 2014 - 8:32 pm
Hi Marcus,
Thank you for your reply and clear direction.
Out of curiosity, why should the locker rooms (they receive transfer air from the field house in the proposed design and contain hydronic radiant panels) be included in the baseline System 7? This would appear to penalize the baseline system as now the field house and the locker rooms receive direct airflow that will increase the baseline fan power.
Your clarification is greatly appreciated.
Thanks,
Don
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
November 7, 2014 - 9:57 am
The configuration of the baseline systems rarely has anything to do with the proposed design (thermal zones being the primary exception). The locker rooms are conditioned space so appendix G defines the baseline system as a system 7, then it must be modeled as a system 7. If this increases the supply air cfm and therefore increases the baseline fan power your energy savings would increase.
Dónal O'Connor
November 8, 2014 - 5:43 pm
Thanks for clarifying Marcus.
Cheers,
Don