Hi
I have not yet found a clear description of the way of modelling a semiheated zone, so I will attempt to summarize. Please correct/append where needed.
- Exterior surfaces for semiheated spaces should be modeled in the Baseline Case using the semi-conditioned values from Tables 5.5-1 to 5.5-8.
- The system types in Appendix G only cover systems serving conditioned spaces, not semi-heated spaces.
- In semi-heated spaces the baseline gets modeled identically to the proposed with the same heating type, capacity ratios, fan volume, and fan power.
- The energy for the ventilation of a semi-heated space is assigned to process energy?
Thanks
Sarah
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
April 15, 2019 - 2:38 pm
Correct
Charlie Christenson
VP of Engineeringstok
4 thumbs up
December 2, 2020 - 3:46 pm
How is this list impacted for an existing building with the semi-heated envelope being improved? Existing space was previously semi-heated, so no change in conditioning level.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
December 4, 2020 - 3:06 pm
The only difference should be that the existing envelop baseline should be modeled according to Table G3.1-5 Baseline (f).
Charlie Christenson
VP of Engineeringstok
4 thumbs up
December 7, 2020 - 1:32 pm
So despite the worse envelope, the baseline is still served by HVAC systems identical to the proposed design?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
December 7, 2020 - 1:42 pm
What are you seeing that makes you feel differently?
Charlie Christenson
VP of Engineeringstok
4 thumbs up
December 10, 2020 - 5:12 pm
If you can provide any source references for this thread, that would be helpful, because I'm not seeing anything!
It just strikes me as a unique scenario that the baseline system sizing would not be adjusted to reflect the baseline envelope. Sounds like it is the exact same system as the proposed design, but subject to a greater load. Just wanted to confirm, thanks so much, Marcus!
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5867 thumbs up
December 10, 2020 - 5:26 pm
It is my understanding that the baseline system would not change.