Hi,
Our project is going for LEED. We have 2 proposed CRAC system that have humidifiers. It's not quite clear which approach we should take regarding the energy associated with the humidifiers:
1) Run a model with the humidifiers, one without; and the discrepancy in energy to be added to the results of both baseline and proposed under process loads.
2) Use the results when humidifiers are modeled (impact on space heating, cooling and heat rejection).
Thank you,
Maria
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Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
May 22, 2017 - 6:34 pm
Humidification is considered a process load so it must be modeled identically. Report the energy use as a separate line item in the modeling results. Often the energy use is not identical even when modeling identical humidification systems.
Maria Spastri
Sustainability ConsultantAECOM
May 22, 2017 - 7:21 pm
Hi Markus, thanks for the prompt reply.
The proposed system uses electricity for the heating and humidifier.
The baseline system uses gas heat exchanger for heating (this is how it has to be modeled per Appendix G).Trace does not allow to incorporate an electric humidifier on an a gas system. A system can only have one source of fuel for the heating side. For reference, the humidifier control in the proposed is 40%. Therefore: we'd model the same 40% humidity control approach both baseline and proposed, even if the fuel is different? Please confirm or advise.
Thanks,
Maria
Francesco Passerini
R2M Solution Srl16 thumbs up
May 23, 2017 - 4:47 am
It seems strange that the design model and the baseline model have different heating sources (see G3.1.1 and Table G3.1.1A).
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
May 24, 2017 - 11:59 am
You should not have different heating fuels except in only the rarest of circumstances. Sounds like the majority of the building is gas heat and these spaces are electric. Do any of the G3.1.1 exceptions apply to these spaces? Sounds like maybe exception b applies. If is does then the baseline is a system 4.
Harini Goteti
September 11, 2023 - 10:58 am
Hello All,
I have electric humidifiers on a DOAS system that is providing ventilation for a historic offices/museum/atriums style building with district heating and cooling.
I am wondering what the baseline humidifiers shall be like. ASHRAE 90.1-2010 doesn't have a guideline, however, 2016 recommends using adiabatic humidifiers for the baseline systems. My question is what fuel source are we expected to use? Electric (same as proposed) or District loop? I'm assuming that it might be a hot water loop, need some guidance on this. Also, the discussion about humidifiers being process loads that need to be identical, might not be possible, since system 7 bunches everything together into larger systems per floor, and assigning a humidifier electric or otherwise will result in huge savings.
Also, using eQuest for this exercise.
Thanks all in advance,
Harini
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5906 thumbs up
September 14, 2023 - 9:20 am
You are posting in a forum related to LEED 2009. Your question appears to be related to v4/v4.1 so please post it in one of those forums.