Hello,
I would like to know if the District Cooling System needs to comply with ASHRAE mandatories. I have read the DES Guide and seem like choosing the Option 2, the project needs to comply with the Standard. However I'm working in a project that the system is existent.
Does the upstream system needs to comply with the ASHRAE mandatories (even the exist system)?
On the same project, they are planning to install a renewable energy system to supply energy for the project (the energy will be supplied only for the project). Can We use the system to account energy efficiency for the Propose building in the both option (Option 1 and Option 2)?
As the renewable energy system supply energy only for the project, even though is outside the LEED boundary, does the system comply with the EAc2?
Thanks
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 18, 2012 - 10:59 am
Correct the DES does not need to meet the minimum efficiency requirements in 90.1.
Counting the renewables for EAc1 and EAc2 is independent of the application of the DES. There are often exceptions granted for renewable supply from outside the LEED project boundary. There should be a few interpretations on the subject. For example, landfill methane piped to the facility or a PV array on a campus.
Marina Andrade
Sustainability Consultancy ServicesCushman & Wakefield
17 thumbs up
October 23, 2012 - 6:53 am
Hi Marcus, thanks for your help.
This project has district cooling and heating system. According to the ASHRAE Standard, the Baseline system is the system 3. According to the Treatment of District or Campus Thermal Energy in LEED Option 1, the Baseline and Proposed model is a 4-pipe CV AHU.
From what I search about this system, it is a constant volume single duct system with pretreated outdoor air. Am I right?
The project has an Energy Recovery System to treat the air before supplied to the zone. Sould I consider this system in the Proposed model, even though the air is already treat in the district system?
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 23, 2012 - 10:18 am
Your baseline system only needs preheat if the proposed system has it (see G3.1.2.3). The rest of the system description sounds right.
You almost always model the proposed as designed. In the baseline you model energy recovery according to G3.1.2.10. Not sure I understand your last statement about the air already being treated in the district system.
Marina Andrade
Sustainability Consultancy ServicesCushman & Wakefield
17 thumbs up
October 23, 2012 - 12:35 pm
The proposed bulding has no preheat coil and fan system capacity is less than 2400 L/s and minimum supply air is less than 70%, so I don't need to model these system in the Baseline.
I'm just confused on how to model the 4-pipe CV AHU, those a 4-pipe fancoil unit meets the requirement?
Thanks.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 23, 2012 - 1:15 pm
Yes a 4-pipe fancoil unit with a single speed fan is the same thing as a 4-pipe CV AHU. Let me know if I misunderstood your question.
Marina Andrade
Sustainability Consultancy ServicesCushman & Wakefield
17 thumbs up
October 23, 2012 - 2:01 pm
Oh no. You help me alot.
Thanks you very much Marcus!
Paula Hernandez
MRS.PAH&A
85 thumbs up
October 24, 2012 - 12:04 pm
I have been reading this discussion and it has been very helpful in clarifying the procedure,
but I have another question about fans and their power allowance, I thought that thsi calculated allowance concerned baseline fans, but somebody told me that this was the power allowance for the project fans as well, is it right?,
thank you
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
October 24, 2012 - 12:53 pm
The proposed fans are modeled as designed and do not use the same methodology as the baseline fan power calculation.
Ramesh Narayanan
95 thumbs up
November 6, 2012 - 2:03 am
Thanks for above discussion. The baseline fan energy calculated based on G3.1.2.9 is including supply,return, exhaust & relief fans. As our project proposed design having only supply fan (no return or relief fans), whether the baseline fan energy also need to be reduced by any calculation for supply fan alone.
Marcus Sheffer
LEED Fellow7group / Energy Opportunities
LEEDuser Expert
5909 thumbs up
November 6, 2012 - 9:38 am
No it is not reduced. Model the Proposed as designed, model the baseline according to G3.1.2.9. There are fan power adjustments for the baseline depending on components of the proposed design in Table 6.5.3.1.1B but this is part of the calucation under G3.1.2.9.