Hi All,
We have a 4-story office building to be LEED certified. The Baseline system is packaged VAV with elec reheat. After reviewed by GBCI, the comment is:
"The Baseline case fan power does not appear to be modeled in accordance with G3.1.2.9. Please revise the sum of the supply, return, exhaust and relief fans for each HVAC system to be equal to the power calculated in G3.1.2.9."
Now I am ready to revise the model, but I am not sure in the baseline case, whether I must choose "system per shell", "system per floor" or "system per zone". Could anyone advise? Thanks in advance.
Rick, PE, LEED AP
Rick:
Isn't Baseline and Proposed system zoning the same? Whatever the Proposed zoning is, that is also what the Baseline zoning must be.
John:
The actual system is ground source heat pump with many different-sized units serving different zones. The zoning in my model is in accordance with the functions, e.g. office area, corridor, restroom area, lobby etc. Therefore, one floor has many zones, same in Baseline and Proposed. The area of each zone is around 50-150 m2. In the proposed building, the fresh air on each floor is served by one ventilator (independent with other GSHP-related components). In this case, which way do you think is most approperiate to define the "system per area" in the Baseline (VAV) and Proposed, "system per zone" or "system per floor"? (My model in the Proposed is not questioned by GBCI.)
Many thanks,
Rick
Hi Ashu,
When I attempt to enter kw/cfm, the space is in grey with "n/a". Can you advise how I can activate the blank and fill in the number?
Many thanks,
Rick
Rick,
Do default on static pressure box then the kw/CFM box can activate.
Thanks
Ashu
Rick,
According to ASHRAE 90.1 addendum u, a base model needs to be served by
" system per floor" for system 5, 6, 7, 8. Your packaged VAV with elec.
reheat will be fall under this category. Also your thermal zone must by
as same as in proposed model.
Kosuke Kato, LEED AP
I'm not terribly familiar with Addendum U and so I'm not sure how much it changes ASHRAE 90.1-2004, but be forewarned that if one prescription of any Addendum is followed, all prescriptions of that Addendum must be followed for the purposes of EAc1.
Hi,
I am trying to follow the advice below to revise the fan power input. After calculation, the result is 0.00101 kW/cfm, as I entered in the model (as attached screen shows). However, I found that the simulation result is not sensitive to this input (in blue). I know the rule is "Use either SUPPLY-STATIC and SUPPLY-EFF or SUPPLY-DELTA-T and SUPPLY-KW/FLOW." , but now, both "SUPPLY-STATIC and SUPPLY-EFF" AND "SUPPLY-DELTA-T and SUPPLY-KW/FLOW" appear in the window. I attempted to remove "SUPPLY-STATIC and SUPPLY-EFF" but failed. Could anyone kindly advise how to make this work?
By the way, I am quite curious to know if problems still exist in the revised models after reviewed by GBCI for the second time, do we have to appeal by then? Is it likely to happen? I am afraid I cannot make sure all inputs are correct..Sorry for being off-topic.
Many thanks,
Rick
Rick,
Just guessing - have you tried directly editing the .inp file in a text
editor? Sometimes, this has helped me with other issues. But sometimes,
upon opening and saving the project again in eQuest, eQuest will modify the
.inp file again. Anyway, it might be worht a try.
Lars Fetzek, EI
Rick,
I think that?s because you have the static in WG enabled. Try right clicking and setting that back to default.
Vikram Sami, LEED AP