Dear eQuesters:
Attached is a baseline for a project I am working on. I do not understand where
I went wrong, since the summary indicates significant space cooling year round.
The labs are on the right side and lower right bottom of the shell. These are
the areas with 2 small labs included. I need 8 ACH for the labs during
occupancy. These are conditioned by Sys 1.
The rest of the building consists of offices and a lecture room conditioned by
Sys 2.
Any feedback would be greatly appreciated.
Thank you,
Paul Diglio
When I open your model, I do not see a ceiling or a roof. Maybe this is
the simple solution to your problem. Add a roof?
Umesh:
The model is of the first floor of a 5 story building and only the defined space
is applying for LEED Silver. The spaces above and below this area are
conditioned.
Thank you,
Paul Diglio
Maybe you can take a look at your wall and window u-values (walls are
currently @ 0.5 and windows are single clear).
Fixing those should hopefully help.
In both of your HVAC systems you have "Outdoor Air From System" object
specified. In most cases, you will want to leave this object blank. The only
time would want to use that object if, for example, you were taking the return
air from one system, and using it in another, separate, system. I am pretty
sure that in your case, especially in the labs, all of the air will be coming
from the outside, or will be recirculated within the same system.
If you reset those values to their default you get much better cooling results,
but you also get heating in the summer, which is another issue you need to look
at in more detail. The "Outdoor Air From System" object is found in your HVAC
system --> Outdoor Air --> Outdoor Air and Economizer
-Eddie
Just to add to what Eddie said - you will spec OA from only when you are borrowing outside air from another system (Like with a DOAS). I've actually never seen this before (where you specify OA-From as the same system). What its probably doing is taking your return air as OA (at around 78) and cooling it (and taking moisture out of it).
I would have thought it would give you an error.
Vikram Sami, LEED AP
Vikram & Eddie:
Thank you, I changed the OA From to undefined and that corrected my cooling
energy during the cold months, but as Eddie mentioned, I have a lot of heating
going on during the summer months. Any idea why?
Sincerely,
Paul Diglio
It looks like its reheat for humidity control. If you set your humidistat to 100% (no humidity control) you?ll see a more normal version.
Vikram Sami, LEED AP
Vikram:
Right you are, thanks, that explains the summer heat usage.
Paul Diglio