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Dear TRNSYS User,
I’m modeling a 3 floors office
building in TRNSYS 16 and
comparing the results to those of EnergyPlus(E+). Using
Energy Rate method in
TRNSYS, I estimated the peak cooling and heating load
which found to be the
same as those from E+. I accordingly used them to size
my HVAC system (package
unit to supply air at 12.8 deg C) and then provide VAV
and reheat for tune up at the
zone level. Since no VAV component is available in
TRNSYS 16 (unless I buy it!), I had to make one simple
model myself using equations
to vary the mass flow rate for each zone based on the
zone load and thermostat response.
The problem:
My VAV damper modulating mechanism is
based on the response received from the
zone. This response is dependent on the internal load
for the Core zone for example (or
zone load for perimeter areas). In E+, lighting load
contributed to the zone is
only 60% and 40% of that will go through the return air
without contributing directly to
the zone. However, the TRNSYS Model sees the entire
lighting load at the zone
level and therefore the zone load is higher than those
seen in E+ which makes
the mass flow rate higher.as well Since my VAV response
is based on the zone load
rather than the system load, is there a way to have this
division in TRNSYS
where I could match the zone loads. I would like to mention that both
models give
a reasonable match at system level which is good for
energy estimation. I’m interested at zone level at this
moment of time but still needs a reasonable results for
energy consumption. Therefor, total
lighting load is needed for energy calculation but
some sort of reducing it at zone level is sought.
Thanks,
Saleh NJ AL-Saadi
University of Colorado at Boulder
Department of Civil, Environmental
and Architectural
Engineering
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