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Dear Trnsys users,
I am simulating an office building in order to
evaluate the summer comfort without air conditionning.
My idea is to base this analysis on the
periods during wich a reference indoor temperature (lets say 25°C) is exceeded,
each period being defined by its duration and the maximum amplitude of
the temperature exceeding, and then calculate the quantity of
periods per month, or year, for couples of durations and exceedings
ranges.
The problem I am facing is the definition of the
meteorological data.
The TMY2 file in Trnsys for the site I am studying
is Lorient - France.
I appears that this file does not include one
day with the extreme annual design dry bulb we can find in Ashrae
tables for design conditions, neither a day with the 0,4% Monthly design
dry bulb temperature.
Example for the period of july and
august:
- maximum design dry bulb in TMY2 file:
27,4°C
- Ashrae extreme annual design dry bulb - Mean :
31.2°C
- Ashrae Monthly design dry bulb 0.4% - July :
30.9°C
- Ashrae Monthly design dry bulb 1% - July :
29.1°C - Ashrae Monthly design dry bulb 0.4%
- August : 30°C
We see that these 4 extremes values are very
far from the maximum found in TMY2.
Even it is clearly stated in TMY2 documentation
that the data are built for energy analysis only, and not for sizing purposes,
it is surprising to see such differences, as "dynamic" comfort analysis is
also very important.
I am therefore looking for some advice on the way
to proceed.
I am ready to make some tricky adjustments by
adding an offset on the extreme temperatures of the TMY2 data in order to reach
the annual extreme (Mean) but I don't know if it makes sense.
Looking forward for your help,
Best regards
Benoît Cogné
DH TECHNOLOGIES
France |