[BLDG-SIM] ventilation airchange function

[Peter Vogelsanger]

WHAT
I am searching for a function which correlates the (natural) ventilation
air change rate due to the (wanted) opening of windows with the indoor
air temperature, outdoor air temperature and possibly with other
quantities (e.g. time of the day, etc.). The function could be used to
model the user behaviour. It would be best suited, if the function was
valid for the winter case, houses without a mechanical ventilation
system and homes, not office buildings, and if it described a statistic,
average behaviour, rather than a single case (people behave very
differently; the function is wanted for a case study, not for the
simulation of one particular house.) 

MORE DETAIL OF WHAT
If a house reasonably airtight but not fitted with a mechanical 
ventilation system, the inhabitants will open windows to achieve a
reasonable air change. Let us assume a winter situation, with the
outdoor temperatures being clearly below the indoor air temperature. The
windows will be opened frequently if the room temperature is fairly
high, as is often the case with homes having massive passive solar
gains. Windows will be opened (or be left open) less frequently if it is
already uncomfortably cold inside. The air change rate is certainly a
function of the room temperature. It seems to be reasonable to assume
that the air change rate is also, and to a great extent, dependent on
the outdoor temperature.  

WHY
Active solar heating systems tend to use the thermal mass of the house
as extra storage capacity. In times of solar gain (or when the
additional water tank is nearly fully charged), these systems supply
extra heat to the building which causes higher room tempartures. In
order to study the effect of such systems it is indispensable to take
the extra ventilation losses due to the higher room temperature into
account.  


I am aware that it must be very difficult to establish such a function.
However, because it is a common problem in building simulation, I
suppose a number of people were already confronted with the problem,
and I dare asking you all. Any help is appreciated.


Peter Vogelsanger


Systemtechnik und Speicher, Institut für Solartechnik SPF
Hochschule für Technik Rapperswil, Oberseestr.10, CH-8640 Rapperswil
Tel +41 55 222 48 23, Fax +41 55 222 48 44, http://www.solarenergy.ch

======================================================
You received this e-mail because you are subscribed 
to the BLDG-SIM at GARD.COM mailing list.  To unsubscribe 
from this mailing list send a blank message to 
BLDG-SIM-UNSUBSCRIBE at GARD.COM