Z E M C H 2 0 1 2 I n t e r n a t i o n a l C o n f e r e n c e
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temperature depends on the higher amount of solar radiation entering in the room in
summer.
Validation of
BENIMPACT Suite
on CasaZeroEnergy
The first step required to prepare an energy analysis model for a building is to divide it
into thermal zones. A higher number of thermal zones affects the time required to run an
energy simulation. Thus, it is really important to individuate the lowest number of zones
able to correctly reproduce the building behavior.
Basing on the previous analysis, the model was divided into
four thermal zones
:
sunspace, laundry, office and the rest of the house
(Fig.3).
Figure 3: Thermal zones of the building model
Some hypothesis on set point temperatures, air change rates and internal heat gains
were made. Set point temperature values were deduced from monitored data, while for
internal gains the starting point were values given by Italian directives.
At first, a model without the sunspace was prepared and verified using summer
monitored data. Summer thermal simulations were run and the building behavior was
checked varying inputs until the model and the real building converged.
The living space was the easier to adjust because it is used as a standard living space,
according to the final use established in the regulation.
For the laundry, increasing internal heat gains were simulated in order to meet the real
behavior of the room, strictly related to the presence of equipment.
Windows opening, scheduled as resulted from monitoring, was then added. The
introduction of this ventilation ratio was necessary for the overlapping of the model to the
real building.
After that, the sunspace was added. In modeling this element the most difficult part was
defining the air ex-change rates between the living space and the sunspace and
between the sunspace and the external environment. Furthermore an appropriate
schedule for the sunspace opening management had to be defined, because of the lack
of real data.
When the whole building model with all the four thermal zones was ready, the winter
thermal simulation was verified. For performing this analysis it was necessary to
complete the office thermal zone definition by the introduction of a standard electric
heater. The schedule of the heater was supposed looking at the monitored data.
As shown in Graph3 and in Graph4, the building model with four thermal zones well
simulates the real temperature evolution of the building.
