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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was reduced to 0,218 W/m
2
K. Also the roof U-value is very low and equal to 0.205
W/m
2
K. Inner walls are made with wood studs and plasterboard finishing. Windows and
glazed parts have a U-value of 1,3 W/m
2
K and 1,1 W/m
2
K respectively.
One of the main features of this building is that is not connected to the gas network and
it works only by using electricity, totally produced by a photovoltaic plant of 14,6 kW of
pick. Other alternative energy systems are installed in the building.
The first one is the sunspace on the South facade, which allows the solar radiation
entering in the space and being conveniently stored.
The external glazes of this system are fully open-able for regulating the temperature both
in summer and winter.
In CasaZeroEnergy exhausted air is naturally replaced through the openings on the
North and South facades. In this way it is possible to ensure a good indoor
environmental quality, the day-time cooling of the living space and the night-time cooling
of the building elements. Shading systems are very important for avoiding overheating
during summer. For this reason these systems were properly sized and selected, in
order to control and adjust the incoming heating and lighting solar radiation.
Furthermore, on the building roof there is a solar collector plant for DHW production. An
under-floor heating and cooling system is connected to a geothermal heat-pump that
exploits the constant temperature of the earth at the deep of 2,5 meters under the
garden surface.
CasaZeroEnergy monitoring
The building is currently monitored. Temperatures and electricity use are measured
respectively by sensors and multi-meters into twelve different rooms of the house. These
spaces were selected because their different exposition and final use (bedrooms, living
room, kitchen, bathrooms, laundry, etc.).
Main scope of the monitoring is understanding which is the real building behavior and
validate the quality of a ZEB project, in light of the increasing necessity and demand this
type of houses.
Starting from monitored data, the typical day was calculated and plotted both for summer
and winter period.
The
typical winter day
(Graph1) shows that ten of the twelve monitored rooms display
similar temperatures, with a difference from the average temperature lower than 1,5°C.
The two exceptions are: the
laundry
and the
office
.
Generally these rooms have a constant set-point temperature of 18°C and warmer hours
depend on internal gains and solar heat gains.
Causes of the different behavior of the laundry are higher internal gains due to the
presence of several equipment, which release sensible and latent heat contribution, and
the windows opening during the first hours in the morning that reduces the room
temperature.
Instead, the different temperature evolution in the office is caused by a different set point
and heating system. This space has a set point of 15°C and is heated during the day by
an electric heater.
There is another important space, which has not been monitored yet: the sunspace. It is
very important for the passive heating of the building, because of its capacity to preheat
the air and store the heat. Properly managed, the green house can be used for
maximizing passive solar gains from October to March, reducing the energy demand.
