Optimized Orientation and Proportion of Transparent Components Based on the Least Annual Heat Demand
Creators: name: Rahmani, A.
name: Wagner, R.
Publisher: name: WIP
Year: 2018
Subjects: PV Systems - Performance, Applications and Integration
Building, Infrastructure, Landscape and Other Applications of PV

description: 35th European Photovoltaic Solar Energy Conference and Exhibition; 1809-1817
description: Transparent components influence every passive house based on their surface proportion compared to
opaque surfaces and their main orientation. These components have to provide appropriative potential of sunlight
absorption to deliver a considerable proportion of heat demand to building. On the other hand, to reach to an optimized
passive house, that be capable in parallel to perform also as a “Zero Energy Building” (ZEB), the very first decision is
minimizing total energy demand of building. So, in the very elementary steps of designing of a building it is crucial to
include passive strategies to minimize energy demands. These modifications should be applied in the first steps of
architectural designing of building and is much wider than only proportion of windows in relation to volumetric and
geometrical characteristics of buildings. Based on enormous economic and technical limitations, there is also an
unavoidable need to implement photovoltaics or solar thermal panels to compensate the energy demand that passive
strategies integrated in buildings are not able to fulfill alone. An accurate implementation of PVs again argues a certain
amount of surrounding building’s skin and consequently an accurate calculation of the surfaces that should be allocated
to PVs is necessary [1]. Also, different geometric proportions result different available surfaces in different orientations
for PV integration that influence the final capacity of power plant. In this step, the crucial question is “which one is in
priority for geometrical modification of a building? Passive strategies or PV integration?”
In this work, a simple architectural prototype has been evaluated to assess the specific effect of its windows in different
orientations. Also, in every orientation, different forms of the same building have been examined to compare the effect
of envelop area factor and different “Treated Floor Area” (TFA). So, four architectural variants with the same
volumetric amount, but with different TFAs and different geometrical proportions have been developed. The main
target of theses comparisons is to assess the annual heat demand of the variants. Also, it would clarify the influence of
orientation of windows to reach to different heat demands. In parallel, it would show the effect of different forms of a
building with the same orientation and the same surface of transparent surfaces to reach to different heat demands.
Design-PH, has been used to determine heat losses and heat gains of these prototypes in different situations. So, in each
variant four different parameters have been measured that are; “heat loss of opaque surfaces &amp; thermal bridges”, “heat
loss of windows”, “ventilation heat loss” and “Solar heat gain of windows”. The effect of “ventilation heat loss” has
been ignored as it always has the same amount in the entire variants with regard to the constant amounts of transparent
surfaces. The main principle of the software clarifies the annual heat demand with regard to the difference between the
total heat losses and total heat gains. To conclude the final criteria, four different variants have been developed; the
entire variants have the same volume of 800 m3 to do the final comparisons fairly. Every variant has been assessed
when its windows has been looking toward south, west, north and east. So, sixteen different sub-variants have been
calculated and compared to each other. U-values of windows, roof and the ceiling of variants has not been modified as
the characteristic of materials has not been topic of this work.
In the second part of theses simulations to assess performance of these variants for integration of PVs, available surfaces
of these four variants have been emerged. For emphasis on effect of the main direction of windows, in each variant
there is only one facade holding 5 squad windows with a total area of 20 m2. The effect of main orientation of building
has been taken into account, so as subdivision of main variants, they are divided also to south-faced, west-faced, northfaced
and east-faced variants. Additionally,