advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...
advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...
advanced building skins 14 | 15 June 2012 - lamp.tugraz.at - Graz ...
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Advanced Building Skins<br />
2 Consider<strong>at</strong>ions Concerning the Compens<strong>at</strong>ion of Energy<br />
The European Parliament Directive 2010/31/EU, Article 9.1 requires all new <strong>building</strong>s to be “nearly<br />
net zero energy” by 2020. As st<strong>at</strong>ed above, solar energy will most likely provide the means to<br />
compens<strong>at</strong>e the use of energy in order to achieve an annual net-zero energy balance.<br />
In order to fulfill this requirement, one needs - in addition to knowledge concerning the solar<br />
irradi<strong>at</strong>ion incident on the <strong>building</strong> - to know :<br />
how much electricity a photovoltaic system is able to gener<strong>at</strong>e per m² of photovoltaic modules<br />
<strong>at</strong> the loc<strong>at</strong>ion the <strong>building</strong> is loc<strong>at</strong>ed<br />
how much electricity a photovoltaic system is able to gener<strong>at</strong>e per m² of ground floor area<br />
considering the orient<strong>at</strong>ion of the <strong>building</strong> and the tilt angle of its roof<br />
how much electricity a photovoltaic system is able to gener<strong>at</strong>e per m² of ground floor<br />
considering the topology of its roof.<br />
Figure 8 shows the global horizontal irradi<strong>at</strong>ion (GHI) map as published by PV-GIS [4].<br />
It shows th<strong>at</strong> the annual irradi<strong>at</strong>ion total in the region covered by the scope of European Parliament<br />
Directive 2010/31/EU varies roughly by the factor of two - from approxim<strong>at</strong>ely 800 kWh/m²/a in<br />
Northern Europe to approxim<strong>at</strong>ely 1600 kWh/m²/a in Southern Europe.<br />
Figure 8: Annual total global horizontal irradi<strong>at</strong>ion [4]<br />
Thus on a ground area of 100 m² the annual GHI total ranges from 80,000 kWh in Scandinavia to<br />
160,000 kWh in southern Spain. Considering an average system efficiency of 13% for crystalline pvcells<br />
(which account for 81.1% of the PV market in Europe [5]), one can estim<strong>at</strong>e 10,400 kWh of<br />
electricity in Scandinavia and 20,800 kWh in southern Spain for a horizontally mounted photovoltaic<br />
system. Since most roofs are not horizontal but are tilted, one requires the dependence of irradi<strong>at</strong>ion<br />
with respect to tilt angle and orient<strong>at</strong>ion of the roof area.<br />
Figure 9 shows the global irradi<strong>at</strong>ion distribution from clear skies for differently oriented and tilted<br />
surfaces rel<strong>at</strong>ive to the maximum achievable value <strong>at</strong> this loc<strong>at</strong>ion. The figure is calcul<strong>at</strong>ed for<br />
Germany, but shows very minor vari<strong>at</strong>ion for all of Central Europe.<br />
Note: Figure 9 does not take account of local we<strong>at</strong>her conditions.<br />
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