Optimal transparent percentage in facade modules for office buildings in different European climates

摘要

In this paper, the influence of the climate on the optimal configuration of a facade module is investigated. An integrated modelling approach is used, coupling thermal and lighting simulations, in a total energy perspective. In fact, the "optimal configuration" of the facade module is the one that minimizes the sum of the energy demand for heating, cooling and artificial lights, solution is searched, by means mean of numerical simulations, in four locations in Europe, by changing the percentage of transparent surface (window-to-wall ratio). All the four main orientations are investigated, and robustness of the solutions is also checked against different HVAC system efficiencies and in buildings with different Surface Area over Volume ratios (SA:V). The results demonstrate that each climate requires a dedicated optimized solution, though it is shown that the facade configuration has a moderate impact on the total energy need of the building - provided that best-available technologies are adopted. It is also shown that, in climates where cooling energy demand is dominant (Athens and Rome), the influence of the building shape (SA:V) on the total energy demand is relatively low, but it has a certain effect on the optimal configuration of the facade module. In these climates, a "wrong" configuration of the facade module may determine an increase in the total energy consumption of about 20%. On the contrary, in climates where the cooling energy demand is not dominant (Frankfurt and Oslo), the shape of the building affects the total energy demand, but the optimal solution is almost independent from the shape of the building. Furthermore, in these conditions, the facade configuration has a less relevant influence on the total energy need.