Abstract:

A microclimatic layer of the green façade is proven to have specific temperature and flow conditions on the building en-velope. Lower temperatures and wind velocities, and higher relative humidity in the microclimatic layer are the characteristics of vertical greenery systems, which cause lower energy consumption for the cooling and heating of buildings. Despite innova-tive architectural solutions, there are some drawbacks to applying vertical greenery on building envelopes. In this study, a bionic façade that mimics the positive effects and eliminates the disadvantages of green façades is presented. The bionic façade consists of bionic leaves, which are made of photovoltaic cells and evaporative matrices. A real scale experiment was carried out in the summer to evaluate the potential of the cooling efficiency of the microclimatic layer and a new photovoltaic cooling technique. The results show a good agreement of the thermal performance between the bionic and the green façade and up to 20.8 K lower surface temperatures of photovoltaic cells, which increase the daily electricity yield by 6.6%.

Key words: green façade, adaptive façade, bionic leaf, PV cooling, evaporative cooling, PV cell temperature