Magnetic zinc ferrite (ZnFe2O4) nanopowders were synthesized using the sol–gel autocombustion method. X‐ray diffraction (XRD) and scanning electron microscopy (SEM) measurements demonstrated that thermal decomposition of the 1‐mm‐thick xerogel layers in air formed monophasic spinel ferrite nanopowders with a particle size less than 30 nm. X‐ray photoelectron spectroscopy (XPS) showed that the obtained reaction product contained antisite defects, with zinc ions occurring at the octahedral sites of the spinel structure. The concentration of antisite defects or inversion degree decreased when the relatively low annealing temperature was increased from 150 to 500 °C. Overall, the obtained ZnFe2O4, which is usually antiferromagnetic (exhibits no magnetic moment), demonstrated high saturation magnetization (60.7 emu g−1), and coercive force (56 Oe). This was due to the presence of the antisite defects in the structure.

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The European Parliament and Council Directive 2010/31/EU states that all member states of EU shall ensure that all new buildings are nearly zero-energy after December 31 2020. For now, there are no efficient, cost effective and widely used tools to achieve such performance. To achieve the goal set out in the legislation there is a need for an appropriate solution in order to minimize energy consumption of a building or obtain energy on site from renewable resources. The first method to achieve it is to minimize heat losses through the envelope of a building in winter and prevent overheating in summer. Traditional construction types used in buildings have static thermal properties. There is an energy efficiency potential in dynamic thermal properties of building constructions. Ideas for such constructions can be found in nature following the biomimicry methodology that solves human problems inspired by processes in nature. In this paper a feasibility is studied of one proposed CABS (Climate Adaptive Building Shell) using a numerical analysis. The proposed CABS is a system where geothermal energy is used for façade heating thus minimizing heat losses through building envelope and utilizing renewable energy. A geothermal heat from shallow depth of 3.2 m is utilized. The CABS consists of a piping system built in the façade of a building ensuring a circulation of a heat-transfer medium which is transporting the heat from the ground where the temperature is constant all year to the façade. Circulation of a fluid is ensured by buoyancy forces alone. The resulting rise of façade temperature reduces peak primary energy demand thus improving building performance. The mechanism of this CABS is inspired by the blood vessel system in animals. For the numerical analysis ANSYS Fluent 16.2 is used.