Domestic tourism is booming – the mountains are calling. Tranquillity, solitude and adventure in the wilderness lure more and more people up to high altitudes, whereby the number of emergencies also grow. Making a distress call requires not only good reception but above all a charged smartphone. Luca Ziörjen’s goal is to make his own smartphone, and other devices, as independently chargable as possible. To this end, he has designed a thermo-electric charging device that generates power through heat.