Cooling is an indispensable issue of all countries, not only in the sun-belt, on Earth. Electricity driven chillers are the standard way of cooling. However, electrically driven machines consume a lot of electrical energy, much more than thermally driven chillers. In most cases they also consume much more primary energy compared to thermally driven chillers. The research program aims to develop a worldwide unique concept for a continuously operating hybrid cooling system with a thermally driven chiller based on renewable energy resources.
The energy for a sustainable cold supply can be developed from solar and from geothermal sources. Solar heat supply is fluctuating, whereas geothermal heat can provide base load heat supply. Therefore, a combination of both, called hybrid cooling, is an excellent solution of this challenge. In order to stabilize the supply system it is advisable to foresee storage systems which can be realized in the underground. Therefore, the third element of the here described innovative cooling system is underground thermal storage.