Refrigeration and air conditioning is globally responsible for at least 10% of the electricity consumption and thus contributes significantly to greenhouse gas emissions. The market for climatisation is growing continuously so this percentage will only increase. Cooling systems consume mostly scarce and therefore expensive electricity during peak hours. In this respect it is interesting that in many places on earth the cooling demand is approximately proportional to the local solar radiation. A sun-powered cooling system is, therefore, a logical concept. The heat pump of Cooll can be driven by heat from relatively simple and low-cost solar collectors, it is a thermally driven cooler. Alternatively, also waste heat can be used, for instance from (small) power plants. The system can be applied in mild climates such as the Netherlands. Of course, application is even more effective in hot climates with large solar radiation and cooling demands. Also for developing countries it is an ideal solution to climatize, for instance, remote hospitals.