Natural cooling techniques.

This paper presents the state of the art on the natural cooling techniques. The development on the evaporative, radiative and earth contact cooling techniques and components is discussed. A classification of the existing systems and techniques is attempted and tbe knowledge on the more important of them is presented. Advantages and disadvantages of the classified systems are evaluated and their suitability for European climates is discussed. The luck of information as well as the existing scientific gaps on the subject are identified. Finally, future research actions are proposed for each topic.