Single Phase Natural Circulation Flow through Solar Evacuated Tubes Collectors on the Equatorial Zone

Thermal performance of water inside of a glass evacuated tubes solar colector under the action of solar radiation in the Equator Andean high lands is presented. The aim is to deepen the understanding of the relations between the water temperature in the tubes and the inclination of single-ended tubes. A salient feature of this study is the employment of temperature sensors located inside of manifold. A data logger was used to collect data during the experiment from early in the morning till the boiling point of the water. The data collected during the experiment shows the highest values of water temperatures for larger inclination angles at earlier stages of the experiment. A consequence of the location of the solar collector is a larger incedence area for solar radiation. This fact results in larger values of water temperature despite the fact that floatability is lower for horizontal tubes. This obsevation gives important insights for the design of the topology of solar thermal devices for the equatorial zone.