Experimental investigation of the solar collector temperature field of a sloped solar updraft power plant prototype

Abstract

A pilot sloped solar updraft power plant has been built in the south campus at Damascus University, Syria. The sloped solar collector has a triangular shape and is tilted at 35° towards the south with an approximate area of 12.5m2. The chimney diameter is 0.31m and it is 9m tall. Eighteen temperature sensors were installed inside the sloped solar collector to measure glass, air, and absorption layer temperatures in different points along the collector. Practical data were recorded every 10min for a total of 40 consecutive days to investigate the temperature changes in the sloped collector. Although measurements were taken during the winter season, the air temperature increased to reach a maximum value of 19°C which generates an updraft velocity in the chimney with a maximum value of 2.9m/s. As a result of this experiment, it is obvious that any change in the solar radiation and the ambient temperature has a direct impact on varying the air temperature between the collector outlet and the ambient. It was also noticed that the absorption layer emits most of stored thermal energy, which is absorbed from the morning to noon, back to the collector air in a short period of time when solar radiation starts to decrease in the afternoon.