Influence of environment and aging materials on the performance of solar chimney power plants

Abstract

The simplicity of solar chimney power plant (SCPP) makes it very attractive for power generation. This paper investigates the technical feasibility of using a locally-produced plastic film (Low-Density Poly-Ethylene “LDPE”) as a solar chimney power plant collector cover. The idea is to combine a very low-cost material with a simple technical solution. As LDPE is subject to deterioration, the effect of aging on the initial properties of the used material is analyzed. Natural aging was privileged over the accelerated one by exposing the studied film, for a time duration of 3 years, to environmental constraints similar to the local conditions where the SCPP collectors are installed. Various experimental tests were carried out to show the decrease of mechanical resistance and to confirm the structural degradation. Results showed that after an exposure time of 3 years, a decrease of more than 50% of the failure stress is recorded. The spectroscopic analysis confirmed the progressive degradation of the structure of the aged films. Pyranometric measurements showed that the transmittance of the film proportionally decreases with the duration of aging which has a direct impact on the SCPP collector performance. A mathematical model is developed and validated to simulate the performance of the SCPP. An increase in the initial dimension of the collector by about 23% is necessary to maintain the design-targeted production during an exploitation period of three years. The study concluded that this type of film can be used in SCPP collectors for a maximum life cycle of 3 years under the considered environmental conditions.