Numerical and Experimental Analyses of Solar Chimney Parameters

Abstract It is important to analyze the variables influencing the performance of the solar chimney power plant (SCPP) according to output power as well as efficiency. The most important of these variables is the geometric dimensions, solar radiation intensity, and ambient temperature. In this experimental and numerical study, a prototype with variable dimensions was manufactured. A theoretical study was presented by creating a numerical model that helps in analyzing the governing equations, such as the continuity, momentum, and energy equations, in addition to the turbulence model equations (k–ε). The calculations show the influence of chimney height, diameter, solar collector diameter, inlet collector gap, temperature, and solar radiation on the SCPP performance. These variables were also tested experimentally, and the effect of each variable on the efficiency and output power was demonstrated. The maximum velocity was at the turbine exit, about 18.5 m/s in the case of the Spanish model, while it was 2.2 m/s for the present prototype. The maximum temperature value was 333 K for the Spanish model at a collector radius ratio of 3. The maximum output power was 156 mW for the Spanish model. For the current prototype, the maximum airflow temperature was 67 °C when the chimney height was 3 m; by decreasing the chimney height to 2.5 and 2 m, the maximum temperature decreased to 63 and 54 °C, respectively, which are about 6.5% and 19% deterioration. The results show that the relationship between the output power and any of the geometric dimensions is direct. The overall efficiency relationship is direct with the height and diameter of the chimney and inverse with the diameter of the collector and the height of the collector entrance. The output power rises with increasing solar radiation and slightly drops with increasing ambient temperature. The reliability of the numerical solution was verified by comparing the numerical and experimental results, as well as the data of the Spanish model. The agreement was satisfactory, with the mean percentage error (MPE) not exceeding 1.5% for all performance parameters.