Thermal-structural optimization and experimental validation of modified pyramid solar stills using finite element analysis

Solar desalination by pyramid solar stills can be an eco-friendly way of solving the problem of water shortage in areas that have a lot of sunlight. Nevertheless, productivity and efficiency are still limited by heat and mass transfer constraints, which require the systematic optimization of design parameters. This research analyzed the thermal and structural behavior of normally and altered pyramidal solar still configurations by means of combined finite element analysis and experimental verification. Both models were analyzed in ANSYS Workbench by means of three-dimensional steady-state thermal and static structural analyses. The changes in design included the geometrical modification of the absorber plate, thus increasing the effective heat transfer surface area by about 20% and at the same time, preserving structural integrity. The modified design reached the temperature of 342.91 K against 338.15 K of the conventional design, which is a 1.41% increase. The highest heat flux was increased from 809.97 W/m2 to 936.84 W/m2 (15.66% increase), while the thermal efficiency was enhanced from 68% to 72%. The structural investigation verified the secure condition with the highest equivalent stresses of 2.07 MPa (modified) and 1.73 MPa (conventional), thus the safety factors were more than 85. The experimental verification proved the excellent agreement with the computational predictions, the temperature, and the heat flux being within 5% and 8% of the predicted values respectively. The geometric optimization of the absorber plates plays a major role in the performance of the pyramid solar still without compromising the structural integrity. The validated computational approach offers a dependable basis for systematic design optimization and acts as a stepping stone for future advanced modeling work.