A novel design of absorber surface of solar chimney power plant (SCPP): Thermal assessment, exergy and regression analysis

•Proposed wavy ground absorber produces more power compared to traditional flat cases.•Higher amplitude (h) triangular wavy absorber enhances power (58.62 %, 82.47 kW).•With increasing h, chimney and collector efficiencies drop but overall efficiency rises.•Collector exergy-utilization efficiency rises with increasing undulations (n).•Developed mathematical correlations closely predict the power and efficiencies of SCPP.