Experimental investigations of thermal performance for flat and dimpled plate solar air heater under turbulent flow conditions

•A comparison between flat and dimpled plate solar air heater was performed.•Experiment were conducted for a mass flow rate (MFR) = 0.028 kg/sec − 0.051 kg/sec.•Thermal performance of DPSAH is better than the FPSAH up to a MFR = 0.045 kg/sec.•For MFR greater than 0.045 kg/sec the major parameters were same for both the SAH.•Hence use of DPSAH is not advisable for MFR higher than 0.045 kg/sec.