Author(s): Shalini Rai, Prabha Chand, S.P. Sharma
) on the thermal and thermohydraulic (effective) efficiencies. Results indicate that the thermal efficiency increases continuously with increase in fluid mass flow rate, whereas thermohydraulic efficiency increases upto an inception value of fluid mass flow rate, attains a maximum and then decreases sharply for a given fin spacing and fin height. For higher value of the fluid temperature rise parameter, the effective efficiency values closely follow the thermal efficiency values. It is found that attaching offset fins below the absorber plate at lower fluid mass flow rate can lead to appreciable enhancement of the thermal and thermohydraulic efficiencies.