Consider a flat plate solar thermal collector with the following characteristics: FR(TA)n= 0.85 FRUL 5.19 W/mK Ac = 2.60 m The solar irradiance with normal incidence on the solar thermal collector plane is 870 W/m and the ambient temperature is 17C. If the inlet to the collector fluid temperature is T-50C, calculate the collector efficiency at the operating conditions. The anti-freeze fluid used is propylene glycol solution 20% by mass and the flow rate 0.015 l/sm. Enter the value for the efficiency n (%) rounding to 1 decimal place.