The flat$-$panel solar collector is $1$m wide and $3$m long with no cover. The absorption surface has an emissivity of $0\mathrm{.}14$ and a sun of $0\mathrm{.}93$ It has the absorption rate. Water enters the collector at $25$ C at a flow rate of $0\mathrm{.}015$ kg$/$s$.$ The solar radiation is $800$ W$/$m$2,$ and the air temperature is Calculate the temperature at the outlet and the efficiency of the collector when the temperature is $20$ C$.$ The efficiency of the collector is to collect the amount of heat transferred to the water It is defined as the amount of radiation incident on the heat divided. The puncture emissivity $($sky$)$ is $0\mathrm{.}6,$ and the number of circulation from the absorption surface Up to the heat flow coefficient, U$=25\mathrm{.}0$ W$/$m$2$K$.$ For the calculation of convective heat transfer from the absorption surface to the atmosphere, hc $=1\mathrm{.}1($Ts$-$ Te$)1/3$ Use. The static pressure ratio of water is Cp $=$It is $4,180$ J$/$kg$.$