$${\begin{align*}P_\text{vesi} &\approx \mathrm{(5,67 \times 10^{-8}\, W/m^2 \cdot K^4)(0,96)\times \\ \times(0,0028\, \mathrm{m^2})[(363\,K)^4 - (293\, K)^4]} \\&= 1,52\, \mathrm{W} \end{align*}}$$