Example 4 Ex.1 A water heating flat plate collector is fitted with two glass covers and a non-selective absorber plate of dimensions 1x 2 m. The collector is tested by the standard procedure and the following data is obtained. T To T Given (C) ("C) (C) W/m n = FR (Ap Ac Ap (T) ave-FR UL Ac |(Tfi-Ta) IT 84.95 93.98 23.0 885 79.97 89.83 22.4 879 (Ta)=0.74 75.63 85.51 22.1 862 m=1.10 kg/minutes 69.54 79.24 21.6 841 68.19 77.36 21.3 827 50.05 61.19 20.4 819 C-4.18 kJ/kgC 43.37 54.06 20.4 792 38.17 49.79 19.3 770 A/A=1.2 33.92 45.44 19.0 761 (a) Calculate the values of 17, and plot these against the parameters (T-T), draw a best fit straight line and determine the values of U, and F (b)How does the value of F, change if the value of mass flow rate is increased to 1.3 kg/minutes? Assume that the value of F' does not change significantly because of increase of mass flow rate (m) SOLUTION q 77 A.IT = mC (T-T) P AIT 40