Sustainable Thermal Technologies UG and Masters please prov

Sustainable Thermal Technologies (UG and Masters) , please provide full solutions, thank you!!

Solution

Answer for the first part

As the solar simulator is turned off, the water passing through the the collector losses energy to ambient bu convection. So the Uo, which is the overall heat transfer coefficient of collector can be found out by the following mecthod.

Reading set - 1

Flow rate, = 10 li/min = 1.6*10^-4 m³/s

So, mass flow rate, m = Q*mass density = 0.16kg/s

Rate of Heat lost by the water = m*C_p*(T1-T2) =0.936 kW = 936W

This should be equal to Uo * A* dT

Where, Uo is the overall heat transfer coefficient

A is the area of collector

dT is the temperature difference between water and ambience.

dT = T_{avg of water} - T_ambience = 34.4 K

A = 1.85m²

^So   Uo = 936 / ( 34.4*1.85) = 14.7 W/m²K for Reading 1

similar way you get

for reading 2

Uo = 574 / ( 34.5*1.85) = 8.99 W/m^₂K

for reading 3

Uo = 702.24 / ( 33*1.85) = 11.5 W/m^₂K

So the Average overall heat transfer coefficient is average of all three

U_oavg = (14.7+8.99+11.5) / 3 = 11.73 W/m²K. Ans