Question

Consider an R-134a based freezer operating at -30°C. The surrounding temperature is at 25°C. External size of the freezer is 33.62" wide x 37.37" tall x 20.68" deep. Wall thickness of the freezer is 1" and made of polystyrene (thermal conductivity=.033 W/mK). Thermal conductivity of the wall is the same as polystyrene. For simplicity, you may assume the inner and outer convection coefficients of the freezer are both equal to 10 W/m2/K.
The heat removal rate is: q(convection)=186.22 W
The mass flow rate is m.=.00095 kg/s
h1=231.46 kJ/kg, h2=269.07 kJ/kg h3=73.33 kJ/kg, h4=73.33 kJ/kg.
The temperature at state 2 is 25.875 ?.
Determine the Outer Surface Areas of the Condenser tube and the evaporator tube if the diameters are both .25 in.
THIS IS TO FIND THE SA OF THE TUBES.

Answer 1