A certain super insulation material having a thermal conductivity of 2 104W m C is used to insulate a tank of liquid nitrogen that is maintained at 196C 199 kJ is required to vaporize each kilogram mass of nitrogen at this temperature Assuming that the tank is a sphere having an inner diameter (ID)...

A certain super insulation material having a thermal conductivity of 2 104W/m C is used

Question:

A certain super insulation material having a thermal conductivity of 2 × 10−4W/m · ºC is used to insulate a tank of liquid nitrogen that is maintained at −196ºC; 199 kJ is required to vaporize each kilogram mass of nitrogen at this temperature. Assuming that the tank is a sphere having an inner diameter (ID) of 0.52 m, estimate the amount of nitrogen vaporized per day for an insulation thickness of 2.5 cm and an ambient temperature of 21ºC. Assume that the outer temperature of the insulation is 21ºC.