The walls of a cold-storage room kept at 8°F are insulated with a 4-

in. layer of cork. The external air is at 72°F and has a dew point of 60°F.

Since cork is porous, air diffuses across the insulating layer and water vapor will start condensing at the point where the temperature is 60°F and freezing where the temperature reaches 32°F.

(a) Find the depths within the cork where liquid water and ice are formed, if cork is assumed to consist of wood solid with k = 0.058 BTU/h ft °F with air-filled pores with porosity ε^p

= 0.50 and if the effects of condensation and freezing in the pores on the thermal conductivity of cork are neglected. Also neglect any convective heat transfer resistance.

(b) Repeat part

(a) if the effects of condensation and freezing in the pores on the thermal conductivity of cork are considered. Note that condensation and freezing within the pores will alter the thermal conductivity.