A dryer has an inlet air temperature of 25C (dry bulb temperature) with a relative humidity (RH) of 55%, the dryer heats the inlet air to 90C. What is the relative humidity of the air in the dryer (to two decimal points)? Hint: the humidity ratio and the dew point temperature of the air remain constant.

The dyer exit air has a dry bulb temperature (DB) of 85C and a wet bulb (WB) temperature of 55C. The dryer air is 100C, what is the relative humidity of the dryer air before going to the exit (to two decimal points)? Hint is the same as Question 1.

A wet material is in a dryer with a drying air temperature of 75C and relative humidity of 10%. If only convective heat transfer is occurring in the dryer what is the surface temperature of the material (to one decimal place)?