Arectangular kiln is exposed to ambient air at 29.6 °c, which has a convection coefficient of 5.0 w/m^2°c around the kiln. for safety reasons the outside surface temperature must be limited to 35 °c. under steady operation the temperature of internal surface of the kiln is 444 °c. find out the total thermal resistance (in °c/w) needed to achieve the safe conditions.

Refrigerant-134a enters the compressor of a refrigerator as superheated vapor at 0.14 mpa and -10°c at a rate of 0.05 ka/s and leaves at 0.8 mpa and 50°c. the refrigerant is cooied in the condenser to 0.72 mpa and 26'c. it is then throttled to 0.15 mpa. sketch the t-s diagram for the system and evaluate: 6) the rate of heat removai from the refrigerated space (kw), it) the power input to the compressor (kw), ii) the isentropic efficiency of the compressor (%), and iv) the cop of the refrigerator.