Electricity used to provide lighting for assembly-line workers at a KitchenAid manufacturing plant is

Avolume of 2.65 m3 of air in a rigid, insulated container fitted with a paddle wheel is initially at 264 k, 5.6 bar. the air receives 432 kj by work from the paddle wheel. assuming the ideal gas model with cv = 0.71 kj/kg • k, determine for the air the amount of entropy produced, in kj/k

To save energy, the air supply to a 2000 ft office has been shut off overnight and the room temperature has dropped to 40°f. in the morning, the thermostat is reset to 70°f and warm air at 120 f begins to flov in at 200ft'/min. the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct. the air pressure is nearly 1 atm everywhere. ignoring heat transfer with the surroundings and kinetic and potential energy effects, estimate how long it takes for the room temperature to reach 70°f. plot the room temperature as a function of time.

Acarnot refrigerator operates in a room in which the temperature is 21°c and of power when operating. if the food compartment of the refrigerator is consumes 3 kw to be maintained at 2°c, determine (a) the coefficient of performance of the cycle and (b) the rate of heat removal from the food compartment. refrigerator cycle that has a higher coefficient of performance than that of the discussed (e) is it possible to develop a carn ot refrigerator, operating between the same temperature limits? explain