A home’s temperature is maintained at 25◦C by an AC system with a COP of 3.2 which cools outside air (38◦C with a 30°C Wet Bulb) to 10 C and injects the cooled air into the home. The 25 C air exits the home. A) draw the process on the attached psychrometric chart. B) If the home gains 50,000 KJ/hr what is the required power in kW? C) How much water is condensed if any? D) Without changing the COP or the heat gain of the home what could be done to lower the power requirement of the AC system and what is the minimum power required?

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 the air is well mixed within the room, and an equal mass flow of air at room temperature (changing with time) is withdrawn through a return duct.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.