Part 2: Detailed Analysis Questions (80 Points total) 1. (25 pts) In a hair dryer, a fan forces air through a row of coiled electrical heater wires to produce a hot

exhaust stream. Consider a hair dryer with inlet air flow rate at 800 L min-¹ and Tin = 25°C, and an exhaust temperature of 90°C. Assume that the shell of the hair dryer is well- insulated and that the fan requires negligible power. Fan blades GB Cool air Cord Motor -Switch Wire coils Heated air a. (9 pts) Draw a schematic of the hair dryer indicating the main material and energy flows in the system. Indicate a control volume around the hair dryer. b. (8 pts) Setup and simplify the energy balance for the control volume around the hair dryer. Solve for the required electrical power to run the hair dryer. c. (8 pts) Now, consider the more realistic situation that the hair dryer is not perfectly insulated. Assume that the plastic shell has a surface area of Aext = 0.05 m² and is at Text = 35°C. Also, assume that the outlet nozzle (Dout = 5 cm) is covered with an emissive metal screen. Provide a quantitative estimate for the additional electrical power required to offset heat losses. • Does heat loss significantly increase the power required to operate the hair dryer?