A Ford Taurus driven 15,000 miles a year will use about 715 gallons of gasoline compared to a Ford Explorer that would use $940$ gallons. About $19.7 \mathrm{~lbm}$ of $\mathrm{CO}_{2}$. which causes global warming, is released to the atmosphere when a gallon of gasoline is burned. Find the extra amount of $\mathrm{CO}_{2}$ production a man is responsible for during a $5$-year period if he trades his Taurus for an Explorer.

A hydraulic turbine has 85 m of elevation difference available at a flow rate of $0.25 m^3/s,$ and its overall turbine– generator efficiency is 91 percent. Determine the electric power output of this turbine.

A piston-cylinder device initially contains 50 L of liquid water at 40$^\circ{}$C and 200 kPa. Heat is transferred to the water at constant pressure until the entire liquid is vaporized. (a) What is the mass of the water? (b) What is the final temperature? (c) Determine the total enthalpy change. (d) Show the process on a $T-v$ diagram with respect to the saturation lines. Answers: (a) 49.51 kg, (b) 120.21$^\circ{}$C, (c) 125,950 kJ

A 7-hp (shaft) pump is used to raise water to an elevation of 15 m. If the mechanical efficiency of the pump is 82 percent, determine the maximum volume flow rate of the water.

A water pump delivers 6 hp of shaft power when operating. If the pressure differential between the outlet and the inlet of the pump is measured to be 1.2 psi when the flow rate is $15 ft^3/s$ and the changes in velocity and elevation are negligible, determine the mechanical efficiency of this pump.

Large wind turbines with blade span diameters of over 100 m are available for electric power generation. Con- sider a wind turbine with a blade span diameter of 100 m installed at a site subjected to steady winds at 8 m/s. Taking the overall efficiency of the wind turbine to be 32 percent and the air density to be $1.25 \mathrm{kg} / \mathrm{m}^{3}$ determine the electric power generated by this wind turbine. Also, assuming steady winds of 8 m/s during a 24-hour period, determine the amount of electric energy and the revenue generated per day for a unit price of $0.09/kWh for electricity.

Consider an electric motor with a shaft power output of 20 kW and an efficiency of 88 percent. Determine the rate at which the motor dissipates heat to the room it is in when the motor operates at full load. In winter, this room is normally heated by a 2-kW resistance heater. Determine if it is necessary to turn the heater on when the motor runs at full load.

A geothermal pump is used to pump brine whose density is $1050 kg/m^3$ at a rate of $0.3 m^3/s$ from a depth of 200 m. For a pump efficiency of 74 percent, determine the required power input to the pump. Disregard frictional losses in the pipes, and assume the geothermal water at 200 m depth to be exposed to the atmosphere.

A wind turbine is rotating at $15 \mathrm{~rpm}$ under steady winds flowing through the turbine at a rate of $42,000 \mathrm{~kg} / \mathrm{s}$. The tip velocity of the turbine blade is measured to be $250$ $\mathrm{km} / \mathrm{h}$. If $180 \mathrm{~kW}$ power is produced by the turbine, Find (a) the average velocity of the air and $(b)$ the conversion efficiency of the turbine. Take the density of air to be $1.31 \mathrm{~kg} / \mathrm{m}^{3}$. and the diameter vary from $20$ to $80 \mathrm{~m}$ in increments of $20 \mathrm{~m}$. Tabulate the results, and discuss their significance.

Determine the specific volume of the refrigerant-134a vapor at 0.9 MPa and 70$^\circ{}$C based on (a) the ideal-gas equation, (b) the generalized compressibility chart, and (c) data from tables. Also, determine the error involved in the first two cases.

A room is cooled by circulating chilled water through a heat exchanger located in a room. The air is circulated through the heat exchanger by a 0.25-hp (shaft output) fan. Typical efficiency of small electric motors driving 0.25-hp equipment is 54 percent. Determine the rate of heat supply by the fan–motor assembly to the room.

Consider a classroom for 55 students and one instructor, each generating heat at a rate of 100 W. Lighting is provided by 18 fluorescent lightbulbs, 40 W each, and the ballasts consume an additional 10 percent. Determine the rate of internal heat generation in this classroom when it is full occupied.

An exercise room has eight weight-lifting machines with no motors and four treadmills, each equipped with a $2.5$-$\mathrm{hp}$ (shaft output) motor. The motors operate at an average load factor of $0.7$, at which their efficiency is $0.77$. During peak evening hours, all 12 pieces of exercising equipment are used continuously, and two people are doing light exercises while waiting in line for one piece of the equipment. Considering the average heat dissipation rate from people in an exercise room is $525 \mathrm{~W}$, find the exercise room's heat gain rate from people and the equipment at peak load conditions.

The steam requirements of a manufacturing facility are being met by a boiler whose rated heat input is 5.5 x 10^6 Btu/h. The combustion efficiency of the boiler is measured to be 0.7 by a handheld flue gas analyzer. After tuning up the boiler, the combustion efficiency rises to 0.8. The boiler operates 4200 h year intermittently. Taking the unit cost of energy to be $13/10^6 Btu, determine the annual energy and cost savings as a result of tuning up the boiler.