热力学代写|thermodynamics代考|高质保分代写热力学作业

Problem 1.5
Consider a subset of the American automotive fleet that comprises one million cars that are driven 10,000 miles annually. The average gasoline consumption for this fleet rises from $26 \mathrm{mpg}$ to $31 \mathrm{mpg}$ over a 5-year period. Calculate the total fuel savings annually and cumulatively over this time.

Given: The estimated rise in an automotive fleet’s miles per gallon over a five-year period.

Find: The total fuel savings and the annual fuel savings over the five-year period.
Analysis: 1 millions cars $\quad 10,000 \mathrm{mi} / \mathrm{yr}$
$26 \mathrm{mpg} \rightarrow 31 \mathrm{mpg}$ over 5 years
Savings per mpg
$$
\begin{array}{ll}
\frac{10,000 \mathrm{mi}}{26 \mathrm{mi} / \mathrm{gal}}=384.62 \mathrm{gal} / \mathrm{car} \text {-year } \
\frac{10,000}{27}=370.37 & \Delta_1=14.25 \
\frac{10,000}{28}=357.14 & \Delta_2=13.23 \
\frac{10,000}{29}=344.83 & \Delta_3=12.31 \
\frac{10,000}{30}=333.33 & \Delta_4=11.50 \
\frac{10,000}{31}=322.58 & \Delta_5=10.75
\end{array}
$$

Problem 1.I
Compare the operating costs of a home refrigerator that uses $700 \mathrm{kwh}$ electricity annually to one that uses $1900 \mathrm{kwh}$. The cost of electricity is $\$ 0.10 \mathrm{kwh}$. If this were enacted nationally, such that 10 million refrigerators were effected, what would be the total savings in kilowatt-hours?

Given: The annual electrical power consumption of refrigerators and the cost of electricity.
Find: The savings in kw-h of electricity by using an energy efficient model.

Sketch \& Given Data:

Analysis: $\left.\begin{array}{c}1900 \mathrm{kw}-\mathrm{hr} \ 700 \mathrm{kw}-\mathrm{hr}\end{array}\right} 1200 \mathrm{kwh}$ savings/unit annually Cost Savings $=(1200 \mathrm{kwh})(0.10 \$ / \mathrm{kwh})=\$ 12 / \mathrm{yr}$
Savings in annual kwh $=\left(1200 \frac{\mathrm{kwh}}{\text { unit }}\right)\left(10 \times 10^6\right.$ units $)=1.2 \times 10^{10} \mathrm{kwh}$