Let $T_{\text{m}\text{i}\text{n}}=10C,$ with the following specifications:

Cooling water$(cw)$:

$T^s=30C,T^{t}80C,costofcw=0\mathrm{.}00015\frac{\text{\$}}{k}g$

Steam$($sat$\text{'}$d$.,$ s$)$:

$T=258C,H^v=1,676k\frac{J}{k}g,costofs=0\mathrm{.}006\frac{\text{\$}}{k}g$

Overall heat$-$transfer coefficients:

$U_{\text{h}\text{e}\text{a}\text{t}\text{e}\text{r}}=1k\frac{W}{m^2}-C,U_{\text{c}\text{o}\text{o}\text{l}\text{e}\text{r}}=U_{\text{e}\text{x}\text{c}\text{h}}=0\mathrm{.}75k\frac{W}{m^2}-C$

Purchase cost of heat exchangers:

$C_P=3,000A^{0\mathrm{.}5},($$$,m^2)$

Equipment operability $=8,500h\frac{r}{y}r,$ return on invest$-$

ment $=i_m=0\mathrm{.}1$