$$ A boiler is rated at $2500$ kW$.$ If the boiler efficiency is $85\%.($a$)$ find the consumed amount of fuel in J$/$hr$.($b$)$ discuss the energy saving opportunities in boilers. $($c$)$ discuss the heat recovery methods and identify the energy saving potentials from waste heat recovery.

$$ An HVAC system provides $800,000$ kJ$/$h of cooling while drawing $45$ kW of electricity. $($a$)$ calculate its COP. $($b$)$ discuss various HVAC Energy Efficiency measures.

$$ For an air compressor, the free air delivery is $100$m$3/$min$.$ The final pressure is $5$ times the initial pressure. The initial pressure is $1\mathrm{.}2$ times the atmospheric pressure. The time taken to reach the final pressure is $5$ minutes. $($a$)$ Select an appropriate sizing of air receiver. $($b$)$ discuss the energy saving opportunities in air compressor.

$$ A building has a gypsum wall of $13$ mm and fiber glass of $13$ cm$.$ The inside and outside temperatures are $20$C and $6$C$,$ respectively. The wind speed is $7$m$/$s$.$ The area of the wall is $25$ m$2.$ The fiberglass thermal conductivity is $0\mathrm{.}04$ W$/$mC$.$ Find the heat transfer.

$25-$watt $20$ fluorescent lamps are replaced with LED lamp that save $12\%$ to give the same output. The cost of one LED lamp is $ $2.$ Provide your opinion regarding this measure using NPV$.$ The required IRR is $25\%.$ Hours of operation are $4900$ hr$.$ the lamp life is $3$yr$.$ KWh cost is $0\mathrm{.}1$$$/$kWh$.$

$$ An auditor has measured the speed, input voltage, input current, and power factor of a motor. The measured values were $1788$ RPM$,440$ V$,29$ A$,0\mathrm{.}8$ power factor. The motor$$s nameplate is presented in Fig$\mathrm{.}2.($a$)$ estimate the motor$$s loading and efficiency. $($b$)$ according to the presented case, suggest opportunities for energy efficiency improvement. $($c$)$ explain the problem associated with VFD$-$based motor and suggest a solution for solving it$.($d$)$ If the three$-$phase line voltages of a motor are $392,382,$ and $410$ V$.$ Calculate the imbalance current. suggest a solution for imbalance problem.