question $4($Los:$3)$

$(50$ Marks$)$

You are asked to increase the thermal efficiencv of the given power plant.

$($Marks $10)$

Suggest the heat exchangers

from the list below that must

be placed for each of the

locations $A,B,C$&$D$ in the

given layout.

Super heater

Condenser

Air preheater

Evaporator

Cooling Tower

Economiser

Air Conditioner

Radiator

EN$8918$ Applied Heat and Process Transfer, $2021$A

An oil cooler is to be designed in a process industry.

A parallel flow heat exchanger is designed to cool ofl $)$ from $120C$ to $85C$ by flow of water.

The water flows at the rate of $75k\frac{g}{m}in$ and gets heated from $40C$ to $75C.$ What heat exchanger area is required for an overall heat transfer coefficient of $0\mathrm{.}35K\frac{W}{m^2}K?$

A change in operating conditions occurs and the water flow rate drops to $50k\frac{g}{m}in$ for the same oil flow rate and the same inlet temperatures of both the fluids.

Work out the exit temperature of the oil and water under the changed conditions.

$($Marks $40)$