Question

A steam power plant receives heat from a furnace at a rate of 280 GJ/h. Heat transfer to the surrounding air from the steam as it passes through the pipes and other components are estimated to be about 8 GJ/h. If the waste energy is transferred to the cooling water at a rate of 145 GJ/h, determine the (a) net power output and (b) thermal efficiency of this power plan

Answer 1

a)
`\dot W = 35.278\,MW`, b)
`\eta_(th) = 45.357\,\%`

Step-by-step explanation:

a) The net power output of the plant is:

`\dot W = \left(280\,(GJ)/(h)-145\,(GJ)/(h) - 8\,(GJ)/(h) \right)\cdot \left(1000\,(MJ)/(GJ) \right)\cdot \left((1)/(3600)\,(h)/(s) \right)`

`\dot W = 35.278\,MW`

b) The thermal efficiency of the power plant is:

`\eta_(th) = (280\,(GJ)/(h)-145\,(GJ)/(h)-8\,(GJ)/(h) )/(280\,(GJ)/(h) ) * 100\,\%`

`\eta_(th) = 45.357\,\%`