# CHEE 222 Lecture Notes - Power Balance

34 views1 pages APPENDIX 2: Sample Calculations
2.1: Power Generation Calculation
Power = ∆H*m*efficiency
ie: Power Generated in Turbine 1 = (Hstream 4 Hstream 6)*mstream 4*efficiency
= (2947.4 kJ/kg 2548.8 kJ/kg)*(8.9 kg/s)*0.72 = 2554.23 kJ/s = 2.554 MW
This method of calculating power was used for all power calculations that involved
turbines, as turbine power generation is simply the product of the mass flowrate and the
change in enthalpy between the inlet and outlet streams. This product is then multiplied
by the efficiency of the turbine to give the actual power generated.
2.2: Power Loss Due to Efficiency Calculation
ie: Power Lost in Turbine 1 = (Hstream 4 Hstream 6)*mstream 4*(1 efficiency)
= (2947.4 kJ/kg 2548.8 kJ/kg)*(8.9 kg/s)*(1-0.72) = 993.3112 kJ/s = 0.993 MW
This calculation is very similar to that in 2.2, the difference being that losses are being
calculated, so instead of multiplying the ideal power generation by the efficiency, it is
multiplied by 1 efficiency. This gives the difference between the actual and ideal power
generated: the losses.
2.3: Power Balance Calculation
Power In = Power Out
Power In
MW
Power Out
MW
Boiler
83.25668
Power Produced in Two Turbines
6.3825104
Inlet Water
0.04656
Pipe Losses
8.553
Pump
0.051666667
Condensor Losses
54.165
Hospital Usage
0.25
Boiler Losses
12.488
Turbine Losses
1.5153496
Pump Losses
0.0060528
ie: 83.25668 + 0.04656 + 0.051666667 = 6.3825104 + 8.553 + 54.165 + 0.250+ 12.488 +
1.5153496 + 0.0060528
This power balance was used to check to make sure that all of the power generated and
consumed in the system balanced out. In reality, there are inherent errors in all
calculations, so this balance was off by 0.05 MW, which we deemed to be a very low
amount of error due to the total power generation being over 83 MW.
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