Summary Examples

Following are four examples of how the terms and formulae provided above are applied to specific representative prime mover systems. All values are given in English units and the assumed fuel is pipeline grade natural gas with an HHV of 1,020 Btu/cf and LHV of 918 Btu/cf. Fuel costs are given for each example on the basis of 1,000 cf (1 Mcf).

For simplicity, the performance + A Operating costs + Annualized capital cost expressions are applied under idealized

This expression can be extended further to reflect life-cycle CCP. Based on an assumed financial discount rate, the life cycle CCP would be the sum of the present values of the annualized CCP over the life of the systems. To perform this calculation, a present value factor is full load operating conditions. In actual applications, prime mover performance will be directly related to continually varying operating conditions. For example, operation under varying load conditions or at varying inlet air temperatures usually results in a change in heat rate from rated full load operation. Numerous other factors will also influence actual performance.


English Units

SI Units

Thermal efficiency (Eq. 2-9)

Net work output

Heat energy input


or iwWh x 100%

Heat energy input Net work input

BtuUh = Btu/hp-h hp

kWhJh or kWW = kWhh/kWhm

Net thermal efficiency (Eq. 2-16) ( Net work output ) jqqo/

/ hp x 2,545 Btu/hp-h \

( kWm x 3,600 kJ/kWhm \

\ Heat added — Heat recovered)

\BtuHeat added/h - BtuHeat recovered/h) X 100%

\kjHeat added/h kJHeat recovered'h/

Heat added — Heat recovered

BtuEnergy added/h — BtuHeat recovered/h

kJEnergy added/h kJHeat recovered/h

Net work output



Energy-chargeable-to-power (Eq. 2-19)

Total heat added — Displaced fuel energy Net power output

BtuHeat added — BtuHeat recovered x tf.Boiler

kkJHeat added ~ kkJHeat recovered x ^Boiler

hp-hOutput— hp-hAuxilliary input

k'^WhmOutput k'^Whm Auxiliary input

Table 2-1 English and SI Units Commonly Used in Performance Terms.

Example 1

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