2.2. Thermodynamic Analysis of the WHR Plant and the Calculation for a Vapour Turbine using
R245fa as a Working Fluid for Full Electrical Power
In this paper, all computations follow the ISO standard conditions. The losses in fluid pressure are
not considered except from between the boiler and the turbine. The computations have been made for
the auxiliary engine using HFO. In the Emission Control Area (ECA), standard HFO is not acceptable;
LGS HFO, marine DO or natural gas is used. In ECA 0.10% sulphur limit is coming into effect on
1 January 2015. That means using of low grade sulphur marine gas oil (LGSMGO) or natural gas as a
ship fuel. As these fuels are more expensive (especially LGSMGO) than HFO, the potential financial
savings are much higher [39]. When using fuel with LGS, the exhaust gas temperature can fall
below 145 °C.
Although the turbine using organic fluid rotates at a significantly lower speed compared to the
steam turbine, no gearbox is needed in a real-life plant; the calculation includes the application of a
gearbox on the shafting between the turbine and the generator. The calculation using steam as a
working fluid was performed previously [40] and has been repeated using R245fa in the supercritical
vapour cycle. The ORC parameters should remain optimal or nearly so. T–s diagram of the CHP plant
with a turbine and R245fa as the working fluid is shown in Figure 4.