Viscosity of the oil is generally larger as compared with that of working fluid or water. For precise simulation, flow frictional resistance of oil should be evaluated.
With N lines of the parallel concentric tubes, the required pump power is obtained by the following :
1.2 Overall thermal efficiency
Net electricity output W is obtained by subtracting oil pump power from net output of the ORC.
w = Wore – Woil (21)
Global electricity efficiency is defined by the proportion of net electricity output to the total irradiation as follows: