Performance analysis of a Concentrating Solar Power system with Organic Rankine Cycle

Hi everyone,
I have been asked to come up with a methodology for how to calculate actual performance of a CSP system with ORC. I can put any measurement device i want.
The system composed of 4 parts;
1)Parabolic trough collector field
2)For back up heater a boiler uses propane as fuel
3)Organic Rankine Cycle uses R245fa as working fluid
4)Wet cooling tower

For the collectors i thought the efficiency will be the amount of energy which collectors can convert into useful heat divided by the total beam insolation on the collectors.

eff_coll = (m_water*C_p*(T_e - T_i))/(I_b*cos_theta*A_p)

where I_b total beam insolation on the collectors, theta is the angle of incidence and the A_p is the aperture area of the collectors. The need of a pyrheliometer is obvious, two thermocouples for the inlet and exit of the collectors, a flow meter and a pressure sensor for pipes of the collector field.

But for the other parts i'm little bit confused how to calculate. Any ideas?