Simulation of set-point feed-forward control of wellhead valves in an organic Rankine cycle geothermal power plant

Organic Rankine cycles (ORCs) are an energy conversion technology particularly suitable for low enthalpy heat resources. In this paper, the application of a different kind of feed-forward scheme called set-point feed-forward control to an organic Rankine cycle geothermal power plant is examined. The set-point feed-forward control scheme uses a set-point for a pressure controller in the plant to govern the position of valves located at the geothermal wellheads. It was tested using a dynamic model of an ORC geothermal plant, which shows an improvement in the time taken to reach steady state by a factor of 4-6. Testing the scheme with a simplified optimisation programme and disturbance in ambient temperature showed it reduced the emission of 4tonnes of geothermal vapour to the atmosphere, which ultimately improves plant sustainability and profitability. (c) 2015 Curtin University of Technology and John Wiley & Sons, Ltd.