An iterative method for modelling the air-cooled organic Rankine cycle geothermal power plant

Abstract

SUMMARYThis work presents an iterative method for modelling the effect of ambient air temperature on the air-cooled organic Rankine cycle. The ambient temperature affects the condenser performance, and hence the performance of the whole cycle, in two ways. First, changing the equilibrium pressure inside the condenser, the turbine outlet pressure and the turbine pressure ratio vary. Since the turbine pressure ratio is a major parameter in determining the power generated by a turbine, the plant output is directly affected. Second, changing the condenser outlet temperature with ambient temperature, the pump inlet and outlet conditions are changed. Thus, the vapourizer equilibrium temperature and pressure are influenced. The developed method iteratively seeks the equilibrium conditions for both the condenser and vapourizer. Two case studies based on a real plant performance have been carried out to demonstrate the validity of the method. The developed method demonstrates robustness and converges regardless of the initial conditions allowed by the physical properties of the working fluid. This method is effective for cycles that use saturated vapour as well as superheated vapour under static or dynamic conditions with appropriate initial conditions and constraints. The developed method may be applied to any Rankine cycle with closed cycle operation.

A methodology to assess suitability of a site for small scale wet and dry CSP systems

“…The off‐design characteristics of an ORC system can be defined as a black box model based on the inlet temperatures of hot and cold heat transfer fluids . The pressure difference between condenser and evaporator is an outcome of pump characteristics, i.e.…”

Minimisation of exergy losses in mono high pressure nitric acid process

“…Exergoeconomic model for the analysis of geothermal power plants proposed by Coskun et al ( 2011) shows that exergy efficiency decreases with increasing outdoor temperature. The performance of the whole cycle depends on the condenser performance that depends upon ambient temperature (Sohel et al, 2011). R-123 can give maximum exergy efficiency for ORC used to recover exhaust waste heat in the range of 500.15 K to 600.15 K from SOFC-GT cycle (Tuo, 2013).…”

An Adaptive Design Approach for A Geothermal Plant with Changing Resource Characteristics

“…Changes in kinetic energy and potential energy may be neglected and equilibrium conditions can be assumed at the cross-sections of both inlet and outlet. Detailed discussion on the modelling of these ORCs is available in our previous work [9].…”

“…Current research and development trends towards geothermal power generation, specifically, low temperature power cycles are noticeable [3][4][5][6][7][8][9][10][11][12]. Geothermal power plants are generally designed based on constant resource characteristics.…”