Experimental Investigation of an Organic Rankine Cycle Prototype Plant Being Developed to Boost the Electric Output of Gas Engine Power Stations

With nowadays rising fuel prices and increasing regulations on CO2 emissions [1, 2] Organic Rankine Cycle (ORC) plants are potential candidates to utilize the waste heat of large stationary combustion engines and convert it into additional electricity, hence boosting the net electric output power and increase the efficiency of the overall power plant. ORCs have the potential to increase the engine net power output by up to 10% without additional fuel consumption. Here our group presents the experimental results of an ORC prototype plant [3]. The facility was designed to take about 250 kW of heat at about 100°C as an input and turn it into electric power of several kilowatts. A water boiler was used as heat source to simulate the hot engine coolant of a gas engine. Both, steady state system response and plant behavior at the complete operating envelope of cycle pump and turbine have been analyzed. The system response data shows linear behavior around the operating point for the most system outputs. Only pressure ratio over the expander and net electric efficiency demonstrate a nonlinear behavior. The plant operation maps reveal that respecting the typical boundary conditions still at least one degree of freedom is not constrained and can be used for operating conditions optimization.