Project Description

Organic Rankine Cycle is a power cycle which utilises low temperature heat sources. The process is the same of Rankine Cycle except ORC systems uses organic fluids instead of water and steam.  The main advantage of these organic fluids that they have low boiling point and they have high molecular weight. These characteristics give organic fluids to be more applicable with low temperature heat inputs.

 

In this thermodynamic cycle, heat trensfer oil is heated by the heat source. Then heat transfer oil goes into the evaporator where the organic fluid changes its phase into gaseous. Heated and pressurized by a pump, organic fluid goes into expander inlet where it expands and loses its temperature. Rotating expander also rotates the attached generator to obtain electricity. Then, the organic fluid goes into the condenser where it cools down with pumped cold water by chiller. The low pressure and temperature organic fluid is now at the inlet of the pump. The closed loop cycle is repeated.

 

In terms of heat inputs, we are seeking to research renewable energy sources that are solar, geothermal and waste heat. In the first step of all this research, solar power with using parabolic trough collectors is taken into account.

 

The ORC system in BURET Laboratory is built with a volume of 25 m3 (5m x 2.5m x 2m). There are three different pumps ( organic fluid, water and heat transfer oil ),  four heat exchangers ( evaporator, condenser, simulator and recuperator ), a scroll type expander, an electric heater, an chiller, two throttle valves to simulate the expander while start up process, an expansion vessel for heat transfer oil, a liquid collector to create fully liquid phase of organic fluid pump inlet, a shell and tube heat exchanger to  regain the organic fluid that is discharged by safety valve.

 

The system’s design pressure and temperature is set to be 30 bar and 2000C. The aim is to find maximum efficiency and net work while staying in our design conditions and changing the organic fluid type.  Steady state and dynamic modelling analyses are done by BURET Lab. MSc. students with using MATLAB and Aspen Plus softwares retrieves data from REFPROP.