Characterization of Low Pressure Micro-turbine Using Low Temperature Heat Source

Abstract

The objective of this research was numerical simulation and experiment studied for power generated with turbine using low-temperature heat source. The performance and efficiency evaluation of organic Rankine cycle (ORC) engine was tested with a micro-radial turbine type. In this research, the refrigerant HCFC-141b (1,1-Dichloro-1-fluoroethane) was selected as a working fluid in the system. Experiment conditions, of the heat source temperatures varied 70 – 100oC to operating temperature, as well as the working fluid at the vapor generator inlet temperature controlled 32oC. The experimental data were considered in order to verify numerical simulation on the overall performance and thermal efficiency of the system. From the numerical simulation and experimental results, the first stage was found that the experiments shows the test rig should be operated in smooth and steady manner, and it satisfied the preliminary design calculation, but the power output and thermal efficiency of the overall unit was much lower than the numerical calculation corresponding to the degradation from the low efficient power turbine as a major factor. Secondly, the overall micro-turbine performance testing has the result that the optimum condition is consider from the maximum power output condition. This power output and turbine torque maximum operating were 15.73 W and 0.11 N-m on the turbine rotating speed of 1,369 rpm respectively, and same condition the vapor generator temperature operation in 96.8oC with working fluid mass flow rate was 384.5 kg/h, the vapor generator was running at the same setting with the 23.7 kWth as a overall efficiency of system was 0.07%. While work turbine and system efficiency calculated from mathematical model were 3.9 kW and 14.3% respectively, with the working fluid mass flow rate was 372 kg/h, the vapor generator was 27.1 kWth. The model predictions are found to be in good satisfactory with the experimental results. The numerical simulated and experiment data will be lead to the improvement and development in the prototype of low-pressure turbine with ORC system up to highly efficiency and the possibilities of the HCFC-141b as a working fluid for the driving of a low-pressure turbine engine in a small electricity production.