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Organic Rankine Cycle (ORC) technology is promising to convert low enthalpy heat sources to electricity. The ORC system utilizes low enthalpy heat sources as the primary heat source to heat and evaporates secondary fluid, so-called working fluid, by using heat exchangers. Organic fluids like hydrocarbon fluids and refrigerants are used as the working fluid in the ORC system. This paper studied the application of the hermetic turbine in the ORC system. The system utilizes n-pentane as its working fluid. Because of its flammability, the turbine should be hermetically sealed to avoid leakage. The main objective of this study is to get the results of the numerical analysis of the 100 kW ORC hermetic turbine design. The design has been carried out and the geometry of a 2-stages turbine has been obtained. This design calculation is then validated by numerical simulation to obtain comparisons and corrections. From the results of this numerical simulation, there are differences in the properties and performance of the fluid per stage of the turbine. In general turbine performance, the CFD simulation with targeted pressure ratio has a smaller difference for -22.1% in power, 0.07% in pressure ratio, -0.26% in efficiency, and 17.05% in mass flow compared to the result of the CFD simulation based on targeted mass flow from the design analytical calculation. This difference indicates that the turbine geometry still need an improvement or optimization to achieve the design target of the analytical design calculation. [ABSTRACT FROM AUTHOR]

Some heat sources, such as biomass, solar heat, and other waste heat, have the potential to be reused. Some air conditioners usually require electrical energy to meet cooling needs in tropical climates. In this type of air conditioner, electrical energy is needed to drive the compressor in the cooling system. Implementing a cooling system using a solar heat source or other low heat sources to evaporate the working fluid as an ejector driving medium could reduce electrical energy consumption. This system can replace the compressor function in conventional air conditioning systems. This study performs a thermodynamic analysis of the ejector performance for the refrigeration cycle. Refrigerant R141b is used as the working fluid. It has low-pressure characteristics and makes a low pump head ideal for use in refrigeration cycles. Simulations were carried out using the saturation temperature parameter of the vapor generator at 80-100°C and the saturation temperature of the condenser at the same temperature at 40°C. It was found that applying the ejector in the refrigeration cycle can reduce electricity consumption by up to 40.78 % compared to conventional air conditioning systems but from the overall comparison, the results have not been fully able to reduce the use of electrical energy. [ABSTRACT FROM AUTHOR]

The 500kW Lahendong binary cycle geothermal power plant is the first low-medium enthalpy generation system commenced in Indonesia. The pilot plant was established through technology research collaboration among BPPT, GFZ and PT. Geothermal Energy. The proven ORC unit is built by a German industry, where heating and cooling systems are manufactured by national industries. Construction and installation of the pilot plant was completed in 2016. Since September 2017, the pilot plant has continued to operate. The main target of the Indonesian-German cooperation is to disseminate the binary cycle technology throughout Indonesia. This paper discusses operating experience of the plant 500kW during the past six-month period. As a result, to achieve the design conditions (500 kW gross and 424.2 kW net), further work needs to be done. [ABSTRACT FROM AUTHOR]