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Session: Poster session & Sponsor Exhibition
Session starts: Monday 07 October, 14:00

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Hyun Dong Kim ()
Eun Koo Yoon ()
Kui Soon Kim ()
Jang Mok Kim ()
Sang Youl Yoon ()
Bum Suk Choi ()
Sangjo Han ()
Yang Bum Jeong ()
Kyung Chun Kim (Pusan National University)

Abstract:
This study demonstrates the realization and performance test of an organic Rankine cycle (ORC) power generation system for waste heat recovery. The ORC system consists of two shell and tube heat exchangers for the evaporator and the condenser, a multi-stage centrifugal pump to feed R-245fa refrigerant into the evaporator, a turbo-expander module expected to deliver a power about 250kW and an electric generator. For the turbo-expander, concept of back-to-back two-stage expansion was adopted to increase expansion ratio up to 9.5 to achieve high thermal efficiency of the ORC system. The design point of the rotational speed of the expander was 15,000 rpm. Principal performance parameters of the whole system and of each component have been investigated on the experimental test bench comprised with two heat transfer loops. Thermal energy was provided into the evaporator through pressurized hot water circulating between 2MW electrical heater and evaporator. The influence of temperature of the heat source on the net power output, thermal efficiency, power consumption, mass flow rate and expander outlet temperature at a given pinch point temperature have been analyzed. From the result of performance test of heat exchanger, it is confirmed that the absolute pressure attained to 20bar at the exit of evaporator and amount of exchanged heat between hot water and refrigerant is about 1,700kWth at the design condition of cycle which is 140°C of hot water temperature and 16.5kg/s of water mass flow rate. Moreover, electric power output of 110kWe from the generator is achieved at the condition of mass flow rate of refrigerant of 5kg/s and isentropic efficiency of turbine expander and thermal efficiency of ORC system is about 70% and 8%, respectively. Acquired performance parameters and efficiencies were compared to those expected from the thermodynamic cycle analysis. Base on these results, numerical simulation of the ORC system was conducted using Matlab Simulink capable to calculate thermodynamic cycles in steady and transient conditions. The simulation results could be used to predict the main working parameters and system performance and choose a suitable operation strategy for the entire system.