Modelling and Experimental Investigations of ORC Systems

Transcription

1 Modelling and Experimental Investigations of ORC Systems Y.T. Ge, L. Li, X. Luo, S.A. Tassou, Brunel University London, Uxbridge, Middlesex, UB83PH, UK

2 Outline of Presentation Test rigs of CO 2 transcritical Rankine cycle (T-CO 2 ) and R245fa ORC Test results of T-CO 2 test rig Test results of R245fa ORC test rig Modelling of T-CO 2 system Conclusions

3 Test rigs of CO 2 Transcritical Rankine Cycle (T-CO 2 ) and R245fa ORC (System Layout) (Picture of Test Rig)

4 Test rig of CO 2 Transcritical Rankine Cycle (T-CO 2 )

5 Test rig of R245fa Organic Rankine Cycle Scroll expander Power generator Oil rig Turbine Shell and tube evaporator Plate evaporator R25fa ORC system layout R245fa rig

6 CO 2 mass flow rate (kg/s) Test Results of CO 2 Transcritical Rankine Cycle (T-CO 2 ) Variations of operating parameters for the system test Oil temperature (⁰C) Oil flow rate (kg/s) Air temperature(⁰c) Air flow rate(m 3 /s) CO2 mass flow rate (kg/s) 140⁰C~150⁰C 0.25~ ~ ~ Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c CO 2 pump speed (Hz) Variation of CO 2 mass flow rate with CO 2 pump speed and heat source parameters

7 Pressure (bar) Test Results of T-CO 2 (Cont.) Turbine inlet (Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c) 40 Turbine inlet (Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c) 30 Turbine outlet (Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c) Turbine outlet (Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c) CO 2 mass flow rate(kg/s) Variation of turbine inlet and outlet pressure with CO 2 mass flow rate and heat source parameters

8 Temperature (⁰C) Test Results of T-CO 2 (Cont.) Turbine inlet (Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c) Turbine inlet (Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c) 60 Turbine outlet (Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c) 50 Turbine outlet (Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c) CO 2 mass flow rate (kg/s) Variation of turbine inlet and outlet temperature with CO 2 mass flow rate and heat source parameters

9 Heat capacity (kw) Test Results of T-CO 2 (Cont.) Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c CO 2 mass flow rate (kg/s) Variation of turbine inlet and outlet temperature with CO 2 mass flow rate and heat source parameters

10 Power generation (W) Turbine efficiency (%) Test Results of T-CO 2 (Cont.) Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c (measurement) Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c (measurement) Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c (calculated from measurement) Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c (calculated from measurement) CO 2 mass flow rate (kg/s) Variation of turbine power with CO 2 mass flow rate and heat source parameters Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c Thermal oil : flow rate=0.364kg/s, temp.=144.4⁰c Thermal oil : flow rate=0.463kg/s, temp.=142.4⁰c 5 Overall efficiency CO 2 mass flow rate (kg/s) Isentropic efficiency Variation of turbine efficiency with CO 2 mass flow rate and heat source parameters

11 Test Results of R245fa ORC System Variation of Turbine inlet and outlet pressures and pressure ratio with oil temperature Variation of power generation and system efficiency with oil temperature

12 Test Results of R245fa ORC System (Cont.) Variation of Turbine efficiency with pressure ratio

13 Modelling of T-CO 2 system T-CO2 system layout TRNSYS model of CO 2 power generation system

14 Component models of T-CO 2 system CO2 Gas generator, Recuperator, R245fa Evaporator (Plate type) T T hi 2 5 T co T ho T ci Temperature profile in the evaporator (R245fa) Temperature profile in the supercritical gas generator (CO 2 ) 3 6 Recuperator Recuperator

15 CO 2 mass flow rate(kg/s) Simulation of T-CO 2 system Operation condition for model simulation Gas generator pressure=80 bar Gas generator pressure=90 bar Gas generator pressure=100 bar Gas generator pressure=110 bar Gas generator pressure=120 bar Air flow temperature at condenser inlet (⁰C) Variation of CO 2 mass flow rate with different condenser air flow inlet temperature gas generator pressure, thermal oil temperature and flow rate

16 Simulation of T-CO 2 system (Cont.) Variation of gas generator capacity, pump power consumption and system overall efficiency with different condenser air flow inlet temperature and CO 2 gas generator (turbine inlet) pressure

17 Conclusions The test rigs of T-CO 2 and R245fa ORC were developed and measurements were carried out at various heat source and sink parameters The heat source temperature has a greater more effect on system performance than heat source flow rate. The system overall efficiency is affected significantly by system design (heat losses and pressure drop) and expander performance System models have been developed and used to simulate performance over a wide range of operating conditions and capacities. The simulations can contribute significantly to understanding of system behaviour, design optimisation and control.