Performance of working-fluid mixtures in an ORC-CHP system for different heat demand segments
File(s)Oyewunmietal_ECOS2016_Fin.pdf (1018.52 KB)
Accepted version
Author(s)
Oyewunmi, OA
Kirmse, CJW
Pantaleo, AM
Markides, C
Type
Conference Paper
Abstract
Organic Rankine cycle (ORC) power systems are being increasingly deployed for waste heat recovery and
conversion to power in several industrial settings. In the present paper, we investigate the use of working-fluid
mixtures in ORC systems operating in combined heat and power mode (ORC-CHP) with shaft power provided
by the expander/turbine and heating provided by the cooling-water exiting the condenser. The waste-heat
source is a flue gas stream from a refinery boiler with a mass flow rate of 560 kg/s and an inlet temperature of
330 °C. When using working fluids comprising normal alkanes, refrigerants and their subsequent mixtures, the
ORC-CHP system is demonstrated as being capable of delivering over 20 MW of net shaft power and up to
15 MW of heating, leading to a fuel energy savings ratio (FESR) in excess of 20%. Single-component working
fluids such as pentane appear optimal at low hot-water supply temperatures, and fluid mixtures become
optimal at higher temperatures, with the combination of octane and pentane giving an ORC-CHP system
design with the highest efficiency. The influence of heat demand intensity on the global system conversion
efficiency and optimal working fluid selection is also explored.
conversion to power in several industrial settings. In the present paper, we investigate the use of working-fluid
mixtures in ORC systems operating in combined heat and power mode (ORC-CHP) with shaft power provided
by the expander/turbine and heating provided by the cooling-water exiting the condenser. The waste-heat
source is a flue gas stream from a refinery boiler with a mass flow rate of 560 kg/s and an inlet temperature of
330 °C. When using working fluids comprising normal alkanes, refrigerants and their subsequent mixtures, the
ORC-CHP system is demonstrated as being capable of delivering over 20 MW of net shaft power and up to
15 MW of heating, leading to a fuel energy savings ratio (FESR) in excess of 20%. Single-component working
fluids such as pentane appear optimal at low hot-water supply temperatures, and fluid mixtures become
optimal at higher temperatures, with the combination of octane and pentane giving an ORC-CHP system
design with the highest efficiency. The influence of heat demand intensity on the global system conversion
efficiency and optimal working fluid selection is also explored.
Date Issued
2016-06-19
Date Acceptance
2016-05-04
Copyright Statement
© the authors
Source
29th international conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems
Publication Status
Accepted
Start Date
2016-06-19
Finish Date
2016-06-23
Coverage Spatial
Portorož, Slovenia