Experimental investigation on a radiative heat pipe heat exchanger - PowerPoint PPT Presentation

Experimental investigation on a radiative heat pipe heat exchanger in steel industry Sulaiman Almahmoud, Amisha Chauhan, Rocio Llera, Francisco lago, Juan-jose Arribas, Hussam Jouhara

Overview • Flat Heat Pipe (FHP) application • Flat Heat Pipe design • Experimental Setup • Results 2 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Introduction • Energy consumption in steel industry presents 5% world energy consumption • 40% of total operating cost is for Energy cost • Challenges :  Limited Space, Inaccessibility, Temperature Restrictions Total operating cost  Payback periods, Project and 40% 60% investment costs Other costs Energy costs 3 Brunel University London Experimental Investigation on a Radiative Heat Pipe Heat Exchanger in Steel Industry

FHP Application • The Flat Heat Pipe (FHP) is designed to recover the heat by radiation and convection from hot sources >500 °C (Mainly hot steel) • Test were carried out at ArcelorMittal steel company (Spain) Moving Shields Up and Down Wire Rod Mill 4 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP Mechanical design Back Panel Top header Rupture Disk FHP Bottom Collector 5 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Mechanical design Number of Vertical pipes: 14 pipes Material: SS 304, Weight: 45 kg 6 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP Design Balance Weight 7 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Heat transfer schematic 8 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP testing Concept Inclination angle: 12.5 ° to 25° Distance from the Barrier Hot Steel 9 Experimental Investigation on a Radiative Heat Pipe Heat Exchanger Brunel University London

FHP Modelling 29 March 2019 T cold, out T cold,in T cold, in T c R co Condenser T ci R cond_c T co R ci R hp T v Evaporator R ei T ei R cond_e T eo R rad R rad : Radiation thermal resistance, R cond_e : Conduction thermal resistance of the evaporator wall, R ei : Boiling thermal resistance R ci : Condensation thermal resistance, T h R cond_c : Conduction thermal resistance at the condenser wall, R co : Forced convection thermal resistance 10 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Experimental Setup • 3 Thermocouples were placed on the bottom collector (EV1 to EV3) • 9 Thermocouples placed on the FHP surface (HP1to HP9) • 3 Thermocouples placed on the top header (AD1,AD2,AD3) • Thermocouples to measure water inlet and outlet temperatures a AD 1 AD 3 AD 2 HP 1 HP 2 HP 3 HP 4 HP 5 HP 6 HP 7 HP 8 HP 9 EV 1 EV 2 EV 3 11 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Tests Conditions The FHP performance is influenced by the following parameters: 1. Steel temperature which is represented by the distance from the laying head 2. The diameter of the steel wires 3. The absorptivity and emissivity of the FHP surface (was tested by painting the FHP with black paint) 4. The overall heat transfer area of the FHP (The effect of the back panel) 12 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP testing FHP testing (unpainted) 13 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP testing FHP testing (unpainted at two inclination angles (25° and 12.5°) And different steel diameters 14 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP testing FHP testing (unpainted at two inclination angles (25° and 12.5°) And positions 15 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP testing FHP testing (unpainted at two inclination angles (25° and 12.5°) Laying Head 16 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

FHP testing FHP testing (Black painted) without and with a back panel 17 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Effect of the steel temperature on the amount of heat recovery • The steel temperature decreases as it moves far from the laying head 18 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Results Comparison • Black Paint Case • No Panel : Steel temperature 580 °C • With Panel: Steel Temperature 500 °C Heat recovery Comparison Steel: 580 °C 12 10 Steel:500 °C Heat recovery (kW) 8 6 4 2 0 Black Paint ( No Panel) Black Paint (With Panel) Experimental (Factory) Theoretical 19 Brunel University London

Experimental Results • FHP Black painted • Steel Temperature 500 °C • The Fluctuation is due to the intermittence of the steel production process 100 Bottom Collector 1 Surface temperature Bottom Collector 90 Bottom Collector 2 80 Adiabatic 1 Temperature (°C) 70 Adiabatic 2 60 Adiabatic 3 Adiabatic 50 Water Inlet Water Inlet & Outlet 40 Water Outlet 30 0 50 100 150 200 250 300 350 400 Average Surface Temperature Time (s) 20 Brunel University London

Test Results 29 March 2019 • FHP Black painted • Steel Temperature 500 °C • The Fluctuation is due to the intermittence of the steel production process Heat Recovery 14 12 Experimental Heat recovery (kW) 10 Theoretical 8 6 4 2 0 0 50 100 150 200 250 300 350 400 Time (sec) Experimental heat recovered Theoretical prediction 21 Brunel University London Presentation Title

Summary 29 March 2019 • A design of Radiative Flat Heat Pipe heat exchanger was presented • Results of the validation in factory were presented • The heat recovery is significantly influenced by the temperature and the diameter of the steel • The black coating of the FHP surface increases the amount of heat recovery 22 Brunel University London Experimental investigation on a radiative heat pipe heat exchanger in steel industry

Acknowledgements This project has received funding from the European Union Horizon 2020 research and innovation programme under grant agreement No 680599 Brunel University London

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