Fluid distribution and investigation of heat transfer on a new type of solar flat-plate collector – STAR Global Conference – Vienna 2014 M.Eng. Pascal Leibbrandt Institut für Regenerative Energietechnik Fachhochschule Nordhausen – University of Applied Sciences STAR Global Conference – Vienna 2014 1
About us ... The institute - founded in 2008 - 20 employees (professors, academical and research staff) Courses of study - renewable energy technology (B.Eng.) - economics engineering for sustainable technologies (B.Eng.) - systems engineering (M.Eng.) Research - photovoltaic systems - flow machines - rotor blade optimization - circular processes (ORC) with membrane engine - hydrogen combustion - cooling of electric motors - mixed pellets - thermal energy storage optimization - energy concepts for special constructions/buildings - collector development Laboratories - photovoltaic - power and operating machines - electrical energy systems - biomass, new energy sources - thermal energy systems STAR Global Conference – Vienna 2014 2
Agenda The Project First Investigations Heat Transfer Fluid Flow Structural Analysis Outlook STAR Global Conference – Vienna 2014 3
The Project Motivation ● Stagnation of the thermal collectors market for since 2008 ● Necessary to reduce system cost ● Metallic absorber (copper, copper / aluminum, continuous casting) have largest costs in materials and manufacturing technology Objectives ● Collector redevelopment of insulating glass in the absorber and the frame area ● Target height < 50mm ● Reduced material and production costs ● Simpler manufacturing and assembly ● Same performance as standard flat-plate collector STAR Global Conference – Vienna 2014 4
The Project Construction Coating (11) – anti reflex Frame (90) Coating (13) – anti reflex Glass (10) 2.4 Bonding (81) Gas (20) 15 Coating (31) – low emission Inlet Structure (43a) Glass (30) 2.4 ~ 50 Fluid (40) Fluid Structure (43) 10 Glass (50) Coating (53a) – high absorption 2.4 Inlet (41) Gas (60) Coating (53b) – low emission 15 Outlet (42) Glass (70) 2.4 Sealing (82) STAR Global Conference – Vienna 2014 5
Agenda The Project First Investigations Heat Transfer Fluid Flow Structural Analysis Outlook STAR Global Conference – Vienna 2014 6
Heat Transfer Problem s Top l Front Back ϕ Bottom STAR Global Conference – Vienna 2014 7
Heat Transfer Gas models Ideal Gas - expression of density as a function of temperature and pressure R = R U / M - specific gas constant ρ= p RT Real Gas - at high pressure and high temperature gas behavior deviates from ideal gas - ideal gas equation is specified: p is replaced by (p+a/v²) v is replaced by (v-b) - a is a measure of attractive forces - b is the co-volume of particles - a ,b = f ( R U ,T C , p C ) 2 )( v − b ) Van der Waals R u T =( p + a / v STAR Global Conference – Vienna 2014 8
Heat Transfer Experiment (Hollands) Pressure Vessel Tube Grid Heater Aluminium Foil Tube Grid Copper Plates (56x61x1cm) Air Layer Thermocouples Screws Frame Rollers Cold Water In Hot Water In STAR Global Conference – Vienna 2014 9
Heat Transfer Experiment Solution 7 6 5 4 Nu 3 2 1 + [ ( − 1 ] Nu BF = 1 + 1,44 ⋅ ( 1 − 1708 ⋅ ) [ 1 − p Ra ⋅ cos ϕ ] 5830 ) p 1 / 3 1,6 ( sin ( 1,8 ⋅ϕ)) Ra ⋅ cos ϕ 1708 Ra ⋅ cos ϕ STAR Global Conference – Vienna 2014 10
Heat Transfer CFD Model STAR Global Conference – Vienna 2014 11
Heat Transfer Mesh Trimmer PH + PLM-2 s s Name Trimmer PH + PLM PH + PLM-2 Models Trimmer Polyhedral Polyhedral Mesher + PLM Mesher + PLM Base Size 0,5 mm 0,5 mm 0,25 mm Cells 20.000 50.591 100.195 STAR Global Conference – Vienna 2014 12
Heat Transfer Scalar Scenes - Trimmer 50°C 70°C 30° 45° 60° STAR Global Conference – Vienna 2014 13
Heat Transfer Scalar Scenes - Polyhedral+PLM 50°C 50°C 50°C 70°C 70°C 70°C 30° 45° 60° STAR Global Conference – Vienna 2014 14
Heat Transfer Solution STAR Global Conference – Vienna 2014 15
Agenda The Project First Investigations Heat Transfer Fluid Flow Structural Analysis Outlook STAR Global Conference – Vienna 2014 16
Fluid Flow Problem Glass (30) Fluid (40) Glass (50) m' STAR Global Conference – Vienna 2014 17
Fluid Flow Problem 100 mm 1412 mm 100 mm Sym. 707 mm Velocity Inlet (V' = 10 … 80 l/m²/h, 20°C) 40 mm Wall (No-Slip, Adiabat) Top View Pressure Outlet (101325 Pa, 20°C) 1412 mm SSD u = √ 2 A f ∑ f ( u f −̄ u ) 707/2 mm Version 03 ∑ f A f (Ref) u u f ̄ 100 mm 1412 mm 100 mm u f =̄ u → SSD u = 0 707/2 mm Version 04 20 mm (Neg) u f =̄ u → SSD u > 0 STAR Global Conference – Vienna 2014 18
Fluid Flow Versions 100 mm 1412 mm 100 mm 100 mm 1412 mm 100 mm 707/2 mm 707/2 mm 5x40 mm 5x40 mm 50 mm 50 mm 50 mm 20 mm 20 mm Version 06 Version 06_10 s=10mm s=10mm 100 mm 1412 mm 100 mm 100 mm 1412 mm 100 mm 707/2 mm 707/2 mm 50 mm 5x40 mm 5x40 mm 50 mm 50 mm 20 mm 20 mm Version 07 Version 07_01 s=5mm s=5mm 100 mm 100 mm 1412 mm SSD u = √ 2 A f 707/2 mm ∑ f ( u f −̄ u ) 50 mm 30 mm 20 mm Version 08 ∑ f A f 5x40 mm s=5mm 100 mm 1412 mm 100 mm 707/2 mm 50 mm 20 mm Version 09 5x5 mm s=5mm STAR Global Conference – Vienna 2014 19
Fluid Flow Mesh Inlet Sym Sym Wall Wall Wall Boundary Layer (PLM) STAR Global Conference – Vienna 2014 20
Fluid Flow Solution V04 V06 V06_01 Position in mm STAR Global Conference – Vienna 2014 21
Fluid Flow Solution STAR Global Conference – Vienna 2014 22
Fluid Flow Solution SSD in m/s Pressure drop STAR Global Conference – Vienna 2014 23
Agenda The Project First Investigations Heat Transfer Fluid Flow Structural Analysis Outlook STAR Global Conference – Vienna 2014 24
Structural Analysis Problem Fixed Free Fixed Fixed V01 V02 Top=Free Top=Free Bottom=5bar Bottom=5bar Fixed Fixed Fixed Free Fixed Fixed Free Fixed V04 V03 Top=Free Top=Free Bottom=5bar Bottom=5bar 10x10 Fixed Free Fixed Fixed Fixed STAR Global Conference – Vienna 2014 25
Structural Analysis Solution STAR Global Conference – Vienna 2014 26
Structural Analysis Solution Variation of Pressure Variation of Thickness p = 1bar Pressure in Pa Pressure in Pa STAR Global Conference – Vienna 2014 27
Agenda The Project First Investigations Heat Transfer Fluid Flow Structural Analysis Outlook STAR Global Conference – Vienna 2014 28
Outlook Fluid Flow ● Optimization of In- and Outlet geometry ● Development of fluid-flow-structure regarding to heat transfer and pressure drop ● Connection port – inlet – fluid-flow-structure (3D simulations) ● Heat transfer in the gas layers (3D simulations) Radiation ● Disk assembly (distance, thickness) and functional coatings (AR, low-e, Absorption) ● Examination by means of ray tracing and CFD by using thermal loads Thermal Model ● Heat loss on edge seal and collector connectors ● Estimate thermal loads on glasses, sealants and adhesives Structure ● Optimization of edge bond and restraints ● Structural analysis of sandwich glasses (30) and (50) with fluid-flow-structure ● Reduction of glass mass Experiment STAR Global Conference – Vienna 2014 29
Pascal Leibbrandt, M.Eng. Institut für Regenerative Energietechnik Fachhochschule Nordhausen – University of Applied Sciences www.fh-nordhausen.de/inret.html Thank you for your attention STAR Global Conference – Vienna 2014 31
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