Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Effektivare kylsystem för kyl & och frysskåp Erik Björk, PhD student, KTH Björn Palm, Supervisor, KTH Per Wennerström, controller, Electrolux/RDE

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Background Black box Rule of thumb design Copy old designs Open box Design based on science (heat transfer, pressure drop and charge) Energy consumption Legislations Customers demand Reduced Energy consumption compressor evaporator cap. tube condenser

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden The plate evaporator (ER8893C) Aluminium, 660 x 490 mm Thickness 1.4 mm 1.35 kg White coated Tube length 6.22 m Hydraulic diameter 3.2 mm Total internal volume ml Accumulator volume 45.6 ml

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden The plate evaporator (ER8893C)

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden On-off cycling characteristics

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Charge distribution – experimental results

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Comparison theory - experimental results Evaporator Condenser

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Activation delayed by redistribution process

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Downward slope reduces activation time

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Accumulator delays activation

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Air side heat transfer – experimental results

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Refrigerant side heat transfer – experimental results Mass flow

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Refrigerant side pressure drop – experimental results

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Optimum pitch

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Fin efficiency for the whole evaporator ≈ 97,2%

Erik Björk, M.Sc. Dept. of Energy Technology Div. of Applied Thermodynamics and Refrigeration Royal Institute of Technology Sweden Increased pitch Distributed accumulator Downward sloping channels Small diameter at inlet – large at outlet Channels close to plate edges Conclusions improved evaporator design