Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®1 The Future of Lighting Fixture Design LED Thermal Management Cavendish Conference Centre, London – Welcome to

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®2 The majority of problems in a LED lighting solution are caused by poor thermal management. The fact is that LED heat dissipation must primarily utilize conduction and convection means rather than radiation. Abstract

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®3 3 LED junction temperatures are limited and hence heat management cannot solely depend upon radiant waste heat dissipation anymore. In fact, radiation is negligible. Heat Management requires a SYSTEM approach This is a paradigm shift, lighting designers must recognize when moving to LEDs Abstract !

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®4 4  Different heat dissipation mechanism in LED system, from conventional light sources  High Power LED Light Engines dissipating more heat and requiring better cooling solutions  Thermal management ensuring customers staying at the forefront of the lighting revolution  Lighting fixtures undergoing the most radical redesign in a century Thermal challenges Abstract

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®5 Proper control of Tj critical and key LED die Tj Case Tc Waste Heat Disposal Inside LED Module Main means = Conduction. → → → → External Main means = Convection. LED Module Manufacturer OEM Lighting Designers The Challenge Junction Temp (Tj) is monitored via Case Temp (Tc) as Junction Temp cannot be measured

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®6 Means Cooling options for LEDs range from natural convection into air, passive or active to liquid cooling meansCooling options for LEDs range from natural convection into air, passive or active to liquid cooling means Air cooling with conventional heat sinks, fans and/or advanced two-phase technology is widely accepted by the market place and will remain the primary choice.Air cooling with conventional heat sinks, fans and/or advanced two-phase technology is widely accepted by the market place and will remain the primary choice. The market reluctantly go for liquid cooling, such as cold plates, due to various issues associated with water near electronics and pumps.The market reluctantly go for liquid cooling, such as cold plates, due to various issues associated with water near electronics and pumps. Cooling Options

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®7 Means Passive AL heatsinks CU heatsinks Advanced passive cooling methods Active Fans assisted heat sink (forced convection) Membrane assisted heat sink (forced convection) Cold Plates Water pumped underneath heatsource (for special applications and not covered here)

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®8 Passive AL or CU heatsinks (natural convection) MaterialThermal Conductivity (W/mK) Aluminum (99.5) ~ 240 Aluminum (Alloys) ~120 - ~180 Copper~ 400 ~ 45° There is little heat transfer in horizontal direction Heat travels downward in a ~ 45° angle to the surface. Therefore increasing the surface area with a larger heat spreader will not significantly improve the thermal design. die !

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®9 ¹ Conventional passive coolers are confined to handling low power LED applications due to the thermal limitations of the materials used AL or CU heatsinks (natural convection) Passive

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®10 Fan or Membrane assisted sinks Fan or membrane assisted heat sinks increase the air flow thus significantly improving the convection properties of the heat sink Results in much smaller area required to achieve the same thermal resistance. SUNON LA A99DN - Cooling module; LED 40 WActive

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®11 Active Fan or Membrane assisted sinks ² Fans can provide a much higher airflow than membranes thus can reach lower thermal resistance requirements

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®12 Advance Passive The Passive Revolution 2-Phase-systems employ evaporative cooling technology to transfer thermal energy from one point to another by evaporation and condensation of a working fluid embedded in a vacuum tight vessel. Heat Input Evaporator Heat Output Capillary wick Vapour Flow Container Q Liquid Flow CondenserAdiabatic section

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®13 Advance Passive The Passive Revolution Based on this physical principle FrigoDynamics® has developed a patented platform of advanced passive HPK-Fin™ 2-Phase heat exchanger solutions. They are extremely effective, light weight, eco friendly, 100% recyclable and easy to apply cooling solutions. They pose neither cost nor risk of operation, and thus are the most cost effective Solid State LED cooling solutions available. They are particularly well suited to cooling high power LEDs with a small heat source foot print due to being able to efficiently spread heat across all areas of the 2-Phase heat exchanger regardless of heat source size and meeting challenging ΔT requirements. MaterialThermal Conductivity (W/mK) Aluminum (99.5) ~ 240 Aluminum (Alloys) ~120 - ~180 Copper~ Phase device~50,000 - ~200,000

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®14 Advance Passive The LED market is highly demanding on eco friendly solutions. Reliability, longevity and cost of ownership are key. Passive cooling means are primarily considered for LEDs and modules. The Passive Revolution Many commercial and industrial LED applications are demanding thermal needs that conventional passive cast or extruded heat sinks can no longer meet, due to the thermal limitations of the materials used. Many commercial and industrial LED applications are demanding thermal needs that conventional passive cast or extruded heat sinks can no longer meet, due to the thermal limitations of the materials used. Substantial size and weight of heat sinks, along with significant and substantial performance degradation, when changing orientation, signifies that things must change. Substantial size and weight of heat sinks, along with significant and substantial performance degradation, when changing orientation, signifies that things must change. Active cooling means are not suitable for your applications Active cooling means are not suitable for your applications Advanced passive cooling solutions can help when …..

Dr Song Lin – 30. May 2012 Advance Passive The Passive Revolution

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®16 Pros & Cons Active Solutions Noise and Sound Echos and Vibrations Proactively attract debris/dust Increasing sound levels Reduced performance Reduced lifetime CO ₂ Emissions, not ecological friendly Wiring, Controllers Cost of operation Specs typically allow for ~ 10% failure rate Severe longevity concerns Everything whichs moves will stop moving High risk of operation Potential replacement cost Unpredictable cost of ownership. More compact form factor Lower weight Lower Tr case to ambient Resource considerate (less material usage) ProsCons Sunon LED 40 W Nuventix Par25 – 32W

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®17 Pros & Cons Passive Heat Sink Solutions Bigger form factor than active Higher Weight Performance limitations Requires more material per W cooling Orientation sensitive No risk of operation No cost of operation Highly reliable No performance degradation Lot of variations possible No CO ₂ Emissions 0 dB operation ProsCons

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®18 Pros & Cons Passive 2-Phase HX Solutions No cost of operation No risk of operation, no friction Highly reliable, nothing moving No performance degradation No CO ₂ Emissions Resource saving Compact form factors Very light weight 0 dB operation Application specifc scaleable Cools all lumen values Lot of variations possible Meets Low ΔT requirements Orientation insensitive ProsCons No functional or operational cons Requires volume

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®19 Pros & Cons Summary in Brief ³ Required Tr case to ambient at Pth levels of 60W + at ΔT 30K (Tr c-a < 0.5 K/W)

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®20 Process Thermal Design Process 1.Determine aesthetic goals 2.Determine envelope (dimensional) contraints 3.Determine operation orientation(s) 4.Calculate thermal power loss of chosen LED 5.Determine max T case at max T ambient 6.Calculate thermal resistance from case to ambient as required. Select cooling means based on the above If an extruded or cast AL heat sink does not meet the thermal requirements, or is too big and/or too heavy and you want to avoid active means or active means are not permitted or desired, FrigoDynamics® is here to help. !

Dr Song Lin – 30. May 2012Copyright © 2012 FrigoDynamics®21 Thank You for your attention