Introduction to Infrared heating principles

2. What is Infrared ?

3. How to heat an object ? Physical possibilities: 1. Conduction 2. Convection 3. Radiation

4. Conduction Heat transfer is made through direct contact from the source to the object (receiver). E.g.: boiled eggs in hot water, coffee pot on a warming plate Source (s) Ts: high Receiver (r) Tr: rises

5. Convection Heat transfer is carried out via flow of liquid or gas, primary heated by a source. E.g. central domestic heating, household oven Tt: low Tt: low Tt: high Source (s) Ts: high Receiver (r) Tr: rises Transfert medium (t)

6. Radiation Heat transfer occurs via radiation emitted from source at high temperature. Surrounding objects in this area are absorbing the radiation. E.g. the sun, infrared lamps Source (s) Ts: high Receiver (r) Tr: rises

10. The infrared wave band UV radiation Visible radiation IR-A IR-B IR-C 800 nm 0.8  380 nm 0.38  1 400 nm 1.4  3 000 nm 3  10 000 nm 10  3620K 2070K 965 K 290 K Short- Medium- Long-waves

13. Examples of short wave infrared emitters Incandescent tungsten lamp Halogen lamp

14. Examples of long wave emitters Metal resistance Ceramic resistance

15. Spectral power distribution of different IR emitters

16. Comparison of short, medium, long wave emitters 0.05% 10% 30% 60% 1.5% 20% 50% 28.5% 6% 46% 44% 4% Visible IR-A IR-B IR-C 4.0 µm 2.2 µm 1.2 µm Emission peak 5 mn 30 sec 1 sec Swith ON/OFF time (90% efficiency) 40 % 60 % 92 % Radiant efficiency Fe-Cr-Alalloy coil in closed steel tube Fe-Cr-Alalloy coil in quartz tube Tungsten coil in sealed quartz tube Material Resistance Quartz emitter Halogen lamp Emitter Long wave Medium wave Short wave Infrared waves

17. Comparison of short, medium, long wave emitters The more the source is hot, the more it emits in the short wavelength. When the colour temperature decreases, the maximum of emission moves towards longer wavelengths Low Medium High Color sensitivity Low Medium High Brightness Hardly not relevant Possible Good focusing recommended Focusing with reflectors Yes, very high Yes No Air draughts sensitivity Convection Radiation and convection Radiation Heating principle 800 K 1 300 K 2 450 K Color Temperature Long-wave Medium-wave Short-wave Infrared-waves

19. Benefits of short wave infrared lamps Benefits Features Instant heat > 90% emission within 1 second Clean No emission by products, no pollution Safe Quartz envelope, heat shock resistant Economical > 85% of consumed energy transmitted into infrared heat Fully dimmable Fully controllable accurately (0 to 100%) Possibility to put On/Off switches do not affect life time of the lamps people sensor Low maintenance Long life: 5 000 hours Heat can be focused Same optical properties as light, can be directed by reflectors Compact heater Compact heat source, narrow diameter of lamps

21. InfraRed halogen lamp Quartz tube Cap base Cable Inert gas + halogen Tungsten filament Exhaust tube Filling tip

23. The halogen cycle: Quartz tube Tungsten filament Halogen molecules Cold part >250°C Hot part > 1000°C

24. Tungsten-halide molecule formation Tungsten molecule evaporation Tungsten molecule dissociation The Halogen cycle The halogen cycle 1 4 3 2

29. Response time

30. Comfort Heating Professional & Patio

34. HeLeN: Infrared Halogen Lamp Unique Philips solution with high heat efficiency and low glare emission

35. HeLeN : More compact, better colour rendering. Ruby sleeve lamp HeLeN lamp

37. HeLeN : Best Spectral distribution with low glare level