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Proceedings Paper

Infrared imaging of LED lighting tubes and fluorescent tubes
Author(s): Sami Siikanen; Sini Kivi; Timo Kauppinen; Mikko Juuti
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Paper Abstract

The low energy efficiency of conventional light sources is mainly caused by generation of waste heat. We used infrared (IR) imaging in order to monitor the heating of both LED tube luminaires and ordinary T8 fluorescent tubes. The IR images showed clearly how the surface temperatures of the fluorescent tube ends quickly rose up to about +50...+70°C, whereas the highest surface temperatures seen on the LED tubes were only about +30...+40°C. The IR images demonstrated how the heat produced by the individual LED chips can be efficiently guided to the supporting structure in order to keep the LED emitters cool and hence maintain efficient operation. The consumed electrical power and produced illuminance were also recorded during 24 hour measurements. In order to assess the total luminous efficacy of the luminaires, separate luminous flux measurements were made in a large integrating sphere. The currently available LED tubes showed efficacies of up to 88 lm/W, whereas a standard "cool white" T8 fluorescent tube produced ca. 75 lm/W. Both lamp types gave ca. 110 - 130 lx right below the ceiling-mounted luminaire, but the LED tubes consume only 40 - 55% of the electric power compared to fluorescent tubes.

Paper Details

Date Published: 10 May 2011
PDF: 11 pages
Proc. SPIE 8013, Thermosense: Thermal Infrared Applications XXXIII, 80130J (10 May 2011); doi: 10.1117/12.883369
Show Author Affiliations
Sami Siikanen, VTT Technical Research Ctr. of Finland (Finland)
Sini Kivi, VTT Technical Research Ctr. of Finland (Finland)
Timo Kauppinen, VTT Technical Research Ctr. of Finland (Finland)
Mikko Juuti, VTT Technical Research Ctr. of Finland (Finland)


Published in SPIE Proceedings Vol. 8013:
Thermosense: Thermal Infrared Applications XXXIII
Morteza Safai; Jeff R. Brown, Editor(s)

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