Efficiency and efficacy of incandescent lamps

Abstract

Planck’s radiation formula is used to estimate the dimensionless efficiency of incandescent lamps as a function of filament temperature, with typical values of 2%–13%. Similarly, using the known spectral luminous efficiency of the eye, the efficacy of incandescent light bulbs is estimated as a function of temperature, showing values of 8–24 L W−1 for bulbs of 10–1000 W. The efficiency and efficacy results compare favorably with published data and enable estimation of the filament temperature for any lamp of known efficacy.

Lifetimes of Incandescent Bulbs

“…It has also prompted many articles that explore various aspects of incandescent lamps. [2][3][4][5][6][7][8][9] An interesting topic discussed by Leff concerns lifetime statistics of bulbs by drawing analogy from radioactive decay of nuclei. Leff obtained an empirical formula for the survival probability of commercial bulbs and also hinted at the approximate equality of the half-life, the average life, and the most probable life of the same.…”

The inclusion of source effect consideration in irradiance determination

“…(5) the emissivity values of lamp filament eðk; TÞ corresponding to the lamp driving currents or temperatures were derived from the published emissivity values [19,20]. The emissivity values given in the work [19,20] include the emissivity of tungsten as a function of wavelength and temperature in the region of 200-2000 nm and 1000-3000 K. Since the temperature values in our measurements corresponding to lamp driving currents lie in this temperature range, the emissivity values at 1800 K, 2000 K and 2200 K temperature points, which are closed to our measurement temperatures, were chosen to use in Eq. (5).…”

Modelling Miniature Incandescent Light Bulbs for Thermal Infrared ‘THz Torch’ Applications

“…As a result, S 21 and S 11 can then be calculated using (13) and (14). The overall power transmittance and reflectance are determined from |S 21 | 2 and |S 11 | 2 , respectively, while power absorptance is given by 1 −|S 11 | 2 −|S 21 | 2 .…”

“…Since then, a great deal of research has been undertaken to investigate the optical, electrical, chemical and thermal properties of tungsten materials; as well as the characteristics of tungsten light bulbs [8][9][10][11][12][13][14]. More recently, due to advances in materials and nanotechnology, higher luminous efficiency has been achieved by improving the emissivity of the filaments or reducing the infrared radiation contribution to the blackbody spectrum without reducing the radiation at visible wavelengths [15][16][17].…”