Energy distribution, light sources

Compare the so-called soft (i.e., widely distributed small sources) and hard (i.e., fewer very large sources) paths for the future provision of energy for light, heat, and power. 

One possibility for supplying household energy is to distribute electricity from central fuel cell-based power plants to houses in the surrounding area. However, it may become cheaper to store methanol in each plant and use it in the co-generation of heat and electricity.19 Such a scheme would also make possible advantages in the distribution of lighting in households via pipes from a central light source powered by fuel cells. This type of situation may provide an application for phosphoric acid cells. 

The spectral energy distribution of CIE light sources A and C is shown in Figure 6-2. CIE illuminant A is an incandescent light operated at 2854°K, and illuminant C is the same light modified by filters to result in a... 

Figure 6-2 Spectral Energy Distribution of Light Sources A and C, the CIE, and Relative Luminosity Function y for the CIE Standard Observer...

Light sources can be described by their spectral power or energy distribution. This simply plots the amount of light (relative power) as a function of wavelength. Figures 2.1-2.5 are examples of standard light sources (Billmeyer and Saltzman, 1981). 

For artificial light sources, two values are important the color temperature in degrees Kelvin and the relative spectral distribution of the light source S(k), where X shows that the radiant energy is dependent on wavelength. 

Hirt RC, Schmitt RG, Searle ND, Sullivan AP. Ultraviolet spectral energy distribution of natural sunlight and accelerated test light sources. J Opt Soc Am 1960 50(7) 706-713. 

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