The Point-By-Point Irradiance Method Applied to Plant Systems Based on the Phytometric System

Since the phytometric system, the new system of plant-based radiation measurement, allows for the expression of radiation measurement in terms of the standard radiation measures of flux, irradiance, exitance, intensity and radiance, one of its immediate advantages is that it makes possible the direct use of the equations of point radiation for plant-lighting applications, including those for bioregeneratve space advanced life support. The objectives of this study were: (1) to use directly the equations of point radiation for plant-lighting applications using the phytometric system; (2) to express the spatial distribution of a luminaire’s luminous intensity in candela into phytometric intensity in phytoW sr⁻¹, enabling luminaire manufacturers to help architects, lighting engineers, lighting designers and plant growers in correctly evaluating the performance of their luminaires for plant-lighting applications, as opposed to visual applications for humans; and (3) to provide examples of calculations for the application of the equations of point radiation for the horizontal and vertical planes in plant growing structures.