SELECTION AND PLACEMENT OF GREENHOUSE LUMINAIRES FOR UNIFORMITY

Abstract

Design considerations regarding the effects of luminaire selection and layout on light level uniformity wereexamined in this study. Flux transfer computer simulations were utilized to determine the effect of luminaire selection andspacing on uniformity in the center, as well as near the perimeter, of a greenhouse. Two design parameters the spacing ratio(luminaire spacingto mounting height ratio divided by the spacing criterion) and the area ratio (greenhouse area perluminaire divided by spacing criterion squared times mounting height squared) were developed and investigated as possibleindicators of light level uniformity. Uniformity at the center of the greenhouse was found to be a function of the area ratioof the lighting design. This information can be used to determine the maximum allowable spacing to achieve a desireduniformity level at the center of the greenhouse. Staggered squarelayouts of luminaires do not give improved uniformityover regular square layouts, but staggered rectangular layouts were more uniform than regular rectangular layouts. Lightuniformity near the perimeter of a greenhouse improves as luminaires are added to the perimeter, with an optimum perimeterspacing depending on the mounting height and overall greenhouse spacing of the luminaires.