| A prototype light collection and transmission device was developed to evaluate the potential of irradiating horticultural crops grown in an opaque, insulated structure with sunlight supplied via fiber optic cables. The objective of the research was to develop an energy efficient method for producing horticultural crops in Northern Canada.;Direct solar radiation, photon flux, spectral photon flux, and temperature were measured in order to evaluate the prototype device. The prototype device was operated under clear and sunny, partly overcast, and overcast sky conditions. The results indicated that the concept of transmitting photosynthetic and photomorphogenic radiation from the sun via fiber optic cables was viable. The prototype device accurately tracked the sun under a variety of sky conditions and produced a photon flux of 130 $mu$mol/s/m$sp2$ (400-700 nm) near the bottom of the growth cabinet when the direct solar radiation was 800 W/m$sp2$ (300-2500 nm) outside. The efficiency of the prototype device for collecting and transmitting daylight in the blue and red regions of the spectrum was 5% and 30%, respectively. The overall collection and transmission efficiency for photosynthetically active radiation was 19.2%. The infra-red component of the transmitted irradiation was minimal. (Abstract shortened by UMI.). |
