ISHS Acta Horticulturae 440: International Symposium on Plant Production in Closed Ecosystems
SIMULATION OF LIGHT ENVIRONMENT WITH FLUORESCENT LAMPS AND DESIGN OF A MOVABLE LIGHT MOUNTING FIXTURE IN A GROWING ROOM |
| Authors: | W. Fang, R.C. Jao |
| Keywords: | fluorescent lamps, light environment, movable light mounting fixture, spectral distribution, spatial distribution |
| Abstract:
Spectral distribution of 18 new fluorescent lamps was measured using spectroradiometer. The wavelength-specific data of lamps was transformed into cumulative distributions that were then formulated using regression technique. The 18 high order nonlinear equations derived can be of great use for the further study. For example, the spectral bin data of any waveband among 300 to 1100 nm can be derived. Ratio of amount of photons within particular wavebands such as red vs. far-red (R/FR) or blue vs. red (B/R) for all lamps can be calculated. Light conversion factors among photometric, quantum and radiometric units can be derived. The computerization of spectral data of 18 lamps enables the analysis of the performance of combine-lamps. With a given luminaries' combination and arrangement, the spectral distribution, the spatial illuminance level, PPFD level and uniformity over a specified growing area can be calculated. A software was developed for this purpose. In order to improve the uniformity on bench in a growing room, reflecting surfaces were used and a movable light mounting fixture with downward and vertical sideward lighting capability was developed. The benefits of the movable light mounting fixture are: (1) spatial uniformity on bench is much better than any fixed lighting fixtures, (2) number of layers per bench can be increased due to the shorter mounting height, i.e., higher space utilization, (3) the smaller distance also leads to more light, which leads to a less requirement for the number of lamps, (4) number of tube lamps can be further reduced due to the utilization of vertical sideward lighting and reflecting surfaces, (5) the higher space utilization and less lamps lead to less cost and electricity fee. | |
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