Energy-Use-Efficiency Differences Between LED Supplemental Lights under Nutrient Film Technique (NFT) and Constant Flood Table (CFT) Systems- Alex Miller, Krishna Nemali, Petrus Langenhoven


Using energy efficient light emitting diodes (LED) and heated nutrient solution (21°C) (HNS) in suboptimal greenhouse air temperatures (16°C), electrical energy use efficiency (EUE) (g·KWh-1) can be optimized to reduce production costs. Our objective was to compare EUE differences between nutrient film technique (NFT) and constant flood table (CFT) systems under LED lighting treatments with different spectrums and using HNS. Eight varieties of lettuce were grown in two production systems (NFT and CFT) under two nighttime SL treatments (White and Purple) with HNS (21°C) in a greenhouse ambient air temperature of 16/10°C (day/night). We found that regardless of variety, EUE was higher in CFT compared to NFT and the difference between CFT and NFT was higher under purple than white LED’s. In conclusion, research indicates that maximum EUE in lettuce production could be achieved in a CFT system using HNS and Purple nighttime SL.


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    1:00 pm - 3:00 pm
    Room(s): Atrium