Evaluation and Enhanced Use of Light Emitting Diodes for Hydroponics

• 作者: Clarence W.DE SILVA Jayasanka RANAWEERA Siripala RANAWEERA
• 来源期刊: 仪器仪表学报:英文版
• 学科: 农学
• 关键词: HYDROPONICS Grow lights Light Emitting Diodes(LEDs) Photosynthesis Photosynthetic Active Radiation(PAR) Photosynthetic Photon Flux Density(PPFD) HPS(High Pressure Sodium) HID(High Intensity Discharge) Daily Light Integral(DLI) Quantum Sensor Digital Light Meter(Lux meter)
• 年，卷（期）: 2019,（3）
• 页码范围: 18-27
• 页数: 10页
• 分类号: S626

摘要

Hydroponic farming is a viable and economical farming method,which can produce safe and healthy greens and vegetables conveniently and at a relatively low cost.It is essential to provide supplemental lighting for crops grown in greenhouses to meet the daily light requirement,Daily Light Integral(DLI).The present paper investigates how effectively and efficiently LEDs can be used as a light source in hydroponics.It is important for a hydroponic grower to assess the requirement of photo synthetically active radiation(PAR)or the Photosynthetic Photon Flux Density(PPFD),in a greenhouse,and adjust the quality and quantity of supplemental lighting accordingly.A Quantum sensor(or PAR sensor)can measure PAR more accurately than a digital light meter,which measures the light intensity or illuminance in the SI unit Lux,but a PAR sensor is relatively expensive and normally not affordable by an ordinary farmer.Therefore,based on the present investigation and experimental results,a very simple way to convert light intensity measured with a Lux meter into PAR is proposed,using a simple conversion factor(41.75 according to the present work).This allows a small-scale hydroponic farmer to use a simple and inexpensive technique to assess the day to day DLI values of PAR in a greenhouse accurately using just an inexpensive light meter.The present paper also proposes a more efficient way of using LED light panels in a hydroponic system.By moving the LED light panels closer to the crop,LED light source can use a fewer number of LEDs to produce the same required daily light requirement and can increase the efficiency of the power usage to more than 80%.Specifically,the present work has determined that it is important to design more efficient vertically movable LED light panels with capabilities of switching individual LEDs on and off,for the use in greenhouses.This allows a user to control the number of LEDs that can be lit at a particular time,as required.By doing so it is possible to increase the efficiency of a LED lighting system