scholarly journals A Supervisory Control Strategy for Improving Energy Efficiency of Artificial Lighting Systems in Greenhouses

Energies ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 202
Author(s):  
Gianluca Serale ◽  
Luca Gnoli ◽  
Emanuele Giraudo ◽  
Enrico Fabrizio

Artificial lighting systems are used in commercial greenhouses to ensure year-round yields. Current Light Emitting Diode (LED) technologies improved the system efficiency. Nevertheless, having artificial lighting systems extended for hectares with power densities over 50W/m2 causes energy and power demand of greenhouses to be really significant. The present paper introduces an innovative supervisory and predictive control strategy to optimize the energy performance of the artificial lights of greenhouses. The controller has been implemented in a multi-span plastic greenhouse located in North Italy. The proposed control strategy has been tested on a greenhouse of 1 hectare with a lighting system with a nominal power density of 50 Wm−2 requiring an overall power supply of 1 MW for a period of 80 days. The results have been compared with the data coming from another greenhouse of 1 hectare in the same conditions implementing a state-of-the-art strategy for artificial lighting control. Results outlines that potential 19.4% cost savings are achievable. Moreover, the algorithm can be used to transform the greenhouse in a viable source of energy flexibility for grid reliability.

Energies ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5994
Author(s):  
Beata Brzychczyk ◽  
Tomasz Hebda ◽  
Norbert Pedryc

Microalgae are a practical source of biological compounds for biodiesel production. This study examined the influence of three different light-emitting diode (LED) systems on the biomass production of green algae Chlorella vulgaris BA0002a. The cultivation was carried out in a photobioreactor illuminated from the bottom with a single side light jacket (PBR I), in a photobioreactor illuminated from the bottom with a double side light jacket (PBR II) and in a photobioreactor illuminated only from the top (PBR III). Research has shown that the intensification of algae cell production and growth depends on the light distribution and exposure time of a single cell to radiation. In the experiment, the highest growth of algae cells was obtained in the photobioreactor with double jacket and lower light panel. The lowest cell growth was observed in the photobioreactor illuminated only from above. For cultures raised in the PBR I and PBR II photobioreactors, increased oxygen production was observed, which was directly related to the increased production of biomass, which in turn was dependent on the increased amount of radiant energy.


2013 ◽  
Vol 753-755 ◽  
pp. 2637-2640
Author(s):  
Bang Cheng Zhang ◽  
Hua Zhen Wang ◽  
Yan Qing Jiang ◽  
Yan Juan Hu

In order to meet the requirements of high stability, high vibration resistance, energy saving and environmental protection and long service life for the railway vehicle car lighting system, this paper designed a LED (Light Emitting Diode) lighting control system suitable for railway vehicles car. Using IPC for the principal computer, microcontroller for the subordinate computer, CAN bus as the communication network. Multiple brightness sensor collect the brightness information of car environment. According to the characteristics that the LED is suitable for high frequency switch power, using PWM technology, the current though the LED light can be control. ATmega16 microcontroller as the control core can automatically to adjust the brightness of the car according to the change of external environment, it ensured that the LED light emitting uniform and stable so that this kind of control system has very high application value.


2019 ◽  
Vol 15 (28) ◽  
Author(s):  
Diego Julián Rodríguez Patarroyo ◽  
Iván Felipe Cely Garzón ◽  
Cristhian Alexander Letrado Forero

Introduction: This Literature Review article is the result of a research on the current situation of smart public lighting systems with light-emitting diode (LED) technology in cities around the world. Problem: How convenient is it to use smart public lighting system with LED luminaires? Objective: To review the context of smart public lighting with LED technology. Methodology: Within this project, a lit review was conducted with more than 50 academic articles found in different databases such as: IEEE Xplore, Scopus, ScienceDirect etc. The selection criteria of the information followed the revision of articles from 2006 to 2018, and also, took into account their installation and performance in different cities and places of the world. Furthermore, articles on polluting and inefficient technologies were excluded. Conclusion: Considering the current context in which LED smart public lighting is, it is more likely to be implemented in the future. Results: Smart LED street lighting systems are more efficient in energy use, leads to savings in costs in medium terms, and finally, present a lower environmental impact compared to conventional lighting systems. Limitations: The review focuses on energy efficiency and economic aspects, not on social aspects. Originality: Smart LED public lighting systems have been researched within the economic and energy efficiency context.


2021 ◽  
Vol 13 (4) ◽  
pp. 1985
Author(s):  
Musa Al Murad ◽  
Kaukab Razi ◽  
Byoung Ryong Jeong ◽  
Prakash Muthu Arjuna Samy ◽  
Sowbiya Muneer

A reduction in crop productivity in cultivable land and challenging environmental factors have directed advancement in indoor cultivation systems, such that the yield parameters are higher in outdoor cultivation systems. In wake of this situation, light emitting diode (LED) lighting has proved to be promising in the field of agricultural lighting. Properties such as energy efficiency, long lifetime, photon flux efficacy and flexibility in application make LEDs better suited for future agricultural lighting systems over traditional lighting systems. Different LED spectrums have varied effects on the morphogenesis and photosynthetic responses in plants. LEDs have a profound effect on plant growth and development and also control key physiological processes such as phototropism, the immigration of chloroplasts, day/night period control and the opening/closing of stomata. Moreover, the synthesis of bioactive compounds and antioxidants on exposure to LED spectrum also provides information on the possible regulation of antioxidative defense genes to protect the cells from oxidative damage. Similarly, LEDs are also seen to escalate the nutrient metabolism in plants and flower initiation, thus improving the quality of the crops as well. However, the complete management of the irradiance and wavelength is the key to maximize the economic efficacy of crop production, quality, and the nutrition potential of plants grown in controlled environments. This review aims to summarize the various advancements made in the area of LED technology in agriculture, focusing on key processes such as morphological changes, photosynthetic activity, nutrient metabolism, antioxidant capacity and flowering in plants. Emphasis is also made on the variation in activities of different LED spectra between different plant species. In addition, research gaps and future perspectives are also discussed of this emerging multidisciplinary field of research and its development.


Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 960
Author(s):  
Jenny Manuela Tabbert ◽  
Hartwig Schulz ◽  
Andrea Krähmer

A light-emitting diode (LED) system covering plant-receptive wavebands from ultraviolet to far-red radiation (360 to 760 nm, “white” light spectrum) was investigated for greenhouse productions of Thymus vulgaris L. Biomass yields and amounts of terpenoids were examined, and the lights’ productivity and electrical efficiency were determined. All results were compared to two conventionally used light fixture types (high-pressure sodium lamps (HPS) and fluorescent lights (FL)) under naturally low irradiation conditions during fall and winter in Berlin, Germany. Under LED, development of Thymus vulgaris L. was highly accelerated resulting in distinct fresh yield increases per square meter by 43% and 82.4% compared to HPS and FL, respectively. Dry yields per square meter also increased by 43.1% and 88.6% under LED compared to the HPS and FL lighting systems. While composition of terpenoids remained unaffected, their quantity per gram of leaf dry matter significantly increased under LED and HPS as compared to FL. Further, the power consumption calculations revealed energy savings of 31.3% and 20.1% for LED and FL, respectively, compared to HPS. In conclusion, the implementation of a broad-spectrum LED system has tremendous potential for increasing quantity and quality of Thymus vulgaris L. during naturally insufficient light conditions while significantly reducing energy consumption.


2021 ◽  
pp. 002199832110595
Author(s):  
Weontae Oh ◽  
Jong-Seong Bae ◽  
Hyoung-Seok Moon

The microstructural change of graphite was studied after ultrasonic treatment of the graphite. When the graphite solution was treated with varying ultrasonic power and time, the microstructure changed gradually, and accordingly, the thermal conductivity characteristics of the composite containing the as-treated graphite was also different with each other. Thermal conductivity showed the best result in the silicone composite containing graphite prepared under the optimum condition of ultrasonic treatment, and the thermal conductivity of the composite improved proportionally along with the particle size of graphite. When the silicone composite was prepared by using a mixture of inorganic oxides and graphite rather than graphite alone, the thermal conductivity of the silicone composite was further increased. A silicone composite containing graphite was used for LED (light emitting diode) lighting system as a thermal interface material (TIM), and the temperature elevation due to heat generated, while the lighting was actually operated, was analyzed.


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Salah M Alabani

This paper studies the manner of energy consumption in Libyan street lighting systems and general road section. It also suggests proposal system with two cases of operation for an attempt to apply the energy saving program by adopting an optimum method in order to decrease the demand of energy in this section and to reduce the use of uneconomic equipment.The proposal system in this paper introduces the Light Emitting Diode (LED) street lighting technology to be used instead of traditional luminaries High Pressure Sodium (HPS). The proposed system is divided into two cases. The first case discusses the replacement of traditional luminaries (HPS) with energy saving luminaries (LED), while second case explains how integrating control node (dynamic dimmer) into LED in order to dim output lighting in streets will save more energy.This study reaches a result that a significant amount of energy of %47 (about 1092.23 GWh/year) of total energy consumed in street lighting sector could be saved if first case is applied. Moreover, it suggests that more energy of %58 (about 1380.02 GWh/year) of total energy consumed in the same sector cloud be saved if the second case is adopted.


Author(s):  
Paolo Visconti ◽  
Daniele Romanello ◽  
Giovanni Zizzari ◽  
Vito Ventura ◽  
Giorgio Cavalera

This work presents an electronic board for driving and control of High Intensity Discharge (HID) lamps and Light Emitting Diode (LED) lamps. The proposed electronic board is able to drive HID or LED lamps by means of a reconfigurable output. This feature allows using the ballast in lighting systems that currently use traditional discharge lamps, as well as keeping the same ballast when discharge lamps are replaced by LED modules in the near future, when LED street lighting systems will be more affordable. Additionally, since the lighting system is designed to be used in rural areas where there is no public electricity, each lighting point incorporates a system to convert solar energy into continuous voltage by means of photovoltaic panels. In this work, energy saving issues are taken into account.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 489
Author(s):  
Carmen Calama-González ◽  
Ángel León-Rodríguez ◽  
Rafael Suárez

One of the main retrofitting strategies in warm climates is the reduction of the effects of solar radiation. Cooling loads, and in turn, cooling consumption, can be reduced through the implementation of reflective materials such as solar control films. However, these devices may also negatively affect daylight illuminance conditions and the electric consumption of artificial lighting systems. In a hospital building, it is crucial to meet daylighting requirements as well as indoor illuminance levels and visibility from the inside, as these have a significant impact on health outcomes. The aim of this paper is to evaluate the influence on natural illuminance conditions of a solar control film installed on the windows of a public hospital building in a Mediterranean climate. To this end, a hospital room, with and without solar film, was monitored for a whole year. A descriptive statistical analysis was conducted on the use of artificial lighting, illuminance levels and rolling shutter aperture levels, as well as an analysis of natural illuminance and electric consumption of the artificial lighting system. The addition of a solar control film to the external surface of the window, in combination with the user-controlled rolling shutter aperture levels, has reduced the electric consumption of the artificial lighting system by 12.2%. Likewise, the solar control film has increased the percentage of annual hours with natural illuminance levels by 100–300 lux.


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