scholarly journals Assessment of Lighting Uniformity as a Factor of Energy Efficiency in Greenhouse Horticulture

2021 ◽  
Vol 31 (3) ◽  
pp. 470-486
Author(s):  
Sergey A. Rakutko ◽  
Elena N. Rakutko

Introduction. Greenhouse lighting systems are an integral part of the system for growing plants in cultivation facilities with an artificial microclimate. The uniformity of light distribution over the growing area is important to increase energy efficiency and improve plant quality, among other requirements. The aim of the work is to consider the mathematical apparatus for describing the distribution of light over the surface and to justify the choice of ways to characterize the degree of lighting uniformity. Materials and Methods. The basic concepts of the subject area such as lighting, lighting body, horizontal lighting curve, luminous intensity curve are considered in terms of theoretical photometry. To assess the energy and ecological friendliness of the greenhouse horticulture, the lighting efficiency factor was used. Various methods for determining the average lighting value are presented. The formulas for the uniformity coefficients are presented. Experimental verification was carried out on a horizontal plane simulating a surface for growing plants. A luminary with a round-symmetric light distribution was used. Results. It has been found that the lighting values calculated by the proposed method at various points of the illuminated surface correspond to the experimentally obtained values. It has been shown that the coefficient taking into account the pattern of lighting distribution over all points of the surface carries a lot of information about the uniformity. A frequency graph for the lighting distribution value has been constructed and its practical applicability has been substantiated. The relationship between the lighting efficiency and uniformity of the generated lighting has been revealed. With reduced suspension height of the luminary, it is possible to increase significantly the lighting efficiency factor, however, the lighting uniformity deteriorates sharply. Discussion and Conclusion. There is proposed a method for assessing the energy efficiency by the lighting efficiency factor, which determines the proportion of the useful lighting falling on the surface in the total lighting generated by light sources. It is suggested that this indicator can characterize the ecological quality of photoculture, since it has been established its relationship with the uniformity of the created lighting, the impact of which on photoculture is described in the literature.

Heritage ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 188-197
Author(s):  
Dorukalp Durmus

Light causes damage when it is absorbed by sensitive artwork, such as oil paintings. However, light is needed to initiate vision and display artwork. The dilemma between visibility and damage, coupled with the inverse relationship between color quality and energy efficiency, poses a challenge for curators, conservators, and lighting designers in identifying optimal light sources. Multi-primary LEDs can provide great flexibility in terms of color quality, damage reduction, and energy efficiency for artwork illumination. However, there are no established metrics that quantify the output variability or highlight the trade-offs between different metrics. Here, various metrics related to museum lighting (damage, the color quality of paintings, illuminance, luminous efficacy of radiation) are analyzed using a voxelated 3-D volume. The continuous data in each dimension of the 3-D volume are converted to discrete data by identifying a significant minimum value (unit voxel). Resulting discretized 3-D volumes display the trade-offs between selected measures. It is possible to quantify the volume of the graph by summing unique voxels, which enables comparison of the performance of different light sources. The proposed representation model can be used for individual pigments or paintings with numerous pigments. The proposed method can be the foundation of a damage appearance model (DAM).


Author(s):  
Rade M. Ciric ◽  
Sasa N. Mandic

AbstractThe Republic of Serbia must make significant efforts to promote and exploit renewable energy sources and increase energy efficiency in all energy sectors to ensure energy security and economic competitiveness, reduce the negative impact on the environment from energy production and use, and contribute to global efforts to reduce greenhouse gases. Within the paper several issues of integration of recently realized CHP plant are introduced and discussed. Firstly, the legal and energy policy issues in the Republic of Serbia regarding connecting CHP to the grid are presented. The challenges and technical solutions for CHP connection to the grid, as well as power quality issues and the role of the CHP plant during the restoration of power supply during the maintenance of the substation and unplanned loss of high voltage supply, are presented and discussed. Finally, the impact of prospective massive integration of CHP on the energy balance and CO2 emission reduction in the province of Vojvodina in Serbia is investigated and discussed. Since it is the first CHP plant realized in Serbia, it is crucial that experience be shared to all potential stakeholders in the future energy efficiency projects.


2021 ◽  
Vol 2021 (29) ◽  
pp. 136-140
Author(s):  
Dorukalp Durmus

The quality of building electric lighting systems can be assessed using color rendition metrics. However, color rendition metrics are limited in quantifying tunable solid-state light sources, since tunable lighting systems can generate a vast number of different white light spectra, providing flexibility in terms of color quality and energy efficiency. Previous research suggests that color rendition is multi-dimensional in nature, and it cannot be simplified to a single number. Color shifts under a test light source in comparison to a reference illuminant, changes in color gamut, and color discrimination are important dimensions of the quality of electric light sources, which are not captured by a single-numbered metric. To address the challenges in color rendition characterization of modern solid-state light sources, the development of a multi-dimensional color rendition space is proposed. The proposed continuous measure can quantify the change in color rendition ability of tunable solid-state light devices with caveats. Future work, discretization of the continuous color rendition space, will be carried out to address the shortcomings of a continuous three-dimensional space.


Work ◽  
2020 ◽  
Vol 67 (3) ◽  
pp. 599-609
Author(s):  
Evandro Eduardo Broday ◽  
Antonio Augusto de Paula Xavier

BACKGROUND: Over the last few decades, there has been a concern to improve the quality of indoor work environments and increase energy efficiency as people spend much of their time in such settings. OBJECTIVE: This study analyzed a group of women developing sedentary activities to determine the Actual Percentage of Dissatisfied (APD) in the environment, considering that all people who voted any value other than zero on the seven-point scale are deemed dissatisfied. METHODS: After this analysis, using the probit regression model, hot and cold air temperature curves were plotted so as to determine in which situation the number of people dissatisfied with the environment is minimal. RESULTS: The results showed an APD of 52.31%, which is different from the ADP recommended by ISO 7730 (2005) [–0.5 < PMV < + 0.5, PPD < 10% ]. The probit analysis using the cut of 10% as dissatisfied, according to category B of ISO 7730 (2005), showed a comfort temperature of 21.1°C, with a comfort temperature range from 19.61 to22.61°C. CONCLUSIONS: Using the fraction of people dissatisfied with the environment (52.31%) as the cutoff, when the air temperature is equivalent to 20.2°C, the lowest percentage dissatisfied by the cold and heat in the environment occurs simultaneously.


2004 ◽  
Vol 12 (3) ◽  
Author(s):  
Phil Davies

This paper reports on a case study that evaluates the validity of assessing students via a computerized peer-marking process, rather than on their production of an essay in a particular subject area. The study assesses the higher-order skills shown by a student in marking and providing consistent feedback on an essay. In order to evaluate the suitability of this method of assessment in judging a student’s ability, their results in performing this peer-marking process are correlated against their results in a number of computerized multiple-choice exercises and also the production of an essay in a cognate area of the subject being undertaken. The results overall show a correlation of the expected results in all three areas of assessment being undertaken, rated by the final grades of the students undertaking the assessment. The results produced by quantifying the quality of the marking and commenting of the students is found to map well to the overall expectations of the results produced for the cohort of students. It is also shown that the higher performing students achieve a greater improvement in their overall marks by performing the marking process than those students of a lower quality. This appears to support previous claims that awarding a ‘mark for marking’ rewards the demonstration of higher order skills of assessment. Finally, note is made of the impact that such an assessment method can have upon eradicating the possibility of plagiarism.DOI: 10.1080/0968776042000259573


2017 ◽  
Vol 26 (2) ◽  
pp. 44
Author(s):  
Enrique Saavedra ◽  
Francisco J. Rey ◽  
Jaime Luyo

El incremento de los precios de la energía eléctrica, las preocupaciones sobre el cambio climático, la independencia y seguridad energética impulsan el cambio del mercado mundial de la iluminación hacia fuentes de luz energéticamente más eficientes. La iluminación, según estimaciones de la International Energy Agency (IEA), representa casi el 20% del consumo mundial de energía eléctrica. En el Perú, según el Ministerio de Energía y Minas, aproximadamente el 35% de la energía primaria (después de la transformación y/o descontadas las pérdidas) es destinada a la generación eléctrica, la cual presenta consumos importantes en iluminación: Sector Residencial 15% a 30%, sector Comercial aprox. 33%, sector Público aprox. 24% y sector industrial 10% a 15%. Dados estos niveles importantes de consumo en sistemas de iluminación, el uso transversal en todos los sectores, la falta de un marco político regulatorio integral, así como la necesidad de determinar y establecer alternativas de eficiencia energética, es necesario el conocimiento de la situación actual y las perspectivas de los sistemas de iluminación. Para lograr el ahorro de energía en iluminación, la IEA recomienda a los gobiernos: Eliminación progresiva de productos de iluminación ineficientes; adoptar iluminación de calidad, fiabilidad y Estándares Mínimos de Eficiencia Energética (MEPS); apoyar el desarrollo, uso y actualización de las normas internacionales de pruebas y los protocolos de medición para reducir los costos de cumplimiento de la industria y apoyar los requerimientos de política nacional; exigir y promover un mejor diseño y gestión de sistemas de iluminación al asegurar que los códigos de construcción promuevan el uso de la luz natural e incluyan MEPS para sistemas de iluminación, incluya información y formación dirigidas a arquitectos, constructores, propietarios y gestores. Actualmente el mercado está dominado por las tecnologías de iluminación convencionales, las cuales están siendo desplazadas por la tecnología de Iluminación de Estado Sólido (SSL). A nivel mundial, la SSL que comprende LED, OLED y la gestión de los sistemas de iluminación, marcan la tendencia con grandes probabilidades de lograr los objetivos de ahorro y eficiencia energética. La SSL ofrece controlabilidad mejorada, nuevos factores de forma (que facilitan el reemplazo de tecnologías convencionales) y nuevas funcionalidades (base de la industria de la iluminación inteligente) que se pueden integrar con sistemas de sensores y de control, lo que permite mayor ahorro de energía. No obstante, la existencia de tecnologías de mayor eficiencia y características lumínicas, existen barreras para su adopción, principalmente: falta de información y sensibilidad, falta de confianza, mayor costo inicial, incentivos inadecuados, temores percibidos relacionados a la salud y el ambiente. Así mismo, hay una serie de barreras para la adopción de productos SSL, estos comprenden principalmente costos iniciales, confiabilidad, estabilidad de color y compatibilidad; que pueden limitar la adopción. Palabras clave.-Sistema de iluminación, Eficiencia energética, Gestión energética, Lámpara, LED. ABSTRACTRising electricity prices, concerns about climate change, independence and energy security drive the shift from the global lighting market to more energy-efficient light sources. Lighting, according to estimates by the International Energy Agency (IEA), accounts for almost 20% of the world's electricity consumption. In Peru, according to the Ministry of Energy and Mines, approximately 35% of primary energy (after processing and / or discounting losses) is destined to electricity generation, which presents important consumption in lighting: Residential Sector 15 % to 30%, Commercial sector approx. 33%, Public sector approx. 24% and industrial sector 10% to 15%. Given these important levels of consumption in lighting systems, transverse use in all sectors, the lack of a comprehensive regulatory policy framework, as well as the need to determine and establish energy efficiency alternatives, it is necessary to know the current situation and The prospects of lighting systems. o achieve energy savings in lighting, the IEA recommends to governments: Progressive elimination of inefficient lighting products; Adopt quality lighting, reliability and minimum Energy Efficiency Standards (MEPS); Support the development, use and updating of international testing standards and measurement protocols to reduce compliance costs and support national policy requirements; Demand and promote better design and management of lighting systems by ensuring that building codes promote the use of natural light and include MEPS for lighting systems, including information and training for architects, builders, owners and managers. Currently the market is dominated by conventional lighting technologies, which are being displaced by Solid State Lighting (SSL) technology. Worldwide, SSL comprising LED, OLED and the management of lighting systems, mark the trend with great probability to achieve the goals of energy saving and efficiency. The SSL offers improved controllability, new form factors (which facilitate the replacement of conventional technologies) and new functionalities (base of the intelligent lighting industry) that can be integrated with sensor and control systems, allowing greater savings of Energy. However, the existence of more efficient technologies and light characteristics, there are barriers to its adoption, mainly: lack of information and sensitivity, lack of confidence, greater initial cost, inadequate incentives, perceived fears related to health and the environment. Also, there are a number of barriers to adoption of SSL products, these mainly include initial costs, reliability, color stability and compatibility; Which may limit adoption. Keywords.-Lighting system, Energy efficiency, Energy management, Lamp, LED


Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8002
Author(s):  
Katarzyna Bobkowska ◽  
Pawel Burdziakowski ◽  
Jakub Szulwic ◽  
Karolina M. Zielinska-Dabkowska

One of the most important elements during photogrammetric studies is the appropriate lighting of the object or area under investigation. Nevertheless, the concept of “adequate lighting” is relative. Therefore, we have attempted, based on experimental proof of concept (technology readiness level—TRL3), to verify the impact of various types of lighting emitted by LED light sources for scene illumination and their direct influence on the quality of the photogrammetric study of a 3D urban mock-up. An important issue in this study was the measurement and evaluation of the artificial light sources used, based on illuminance (E), correlated colour temperature (CCT), colour rendering index (CRI) and Spectral power distribution (SPD) and the evaluation of the obtained point clouds (seven photogrammetric products of the same object, developed for seven different lighting conditions). The general values of the quality of the photogrammetric studies were compared. Additionally, we determined seventeen features concerning the group of tie-points in the vicinity of each F-point and the type of study. The acquired traits were related to the number of tie-points in the vicinity, their luminosities and spectral characteristics for each of the colours (red, green, blue). The dependencies between the identified features and the obtained XYZ total error were verified, and the possibility of detecting F-points depending on their luminosity was also analysed. The obtained results can be important in the process of developing a photogrammetric method of urban lighting monitoring or in selecting additional lighting for objects that are the subject of a short-range photogrammetric study.


2021 ◽  
Vol 247 ◽  
pp. 01040
Author(s):  
Dmitry Gladin ◽  
Alexey Kavtarashvili

The article discusses the influence of light pulsation on the physiological state of humans and birds, some aspects of its occurrence, the main characteristics and the alleged role in the deterioration of chickens’ zootechnical indicators under the conditions of using light sources with light flux pulsations of different frequencies. The current state of lighting equipment in poultry farming is characterized by the rapid development of technologies and the active introduction of LED lighting. Having undeniable advantages, LED lighting systems have some technical features that are currently insufficiently studied and can affect the zootechnical indicators of poultry. A clear definition of the threshold values of the characteristics of the pulsation of illumination in the poultry house will make it possible to produce lighting equipment for poultry farming with a safe value of the pulsations of the luminous flux of light sources in their composition. The analysis of numerous literature sources has shown that the influence of light pulsation on the physiological state of humans and zootechnical indicators in birds is associated with a complex effect, depending on such characteristics as the depth and frequency of the pulsation of the light flux of light sources. Despite some differences in the values of the threshold impact of light pulsation, the nature of its impact is similar in humans and birds, which allows us to develop and apply targeted measures to reduce the impact of light pulsation on poultry and the deterioration of its zootechnical indicators.


2015 ◽  
Vol 4 (3) ◽  
pp. 268-309
Author(s):  
Fernanda Acre ◽  
Annemie Wyckmans

Purpose – Non-technical dimensions such as spatial quality are just as relevant for energy efficiency as technical and economic dimensions in the renovation of dwellings. However, the significance of non-technical dimensions is often neglected in the energy renovation of dwellings. The purpose of this paper is to demonstrate how the renovation of dwellings for energy efficiency influences spatial quality in the MS-1 building in the neighbourhood of Arlequin, Grenoble, France. The Arlequin case study is part of the ZenN project, nearly zero energy neighbourhoods, funded by the European 7th Framework Programme (Grant Agreement No. 314363). Design/methodology/approach – The impact of the renovation on spatial quality is analysed by crossing technical measures, applied in the energy renovation of dwellings with the definition of spatial quality proposed by Acre and Wyckmans (2014). The spatial quality definition results from a literature review on quality of design and urban life, wherein works of Weber (1995) and Gehl (2010, 2011) are related to the residential use in the scales of the building and block. The impact of renovation on spatial quality is further evaluated by using the spatial quality assessment developed by Acre and Wyckmans (2015). The impact on spatial quality is observed by considering all the renovation measures, instead of only considering the measures primarily related to energy performance. This emphasises the need for a cross-disciplinary approach between technical and non-technical dimensions in the energy renovation of dwellings. Findings – The results display both negative and positive impacts of the energy renovation on spatial quality in the dwellings and emphasise the potential of non-technical dimensions in promoting renovation. The impact on spatial quality is primarily negative when only measures adopted in order to improve energy efficiency are considered in the evaluation. Originality/value – This paper consists of a novel crossing of technical and non-technical dimensions in energy renovation of dwellings. The work aligns with the current European trend of nurturing energy-deep renovation to reach Europe’s 2050 energy-efficiency targets (Buildings Performance Institute Europe (BPIE) 2011).


Author(s):  
I. I. Bayneva ◽  
I. A. Lychagin

The article discusses modern light sources – LED retrofit lamps, which are used to replace traditional light sources (incandescent, fluorescent lamps). The article provides calculated data showing energy savings as a result of replacing traditional light sources with LED ones. LEDs have undeniable advantages over such light sources. This is a high luminous efficiency, durability, color reproduction and much more. Ample opportunities for direct replacement of LED lamps are associated with their form factor, which is the same as that of traditional light sources. The main parameters of the form factor in this case are the sizes of the light sources (bulb diameter) and the type of cap. However, direct replacement has many controversial sides. Firstly, the light environment created by traditional incandescent lamps is very different from that for LED light sources due to the difference in their spectral light distribution. Secondly, the light intensity curves of LED and traditional light sources are very different in a number of cases. Therefore, direct replacement must be carried out very carefully, taking into account the final light distribution of the light device, where they are used. Thirdly, due to the incompleteness of research in the field of safety of LED lighting, the use of such light sources can be limited due to the potential hazard that may lead to a decrease in labor productivity and quality of life. Fourth, the design of LED lamps is complex, their quality depends on the quality of LEDs, phosphors and electronics, so consumer properties may not be at the highest level, even at fairly high prices. Fifthly, for any, even the simplest LED lamp, a heat sink system is necessary, since the thermal regime of the lamps imposes certain restrictions on their use.


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