scholarly journals Criticality assessment of metal resources for light-emitting diode (LED) production – A case study in China

2021 ◽  
pp. 100380
Author(s):  
Wenfang Gao ◽  
Zhi Sun ◽  
Yufeng Wu ◽  
Jiali Song ◽  
Tianyi Tao ◽  
...  
Keyword(s):  
Light Emitting Diode ◽  
Light Emitting ◽  
Criticality Assessment

Temperature and Humidity Dependent Reliability Analysis of RGB LED Chips

2006 ◽  
Author(s):  
Jun-Xian Fu ◽  
Shukri Souri ◽  
James S. Harris
Keyword(s):  
Reliability Analysis ◽  
Printed Circuit Board ◽  
Light Emitting Diode ◽  
Circuit Board ◽  
Light Emitting ◽  
Printed Circuit ◽  
Root Cause ◽  
Micro Cracks ◽  
Temperature And Humidity

Abstract Temperature and humidity dependent reliability analysis was performed based on a case study involving an indicator printed-circuit board with surface-mounted multiple-die red, green and blue light-emitting diode chips. Reported intermittent failures were investigated and the root cause was attributed to a non-optimized reflow process that resulted in micro-cracks and delaminations within the molding resin of the chips.

Using the private finance initiative for energy efficiency projects at the urban scale

2016 ◽  
Vol 10 (1) ◽  
pp. 99-117 ◽  
Author(s):  
Alberto De Marco ◽  
Giulio Mangano ◽  
Fania Valeria Michelucci ◽  
Giovanni Zenezini
Keyword(s):  
Energy Efficiency ◽  
Urban Areas ◽  
Light Emitting Diode ◽  
Project Finance ◽  
Private Finance Initiative ◽  
Content Type ◽  
Light Emitting ◽  
Alternate Forms ◽  
Private Investors

Purpose – The purpose of this paper is to suggest the usage of the project finance (PF) scheme as a suitable mechanism to fund energy efficiency projects at the urban scale and present its advantages and adoption barriers. Design/methodology/approach – A case study is developed to renew the traffic lighting system of an Italian town via replacement of the old lamps with new light-emitting diode (LED) technology. Several partners are involved in the case project to construct a viable PF arrangement. Findings – The case study presents the viability of the proposed PF scheme that provides for acceptable financial returns and bankability. However, it also shows that the need for short concession periods may call for a public contribution to the initial funding to make the project more attractive to private investors. Practical implications – This case study is a useful guideline for governments and promoters to using the PF arrangement to fund energy efficiency investments in urban settings. It helps designing an appropriate PF scheme and understanding the advantages of PF to reduce risk and, consequently, increase the debt leverage and profitability of energy efficiency projects. Originality/value – This paper contributes to bridging the gap about the lack of works addressing the implementation of the PF mechanism in the energy efficiency sector in urban areas. The importance of this paper is also associated with the shortage of traditional public finance faced by many cities that forces to seek for alternate forms of financing.

scholarly journals Increased Plant Quality, Greenhouse Productivity and Energy Efficiency with Broad-Spectrum LED Systems: A Case Study for Thyme (Thymus vulgaris L.)

Plants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 960
Author(s):  
Jenny Manuela Tabbert ◽  
Hartwig Schulz ◽  
Andrea Krähmer
Keyword(s):  
Broad Spectrum ◽  
Energy Savings ◽  
Light Emitting Diode ◽  
Thymus Vulgaris ◽  
Light Spectrum ◽  
Light Emitting ◽  
Biomass Yields ◽  
Lighting Systems

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.

Case Study for Replacement of Conventional Lights by Led Lights

2019 ◽  
Vol 7 ◽  
pp. 44-51
Author(s):  
Indu Duwal
Keyword(s):  
Energy Saving ◽  
Energy Demand ◽  
Light Emitting Diode ◽  
Light Sources ◽  
Demand And Supply ◽  
Light Emitting ◽  
Return Of Investment ◽  
Science Group ◽  
Led Lights

With the increment in the gap between the demand and supply of energy, various alternatives for decreasing the demand of energy are major concern for the various stakeholders. In order to decrease the energy demand by lighting various energy efficient lights are available in market. However it is difficult to convince the residents to change conventional artificial light sources, since lighting system is an essential part in the building which ensures the comfort, productivity and safety of the occupants in the buildings. Among the various Light Emitting Diode (LED) lights are termed as one of the most efficient energy saving lights which aims to save almost more than 50 % of energy demand than that of CFL lights with same power of illumination. Hence, this study is carried out to calculate energy saving percentage after replacing the conventional lights like florescent, mercury lights and other forms of conventional lights by LED lights. Additionally the study also was focused to evaluate feasibility of the replacement of lights by LED lights in terms of energy saving and return of investment. The research was carried out in building used by Agrotechnology and Food Science (AFSG) science group of Wageningen University in the Netherlands. The results from the study showed that almost 50% of the energy can be saved after replacement by LED lights with around 5 years for return of investment. However, factors like 1) Number of operating hours, 2) Price of lights, 3) Energy cost, 4) Labour cost for replacement and adjustment and 5) Number of replacement and adjustment per hour are the influential features that effects in the performance of various types of lights

scholarly journals Technology-Driven Transition in Urban Food Production Practices: A Case Study of Shanghai

2019 ◽  
Vol 11 (21) ◽  
pp. 6070 ◽  
Author(s):  
Mohsen Hosseinifarhangi ◽  
Margherita E. Turvani ◽  
Arnold van der Valk ◽  
Gerrit J. Carsjens
Keyword(s):  
Urban Planning ◽  
Light Emitting Diode ◽  
Arable Land ◽  
Agricultural Practices ◽  
Actor Network Theory ◽  
High Tech ◽  
Light Emitting ◽  
Urban Planning And Development ◽  
Controlled Environments

The continuing decline of arable land per person and global human population growth are raising concerns about food security. Recent advances in horticultural technology (i.e., growing using light-emitting diode (LED) lighting, hydroponics, vertical farming, and controlled environments) have changed the ways in which vegetables can be produced and supplied. The emerging technology makes it possible to produce more food using fewer resources, independent of the weather and the need for land. They allow bringing agricultural practices inside urban built up spaces and making horticultural production an integrated part of the daily life of urban residents. However, the process and consequences of this technology-driven transition on urban planning and development are hardly understood. This paper uses the theory of multi-level perspective (MLP) on sustainability transitions and actor–network theory (ANT) to explore this technology-driven transition and its adoption in urban planning and development. The high-tech horticulture zone development in Shanghai was used as a case study. The results show the importance of both social (i.e., policymakers and planners) and material (i.e., technologies and policy documents) actants in the transition of the sociotechnical regime. Furthermore, the transition toward sustainable urban horticulture practices requires the simultaneous preparation of supportive and compatible spatial development, agricultural and sustainable development policies, and adequate policy implementation and evaluation tools to increase the competitive strength of innovative practices.

scholarly journals A method to estimate savings of led lighting instalation in public buildings: The case study of secondary schools in Serbia

2017 ◽  
Vol 21 (6 Part B) ◽  
pp. 2931-2943 ◽  
Author(s):  
Mladen Josijevic ◽  
Dusan Gordic ◽  
Dobrica Milovanovic ◽  
Nebojsa Jurisevic ◽  
Nikola Rakic
Keyword(s):  
Cost Reduction ◽  
Light Emitting Diode ◽  
Electric Energy ◽  
Light Flux ◽  
Electricity Consumption ◽  
Maintenance Cost ◽  
Light Emitting ◽  
Led Lighting ◽  
Lighting Systems

This paper examines the potentials of saving electric energy in school lighting by replacing the existent systems of lighting with more adequate ones which are based on light-emitting diode technology. Our primary goal is to present the methodology used in this analysis since it can be used to determine potential savings in lighting systems of any public building. We have performed the detailed analysis of nine high schools located in Kragujevac, Serbia. The first step was to collect the data about the numbers and types of systems utilized, as well as about the habits of their users. This has revealed the share of electricity consumption for lighting in total electricity consumption. The replacements for each existent light source have been proposed taking into consideration the projected value of light flux depending on the purpose of each room. The calculations of potential savings through the replacement of lighting systems have been conducted taking into consideration not only the savings in electric energy but also the savings made through the maintenance cost reduction. Based on the results, the potential savings range from 53-62% while the payback period for the analysed schools is about four years in average.

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