In the last decades, lighting installations in plant tissue culture have generally been renewed or designed based on LED technology. Thanks to this, many different light quality advances are available but, with their massive implementation, the same issue is occurring as in the 1960s with the appearance of the Grolux (Sylvania) fluorescent tubes: there is a lack of a methodological standardization of lighting. This review analyzes the main parameters and variables that must be taken into account in the design of LED-based systems, and how these need to be described and quantified in order to homogenize and standardize the experimental conditions to obtain reproducible and comparable results and conclusions. We have designed an experimental system in which the values of the physical environment and microenvironment conditions and the behavior of plant tissue cultures maintained in cabins illuminated with two lighting designs can be compared. Grolux tubes are compared with a combination of monochromatic LED lamps calibrated to provide a spectral emission, and light irradiance values similar to those generated by the previous discharge lamps, achieving in both cases wide uniformity of radiation conditions on the shelves of the culture cabins. This study can help to understand whether it is possible to use LEDs as one standard lighting source in plant tissue culture without affecting the development of the cultures maintained with the previously regulated protocols in the different laboratories. Finally, the results presented from this caparison indicate how temperature is one of the main factors that is affected by the chosen light source.

In this work, a practical methodology is proposed to analyze, before undertaking a large investment, an outdoor lighting installation renewal with light-emitting diode (LED) luminaires. The main problems found in many of the luminaires tested are associated with inrush peak currents in cold start (which may cause ignition problems with random shutdowns), the harmonic distortions caused by their AC/DC associated electronic nature driver, and their working and efficiency dependency on the ambient temperature. All these issues have been tested in the context of a large metal halide (MH) to LED luminaires lighting point renewal where six commercial LED projectors have been analyzed with the above considerations. This research has isolated a single-phase circuit powered with constant stabilized 230 V_AC voltage source in a real public lighting installation. All of them have been sequentially installed and their main electrical and power-quality parameters measured and recorded. The results indicate that each luminaire option will influence the expected long-term reliability (>50.000 h or more as expressed by the U.S. Department of Energy) of the lighting installation (in the case poor power quality is generated on the grid). The economic analysis made to estimate the profitability of the investment may be severely affected by the difference between the declared and the real consumption values in which they perform in our specific installation.

This paper analyzes the technical and economic viability and sustainability of urban street lighting installation projects using equipment powered by photovoltaic (PV) energy. First, a description of the state-of-the-art of the technology is performed, studying the components involved in solar LED luminaires for street lighting application and examples of autonomous PV systems installed in different countries. Later, a case study a based on a renovation project of the street lighting installation at a 5000-inhabitant municipality in Lanzarote (Spain) is presented. Two alternatives are analyzed: underground channeling of the previous aerial electrical grid and the installation of LED luminaires, and, on the other hand, the installation of autonomous LED solar luminaires. Simulations concluded that a PV lighting installation proposal guarantees the existing M3 lighting requirements (EN 13201-2:2015) and represents a saving in the material execution budget of 43.78% with respect to the channeled power grid option. Finally, a statistical study has been carried out to assess the social acceptance of Spanish citizens of this autonomous PV technology in urban environments. This considers strengths and weakness of the technology: sustainability, robustness, visual impact, or risk of vandalism. In general, most subjects of all age segments are aware of the problem that means having aerial wiring running at facades (95%) and considers the use of PV in urban lighting sustainable (88%). However, 47% of those surveyed consider that shutdowns due to lack of energy harvesting is problematic and 17% consider this very problematic. This major drawback (visual impact of PV equipment is mostly evaluated as neutral) gives rise to social reluctance, especially in people younger than 50 who remarked this as more problematic than senior segments. Thus, guaranteed operational service is fundamental to have social agreement for PV technology implementation.

The replacement of luminaires with discharge lamps with high luminous efficacy and long life-time LED based equipment is a reality worldwide promoted by policies that favor their gradual substitution. There is a great concern in this manufacturing industry to develop new luminaires with low environmental impact during the manufacturing and transportation processes and its end-of-life disposal (reducing greenhouse gas emissions, toxic or hazardous components, …). Life cycle assessment (LCA) is a very extended tool used to provide information on the quality and quantity of environmental impacts in the life cycle phases of any product, system, or service. This article includes all phases of the LCA analysis of a selected streetlight LED luminaire manufactured by a SME where a landfill deposit is the end-of-life scenario. In a second phase, alternatives are sought for the reuse of the most significant elements that improve its local economy. The results are classified and sorted according to the ISO 14040 standard.

Energy saving in street lighting is garnering more interest and has become a priority in municipal management. Therefore, LED luminaires are gradually becoming prevalent in our cities. Beyond their energy/economic saving potential, quality in public lighting installations concerns aspects such as uniformity and glare which must be maintained if not improved in any installation renewal project using this technology. The high light intensity generated in a discrete point in LED packages and its directional nature result in significant deficiencies in these last two parameters. To soften these effects, translucent covers are being used as one of the most common solutions with the drawback of significant light intensity losses. The objective of this paper is to evaluate the behavior of LED luminaire’s polyamide-based optical covers manufactured with a laser-sintered process. These are designed to improve glare and uniformity output, to minimize light output reductions, and to be industrially manufactured with no increment of cost for their lighting equipment compared to conventional transparent polycarbonate solutions. A laboratory and field lighting test study has been applied to different covers with the same LED lamp and luminaire to compare the performance of three different solutions built with different polymeric materials and with different light transmission surface textures. The photometric results have been observed and discussed to demonstrate the ability to significantly improve the lighting performance of LED luminaires—illuminance and uniformity levels and discomfort and disability glare indexes— using an improved optic cover.