Plus ME, the lighting engine for motorized streets

The lighting fixture design and research of the PLUS project previously developed at the Politecnico di Milano, Laboratorio Luce was upgraded in 2012 in order to accomplish lighting performances for motorized street categories (ME3 -4 -5- 6) [1 – 2] Performed in collaboration with ENEA and NERI (for the prototyping phase), the project was focused on applying the idea of design by components, modularity, interchangeability and de-materialization of the lighting fixture for roads and street applications.

More than accomplishing lighting performances both in terms of optics and thermal dissipation, the Plus ME modular lighting system was also studied for demonstrating the possibilities of implementing innovative lighting fixture with a different design, without emulating shapes and geometries of the traditional lighting sources, but trying to figure out new morphologies, both functional and aesthetically designed. The modular idea was useful to guarantee the interchangeability of the LEDs based technology but also to create a scalable luminous system that could be adapted to different lighting purpose.

First sketches of rectangular shapes, conceived as the minimum basic design,  were step by step transformed in a more organic and natural morphology with the idea of complementing technology with bio-mimicry both for aesthetic and functional aims. This was particularly made for the thermal heat-sink, taking inspiration from nature and previous studies about better performance of air convection with natural geometries. [3]2_plus me

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5_plus mePLUS ME was studied to reduce the components, materials, thickness of the system and, by using more than one module, to achieve different street lighting categories withing the same module (and so the same injection molding productive processes).  More than this, the development of the module, from the photometric and also from the thermal point of view was fundamental to ensure the efficiency of the system and to select the best solution in terms of DLOR (downward luminous output ratio)  and CU (utilization coefficient). The composition of free form lenses by Ledil and the use of a protective screen in PMMA were studied to ensure the highest efficiency of the system but also to give  higher protection to lenses (atmosphere, dust, UV, etc) and to ensure a higher maintenance factor thanks to an ease of cleaning.

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The heat sink was studied using CFD design in order to ensure that TJ was lower than 80°C and the organic natural shaped of the fins was enabling a good thermal dissipation.

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10_plus meAs well as PLUS, this module was intended to be an open project, free from patent that could be used from companies to understand the process of development but also to take partially or completely the idea by reusing it with an internal customized design. In this regard, several visualization of the possibilities of design proposal were presented.

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Finally the module was prototyped by Neri in order to elaborate design verification tests in the Laboratory in terms of thermal and optical features.

More details are in the following presentation (italian language): design__PLUSME_ENEA

A shorter and revised version in english (part of a Lecture presented at  the Politecnico di Milano, Laboratorio Luce – LIGHTING PRODUCT DESIGN Introductory course on lighting fixture design) can be found here: LECTURE_PART1_DARIACASCIANI_PLUS

Design & Engineering by Daria Casciani in collaboration with Eng. Danilo Paleari and Eng. Fulvio Musante.


[1] UNI EN 13201 – 1 (2014)

[2] UNI EN 11248 (2012)

[3] Herbold C. Neumann C. (2013) BIONIC HEAT SINK DESIGN Natural Design for Heat Sinks Issue 39 2013 © 2013 LUGER RESEARCH e.U.


Published report about the research and design

Rossi, M; Casciani, D.; Musante, F. (2012) Report Ricerca di Sistema Elettrico. Advance LED lighting design nell’illuminazione pubblica. Relazione tecnica Attività C.2: Ricerca progettuale PLUS ME. Report RdS 2012-275 September 2012, accessed the 08/09/2014

Published paper about this research

M. Rossi, Musante F., Casciani D., Fumagalli S. (2013) PLUS, Public Lighting Unit System, Lux Europa, Polski Komitet Oswietleniowy SEP Krakòw

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