High pressure sodium discharge lamps have been the default choice in street lighting for a number of years but with the introduction of LEDs this is rapidly changing. Alan Grant, Design and Development Director at DW Windsor Lighting explains why it is now possible to incorporate stylish design with exceptional energy efficiency and good colour rendering.
If you look as far back as 1417, lanterns with candles were used in London to illuminate the streets during the winter nights. The subsequent invention of gas, oil and eventually electric street lighting helped to bring urban areas out of the dark ages and is something that today we all take for granted. But just because we take it for granted does not mean that it will always be there – as recently evidenced within a number of local authorities, who have taken the decision to switch off street lighting in certain areas to reduce costs.
Understandably this has caused a backlash with local residents and road users concerned with the issue of safety on their streets at night. There are many arguments for and against; local authorities have cut back, but at what cost? And are they aware that with new technology in place they could still achieve notable savings without turning the lights off at all.
LED technology is therefore proving to be a popular choice for a number of reasons.
Superior colour rendering
One of the first factors which we should take into account is the colour of the light emitted. In the case of more traditional discharge lighting solutions, yellow light is a major limiting factor, resulting in poor colour rendering of the environment. While over the years this type of lighting is something we have all grown accustomed to, this should not be an excuse for us to continue to live with it and key issues such as safety and security, as a result of poor lighting, compel us to actively address it.
With LED street lighting, the situation is very different because the white light emitted provides the perception of a safer environment for both drivers and pedestrians. In fact tests show that motorists are able to detect roadside movement faster, and from a greater distance, with white light; allowing more time to react to danger or to stop if, for example, a child steps out into their path.
White light also addresses the issue of pedestrian safety because it makes the general public feel safer when they are out at night. Superior colour rendering and a high level of brightness make it easier to distinguish shapes and people’s features during the hours of darkness. As a result of this increased visibility white light helps to reduce anxiety levels and make the streets feel a safer place to be.
Light, bright and more efficient
Having addressed the issue of safety and general security which comes from the white light emitted by LEDs, we can focus on another very important reason for switching to LED technology; the cost savings involved.
Over the past few years as budgets have been cut there has been a great deal of pressure to reduce the energy consumption of street lighting and its associated carbon emissions. Traditional light sources are not very efficient and up until now many local authorities have had to make a choice between the high cost quality illumination of LED lighting or a low cost alternative with poor colour rendering and high energy consumption that make the streets a far from inviting place. Therefore it’s no wonder that many local authorities have resorted to this wholesale ‘switch off’ solution.
However as the relative energy efficiency of LED luminaires has improved it has become possible to achieve a better quality of light at lower running costs throughout the lifetime of the product. As a result the attitude towards LED street lighting has dramatically shifted and new products have entered the market which are extremely versatile; meeting the end user need for a cost effective solution and providing the necessary level of light to achieve a safe and secure environment after dark at significantly reduced energy consumption.
A new solution
The desire to achieve cost effective illumination is one of the driving factors behind our new range of street lighting; but it isn’t the only consideration because we believe that good design should go hand in hand with an energy efficient product.
Kirium is a class leading LED road lantern which answers the need for an energy efficient solution using the very latest LED technology. It has been designed from the ground up and what this means for the end user is that we have invested a considerable amount of time into ensuing that it meets a very real need in the market.
For a start Kirium offers a truly future proof solution. LED technology is advancing at a very fast pace, so while Kirium is state-of-the-art technology now we appreciate that this technology will change. To that end we have ensured that it can easily accept new and emerging technology in the future. Kirium is available as a modular solution which incorporates one, two or three LED modules and as a result it is possible to achieve a uniform look throughout a town or city using one product with a combination of modules.
The innovative organic shape is perhaps one of the main talking points. On one hand it looks great, but as we all know – it isn’t just about the look. In fact this innovative design is one of the areas which make it so efficient because, through the use of CFD software, we have optimised the design to produce exceptional thermal management which will improve the longevity and optical performance of the luminaire.
It is well known that LEDs generate considerable heat and if this isn’t dissipated and managed efficiently it can rapidly degrade the light source and significantly reduce the life of the LEDs. The design incorporates an air gap which provides a barrier between the LED zone and driver electronics and additional vents between the LED modules also stimulate airflow. Furthermore thermal management of the driver is inbuilt within the electronics chamber to ensure the temperature of this vital component is kept as low as possible. This all adds up to excellent thermal management in a great looking product with impressive longevity.
The future is looking better
There is a lot of discussion about achieving energy efficiency in outdoor lighting and while for some the solution is to just switch off the lights, it is clear that this isn’t the only solution.
With the introduction of new technology we are able to develop new products which provide a sensible and cost effective solution to the need for energy reduction and which vastly improves the aesthetics of our towns and cities.
So whether you are looking at street lighting for a major city, a small housing development or a university campus, the same reasoning applies. LED technology is cheaper to run than traditional lamped products and provides a source of light which increases safety and security.