Electrical Contracting News (ECN) November 2016 - Page 46

SPECIAL FEATURE HOME AUTOMATION & INTELLIGENT BUILDINGS requirements than traditional incandescent and discharge lighting. This enables the electrical power, as well as data for monitoring and control, to be carried over the network cables (Power over Ethernet) rather than requiring a separate power supply. For instance, a single LED may only require a voltage of 3V, so an array that uses 10 LEDs will only require 30V. Power-over-Ethernet (PoE) can be deployed even in situations where the majority of networking is carried out over a Wi-Fi network, as is now the case in many commercial environments, rather than hard-wired ethernet connections to devices. Despite the heavy reliance on WiFi there will still be ethernet cables present to connect Wi-Fi repeaters throughout the various spaces. From an installation perspective, the use of low voltage ethernet cable means that the cabling work can be done more efficiently. There is no need to terminate individual wires and the strain relief is integrated into the termination method. However, if this opportunity is to be fully exploited it is essential to ensure that all of the lighting – including the emergency lighting – is using a low voltage supply. If the emergency lighting still requires line voltage in the ceiling/luminaires then costly isolation, as well as additional terminations, are required. It is immediately apparent that using PoE in this way offers significant savings in material costs and installation time as less cable is used and connections can be made for more quickly. There will also be additional benefits in terms of the reduced maintenance requirements for the cabling infrastructure. In addition, in using ethernet cabling rather than the more traditional twistedpair control cable, larger volumes of data can be transported more quickly between the points on the network. There are also aesthetic benefits, as there are fewer constraints on luminaire design when there is no need for a separate power supply and LED drivers can be located remotely with just a low voltage connection to the luminaires. Power-over-Ethernet can be deployed in situations where the majority of networking is carried out over a Wi-Fi network. Opportunity Beyond these basic lighting requirements, though, there is considerable opportunity to do much more with lighting, utilising the lighting infrastructure that already exists in the majority of buildings and many outdoor spaces. For example, most modern lighting systems incorporate occupancy sensors to switch or dim lighting in response to people leaving and entering a space. Much has already been written about using this occupancy data to better understand how such spaces are used through the days and years. Nor is this approach confined to improving space utilisation. Measuring occupancy and the movement of people is also invaluable for retailers who want to fine tune the layout of their stores. They might, for instance, use that information to optimise the positioning of special offers so that they have higher visibility. There is also potential to combine this with mobile connectivity. A shopper with an appropriate App might make a product selection online before visiting a store, and then be guided to those products within the store by the App. In a highly competitive retail environment this ability to add value for the customer can deliver significant competitive advantages. In parallel, increased connectivity enables lighting to become part of the ‘Internet of Things’ (IoT) that we now hear so much about. Essentially, this just means different devices communicating with each other, as well as with us. Most references to the IoT concern domestic appliances – turn the heating on from your smartphone or have your fridge tell you what shopping you need. However, there is also scope for the services within a building to communicate with each other more effectively. Again, this idea isn’t new but its application has been hindered by the use of different protocols. Improved collaboration between the manufacturers of such systems is now driving a move towards interoperable systems where a combination of comfort parameters can be combined to create healthier and more productive workplaces. There are, of course, many other examples of how better data about a space – and exchange of data between different systems – can be used to positive effect. The challenge has always been not just how to gather that data but also how to bring it all together in a central location for analysis. Making use of an existing, connected infrastructure that would be in the building anyway clearly makes perfect sense. For electrical specifiers, the challenge now is to look beyond traditional approaches and see how lighting systems can be used more widely to add even more value for the end client. ‘PoE offers significant savings in material costs and installation time as less cable is used and connections can be made for more quickly.’ Summary The hierarchy of light is about meeting basic needs and working our way up to the ultimate interaction of light as part