﻿Designing for change
A flexible approach to the design of lighting control systems is key to achieving performance and maximum energy-saving benefits, now and in the future, says Stephen Woodnutt.
It is now generally accepted that maximum energy efficiency for lighting systems will only be achieved by combining the inherent efficiencies of luminaires and lamps with effective control. Indeed, this premise is reflected in the Building Regulations and industry best practice.
In parallel, as buildings become better insulated and the demand for space heating declines, the contribution of lighting to a building’s total energy consumption is assuming greater importance.
All of which has created a situation where lighting controls are now integral to every new build and major refurbishment — albeit to varying degrees. Similarly, many more building operators are retrofitting controls to existing lighting systems — a situation that has been partly fuelled by the various items of legislation that have come into force in the last few years. For example, if a major energy user can save enough energy on lighting to remain below the Carbon Reduction Commitment threshold, this will have a substantial influence on the return on investment calculations.
In all cases, though, it is important to get the balance right between the level of functionality required to achieve the desired energy savings and the investment in the control strategy. Just as importantly, lighting controls should have the flexibility to adapt to the changing usage of the building.
Any such controls should minimise the cost of ownership through features such as ease of installation and commissioning — the latter also helping to ensure the system performs as it was designed to. So these are all things the specifier needs to consider when guiding the end client to the best solution.
A common scenario illustrating these points can be seen in most speculative developments. Initially, the developer may choose to install controls that meet the minimum requirements of the Building Regulations, thus keeping the initial outlay to a minimum in the early phases of the project.
However, basic lighting control will rarely suit tenants that are looking for an adaptable system that suits their configuration of the space and also helps them to minimise energy consumption. Tenants often remove these ‘shell-and-core’ controls and replace them with a control system that has a higher level of functionality. Clearly, as well as representing additional expense for the tenant, the inherent waste of this approach hardly sits well with the ethos of sustainability that many organisations are seeking to cultivate. It is also likely that such considerations will have a bearing on a tenant’s choice of property at a time when they are spoilt for choice in many areas.
All these factors have led to a situation where developers want to be able to minimise their own costs while making the space as attractive as possible to potential tenants. This is where the flexibility mentioned at the beginning of this article comes into play, and where the specifier’s expertise comes into its own.
For example, it is now possible to source controls that will meet the requirements of Part L as standard but also have the potential to be quickly and easily upgraded to a more powerful system as and when needed. Thus, a standard version may incorporate local user control with plug-in connection points for local control devices, corridor linking and emergency lighting testing.
Such a system will easily meet the requirements of Part L and also provide the basis of an effective control system that will deliver energy savings and help to minimise wastage. However, there are many situations where the minimum will not satisfy the requirements or aspirations of the occupants and where even greater benefits can be achieved through higher levels of flexibility and functionality. So if the same system has the potential for adding that additional functionality such as enhanced flexibility, web browsers and IP telephone control etc., easily and cost-effectively, so much the better.
Systems recently introduced to the market do offer this ability to adapt, with the potential to upgrade to a higher level of functionality simply by inserting a capsule into a standard controller. This could be an upgrade to either analogue or DALI digital dimming, or to a fully addressable interoperable Lon-based system.
The key thing here is that the original system is retained — so the upgrade is very straightforward, while potentially delivering significant energy savings and a fast payback. Consequently, this is an area where a flexible, forward-looking mindset on the part of the specifier from the beginning of a project can influence the way the building is operated many years down the line.
Stephen Woodnutt is managing director of Delmatic