Enjoying the benefits of integrated services
Standalone systems for controlling the various aspects of a building’s services and systems should be a thing of the past. Iain Gordon of the KNX UK Association takes up the story.
With any 21st-century building development, design for energy conservation is paramount to the demands of regulations, industry targets and client requirements. Building controls play a major role in the electrical and mechanical design process by providing the operating parameters, strategy, measurement and monitoring to which all systems operate. Indeed, without a functional, well designed and commissioned building control system, achieving optimum efficiency would be very difficult.
However, this is only the start of the process — as the control system should be able to evolve and change as the building does over time. Intelligent building control systems should be designed to cater for the changing needs of the building and offer suitable upgrade paths and expansion capability for the future.
In the traditional approach to building services and control systems, it is not uncommon for them to be installed by a number of different companies with many different sets of cables, materials, components, plant and tools. This approach is rarely cost effective and can lead to higher wastage —both in terms of energy usage and components such as cable off-cuts, left over containment and packaging. They all contribute to the overall carbon cost of the construction process.
A further consideration of an installation is how easy it will be to maintain and whether there is an upgrade path and spares availability in the future. For example, if a proprietary system is installed which after time needs to be repaired or parts replaced, is there any guarantee that the manufacturer has not moved on to a new product, with very little support for the old one?
The requirement for intelligent building control systems has never been in more demand than now due to more stringent regulations, the cost of energy, the need to reduce carbon emissions and the desire to enhance human environmental comfort within buildings. The basis to good design practice should start with considering concurrently both the mechanical and the electrical design. The two should not be separated, as there are many cross-over points and many aspects that could be designed together.
Consultants should also have an open mind to integration or one system to control all aspects of building services. With today’s KNX open-protocol system there is no need for different standalone separate systems. The traditional approach of treating every individual building control application separately can now be reconsidered. Making different applications work together on one single bus network has many advantages. Linking control applications such as lighting control, façade control, underfloor heating and radiator zone control on the same bus network allows them to share information about the space being controlled and provide the most energy efficient solution.
Consider a small office with lighting control, fan coil unit heating/cooling, automatic blind control and perimeter low level heating, all being controlled on a single bus network. There is one wall-mounted control device for room-temperature control, lighting scene set control and blind override — as well as a single ceiling-mounted presence detector. This example may consist of a number of different manufacturers’ products, but the bus network will be common to them all.
The presence detector will set the room to occupied mode, taking the fan-coil unit to setpoint from the standby temperature, activate the lighting and daylight dimming strategy, set the blinds to the correct position based on external lux levels and solar radiation. The wall-mounted temperature controller ensures that the space will be controlled to achieve optimum efficiency and comfort, with some manual override if needed. All this capability is simply controlled by the various devices communicating together within the space and not via some central PC or outstation.
When this form of integrated control is implemented across a large site, it becomes evident how major savings can be made over and above the traditional approach, while still maintaining a solid robust system.
With KNX this approach is a reality. Its underlying philosophy is to bring different manufacturers’ products together on one bus network. Furthermore, these products will be guaranteed to be completely interoperable between different manufacturers’ products because they have been certified to be so.
So when integration is discussed, KNX can be at the heart of building-wide integration of control applications. Other advantages include reduced site installation times and costs as well as less cabling, containment and wastage. With one integrated system, only one contractor is required, and there are standard commissioning procedures. Maintenance can be similarly managed more effectively by one contractor. There are increased levels of control and functionality provided by fewer wall-mounted controllers, as applications can share devices, and data can be passed from one application to another.
For the end user, there is also improved environmental comfort for both lifestyle and the working environment. The user also has full access to the installation as it is based on KNX's open protocol. He also has a vast range of products to select from and is not locked into any one supplier. Any installation is fully upgradeable and forwards compatibility is also guaranteed.
Integration of building control applications is just one of the topics discussed in the KNX Consultants Guide, available from KNX UK, PO Box 4082, Bracknell, Berkshire, RG42 9EQ, Tel: 0845 8695908, Email: email@example.com
Iain Gordon is president of the KNX UK Association.