KNX UK Association Board Member Andy Davis discusses the implications of BS EN 15232 on achieving effective building automation and energy efficiency throughout the life cycle of a building. He explains why KNX represents the most efficient means of implementing the approved Document and achieving Class A building performance.
It is estimated that some 40% of the world’s energy consumption is taken up by the operation of buildings. The use of electricity and primary energy sources within buildings contributes to over 21% of global greenhouse emissions. It is therefore clear that efficient energy usage within a building is essential at a time when energy costs continue to soar and a green approach is at the top of everyone’s agenda.
KNX UK believes that during the operational life cycle of a building, efficient energy usage can only be achieved properly if it is continually optimised with demand based BACS (Building Automation & Control System[s]) coupled with continual monitoring and adjustment of energy saving measures.
Energy consumed
According to the European Union Directive for Energy performance of Buildings (EPBD), the energy performance of a building means the amount of energy actually consumed to meet a building’s different needs for heating, hot water, cooling, ventilation, lighting and auxiliary energy. The European Union mandated CEN (European Committee for Standardisation) has standardised calculation methods in order to improve energy savings within CEN TC247. This has been approved to BS EN 15232 – 2012 Energy Performance of Buildings – Impact of Building Automation, Controls & Building Management.
This Approved Document sets out procedures to calculate the energy performance of a building and covers the use of building services devices to control thermal and electrical energy within a building which can then be categorised as A, B, C or D Class. Although not yet enforceable, BS EN 15232-2012 is just one of many regulations, laws and directives that impact upon buildings.
In BS EN 15232-2012, BACS energy performance Class A covers a building with automatic high energy performance building automation and control systems; TBM (Technical Building Management Systems) and include integrated individual room control, including demand control. Different efficiency factors are also laid out for different types of buildings from offices, lecture halls and hotels, through to shopping centres, schools, restaurants, hospitals, industrial facilities and wholesale centres amongst others. Whilst all of these types of premises are recognised as having the potential to save energy, they are treated separately due to the way that they may be used, hours of occupancy and so on.
Different types of room may be included within one large building or plant and the control of energy supply with networked room automation based demand is key to maximum energy efficiency. For example, to turn an office from a Class C space to a Class A rating, the use of ventilation plant within a restaurant can be optimised through the use of time controls and air flow control using fans with variable speed drives. Lighting in an office can be improved from Class D to Class A by dispensing with manual switching in favour of automatically controlled lighting with presence detectors and the introduction of air quality sensors.
KNX UK recognises too that the monitoring and analysis of the performance of building services is essential so that operational parameters can be continuously adapted and any additional measures can be decided upon. Carrying out practical energy saving activities such as regular planned maintenance, turning energy consuming devices off/down, repairing faults and recycling components wherever possible are also essential.
Optimum approach
So why does KNX provide the optimum approach to achieving Class A energy performance as outlined in BS EN 15232? In the traditional approach to building controls, it has not been uncommon for installations to be carried out by a number of different companies with many different sets of cables, components and tools. With the KNX open protocol system there is no need for different standalone separate systems and with an integrated system only one contractor is required and there are standard commissioning procedures. Allowing different applications to work together on one single bus network has many advantages: linking lighting control, façade control, ventilation systems, underfloor heating and radiator zone control and smart metering together on the same bus network allows them to share information about the space being controlled and provide the most energy efficient solution.
A key factor is that the building control system should be able to evolve and change as the building’s usage and occupancy changes over time. KNX intelligent building control systems are designed to cater for these changing needs and offer suitable upgrade paths and expansion capability for the future.
KNX certified products are guaranteed to be completely interoperable between different manufacturers. The user 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. Maintenance can be similarly managed more effectively by one contractor.