Driving long-term savings
The construction costs of a building are typically less than 10% of its total costs over its life, which motivates Ian Ellis of Siemens Building Technologies division to argue the importance of a specifying an adequate building-management system and making full use of its capabilities.
For any building owner or operator the knowledge of a building’s costs over its full life span is an important factor in achieving best value, both in terms of the capital costs of construction and ongoing operating costs. Being fully aware of whole-life costs helps to inform design decisions and the selection of the most suitable building materials, components and systems.
It is generally accepted that the incurred expenditure for ongoing building operation can often exceed the initial capital investment of construction by some tenfold. An integral part of any building operation is its energy use. Buildings now account for 41% of all primary energy consumption. Of this, some 85% is used for room heating and cooling. The other 15% is electrical energy, in particular for lighting requirements.
A central consideration for building owners and managers should be seeking out efficiencies to ensure that the energy management of their buildings (and therefore a large proportion of their whole-life costs) is strategically monitored, managed and acted upon. The implementation of a BEMS (building energy management system) is the first step towards achieving typical energy cost savings of up to 30% per annum.
When considering the benefits of a BEMS it is important to assess a number of key areas so that its adoption can deliver true value not just in the short term, but also over the course of the building’s life span. These include: thinking for the long term via the initial engineering specification; relying upon independent verification; driving continuous monitoring and implementation of key data; and realising the benefits of system integration.
When specifying a BEMS the long-term benefit should not be compromised in an effort to cut initial capital costs. Omitting some functionality from the system may save expenditure during the construction phase but will inevitably have a detrimental effect over the long term, as the system is unable to generate the holistic and broad-based data and control from which substantial energy management efficiencies can be gained.
As proof of errors of such a short-term approach, for anyone specifying controls as part of BEMS, the British and European Standard BS EN 15232 should be essential reading. This internationally recognised standard specifies a structured list of control, building automation and technical building-management functions which have an impact on the energy performance of a building. This standard is an independent definition of the minimum levels of building controls required to achieve different levels of energy efficiency across a number of building types.
|While a BMS will reduce a building’s energy consumption, using it effectively and using the information it provides to implement energy-efficiency measures increases its effectiveness enormously.|
This standard’s classification categories highlights the indisputable fact that the installation of a Class A BEMS system versus one classified as C would deliver energy savings differential between the two of around 30% year on year. Short-termism to reduce upfront capital costs is a false economy compared to the life-cycle cost benefits that can be gained from a full BEMS installation.
Another important aspect in deriving maximum long-term value from a BEMS is the requirement for the building operator to be fully conversant with the system. They need to take responsibility for understanding and implementing the range of features a BEMS can deliver.
Buildings are constantly changing environments, and building-services equipment can drift in performance due to maintenance (or lack of it). The BS EN 15232 standard recommends at least annual reviews of the performance of building controls and annual training for users. Continually assessing, checking and updating the system is not only a smart way to get the most from any BEMS, it is a proactive management strategy that chimes with what regulatory and Government bodies are seeking through their ‘soft-landing’ initiative. They do not wish to see buildings simply handed over post construction, but want a far more collaborative manner of building operation so that the structure operates effectively going forward — especially in the area of energy efficiency.
While a BEMS will monitor a building’s performance and provide management data, access to such information is essentially a means to an end. Only when such data is analysed and acted upon can the true value of a BEMS be realised.
Alongside the benefits to be derived from strategic data analysis, the full integration of BEMS, for example linking the heating and lighting controls for a building via the same control system through so-called ‘enterprise systems’, offers the best route to the kind of 30% per annum energy savings indicated by BS EN 15232. Users should join up building-automation systems with the other applications such as alarms, service and maintenance and monitoring and compliance. Bridging this gap through software enables, for example, the display of all information for the various systems to be delivered on a single user interface. This makes operational control simple and meets the changing service expectations of building owners and end-users.
Building energy management systems, such as Desigo from the Siemens Building Technologies division, not only integrate the various functionality across a building’s energy use, they also enable building owners to react to future changes and protect investments for the long term. Features such as integrated demand-based optimum room climate control, data monitoring and total system compatibility through open communication are the means to ensure a building’s energy-management system delivers essential energy-consumption reductions and much needed cost savings over the short, medium and long term.
Ian Ellis, marketing manager for UK control product and systems within the Siemens Building Technologies division.