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Holistic approach

All building services need to communicate effectively to get the best performance from a building, says Scott McGavin

In October, the International Energy Agency’s Energy Efficiency Market Report identified energy efficiency as the ‘invisible powerhouse’ that is improving energy security, lowering bills and helping to reach climate goals in many of the world’s most developed countries.

For those involved in managing buildings, the report is significant because it shows that energy efficiency is an achievable goal that our sector should be taking seriously, if they are not already doing so.

The technology for achieving energy efficiency in buildings is now readily available, particularly in areas such as heating, ventilation and cooling, which are widely acknowledged as the biggest users of energy in most office buildings. The main problem lies in the way that the plant is controlled.

The ability to control the building is a key factor in ensuring long term energy efficiency, but one of the main issues here is that in the commercial environment, controls are often used as a glorified on/off switch – as a result, they are not being used to achieve their full potential.

An additional problem comes from the fact that all of the plant and services come with their own control system, which invariably works in isolation. This can mean that the control of the heating, for example, is working independently from the control of the air conditioning. While the controls will still work, they are not communicating with each other to achieve the best results.

A more holistic approach, which allows the integration of these controls into a single Building Energy Management System (BEMS) can initially be more costly and time-consuming, but it is now widely accepted that this would result in a more usable and useful system to enable building managers to achieve efficiency in the longer term.

Legislation considerations

A number of reports and studies from organisations such as CIBSE, BRE and BSRIA have asked the question about why buildings are not as energy-efficient as they might be.

Most point to the consideration of long term efficiency right from the design stage. Whether it is factored in at the design stage or introduced as a retrofit, the installation of building controls equipment should be a priority.

One of the key factors driving this view is legislation. The rising interest in controls as a means to save energy was bolstered by the recognition in the new Part L 2013 Compliance Guide of British and European Standard, BS: EN15232: 2012 Energy performance of buildings – impact of building automation, controls and building management.

This standard is based on a structured list of controls and building automation technologies that have an impact on energy use in buildings and classes are assigned to levels of control in a building (A, B, C and D) to show the resulting energy savings that can be expected.

At the heart of the BS EN15232 is a very straightforward and well-known approach to building services, which is demand-driven.

This ensures that services such as lighting, heating and air conditioning are only used when required.

For many organisations, there is another pressing reason to think about the energy efficiency of a building because here in the UK, the Energy Saving Opportunities Scheme (ESOS) was introduced in July 2014, with the first audits required by December 2015.

The ESOS will apply to large organisations (excluding the public sector) with more than 250 employees. Current estimates are that between 7,500 and 9,000 organisations will be affected.

The Department for Energy and Climate Change (DECC) predicts that ESOS will result in an average investment ‘per enterprise’ of £15,000 and that the average potential energy bill savings as a result will be £56,400 per year.

The figures are compelling, and the Carbon Trust estimates that most energy-efficiency investments have a return on investment of 50 per cent – far higher than most other business investment in new technology, for example, Unfortunately, experience shows that 60 per cent of energy savings opportunities (identified by energy surveys, for example) are not implemented.

Correct use

What is important to note is that with today’s controls technology, achieving a demand-driven approach is simple and one which can be adopted in almost any size of building – but only if the controls technology is used correctly.

The need for controls technology is clear, but it needs to be ‘intelligent’ – and that means using the controls as more than a simple on/off switch.

The air conditioning, for example, needs to be able to respond to different building requirements so that factors such as different room sizes, usage and occupancy levels – as well as heat loads from electronic equipment and lighting – can be taken into account. This can only be achieved if the technology is working together.

This was one of the driving forces behind the introduction of our MelcoBEMS, which provides an interface between Mitsubishi Electric air conditioning equipment and BEMS via the Modbus or BACnet protocol.

This type of solution is increasingly being demanded in the commercial market by building owners and managers who recognise that the only way to achieve true energy savings and meet the legislative requirements is through the use of a flexible and intelligent solution that effectively joins the dots as far as building-wide control is concerned.

The enhanced capabilities that modern air conditioning systems offer is something that the industry now takes for granted because the rapid evolution of technology means that we now expect a high level of efficiency from this type of equipment.

But even the most efficient piece of kit has its limitations if it is not controlled effectively because the ability to anticipate, control, monitor and report performance remains a key factor in achieving reductions in energy use and running costs.

The message is therefore clear – we need a joined-up approach to control to enable our building services and plant to talk to each other, because this is the only way that we will ensure that the building continues to operate at peak efficiency.

Scott McGavin is product manager for Mitsubishi Electric

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