Getting back to basics
Buildings have a large role to play in reaching energy efficiency targets set out by European and UK government. Increasing concern about the cost and sustainability of energy suppliers in the UK, energy consumption and more efficient energy usage have become important criteria for choosing the most appropriate technologies for heating and air conditioning solutions.
In the non-domestic sector there is evidence of a fundamental gap between the energy use as modelled for building regulations compliance purposes according to CIBSE, and the actual energy use as measured by utility meters and billed by utilities.
Helping to address issues, CarbonBuzz, an energy benchmarking platform, has recently been launched. Supported by CIBSE and RIBA and led by Aedas R&D, the CarbonBuzz platform is a free online tool enabling users to record, share and compare the real energy use of their building portfolios, and track the energy use of existing buildings, refurbishments and new build projects.
It is clear that the importance of saving energy as a major topic is being recognised.
A recent article in BSEE ‘The proactive approach to energy saving’ explains ‘why this will reap rewards’ and looks at energy monitoring solutions to help understand usage. However, occupant behaviour has a critical role to play in saving energy too.
Energy efficiency can also happen as a simple act of some very basic changes in occupant behaviour.
For instance, a public-private-NGO partnership between Barts Health NHS Trust, GE, Skanska, and environmental charity Global Action Plan conducted a pilot behaviour change project at Barts Health NHS Trust in London which reported that its energy bills were cut by £100,000. The initiative included encouraging 15,000 nurses, doctors and hospital staff to turn off unused equipment, switch off lights and close hospital doors.
In the commercial environment, occupant comfort is also a major consideration, whilst still answering demands for energy efficient solutions. Solutions specified must not only be cost effective and energy efficient to achieve legislative or ratings stipulations, it must also answer specific occupant comfort needs and be visually appealing to help attract and retain staff. A comfortable environment makes for a satisfied worker who is perhaps more productive – but what’s important to them?
Findings from the recent BCO (British Council for Offices) and Savills report highlighted the relationship between office fit-out and employee comfort as well as easy wins for both occupiers and landlords which included ensuring that space is comfortable through adequate temperature control, lighting and space.
Temperature control of course is a key consideration in terms of energy efficiency. At King’s College London’s Strand building for instance active chilled beams feature in 75 cellular offices and allow local control of the temperature via wall mounted thermostats.
Choosing options such as chilled ceilings or chilled beams can satisfy the thermal, aural and visual comfort of occupants whilst providing a cost effective, energy efficient solution that will satisfy both occupants and developers.
Chilled ceilings for example radiate cooling downwards providing quiet, draft free comfort cooling to occupants. These energy efficient solutions also ensure comfort within a building at every level.
Passive beams use natural convection, while active chilled beams are induction engines and offer an effective air supply through their ability to recirculate air within a space. Primary air is supplied to the room at a high velocity via nozzles, which induce secondary room air over the water driven heat exchanger to produce required performance.
Operational savings are achieved because chilled beams can use higher water temperatures than traditional cooling systems. This has the advantage that it allows chillers to operate more efficiently and take advantage of free cooling for much of the year. The raised water temperatures also enable renewable solutions such as ground source water cooling to be considered.
The absence of moving and consumable parts, such as motorised fans or filters, not only leads to reduced maintenance costs it also reduces maintenance requirements.
Many designs today are utilising an exposed soffit to help with energy efficiency. Integrated Service Modules at Wakefield Civic Offices provided a solution that offered cooling, acoustic absorption and lighting in office areas, with the exposed soffit providing the benefit of height and thermal mass to absorb heat during the working day. Cartwright Pickard Architects have also reported that structural, environmental and architectural elements all contribute in providing a low energy BREEAM Excellent solution which aims to produce 30% less carbon than a conventional comfort cooled office.
Reducing operating costs of buildings remains a primary driver of retrofit activity, whilst with new build, energy efficiencies can be taken into account from design stage. Options specified must satisfy energy efficiency targets but once installed it is important for building occupants to understand how they can save energy.