OPINION
A more serious difficulty is that people like what they are used to, and may consider any reduction in illuminance to be a backward step. This objection might be overcome by ensuring the brightness of the space is maintained, either by choosing an appropriate light spectrum or by light distribution. In any case, it is important to appreciate that the reduction in illuminance need not be very large to have a significant effect on electricity use. The fact is the response of the human visual system to illuminance is broadly logarithmic, while the influence of changing illuminance on electricity demand is broadly linear. As the Chinese say: ‘May you live
in interesting times.’ We do, and they look like becoming even more interesting. The lighting community needs to consider how it is going to respond to the pressure upon it; to fight for current standards, to accept defeat and take whatever the politicians impose, or to use our knowledge to maximise the benefits of lighting while minimising the environmental costs. You choose.
l Author and academic Peter Boyce is technical editor of Lighting Research & Technology Journal where this first appeared as an editorial and is reproduced courtesy of Sage Publishing
LR&T is available free to SLL members at
www.cibse.org
MANUFACTURER’S VIEWPOINT
The introduction of Part L 2010 presents many opportunities for technologies to help cut emissions, writes Martin Fahey of Mitsubishi Electric, sponsor of this column
The changes to Part L of the Building Regulations,
which came into force in October 2010, will continue to have a major impact on the way that buildings are designed and constructed, in addition to the way we refurbish existing buildings. The latest version requires a variety of savings in CO2 – averaging 18% to 38%, depending on the type of building being planned or extended. This increase in the standards of energy efficiency is partly a reflection of the increases in performance of modern technology, and places building services right at the heart of the issue. It also reflects changes in the way the main energy sources are calculated, whether fossil fuel- based or renewables. In the 2006 version of Part
L, the CO2 emission factor for electricity consumption was 0.43kg CO2/kWh, whereas the 2010 value has risen to 0.517kg CO2/kWh. Due to this rise, all consumption of electricity is having a detrimental effect upon the overall search for emission reductions.
For a heat pump, for example, this means it must have a higher efficiency to match the same CO2 level as alternative fuel technologies whose emission factors haven’t changed as significantly. It is now vital that the need
The rise in the CO2 emissions factor is having a detrimental effect on the overall search for emission reduction
for energy consumption be reduced as much as possible. Also key is the CO2 emission
factor when generating energy. Electricity can be generated using photovoltaics (PV); and for every kWh produced, it is considered that PV can mitigate 0.529kg CO2, adding towards reducing emissions and to the renewables on site. Although the use
of renewables is not a
requirement by Part L, using them will help significantly towards meeting the aggregate 25% emission reduction requirement. And a renewable element is still likely to be required as part of local council planning permission. Modern technology can
have a key role in helping to achieve the required 25% reduction in CO2 emissions, and the points of impact vary from the seasonal efficiency of a product, to whether it is ECA (Enhanced Capital Allowance) approved, or appropriately controlled and metered. Part L 2010 also puts in
place the need to control and meter efficient equipment effectively so that the building achieves maximum efficiency and CO2 reductions. Information and training should also be available to the owner to allow the building to be operated efficiently.
SPONSORED BY
www.cibsejournal.com
May 2011 CIBSE Journal
27
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