Energy
| What does the new Part L mean to you? |
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| Written by David Stillman, July 2006 | |
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Part L of the Building Regulations has been in existence for over ten years. Since its inception, there have been a number of revisions - and with each the regulations get stricter in forcing downward the overall energy use of buildings. Part L pertains to the conservation of energy in new and refurbished buildings, and contains a number of methods with which to evaluate an individual building's overall energy consumption in comparison to a theoretically acceptable similar 'notional' building.
The latest revisions, which came into force in April 2006, have a goal of reducing energy consumption and carbon emissions by approximately 30 per cent over the previous version of the regulations. The new Part L requires very efficient mechanical and electrical systems, and good overall U-values for a building's façades and roof. In addition, the controls for the building systems must minimise energy use and all services must be metered to individual users to encourage conservation by occupants. Big changes in design...The list of options verges on the infinite, as the regulations allow designers, as an alternative, to prove that their building's carbon emissions are lower than those of the 'notional' standard building's carbon emissions. To demonstrate this, consider that a designer incorporates fuel cells that generate electricity from biomass, which produces almost zero carbon emissions. The building can use this 'carbon emission-free' electricity to power an electric heating system and still comply with Part L. Similarly, an architect can specify , , or argon-filled double-glazing for a façade which provides insulation values equivalent to masonry walls, which then enables them to have virtually all-glass façades.A great deal has been written about the new Part L and how this affects building managers. For managers of new office buildings, one would logically think that most of the energy savings, and therefore the operating cost savings, flow from the design of the building. If the designers have done their job properly, the building should be miserly with its energy consumption. Given this situation, it would be somewhat frustrating for managers who are looking to show how well they can run a building by reducing the annual energy costs, as there should be only relatively small improvements obtainable. But everything will now shift to making sure all the high-tech systems incorporated into the building by its designers actually work. The new Part L will result in office buildings with sub-metered electricity, hot water and chilled water services, active ventilated façades, solar photovoltaic cells, mixed-mode ventilation systems, CHP plants running on bio-fuels, fuel cells, thermal mass cooling, evaporative cooling, bore hole cooling systems, earth-connected heating and cooling systems, sophisticated lighting control systems etc. The technical skills necessary within the management team to enable the building to actually achieve what it was designed to do will be significant. The regulations also now include a requirement that building managers keep a logbook to demonstrate that they are operating the building as it was intended. ...mean big challenges for managersWithout properly trained management and maintenance engineers, there is a good chance that the operation of these high-tech systems will go awry. Should that happen, the effect upon the comfort and safety of the occupants will be greatly magnified. For example, an office building that incorporates a bore hole cooling system uses the constant supply of 12°C well water to reduce the size of the mechanical cooling plant, or in some instances eliminate it altogether. If the bore hole system failed, the building would not have all or part of its cooling capacity available.Fuel cells are now being incorporated into buildings in the UK and will become quite common in the very near future. The fuel cell uses a chemical process rather than combustion to generate electricity and hot water. This is just the first wave of systems that will operate with hydrogen and/or bio-mass fuels. A whole new set of skills will be required to operate and maintain these systems. Mixed-mode ventilation systems, which enable a building to use natural ventilation whenever the conditions outside are favourable, but that have a full mechanical cooling and ventilation system for those times when natural ventilation is insufficient, will become commonplace. These systems, by nature, have a number of operable controls for multiple openings in the façades, and if they are not maintained properly the comfort levels in the building will suffer drastically. So, the days of simple office buildings with just air-cooled chillers on the roof and gas-fired hot water boilers in the basement are over. Building managers will increasingly need to be up-to-date on all the techniques that are now being used to enable a building to comply with Part L - and they will have to be prepared to show their logbooks to prove it. About the author David Stillman is Managing Director at DSA Engineering Ltd. Please visit www.dsaengineers.com/ |
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