There are some well-established, over-arching principles of low carbon design as established by the RIBA. Below are details of these principles and how the use of renewable energy products can help architects to achieve them.
1 Understand energy use in the building type
It's vital that architects understand the breakdown of energy use for the building type, at least by fuel type and ideally by end-use, i.e. heating, cooling, lighting etc. This enables the designer to focus on the most important issues and identify how to minimise carbon dioxide emissions. The pattern of energy use is important, not just annual totals, particularly when renewable energy technologies are being considered.
Over the life of the average building 90% of its energy use will be accounted for by running the building (heating and hot water). Technology exists today to hugely reduce the amount of energy consumed by buildings, so the onerous on buildings to reduce their energy use is even more important. The ultimate green building in this aspect is the Passive House or zero energy houses, because they consume the absolute minimum amount of energy. Click here to read more about NuTech Solar passive houses
2 Use the form and fabric of the building to do the work
Architects should use the form and fabric of the building to do as much of the work of environmental modification as possible, thus minimising the demand on services such as heating and lighting. Low carbon buildings should exploit useful solar and internal heat gains (from people, equipment, etc.) to satisfy as much of the heat demand as possible, but exclude unwanted solar gains when they may lead to overheating. Two examples of this are listed below
Site Orientation
- A Southerly faced building will benefit maximum passive gain and for maximum shading in Summer months.
- A compact building form of minimum surface-to-volume ratio is best for reducing heat loss. However, a rectangular building with one of the longer facades facing south can allow for increased passive solar heating, day-lighting and natural ventilation. As well as reducing energy costs, sunny south-facing rooms also have high amenity value.
- Projections such as bay and dormer windows should be kept to a minimum as you will increase the surface to volume ratio of the building and this in turn will increase heat loss and they are also difficult to insulate.
- Pitched roofs with one slope orientated to South will allow for the optimum performance of a solar heating system.
Windows
- Large windows are most efficient on South facing walls for solar gain although you should provide shading e.g. curtains, blinds in Summer.
- Smaller and less windows can reduce the amount of heat loss through your windows.
- It is also important to consider the number of glazing layers e.g. double, triple. The thermal performance of windows depends not only on the number of glazing layers, but also on the air space between the glazing layers
- Windows should ideally have a U Value greater than 1.4w/m2
- If you're house is south facing then it is unlikely you will need triple glazed south facing windows, as over a year you'll gain more heat than lose even if you choose double glazing
- Windows also have a huge bearing on the buildings independence from natural light. 50% of daylight hours the light outside is 15,000 lux. Inside a building you need around 300 lux so therefore we leave most of the light outside.
3 Focus on insulation and air tightness
Low carbon designs seek to reduce unwanted heat losses and gains by adopting appropriate standards of insulation and air tightness. To identify appropriate standards it is necessary to understand the heating and/or cooling balance of the building. Generally the design of a dwelling will focus on keeping heat in and making use of heat gains, while the design of an office will focus on keeping the building cool, especially in summer.
NuTech Renewables Ltd can assist you with testing the air tightness of the building through an
air tightness test.
4 Use high efficiency building services with low carbon fuels
The architect should satisfy the remaining energy demand with building services that are as efficient as possible, and that use fuels with low carbon dioxide emissions factors. Emissions factors are explained in more detail in the Carbon Literacy Briefing that forms part of the RIBA Climate Change Tools. Architects should also ensure that heating controls are as responsive as possible, making use of solar and internal heat gains without over-heating the building.
NuTech Renewables Ltd can offer a wide range of renewable energy technology solutions with incoporate
solar, please contact NuTech for
further information.
5 Use renewable energy systems
Low carbon buildings use renewable energy systems to reduce the carbon dioxide emissions associated with the provision of heat and power within the building. Examples Include
6.Manage energy within the building
Low carbon design is not enough; low carbon operation is also needed. Architects can enable efficient operation of the building by ensuring that appropriate metering and energy management systems are in place, and that the occupants are well-informed about how the building and its services are intended to be used.
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