Thursday, 19 January 2012

Positive Energy Efficiency - Solar Shading Holds the Key


The Benefits of Solar Shading as a Way of Reducing Energy Consumption
Energy efficiency and conservation has always been high on the agenda. With the introduction of the Climate Change Levy and with increasingly stringent Building Regulations impacting on the design of new buildings, the issue of energy efficiency is more critical than ever. As part of the Government’s commitment to reducing carbon dioxide emissions, we now have to look at ways in which to deliver low energy consumption without affecting the comfort, usability and aesthetics of our architecture. 

30% of the energy consumed in the UK is wasted
It is a fact that around 30% of the energy consumed in the UK is wasted, contributing to global environment problems such as climate change, and this waste is costing billions of pounds. In buildings, air conditioning, once seen as the ‘summer saviour’, is now increasingly identified as a major drain of energy. 

According to the Carbon Trust, air conditioning accounts for more than 50% of many buildings’ energy costs, with lighting accounting for around a further 15% and heating the next significant contributor. According to CEN (Creative Environmental Networks), a 20% reduction in energy consumption can easily be achieved by most businesses, and this reduction can have the same positive effect as a 5% increase in sales. 

So how can we reduce this huge energy consumption created by air conditioning, lighting and heating, whilst providing comfortable working environments? The answer lies with solar shading and control. 

Controlling and diffusing sunlight improves natural daylight in buildings
Controlling and maximising the potential of our biggest natural heat and light source – the sun – is, in theory, a simple proposition. However, with the sun come the issues of solar heat gain and the necessity to have control. In cold climates winter sun entering a south-facing window can contribute to passive solar heating whilst in warm climates, excess solar heat gain may result in high cooling energy consumption, such as air conditioning. In nearly all climates, controlling and diffusing sunlight will improve natural daylight in buildings. 

Building Regulations suggest that there are three strategies for avoiding solar overheating
  1. appropriate glazing design
  2. the use of exposed thermal mass with night ventilation
  3. the use of solar shading.
Solar shading is not a new concept. In fact it has been around for hundreds of years in the shape of external awnings. Today, awnings are still frequently used to shade the sun, as are roller, vertical and Venetian blinds. 

Maximum benefits from external solar shading systems
However, it is with external solar shading systems that maximum benefits and returns in terms of heat, light and glare control within buildings can be achieved. Fitting in with the Government’s plans for energy conservation, their promotion as a core function in building design is being led by the Office of the Deputy Prime Minister (ODPM). 

In terms of costs, they also provide significant savings. When compared to the reduction in air conditioning requirements – both installation and running costs – solar shading can pay for itself in a matter of years. 

Enhancing the aesthetic appeal
As well as providing vital control of heat, light and glare, many architects are using external solar shading systems as a way of enhancing the aesthetic appeal of buildings. Levolux has developed a range of systems that are specifically designed to complement the architecture of a building whilst providing passive temperature control, through effective shading. This can all be achieved without obscuring the view through the glass. 

So how exactly do they work? 
External solar shading systems are largely produced in extruded aluminium, which can be anodised or powder coated. Steel, timber, polycarbonate and glass systems are also available. Systems can be customised to fit almost any elevation, arranged vertically, horizontally or inclined, while integrating seamlessly with the building envelope. 

Aerofoil fins are perhaps the most popular form of external shading, applied in bays, above windows or on glazed elevations. Matrix louvres are also effective for projecting horizontally, or at an angle above openings.

During the spring, summer and autumn, fixed horizontal fins or louvres projecting above windows on a south facing façade will provide shading throughout the day. During winter months, the sun is much lower in the sky and its rays may pass between the fins or louvres. However, as the rays are significantly weaker in the winter, solar heat gain is not a major problem. In fact passive heat gain in buildings from the sun during the winter months can be a positive contributor to heating.

For east and west facing façades, as the altitude of the sun is much lower, a slightly different system is required. Fins can be arranged vertically to cast shade along the building, across glazed openings. As an alternative, motorised fins can be installed, which when linked to a shading management system, can follow the path of the sun. This provides optimum protection against the sun whilst ensuring maximum visibility and natural daylight.

Government pressure to make significant reductions in carbon dioxide emissions.  
Energy efficiency and consumption will continue to cause concern amongst architects and building owners, and the Government will be sure to keep pressure on to make significant reductions in carbon dioxide emissions.  

As long as glass is used on new buildings, then controlling solar heat gain will continue to be a critical factor in their design. By involving a specialist like Levolux in the initial design stages and creating an integrated solar shading system, the issues of limiting solar heat gain, maximising daylight and preventing glare can easily be overcome. While solar shading has often been overlooked in the past, to reduce costs or for aesthetic reasons, surely this cannot continue if a building’s energy efficiency is to be optimised.

Over recent years, the range of solar shading solutions available from Levolux has exploded and we now believe it is possible to create a cost-effective, aesthetically impressive, highly efficient solution for any building. Please put us to the test.

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