All the numbers relating to the sun are mind-numbingly large. For example, it’s ancient – 4.6 billion years old. It’s hot – with a surface temperature around 5,500°C and a core temperature of 15m°C. Its mass is a staggering 1,989,100,000,000,000,000,000 billion kg and the Earth could fit inside it around a million times.
One of the most compelling statistics about the sun from a building services perspective is that the solar energy received by the Earth in just 30 minutes is the equivalent to all the energy used by the world’s population in a year.
Harnessing just a fraction of this energy can cut fossil-fuel derived energy output dramatically as well as shrink carbon emissions and slash fuel bills. That is where solar thermal water heating comes in, especially when it comes to leisure centres and sports facilities.
Leisure centres require enormous quantities of heat – it accounts for about 30 per cent of running costs, second only to staff. This is not only to ensure a comfortable space, but also for hot water to service showers, cafés, swimming pools, and so on. Solar heating can supplement the water heating requirements.
Save money and the environment
According to the Carbon Trust, UK leisure facilities could save up to £70 million each year and reduce carbon emissions by hundreds of thousands of tonnes simply by making a 10 per cent improvement in the management of energy use.
Solar panels have a significant part to play in achieving this improvement. The Carbon Trust said solar water heating can be very effective for swimming pools and is relatively easy to connect to a conventional heating system. Unglazed solar collectors perform well in summer and are generally the cheapest to buy and install.
Glazed collectors also provide more energy in spring and autumn and can give a substantial contribution to pool heating throughout the year, with the remainder provided by a conventional heating system, according to The Carbon Trust.
Many leisure centres are equipped with modern boilers running on gas or other fossil fuel to offer reliability of both heating and hot water. However, not even using the latest modulating gas boilers to supply hot water to large buffer vessels is the best option.
Even well-insulated storage vessels lose heat, causing the boiler to cycle on and off, as the temperature drops. Maintaining the temperature will waste fuel and this is exacerbated by the need for regular temperature boosts to kill potential Legionella bacteria in the water.
It is far more efficient to have an array of solar panels storing the free energy collected within what serves as a preheat storage vessel. This way, the temperature of incoming water can be raised. And, when the temperature of the water needs to be raised further, a boiler with a plate heat exchanger (PHE) can do this efficiently and instantaneously.
Paul Sands is sales & marketing director at Stokvis Energy Systems