Getting smart with system design
Achieving maximum efficiencies is the common goal of heating manufacturers and installers. James Porter, National Sales Manager of Remeha Commercial, looks at simple, effective measures we can take to achieve lower energy bills and cut greenhouse gas emissions.
According to the media, the UK economy is on the up once more and we will all soon feel the benefit. Welcome as that news is, it’s safe to say that at present, in the words of a well-known retailer, ‘every little helps’.
This is particularly true where heating is concerned. According to the Carbon Trust, heating and hot water alone can account for 60 per cent of our total energy use – which can translate into hefty bills at a time when fuel prices are continuing on their upward spiral.
The good news is that by adopting relatively simple measures to improve our energy efficiency and reduce waste, we can make important savings on our fuel bills and reduce harmful greenhouse gas emissions.
The Government is preparing for our future with a balanced energy mix. However, our main source of fuel in the UK is still gas, with boilers the predominant form of heating. While our long-term goal is to generate our energy from renewable sources, the reality is that at present, this is not always feasible. Renewable technologies still require significant financial investment which might rule them out as a heating alternative. What’s more, the age and nature of the building and existing heating system might mean that renewables are simply not an option.
Upgrade the boiler
At present, replacing inefficient boilers with a modern, fully modulating condensing boiler is still the most cost-effective way of bringing substantial energy savings. As a general recommendation, any boiler between 10 and 15 years old should be replaced with a green, clean burning condensing model. Today’s models are more flexible, more versatile and more slimline to facilitate quick and easy installation.
Get in control
Modern condensing boilers can achieve outstanding efficiencies of up to 107 per cent NCV. Yet this figure can drop to the standard 80 per cent if operated at higher flow and return temperatures. As a result, the challenge for manufacturers and installers today is to ensure not only that the most appropriate product is used in a particular project within the budget framework, but that these products are used as efficiently as possible to achieve their maximum potential.
One simple step to ensure that a boiler is operating at its maximum efficiency is to add the appropriate control. The minimum control strategy should encompass valved zone control, thermostats and timers. The Carbon Trust suggests that lowering set points by one degree could bring a reduction in an annual heating bill of up to eight per cent.
Further improvements can be achieved by two-zoned temperature and time control, weather compensation, and sequential control of boilers where applicable, which help the system use less energy and thereby increase its efficiency.
On inefficient heating systems, it is worth thinking beyond ‘condensing’ to what we at Remeha call ‘super condensing’ technology. Heating solutions incorporating heat recovery devices recover what would otherwise be wasted energy, passing it back into the system for the benefit of space heating (underfloor heating or low temperature radiators) or pre-heating domestic hot water. This means that they can deliver around 10 to 15 per cent higher efficiency levels than condensing boilers. Such solutions are particularly effective on old heating systems which by their nature take more energy to heat. ‘Super condensing’ technology would deliver an impressive £98 of usable energy for every £100 of energy input – even at high temperatures and high load.
When designing bivalent heating systems, where condensing boilers support renewable equipment (such as solar or heat pumps), it’s important to consider how both components can achieve their full potential when working in tandem. One solution is to choose a ‘renewable ready’ boiler with a secondary return feature as this enables the boilers and renewables to achieve their maximum efficiency levels over the course of the year.
Finally, if a boiler is to achieve its optimum performance level, it should not be a fit and forget item. Think of it more in terms of a car that needs its annual service. Regular services could prevent soot accumulating on the fire side of the boiler’s heat exchanger, for example, if the combustion conditions are not correct, creating an insulating layer and inhibiting heat transfer to the water. A 1mm layer of soot will cause a 10 per cent increase in energy input to the boiler to meet the same heat demand.
Similarly, in hard water areas scale can build up inside the boiler. Scale can create an insulating layer on the water side of the boiler’s heat exchanger which inhibits heat transfer to the water, requiring more energy input to the boiler in order to meet the same heat demand. A 1mm layer of scale can cause a 7 per cent increase in energy requirement. Specialist chemical treatment is necessary to remove the scale and should be carried out annually.
The insulation on existing boilers should also be checked for wear and tear. Replacing worn insulation can prevent heat losses of up to 10 per cent of the energy output. Also check the insulation on the pipework and valves. Replacing it at the appropriate time can save up to 10 per cent of the energy input.
Examining the quality of the water is important in both new and existing boilers. Water in existing boilers or heating systems is often contaminated with sludge or slime that can cause metal corrosion, increased noise in operation, and poor water flow or blockages. Even new systems can have contaminants from either the manufacturing process or from the installation itself. Contaminated water can reduce the efficiency of a boiler and system considerably, potentially by up to 10 per cent. Again, chemical treatment is the most effective means of purification.
As technology has advanced, so the choice of heating equipment has increased. At Remeha Commercial, we look forward to sharing our knowledge of our products and assisting with best system design. By reducing unnecessary energy waste, together we can help the nation move forward to a low carbon future.
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