Time to invest in energy efficiency

With the heating season officially over, now is the time for businesses to invest in energy efficiency refurbishments. Relatively simple, cost-effective improvements made in these summer months will bring welcome savings in the autumn.

After one of the coldest winters on record, businesses will be enjoying a few months’ welcome respite from high fuel bills. However, as the energy-savvy will know, now is the perfect time to plan energy efficiency improvements action ahead of the autumn. The impact of energy efficiency refurbishment is immediate and considerable as shown by a recent report by Dena, the German Government’s energy agency, on a project that involved extensively refurbishing 350 residential buildings. Energy use in each home reduced by 76 per cent, dropping from 223 to 54kWh/m2, leading Dena to conclude that energy efficiency refurbishment is indeed ‘worth the investment’. The benefits to businesses are equally impressive with simple, cost-effective measures bringing significant reductions in energy demand, carbon emissions and operational costs.

As heating and hot water generation account for a third of the UK’s total energy usage and around 40 per cent of our carbon emissions, according to the Carbon Trust, improving the efficiency of an organisation’s heating system is a good starting point when addressing efficiency improvements.

For the UK’s high percentage of old commercial building stock, retrofitting a modern condensing boiler is often the only solution to energy efficient heating, given the impossibility of redesigning the existing heating systems. As a general recommendation, any boiler between 10 and 15 years old should be replaced with a green, clean burning condensing model. The energy savings are immediate, halving fuel bills and reducing greenhouse gas emissions by at least 90 per cent. Disruption and downtime is also minimal as new models are designed for quick and easy installation which results in greater productivity for the organisation.

For the optimal retrofit solution, think beyond ‘condensing’ to ‘super condensing’. If it takes more energy to heat an old system, then it makes absolute sense to recover otherwise wasted energy. A ‘super condensing’ heat recovery system will deliver 100 per cent efficiency at all times, irrespective of primary circuit temperatures, using the recovered energy for the benefit of pre-heating domestic hot water or space heating.

Controls are the next consideration. Regardless of the age of the boiler, controls are the most effective means of ensuring that it and the heating system operate at their maximum efficiency. This also applies to systems combining renewable equipment with condensing boilers; the controls not only link the separate components, but help the system use less energy and reduce the level of greenhouse gases. We recommend that the minimum control strategy should encompass valved zone control, thermostats and timers. Further improvements and energy savings can be achieved by sequential control of boilers, two zoned temperature and time control, and weather compensation.

Just as cars require annual MOTs, all boilers need an annual service to ensure clean, efficient operation. The summer is the perfect time to carry out such a service, which should include flue gas analysis, controls calibration and burner cleaning. 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, a significant figure for commercial operations. Again, chemical treatment is the most effective means of purification.

We at Remeha Commercial are keen to support engineers and building operators in investing in energy efficiency refurbishment in commercial boiler plant by offering a financing scheme to help businesses with the initial investment, with payments offset against the anticipated energy savings. In this time of austerity, when a question mark hangs over the future of our energy supply, every little helps.

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