Time to invest in energy efficiency
With the heating season officially over, now is the time for businesses to invest in energy efficiency refurbishments, says Mark Northcott of Remeha Commercial. 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%, dropping from 223 to 54k Wh/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 the generation of hot-water account for a third of the UK’s total energy usage and around 40% 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%. Disruption and downtime is also minimal, as new models are designed for quick and easy installation — which results in greater productivity for the organisation.
|Energy consumption plummeted from 660 995kWh to 273 148kWh at Farley Junior School in Luton, with carbon savings in the region of 53 t a year and a 15% reduced carbon footprint in one year following the installation of three Remeha Quinta Pro 115 condensing boilers with low-temperature radiators and fan heaters.|
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% 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 zones of temperature and time control, and weather compensation.
Just as cars require annual MOTs, all boilers need an annual service to ensure clean and 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 servicing 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 1 mm layer of soot will require a 10% increase in energy input to the boiler to meet the same heat demand.
|Remeha’s ‘super condensing’ Quinta Eco Plus heat recovery unit was specified as the affordable ‘green’ heating option for the new-build Taunton Academy in Somerset to reduce energy consumption and carbon emissions whilst offering fast financial payback.|
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 to meet the same heat demand. A 1 mm layer of scale can cause a 7% increase in energy requirement. Specialist chemical treatment is necessary to remove 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% of the energy output. Also check the insulation on the pipework and valves. Replacing it at the appropriate time can save up to 10% 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%, 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.
Mark Northcott is managing director of Remeha Commercial.