Getting back to normal

Lochinvar, DHW, domestic hot water, quick fixes
Consistent energy savings — David Pepper.

Water heaters installed in the 1980s to improve energy efficiency are due for replacement — and their successors are even more energy efficient, explains David Pepper of Lochinvar UK, who also believes that the new generation of water heaters are more effective at reducing energy use than more exotic engineering.

This year’s CIBSE president David Fisk is not a man to mince his words. In his inaugural address, he savaged the role of ‘spin doctors’ and the way in which engineering language has been ‘prostituted’ to aid commercial goals. He urged the engineering community to ‘reclaim its language’ and put a halt to the spread of ‘greenwash’.

Professor Fisk wants the industry to get back to what he calls ‘normal’ engineering values and reduce complexity. He believes that the issue of carbon reduction has become confused, leading to overly complex engineering when good, basic energy efficiency would have achieved so much more.

His message is very much in tune with the new mood of austerity, and the building-services sector is living through a more pragmatic period with tighter budgets and more demanding clients. The expression ‘cost optimal’ is cropping up in much of our legislation and, particularly, in the draft revisions to Part L of the Building Regulations due to come into force next year. Cutting energy and carbon is the aim, but solutions must be financially sensible.

One excellent example is the upgrading of hot-water generation. With commercial building owners and operators looking for cost-effective ways of reducing their energy bills, there is a growing market for boiler and water-heater upgrades. In particular, demand for direct-fired water heaters is on the up.

The Carbon Trust estimates that UK businesses waste over £400 million a year by failing to take simple, low-cost measures to improve the efficiency of their hot water equipment. As heating and hot water accounts for over one third of UK firms’ total energy consumption and up to 60% of carbon emissions, this is a pretty important area.

The energy-efficiency improvements, driven by the regular revisions to Part L, have seen hot water overtake space heating as the predominant load in many commercial properties. Improving or adding controls to the hot-water system and insulating individual components, as well as the building fabric, could cut commercial energy bills by 30%, according to the trust’s research.

The media may be more fixated on more glamorous — less ‘normal’ — technology developments such as solar, wind and biomass, but most commercial energy users can’t afford glamour. They need to see a good return on their investment. Replacing older appliances with direct-fired condensing water heaters is one example of a simple design approach that can quickly reduce the energy usage of a building, with minimal disruption and for a modest financial outlay.

Newcastle City Council, for example, has several hundred buildings and an annual energy bill of around £6 million. It has been developing its energy- and carbon-saving strategy for many years and, back in 2005, confirmed that the ‘energy-efficiency measures which have consistently provided the best financial payback and CO2 savings have been the installation of direct-fired gas water heaters’.

The replacement market for commercial water heaters is growing because many were installed in the 1980s when the Government supported a programme of decentralisation of water-heating systems to improve energy efficiency. A large percentage of that market is now ready to be replaced, and there is a big opportunity here for carbon and cost savings as ageing heaters can be easily replaced with more modern high-efficiency alternatives.

To achieve the best savings, it is also sensible to keep space and water heating apart. The high-efficiency condensing-boiler technology, now widely adopted, was not specifically designed to produce hot water. If you run condensing boilers at 60°C and above just to produce hot water at a temperature that reduces legionella risk, they will not condense — rather defeating the object.

If heating and hot-water systems are separate, there is less need for large storage vessels, which means smaller plant rooms. They can be even smaller if the hot-water generation system is decentralised with units installed close to the point of use. Reducing the amount of stored water also limits the risk of legionella bacteria growth.

Separation also makes it easier for the system designer to closely match appliance capacity to demand and heating loads. This reduces the seasonal inefficiencies caused by boiler plant running through the summer just to heat water.

All of this meets Professor Fisk’s call for good, energy-efficient design solutions, but his desire — shared by many — for ‘normal’ engineering does not preclude the use of more expensive renewable technologies. They will definitely continue to play an important role. It just means it is not acceptable to throw money at the carbon-saving problem. Budgets are tight, and payback needs to be attractive enough to get building owners to do the right thing. Making your building more efficient also makes it more suitable for renewables.

Upgrading water heating might not be glamorous, but it ticks all the other boxes — and it is definitely the normal thing to do.

David Pepper is managing director of Lochinvar UK.

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