Heating engineers must learn a new language
A change of emphasis from cutting carbon to saving energy is a subtle, but significant one for the commercial heating sector, says B&ES head of sustainability David Frise.
Since the economic crash, the word ‘carbon’ has started to feature less and the word ‘energy’ far more in the rhetoric of British and European politicians. With the UK now a net importer of energy; economic and security of supply fears have moved to the top of the agenda.
Whatever we might feel about the Chancellor George Osborne’s attitude to sustainability, he has always been clear that any new measures to tackle energy consumption in the built environment must not add to the cost burden on British businesses and consumers. There is no point railing against this stance, we have to find a way to work within these constraints and heating engineers should relish the challenge.
The truth is that cutting carbon is relatively easy if you can afford to deploy renewable technologies with little thought for energy efficiency. In our economically constrained circumstances, this is no longer a practical or acceptable solution.
Much of government policy in our area calls for new measures to be self-financing – the Green Deal being the most obvious example. The current consultation about changes to Part L of the Building Regulations will also see an adjustment in targets that is more realistic about what can be achieved affordably.
The original ‘zero carbon’ target is being adjusted to a more realistic goal of making new buildings around 50 per cent more energy efficient by 2019 (compared with 2006 regulations), which is still a significant engineering challenge.
In the recast Energy Performance of Buildings Directive (EPBD), which came into force on February 1 this year, all new buildings are to be “nearly zero energy” by December 2020, with all public buildings two years ahead of this deadline. Targets are no longer expressed in terms of carbon, but in kWh/m2 per year, which is a language engineers can relate to more easily.
The Royal Academy of Engineering believes the Government is starting to realise that current targets for renewable heating in the domestic market are unrealistic and unaffordable. “To switch a large part of the domestic heating load to electric heating would greatly increase the demand on the grid and increase the challenge of meeting peaks in demand,” it said in its ‘Heat: Degrees of Comfort’ report.
“To attempt to meet the whole of such a load by renewables would require a level of installed capacity that would be almost impossible to build. Storage, whether of natural gas, biomass, large scale thermal storage… will be essential,” it added.
The Academy is also concerned that there are a number of technologies, such as combined heat and power (CHP) and heat pumps, which could make a significant contribution to carbon reduction by improving efficiency, but are ignored by policy makers because they are not renewables.
However, at the recent ‘New Solutions for Heating System Design’ conference hosted by the Institution of Mechanical Engineers it was clear that commercial heating experts believe there is a strong move towards more pragmatic and cost-effective measures. In the main, they saw increasing roles for district and community heating schemes; CHP and thermal storage systems – all solutions that were also identified by the Royal Academy’s report.
Frank Mills of consultants Sinclair Knight Merz said large-scale renewables that supply multiple buildings are more cost-effective than the individual building-by-building approach currently supported by the Feed-in Tariff scheme. Using off-site renewables in tandem with thermal storage could overcome the problem of renewables not always producing energy when it is most needed.
However, if we are to achieve the greatest benefit we must make faster progress on district heating. Currently only two per cent of UK heat comes from district schemes, but the new heating strategy to be unveiled by the Department of Energy and Climate Change (DECC) puts community heating front and centre of its plans for urban development. Schemes like the Greater London Authority’s energy network show what can be achieved by making good use of existing and new infrastructure to share heat between multiple buildings – this needs to be more widely replicated.
The role of heat pumps was another major talking point at the IMechE conference. None of the installations studied in the 2010 Energy Savings Trust field trials had a higher coefficient of performance (COP) than 2.5, which defeats the object of spending on them in the first place. There is nothing inherently wrong with the technology, it is how it is deployed, commissioned and operated that counts. Ground source systems are ideal with low temperature heating systems, such as underfloor, and this combination works really well where it is properly applied – and that’s the key.
The ability to deliver on our promises must be the main objective for the heating sector. The Green Deal and the Renewable Heat Incentive (RHI) put this issue fully in the spotlight. If the systems do not perform as promised then the right level of payments will not be forthcoming and the whole premise of these flagship government policies will collapse.
There is the added problem of heat metering, which threatens to undermine our sector’s efforts to meet performance targets. If heat meters are not being correctly installed or calibrated, it will lead to erroneous data that could undermine the RHI payment system. Further guidance on this will be produced later this year by B&ES because it is a potential Achilles heel for the whole process.
The one thing all the technical solutions have in common is the need for robust commissioning and expert integration of technologies as part of overall building energy saving strategies. Integration is the key to delivering the ongoing performance and energy savings so vital to our future economic prosperity.
The Building & Engineering Services Association (B&ES) – formerly the HVCA – is developing a systems integrator guide in partnership with CIBSE, the Building Controls Industry Association (BCIA) and BSRIA, which will be published later this year. This cross-industry venture shows that integration is seen as the key to all our future efforts and, in this more pragmatic world, offers the best return on investment.
This article first appeared in H&V Review magazine.