Let’s get radical … about heat
The heating sector needs to shift up a gear in using energy efficiently to keep pace with dramatic changes in demand and technology, according to Tim Rook of the Building Engineering Services Association.
The link between the growing market for electric cars and the way we heat our buildings is not immediately obvious, but it is fundamental to the way we will need to adapt.
Electric cars are increasingly numerous, and the trajectory is only going one way — but if you have one you have to charge it somewhere, and buildings (residential and commercial) are the obvious place.
Heat pumps have also been identified as a favoured technology for improving energy efficiency and upgrading heating (and cooling) in a wide range of buildings. So our industry is moving inexorably towards an electric model increasingly powered by renewables and ‘clean’ power from nuclear.
At the same time, this opens the door to a fundamental review of the way British heating systems are designed. We have been wedded to systems working at 80°C for decades, and there is an element of social conditioning around how hot a radiator should feel. We are also beholden to health-and-safety rules that suggest we must maintain high temperatures in storage tanks to reduce the threat from legionella bacteria.
However, the push for more renewable/heat-pump heating requires acceptance of a low-temperature heating model, which is already prevalent in continental Europe. For example, domestic hot water is stored at 50°C in several European countries, including Germany and Sweden, and underfloor heating is widespread.
As a result, these countries enjoy significantly lower energy use and costs, lower carbon emissions and systems that are better suited to integration with renewable sources that produce low-temperature heating — like heat pumps. The legionella threat is handled by disinfection rather than by using more expensive heat.
Opportunities to combine low-carbon heat sources with district-heating schemes, energy storage and demand-response technologies are also emerging. The Government is rolling out its £320 million fund to support the development of more district-heating schemes — and this could be the key that unlocks this whole area.
The five-year Heat Networks Investment Project (HNIP) is designed to help build more networks and improve the efficiency of existing low-carbon heating schemes in England and Wales. The Department for Business, Energy & Industrial Strategy (BEIS) wants to drive the use of recycled waste heat from factories, power stations and even the London Underground, as well as CHP and biomass schemes to cut costs and emissions by as much as 30%.
Heat networks are a great enabling technology and, once the pipes are in the ground, a variety of low-carbon and renewable sources can be linked up to them to supply large-scale schemes serving both domestic and non-domestic consumers.
This opens up possibilities for large or multiple heat pumps working as part of an integrated system.
These are exciting times for our industry because of the mix of solutions available and the potential of combining waste heat and low-carbon sources, but the Government must play its part by being smart about the incentives it creates to support development of the supply chain.
In tandem, the Government needs to be investing in the power grid to make it flexible enough to work with new energy sources. The capacity market system, which is designed to reduce the risk of power cuts at times of extreme demand, will encourage more energy storage. This would provide much needed stability and increase the amount of renewable energy feeding into the grid.
If the Government does succeed in driving up the electric-car market and increasing the number of heat-pump installations as it intends, this will create extra stress on the grid — particularly during the winter when demand is high anyway. Each heat pump will need a certain amount of electricity, so energy storage and the ability to reduce demand from other parts of the system through ‘smart’ response technologies can smooth out the peaks and support an extended car-charging network.
All this requires ‘joined up’ and long-term thinking. Any incentive system the Government puts in place must reflect this and recognise that true carbon savings will only be delivered if the total system is of sufficient quality. For example, heat pumps must achieve a good coefficient of performance (COP) and where condensing boilers are used, the system must allow them to condense.
This requires a well-trained workforce backed by employers with the confidence to invest in new skills and technologies. Our industry also needs to be able to operate in an environment where they are allowed to innovate and actually ‘engineer’ the right solution for each project. So, rather than a prescriptive regulatory approach; a performance target measured in kWh/m2 would allow designers to look for the most appropriate answer to each project challenge.
The production of heat is responsible for more energy consumption than any other process in the UK — about 40% of the total. So any progress in this area will be hugely significant for both our climate-change targets and also the future economic growth of UK Plc — including our enthusiasm for an electrified transport infrastructure.
Tim Rook is technical director of the Building Engineering Services Association (BESA).