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Professor John Counsell and Dr Yousaf Khalid in the Energy Centre at Thornton Science Park.

Professor John Counsell is Head of the Department of Electronic and Electrical Engineering and has created a new concept of a hybrid heating system which uses off-peak electricity (and therefore takes pressure off the National Grid), as well as reducing carbon emissions.

Together with his colleague Dr Yousaf Khalid, they have computer-modelled the ‘Renewable Integrated and Sustainable Electric’ (RISE) hybrid heating system, which consists of an Air Source Heat Pump (ASHP), a thermal storage tank (hot water), and an off-peak powered thermal storage boiler. ‘RISE’ stores up energy during periods of low electricity demand from the National Grid, turning it into a dynamic supply of low cost heat which is utilised only when required, making it not only cost effective, but a more environmentally friendly approach to heating a home.

Its research and development (R&D) has been part of a collaborative project funded by Innovate UK, in partnership with EDF Energy, for tariff design; BRE, for regulatory compliance and standards; Glen Dimplex, for innovation of the system implementation and the thermal storage boiler; and Eastbourne Homes, for consumer requirements. A prototype of ‘RISE’ was developed and tested for a year in the Watford BRE Innovation Park in the BRE’s Prince’s Trust house.

The Government has recognised a need to reduce the emissions created by heating our homes. According to the Government’s Clean Growth Strategy – which experts believe places increasing emphasis on decarbonising the UK -  by 2050, the UK ‘will also likely need to fully decarbonise how we heat our homes’. Heat pumps are one of the potential low carbon heating technologies the Government recognises may be needed.

The cold temperatures in March last year also saw the National Grid issuing a warning that the UK would not have enough gas to meet public demand. While this does not automatically affect households, who are the priority in such scenarios, it impacts instead on industrial use, which potentially becomes limited – as well as on the cost of future supply.

Professor Counsell said: “Everyone talks about decarbonising electricity, but no-one talks about how to decarbonise heat realistically, which is what ‘RISE’ is. At the moment, gas is the major fuel being used to generate electricity in power stations (as well as being used directly in people’s homes). Electrical energy efficiency of appliances and lighting since 2006 has contributed to the removal of national grid coal fired power stations. It has also reduced the free heat gains into the home and, consequently, we will see a rise in domestic heating gas demand that has the potential to result in low gas supplies and increasing electricity prices.

“I believe that a long term affordable and secure heating supply to homes is essential to offset the increasing threat of fuel poverty in the UK. A novel heating solution is needed. The RISE project was developed and funded to take this challenge and deliver affordable electric heating.”

In a similar way to hybrid cars using two sources of energy to provide power to the car, a hybrid heating system uses two sources for heating a house.

One source is an ‘off-peak’ thermal storage boiler, based on Glen Dimplex’s Quantum Storage heater technology, that uses cheaper night time electricity to heat the bricks inside it. The hot water pipes in the house are passed through the off-peak boiler to warm the water for the house radiators providing heat during peak heating hours from 7am to 9am and 4pm to 8pm.

During off-peak hours, the off-peak boiler charges itself and the heating is provided by the second heat source – the Air Source Heat Pump. The heat pump operates like a fridge in reverse. (A fridge extracts heat from inside the fridge to inside the kitchen.) Similarly, the heat pump extracts heat from outside air and uses it to heat the water stored in the hot water storage tank. When the next peak heating time arrives, the hot water from the storage tank is circulated to the radiators and topped up with heat from the off-peak boiler. Hence this configuration avoids placing heat demand on the National Grid during peak times and thus reduces the need for network reinforcement.

Dr Yousaf Khalid added: “The RISE heating system can be configured, where the heat pump can be shared across several small dwellings (such as flats) while the off-peak  boiler in each dwelling supports heating during peak hours. This helps with the capital cost of the system, which could make this particularly attractive to local authorities and housing associations. For larger dwellings, one heat pump with one storage boiler would be the normal approach.

“So far, the results show that the RISE system can outperform a heat pump only heating system in terms of carbon emissions, whilst being competitive in running costs with a conventional gas boiler heating system.”

The RISE hybrid heating system research continues, with a move to develop second generation prototypes of the control system and the off-peak boilers. The aim of the next phase of the project is to use these new prototypes for field trial testing, ideally throughout the local authority regions of the UK.

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