To meet the nation’s ambitious net zero target, we need to rethink how we keep our homes warm. Electrical heat pumps are already making waves, and there is a growing buzz around using the existing natural gas network to distribute hydrogen and burn it in boilers. We have also explored blending these two solutions in ‘hybrid boilers’. But, as the energy landscape evolves, it is only natural to wonder – could there be other groundbreaking solutions to help us revolutionise the way we heat our homes?
A recent event organised by the Energy Research Accelerator and the University of Nottingham set out to answer that question. Held on 6 November 2024 at the IMechE headquarters in Westminster, the event brought together a mix of academics, industry leaders and policymakers to explore ideas to reduce carbon emissions from domestic heating.
New space heating solutions could have a broad impact on the UK electricity system, especially if the use of heat pumps becomes widespread. There are three key reasons why this shift is so significant: we may need to generate much more electricity to meet the increased heating demand; heat pumps could offer flexibility, allowing us to absorb electricity when it is abundant; and the strain on the system during the coldest times of the year could become very severe, underscoring the importance of ensuring heat pumps perform optimally even in the harshest winter conditions.
The event was chaired by Dr Anna Stephenson, deputy director for energy engineering and research at the Department of Energy Security and Net Zero, enabling a comprehensive exploration of the challenges and opportunities involved and providing valuable insight into the government’s plans.
Throughout the day, 16 academic experts presented their latest research findings, providing useful perspectives on developing, implementing and scaling clean heating solutions. The presentations focused on three main areas: heating systems and heat pumps, energy storage and system integration.
Heating systems and heat pumps
Dr Ramin Mehdipour from the University of Nottingham discussed repurposing the existing gas network to distribute non-potable water to houses. During very cold days, the water will be warmer than the ambient air, which can improve the performance of heat pumps. In a similar vein, Dr Zahra Baniamerian (University of Nottingham) explored the use of the existing gas pipelines to distribute aqueous ammonia, which could be easily separated and burned cleanly in a boiler to provide heating.
Thinking even further outside the box, Olivia Davies (University of Nottingham) presented an innovative system that injects warm air directly into a space and therefore requires no additional refrigerant.
Another colleague from the University of Nottingham, Dr Bruno Cardenas, introduced a heat-driven heat pump that uses hydrogen as fuel. This concept allows continued use of the gas network, offers much higher efficiency than a simple hydrogen boiler and avoids overwhelming the electricity grid during peak times.
Dr Muhammad Abid from the University of Liverpool explained how we could increase the efficiency of a heat pump by integrating it with a hot water tank to store and reuse some of the heat the refrigerant retains after it emerges from the condenser.
Lastly, Professor Yunting Ge (London South Bank University) moved away from vapour-compression cycles and talked about chemical heat pumps based on metal hydrides. These heat pumps achieve a similar coefficient of performance to absorption heat pumps, but are physically smaller and have a much wider range of output temperatures.
Energy storage
Addressing this topic, Dr Rahul Ravindran (Ulster University) and Dr Sai Yagnamurthy (University of Warwick) presented results of experimental tests done on new designs of thermal stores, based on phase change materials and absorption reactions respectively. These heat stores could enhance the efficiency of heat pumps and enable them to load-shift.
Similarly, Professor Yuehong Su (University of Nottingham) reported on work integrating a thermochemical energy storage system into an existing domestic central heating system, showing that water at temperatures between 27-35°C can be provided for up to 16 hours.
Dr Zhiwei Ma from Durham University took things a step further with an innovative hybrid system. By combining a heat pump with an ammonia-based thermochemical energy store, his system can store solar energy throughout the year, ready to provide space heating during the coldest winter months.
Lastly, Dr Adriano Sciacovelli from the University of Birmingham discussed the use of an iron oxidation-reduction cycle to provide high temperature heat and long duration energy storage.
These cutting-edge developments are pushing the boundaries of what is possible in sustainable heating, offering a glimpse into a future where energy is both efficient and flexible. All researchers emphasised the key role that advanced thermal storage systems can play in decarbonising heating.
System integration
Professor Patrick James from the University of Southampton talked about the possibility of remotely controlling residential heat pumps. After conducting field trials involving over 100 houses, James has found a generally positive response to heat deferral. He emphasised the potential of this non-disruptive method to contribute to grid flexibility and energy decarbonisation.
Building on this theme of innovative solutions, Professor Yongliang Li from the University of Birmingham introduced his groundbreaking concept called the ‘e-thermal bank’. By combining microwave technology with a chemical heat pump, this idea – essentially a smaller, more affordable and easier to use combination of battery and heat pump – turns intermittent renewable electricity into on-demand heating and cooling.
Next, Professor Daniel Friedrich from the University of Edinburgh presented a bold vision for decarbonising heating in the UK. His holistic approach included using curtailed wind energy to charge large-scale thermal energy storage systems, which not only boosts system flexibility and resilience, but also eases the electricity demand during long, cold winters. Friedrich also highlighted how integrating flexible domestic transport and heating could provide massive benefits to the wider energy network.
Finally, Dr Miguel Angel Pans Castillo from the University of Loughborough presented some interesting simulation results from an ultra low-carbon district heating network in Loughborough, which combined heat pumps, evacuated-tube solar thermal collectors and seasonal thermal storage. Pans Castillo’s presentation also highlighted the pivotal role of distributed thermal energy storage in decarbonising space heating.
Overcoming blocks to progress
The day concluded with a panel session featuring Carl Arntzen, CEO of Worcester-Bosch UK, Richard Hynes-Cooper, head of operations at Net Zero Research Village (run by Northern Gas Networks) and Elliott Sharpe, strategy and partnerships director at Vital Energi.
This panel tackled the current blocks to progress, and discussed how disruptive approaches and scalable solutions could help achieve the UK’s energy and climate goals. The panellists emphasised the importance of collaboration between industry and academia in driving forward innovative heating and energy storage technologies.
Some of the key takeaways from the event were:
• Diversity of solutions: Swift action is needed to identify and deploy the most effective technologies. A one-size-fits-all approach is unlikely; instead, diverse solutions tailored to different scenarios will be necessary. Promising solutions should be trialled quickly to see how effective they might be.
• Focus on scalability: All of the solutions that will make any significant impact will have to be scalable. Many of them will need to be retrofittable to existing properties currently heated by gas.
• Flexibility: The flexibility provided by some heating solutions into the electricity system is going to be extremely important. The role for integrating thermal storage will be very high in future.
• Holistic energy system interaction: Stronger connections between space heating, electricity networks, water systems, digital processes and transportation will shape the energy landscape in the years ahead.
• Dynamic pricing: Electricity pricing that is zonal and time-varied can influence the way in which electrical heating is operated to great benefit, but measures are needed to protect the vulnerable if this is operated.
• The growing role of heat networks: Heat networks will play an increasingly important role and siting these with sources of low-grade heat can be effective.
• Stable, long-term policy support: Decarbonisation of heat (and all other sectors) requires consistent policy backing that extends beyond short-term political cycles. Establishing an all-party parliamentary group could provide the stability and continuity needed to drive long-term change.
• Public engagement is key: Transitioning to clean heating solutions requires active public participation. This transition cannot rely solely on heating solution providers; government support and clear communication strategies are vital.
The event underscored the commitment of academic, industrial and policy leaders to collaboratively explore and implement diverse, scalable solutions for decarbonising heating in the UK. The shared insights and innovative concepts presented offer promising pathways toward a sustainable and low-carbon future.
The complete set of presentations and session videos are available to view online.
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