Harnessing waste heat to achieve zero carbon heating for UK communities

Friday, 28 May 2021

The University of Nottingham has received £1.3m to develop a novel, low-carbon energy storage system to supply cheap, on-demand heat for people living and working in UK neighbourhoods.

The technology will help to decarbonise the buildings sector, while also addressing issues of fuel poverty and pollution.

The project aims to overcome technical challenges that currently limit the capabilities of conventional thermochemical energy storage systems. Simultaneously, the researchers will investigate social, economic, environmental barriers that prevent the uptake of community-based heat networks in the UK.

Once tested and operational, a pilot model of the new thermochemical energy storage system will be connected to a small-scale district heating network already in operation at the Creative Energy Homes complex at the University of Nottingham. This test-bed demonstrator, which represents about five or six buildings on University Park campus, will then be evaluated for effectiveness and performance.

Nottingham City Council is a key partner on this project. With the City aiming to be carbon neutral by 2028, the Council is keen to understand whether the prototype could be adopted on its District Heat Network. Gathering statistical data from real-life communities that evaluates the effectiveness of the technology is vital to deliver a product that has buy-in from future users and is capable of meeting their disparate heating needs.

Nottingham City Council’s Deputy Leader and Portfolio Holder for Energy, Environment & Waste Services, Cllr Sally Longford, said: “As a council that’s leading the drive for Nottingham to become carbon neutral by 2028, we’re pleased to be part of this project and keen to explore innovative ways of achieving our carbon reduction goals.

“Decarbonisation of heat is a key challenge we need to find solutions for, and we’re interested to find out if this approach being piloted by the University of Nottingham could be applied to our own district heating network.”

“From 2030 individual homes and commissioned buildings won’t be able to use individual gas boilers, so we need low carbon and zero carbon heating systems that can replace fossil-fuelled systems. A key alternative is district heating systems which distribute hot water into multiple properties via networks of communal pipes. “District heating systems are advantageous, because they can use excess heat - a free raw material - from industrial processes or sustainable sources such as geothermal to heat water for large numbers of homes. It’s very common in Scandinavia, Germany and China.”
Project lead investigator, Professor Jo Darkwa

However, the variable nature and temperatures of the low-zero carbon sources, both short-term (daily) and long-term (seasonal), and mismatches between needs and availability of energy, make decarbonisation more difficult to achieve at an individual building level.

“District heating systems are ideally placed to provide the infrastructure to overcome this issue in urban settings, but require suitable energy storage facilities that can cope with an influx of varying source temperatures; commercial waste is a much higher temperature than solar thermal heat, for example. At present, we have limited and effective ways to store recovered waste heat for later usage,” adds Professor Darkwa, from the Department of Architecture and Built Environment.

How it works

The system involves a very unique double-acting agitated heat recovery and heat charging mechanism to store and discharge the heat. The system also consists of two fluidised beds of inorganic oxide compounds that have very high energy density. The heat can be stored in this material and then at a later date be reactivated by means of chemical reaction.

The project is looking at the most effective material to store heat for later application. Basic materials are commercially-available but they have limitations. Part of the research is to characterise all available materials in the lab and then enhance their heat transfer capabilities.

Why it’s a game-changer

While conventional thermochemical energy storage systems require intermittent operation, thanks to the mechanism and material to be developed for the project, the novel system proposed will operate continuously at variable temperatures.

Professor Darkwa said, “To maximise its supply, the new system will be able to collect heat from different sources and temperatures. It will be flexible and smart; able to sense the temperature that is being delivered and store it appropriately. It will also be relatively cheap to run compared to conventional systems, which store heat in large water tanks at fixed temperature. At domestic level, it removes the fossil fuel cost, and the financial burden of boiler purchase, servicing and maintenance.

“Our system is decentralised. With that you can minimise the amount of heat lost through very long communal heating pipe systems. It can retain the energy in its absorbed state, with near-zero losses and so potentially allow storage inter-seasonally, e.g. storing solar energy in summer during low demand and discharging in winter during high demand.”

Funded by the Engineering and Physical Sciences Research Council, the three-year project involves expertise from the Faculty of Engineering, the School of Chemistry and Nottingham University Business School.

Minister for Climate Change Lord Callanan said: “The way we use energy in our buildings makes up almost a third of all UK carbon emissions. Reducing that to virtually zero is going to be key to eradicating our contribution to climate change by 2050.

“That’s why it’s important that innovative projects like Decarbonisation Of Food Cold Chain Through Integrated Hydrogen Technologies and Variable-Temperature Thermochemical Energy Storage System (VTTESS) in Nottingham receive backing to develop new and effective ways to heat and cool our homes and workspaces, helping drive down the costs of low-carbon technologies so everyone can feel the benefits of cheaper and greener energy.”

Story credits

More information is available from Professor Jo Darkwa on 0115 961 3156 or or Emma Lowry, Media Relations Manager (Engineering) on 0115 84 67156 or

Emma Lowry - Media Relations Manager Engineering
Phone: 0115 846 7156
Location: University Park

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Notes to editors:

The University of Nottingham is a research-intensive university with a proud heritage. Studying at the University of Nottingham is a life-changing experience and we pride ourselves on unlocking the potential of our students. We have a pioneering spirit, expressed in the vision of our founder Sir Jesse Boot, which has seen us lead the way in establishing campuses in China and Malaysia - part of a globally connected network of education, research and industrial engagement. Ranked 103rd out of more than 1,000 institutions globally and 18th in the UK by the QS World University Rankings 2022, the University’s state-of-the-art facilities and inclusive and disability sport provision is reflected in its crowning as The Times and Sunday Times Good University Guide 2021 Sports University of the Year. We are ranked eighth for research power in the UK according to REF 2014. We have six beacons of research excellence helping to transform lives and change the world; we are also a major employer and industry partner - locally and globally. Alongside Nottingham Trent University, we lead the Universities for Nottingham initiative, a pioneering collaboration which brings together the combined strength and civic missions of Nottingham’s two world-class universities and is working with local communities and partners to aid recovery and renewal following the COVID-19 pandemic.

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