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Game changing heat recovery and storage technology: Trigeneration Recovery Efficient Energy Storage (TREES).

Almost half of the final energy consumed in the UK is to provide heat – more than that used to produce electricity or for transport. Maximising the use of renewable low grade heat, such as geothermal and solar thermal, is essential for decarbonising UK heating.

BEIS estimates that the 8 most heat-intensive industrial sectors generate 48 TWh/yr of industrial waste heat per year. The recovery and re-use of this waste heat would significantly reduce energy costs and carbon emissions.

However recovering and utilising low- and ultra-low-grade heat is technically challenging and, although there are technologies in existence that can do this, few of them have been widely adopted due to their poor economic viability.

Addressing the heat decarbonisation challenge

To meet the challenge the Durham Energy Institute team have developed the Trigeneration Recovery Efficient Energy Storage (TREES) technology. This zero carbon emission solution based on thermochemical sorption reactions:

  • uses low- and ultra-low-grade heat sources,
  • provides combined thermal and electrical energy storage, and
  • delivers heating, cooling and/or electrical power in one integrated system.

The TREES system is a highly disruptive and flexible zero-loss energy storage and zero carbon energy conversion system. It has potential to substantially reduce fossil fuel consumption and energy demand in a wide range of applications particularly in industrial sectors where a large amount of waste heat is generated.

Moving the technology closer to market with InnovateUK support

In work funded through InnovateUK we designed a first-of-a-kind TREES energy storage system and have undertaken the necessary mathematical modelling, simulation, control strategies and industrial case studies for a commercial prototype. We have also undertaken a techno-economic analysis and an understanding of the market potential for the TREES system and the potential for a UK based thermochemical systems business.

This has enabled the project team to build a deeper understanding of the TREES technology and detailed insight into the requirements of the successful design, manufacture and industrialisation of TREES technology.

Demonstrating at scale

The project ended in October 2020, however the exploitation of the technology and its route to market has not stopped. Initial target customers are those operating in industry sectors where large amounts of waste heat are generated, such as the traditional petrochemical sector and the bioprocessing sector. The project team has worked with contacts in these sectors, via existing relationships with the Centre for Process Innovation (CPI) and the North East Process Industry Cluster (NEPIC), and has generated interest in the technology as the project progresses.

The demonstration and testing of a prototype TREES system will allow these key stakeholders to directly observe the potential cost benefits of adopting the technology and the operational efficiency advantages of the technology over other heat recovery and energy storage systems available on the market.

The team’s longer-term plan is to expand, both nationally and internationally, to target users in other industries where efforts to reduce waste heat are already underway such as food and waste water industries.

Find out more about Durham Energy Institute’s research on decarbonising heating and cooling.

University student
There is enormous source of low-grade and ultra-low-grade heat which is usually considered useless and/or not economically viable to use. The successful recovery and reuse of this heat in an efficient and low-cost way would be a game changer for making a net-zero future. TREES technology has the potential to be the choice due to its high efficiency and flexibility. We look forward to working closely with industrial partners to demonstrate and commercialise this technology.

Dr Zhiwei Ma
Durham University, Department of Engineering.