Increased pressure on reducing the carbon footprint from energy intensive industry such as glas, iron and steel, cement and oil and gas, with substantial waste heat streams is leading to the need to develop efficient and cost-effective waste heat recovery technologies. With waste heat stream at temperatures typically below 500 deg C, and low flow rates that mean commercially available steam power generation systems are unsuitable, attention is focused on other waste heat recovery technologies. Thus, significant research efforts have focused on the next generation of thermal-power systems, operating with novel working fluids such as organic fluids and supercritical carbon dioxide (sCO2). The ORC, which uses an organic working fluid, has been proven for conversion of heat between approximately 100 and 350 deg C into electricity, and commercial systems are available. However, ORC systems remain associated with high investment costs, whilst organic fluids are often flammable, unstable at high operating temperatures, and associated with a detrimental environmental impact. Alternatively, CO2 is an extremely promising candidate with benefits including low cost, is non-flammable and has a lower environmental impact than organic fluids. It facilitates compact components owing to high fluid densities, and high cycle efficiencies can be obtained at moderate heat-source temperatures. Despite its significant potential, sCO2 systems for waste heat recovery applications have not been commercialised yet, due to significant technical challenges that need to be overcome. This includes the development of suitable heat exchangers and turbomachinery, as well as the identification of optimal systems that adequately address the trade-off between performance and complexity The focus of this proposal is to conduct original research to improve the fundamental understanding of the performance sCO2 cycles and the design aspects of the key components, namely compressors, expanders and heat exchangers. Computational and experimental methods will be used to investigate the performance and design characteristics across a wide range of operating conditions. These studies must account for the complexities of using sCO2 that exhibit complex fluid behaviour not observed in conventional fluids such as air and steam, in addition to considering the high-speed flows, and two-phase conditions close to the critical point at the compressor inlet, and the corrosive nature of sCO2 with low level of humidity to the heat exchanger materials. Ultimately, the results from these studies will improve the existing scientific understanding, and will facilitate the development of new performance prediction methods for the cycle and components. Understanding these aspects will not only lead to improved performance prediction, but could also lead to improved component design in the future. Within this project the new prediction methods will be used to investigate and compare the performance of different cycle architectures and component designs. The results from these comparisons will enable the identification of the optimal systems that can operate across a wide range of heat input and load conditions, and therefore best facilitate improvements to sCO2 systems. The primary outcomes of this research will be improved fundamental understanding of the performance of sCO2 cycles and component designs and validated performance models for compressors and expanders. Furthermore, recommendations will be made on the most appropriate system configurations that offer improvements to operational aspects, thus enabling the future commercialisation of small-scale sCO2 technology for waste heat recovery. Therefore this project has the potential to stimulate investment and create new jobs within the low carbon energy market, whilst positively contributing to the UK's existing research portfolio in waste heat recovery from energy intensive industry.

The decarbonisation of industrial clusters is of critical importance to the UK's ambitions of cutting greenhouse gas emissions to net zero by 2050. The UK Industrial Decarbonisation Challenge (IDC) of the Industrial Strategy Challenge Fund (ISCF) aims to establish the world's first net-zero carbon industrial cluster by 2040 and at least one low-carbon cluster by 2030. The Industrial Decarbonisation Research and Innovation Centre (IDRIC) has been formed to support this Challenge through funding a multidisciplinary research and innovation centre, which currently does not exist at the scale, to accelerate decarbonisation of industrial clusters. IDRIC works with academia, industry, government and other stakeholders to deliver the multidisciplinary research and innovation agenda needed to decarbonise the UK's industrial clusters. IDRIC's research and innovation programme is delivered through a range of activities that enable industry-led, multidisciplinary research in cross-cutting areas of technology, policy, economics and regulation. IDRIC connects and empowers the UK industrial decarbonisation community to deliver an impactful innovation hub for industrial decarbonisation. The establishment of IDRIC as the "one stop shop" for research and innovation, as well as knowledge exchange, regulation, policy and key skills will be beneficial across the industry sectors and clusters. In summary, IDRIC will connect stakeholders, inspire and deliver innovation and maximise impact to help the UK industrial clusters to grow our existing energy intensive industrial sectors, and to attract new, advanced manufacturing industries of the future.