This PhD project aims to design heat integration strategies within multi-vector energy systems to enhance overall system flexibility and efficiency.The route to net zero faces two main challenges: first, the increasing integration of non-dispatchable and variable renewable energy resources, such as wind and solar power, creates significant challenges for energy systems, notably in terms of maintaining reliability and balancing supply with demand; and, second, there is almost no progress and not even a credible roadmap for heat decarbonisation (low temperature space heating as well as high temperature industrial heat). By focusing on the thermal aspects of energy systems, and particularly on strategies for efficient heat integration, this research aims to provide novel solutions that enhance system stability and provide affordable and sustainable heat.The project will investigate heat integration techniques across various levels of the energy system, including industrial processes, district heating networks, and residential heating solutions. Key areas of focus will include the integration of advanced thermal storage technologies, the utilisation of waste heat recovery, and the implementation of innovative heat pump technologies. This multi-scale approach ensures that the project addresses both high-grade industrial heat and low-grade residential heat requirements.A significant component of the research will involve the development of mathematical models and simulation tools to evaluate potential heat integration scenarios. The models and tools will be built on existing open-source tools in the Institute for Energy Systems, commercials tools such as TRNSYS and open-source tools such as PyPSA. These tools will help in identifying optimal ways to deploy thermal energy storage and recovery, thus enabling better management of renewable generation variability. The methodologies developed will consider not only energy efficiency but also economic and environmental impacts, ensuring that the solutions are sustainable both technically and financially.The candidate will develop a wide range of skills in simulation, optimisation, and data analysis which are widely applicable to future career development. Additionally, there are opportunities for engaging with an open and inclusive community of open-source energy system developers both within IES and globally. Overall, this PhD project offers a comprehensive approach to enhancing system flexibility through heat integration, addressing critical challenges in the transition to a more sustainable and reliable energy future. Further information Please note this position will remain open until filled. Closing date:  Wed, 31/12/2025 - 12:00 Apply now Principal Supervisor Professor Daniel Friedrich Assistant Supervisor Dr Andrew Lyden Eligibility Minimum entry qualification - an Honours degree at 2:1 or above (or International equivalent) in a relevant science or engineering discipline, possibly supported by an MSc Degree. Further information on English language requirements for EU/Overseas applicants.Essential background: 2.1 or above (or equivalent) in Engineering, Mathematics, Physics, Energy Engineering/Economics, Informatics, or similarProgramming in Python, Julia or other high-level languageDesirable background:Energy system modelling and optimisationData analysis, optimisation and/or machine learningExperience in thermal energy system modelling Funding Applications are welcomed from self-funded students, or students who are applying for scholarships from the University of Edinburgh or elsewhereFurther information and other funding options. Informal Enquiries d.friedrich@ed.ac.uk