Phd development and Experimental Validation of Underground Sand-based Thermal Energy Storage Systems for Medium-temperature Applications

As **Austria's largest research and technology organisation** for applied research, we are dedicated to make substantial contributions to solving the major challenges of our time, climate change and digitisation. To achieve our goals, we rely on our specific research, development and technology competencies, which are the basis of our commitment to excellence in all areas. With our open culture of innovation and our motivated, international teams, we are working to position AIT as Austria's leading research institution at the highest international level and to make a positive contribution to the economy and society. PHD "DEVELOPMENT AND EXPERIMENTAL VALIDATION OF UNDERGROUND SAND-BASED THERMAL ENERGY STORAGE SYSTEMS FOR MEDIUM-TEMPERATURE APPLICATIONS In Cooperation with TU Wien - You will carry out **laboratory-scale tests** to examine the thermo-physical behavior of storage media under controlled charging and discharging cycles. - You will contribute to the **design, construction, and operation of an upscaled SMTES prototype** (20-foot container scale) to investigate realistic thermal behavior, temperature stratification, and system dynamics. - You will **evaluate the** **storage envelope**and** insulation performance** (e.g. glass foam aggregate) from a building-physics perspective, focusing on heat losses, moisture migration, and mechanical stability. - You will support **data acquisition** and **sensor setup** for temperature profiling, model calibration and validation. - You will use experimental results to** validate models** and **create a digital twin** for real-time operational optimisation. - Based on your findings, you will **establish a design and optimisation framework**, including dimensioning and layout principles and correlations between material properties, geometry and operational parameters. - You will conduct **technical** **performance and environmental analyses**, including energy density, thermal efficiency, response time and materials reuse aspects in cooperation with project partners. - Last but not least, you will** evaluate the storage concept and integrate validated models into system-level optimisation**, such as coupling with heat pumps or district heating networks. - You will **engage in scientific planning**, will **publish your findings** in international journals and present them at conferences. **Your qualifications as an Ingenious Partner**: - Completed master’s studies or close to completion in the field of Thermal Engineering, Sustainable Energy Systems, Mechanical Engineering, Geotechnical Engineering, Technical Physicsor a related technical field - Good skills in modelling and simulation (Modelica/Dymola, COMSOL Multiphysics ) - Very good understanding of thermal energy storage and heat transfer processes - First experience in data acquisition and sensor-based-measurements would be a plus - Good competence in experimental work (design, evaluation) - High commitment and ability to work individually as well as in a multi-disciplinary-team environment as well - Strong interest in experimental work and willingness to collaborate with industrial and scientific partners - Very good command of English (spoken and written) - **Details**: - **Duration of the PhD project**: 3 years - **Start date**: ideally 01.04.2026 - To obtain the PhD degree, you will have to enroll to TU Wien, our academic partner institution. Throughout your PhD, you will be supervised by an academic supervisor from TU Wien, Institute of Fluid Mechanics and Heat Transfer as well by a supervisor and advisor at AIT. - **What to expect**: - EUR 2.786,10 gross per month (14 times / year), for 30 h / week. - Access to state-of-the-art infrastructure on site at AIT - In addition to numerous events, seminars, networking opportunities and additional company benefits, you will be part of our AIT PhD community with around 150 international students. - Knowledge exchange with and complementary research input and support for experimental and modelling activities from our collaborating partners: KTH Royal Institute of Technology (Sweden) and University of Stavanger (Norway) - Please submit your documents including your **CV**, **cover letter** (ideally one page, including a brief introduction of yourself, an explanation how your previous studies and experience have prepared you for this PhD position, and a motivation why you are interested in this specific position) and your **certificates** (Transcript of records) online.