Research & Development

From theory to validated prototype

Technology Readiness Level Progress

Current Status: TRL 3-4

GREC has progressed from theoretical concept to validated laboratory prototype with experimental proof-of-concept. We are now advancing from TRL 3 to TRL 4 through advanced CFD simulations and systematic validation at Linköping University.

TRL Milestones

Research Timeline at Linköping University

Since 2022, GREC has been systematically studied through comprehensive student and research projects.

Spring 2022 - Part 1

Theoretical Proof of Concept

Team: Gustav Edholm, John Malmdal, Lukas Haglund, Markus Eriksson, Oscar Magnusson

Key achievements:

  • Developed mathematical model based on Carnot engine principles
  • Created calculation models in MATLAB
  • Thermal simulations in ANSYS and CAD geometry in CREO
  • Demonstrated that larger GREC models are more effective and produce more power
  • Showed revolving speed impacts heat transfer capability
  • Higher temperature difference leads to significantly higher power output and efficiency
Autumn 2022 - Part 2A

Internal Heat Transfer Investigation

Team: Johan Hagströmer, Mattias Reijm, Oscar Torsteinsrud, Vendela Stenholm

Key achievements:

  • 3D CFD simulations in COMSOL Multiphysics
  • Modeled Work Generating Volume (WGV) with moving mesh
  • High work output correlates with elevated heat transfer coefficients
  • Larger GREC configurations showed stronger pressure and temperature oscillations
  • Validated against LabModel v2.0 experimental data
Autumn 2022 - Part 2B

External Heat Transfer Investigation

Team: Emma Gustafsson, Maja Abrahamsson Bolstad, Matilda Eriksson, Wilma Fager, Emma Andersson

Key achievements:

  • Evaluated None Pipe Heat Transfer (NPHT) and Pipe Heat Transfer (PHT) architectures
  • PHT achieved ~3x higher heat transfer rates with more uniform temperature distribution
  • Demonstrated GREC compatibility with district heating systems (80°C) via PHT
  • Showed viability for high-temperature applications including fuel cell waste heat (500°C)
Spring 2023 - Part 3

LabModel v3 Development

Three specialized teams:

Construction Team: Andrei Toader, Ida Hellström, Simon Sandström
Complete design and CAD documentation for LabModel v3 mechanical architecture

Thermodynamics Team: Johan Åsmo, Jakob Ross, Vidar Jeirud
Theoretical and experimental investigations of thermodynamic cycle performance

Mechatronics Team: Oskar Brodin, Lisa Vilhemsson, Max Hollsten
Electronic components, sensor integration, and real-time control system

Result: First fully operational prototype capable of systematic experimental validation

Spring 2024 - Part 4

Further Development and Validation

Team: Erik Widström, Simon Eriksson, Richard Zetterman

Key achievements:

  • Systematic experimental characterization of LabModel v3
  • Achieved pressure homogeneity at 3 Hz with 80°C temperature difference
  • Demonstrated repeatable pressure oscillations
  • Power output characterization enabling extrapolation to larger geometries
  • Implemented Raspberry Pi-based control with web interface
  • Pressure differential increased exponentially with thermal gradient
Winter 2024/25 - Part 5

International Validation at ICAM Toulouse

Team: Michael Peyrony-Rapatout, Pierre Le Provost

Key achievements:

  • Developed coupled thermal-thermodynamic numerical models
  • ANSYS transient model of WGV and fin blocks
  • MATLAB dynamic model of pV-cycle
  • Predicted 340 W/m³ power density and 6% efficiency
  • Confirmed potential comparable to compact low-temperature Rankine or Ericsson-type systems

Current Research Focus (2025-2026)

Advanced CFD Simulations

High-resolution CFD modeling using RANS and LES in OpenFOAM on supercomputer. Systematic parameter studies of geometry, rotation speed, temperature gradients, and working media.

Experimental Validation

Systematic verification of CFD predictions in LabModel v3. High-speed measurements with improved instrumentation. Development of complementary test rigs for specific phenomena.

Scaling Laws

Verification of scaling principles for different geometries and temperatures. Development of design guidelines for specific applications. Quantification of power density and efficiency across operating ranges.

Commercialization Analysis

Market and competitive analysis. Technical-economic evaluation for priority applications. Development of go-to-market strategy and business model. Contact with potential pilot partners.

Publications & Documentation

All research reports and presentations are available for download at nilsinside.com and through Linköping University at liu.se