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at Linköping University (Li.U), Sweden

All nine members of the spring 2023 GREC Sustainable Group started with a joint introduction to their common project building a GREC Lab-Model


The severe impacts of greenhouse gas emissions on global warming are an undeniable reality today. The emissions are associated with various sectors where heat and electricity production were the sectors with the highest increase of CO2 emissions in 2021. The complexity of this is even greater than anticipated, as significant improvements have NOT been achieved since the signing of the Paris Agreement by 196 UN countries in 2015, not even after the COP27. Still new technology solutions to inverstigate and fortunately, this spring (2023), three new groups at Linköping University in Sweden are dedicated to the challenge of transitioning to a world free from fossil fuels. The GREC SUSTAINABLE REVOLUTION PART 3 project in Sweden thoroughly investigates a new technology aiming to be applied in both the electricity production and transport sectors.

nilsinside AB Eva Karlberg at Linköping University Sweden
Invited to the presentation at Linköping University was Eva Karlberg representing nilsinside AB

The Green Revolution Energy Converter (GREC) sustainable research at Linköping University are building a physical model Lab Model v3.

The presentation showcased the joint efforts of the nine members of the spring 2023 GREC Sustainable Group. The group embarked on a common project to build a GREC Lab-Model, aiming to understanding the behavior of the GREC Work Generating Volume (WGV) and its real-world performance and potential for sustainable energy production applications.

The project goal is to build a simple tight model to deliver data in the simplest way within the specified time frame. Time is important. The model does not need to be optimal nor elegant but it has to be able to revolve its Work Generating Volume (WGV) with electric control at different speeds while logging pressure and average temperatures.
The GREC Lab Model v3 will answer how a real world revolving physical "Work Generating Volume" really behaves.
• Is it possible at all to build a Lab Model with a very restricted time and money budget?
• Will the GREC perform as predicted in earlier Li.U theoretical research?
• Does theory and reality converge?
• Will the Lab Model v3 be the tool we need to understand the WGV and "dead Volume" relation?
• Will it be able to run a saturated vapor close to phase shift?
• Is the GREC a future crucial climate-positive concept for a planable, scalable, adjustable clean energy production wihtout emissions?

After the common intro the CONSTRUCTION group, Ida H, Andrei T and Simon S, presented their thoughtfull design which included a thicker "Revolver" but with a smaller diameter and with a slick counter weight. They also added a hollow Revolver shaft to channel the pressure/volume changes to an external moving boundary (like a piston...), still within budget.

You may download the CONSTRUCTION Group Report as a .pdf file by clicking this link:
Design and development of a working prototype for the Green Revolution Energy Converter - Lab model V.3 - Project Report

The MECHATRONICS group continued the presentation and explained their programming and method of revolving the WGV and, at the same time capture and logging data for analysis. Tested with dry runs on the wooden sensor set-up. Not the fastest method but performing within specifications and budget.

You may download the MECHATRONICS Group Report as a .pdf file by clicking this link:
Development of a mechatronic solution for a new type of heat engine - The selection of relevant electronic components and control system for the mechatronics for the lab model of the new heat engine the Green Revolution Energy Converter

This was followed by the THERMODYNAMICS group presentation who integrated an electric heat source into the Lab Model design. They also worked out a method to calculate the real world performance of the WGV at different revolutions per minute and at different temperature spans.

You may download the THERMODYNAMICS Group Report as a .pdf file by clicking this link:
The thermodynamics of the GREC version 3 - Investigation of engine performance and energy conversion

Presentation GREC sustainability part3 at Linköping University Sweden

From the left: Eva K, Jakob R, Oskar B, Max H, Lisa V, Simon S, Andrei T, Ida H, Johan Å, Vidar J and examinator Jonas D

As flagged by the University Workshop, the construction time was very tight so their GREC Lab Model was not fully assembled and no tests had been done. A half assembly of the GREC with its counterweighted Work Generating Volume "WGV" was on display on the podium.

A talented and well-read opposition group also showed up for the presentation.
We trust that this new Lab Model Version 3 will perfom in future test runs and deliver measurement results for extrapolation to much larger volumes.

The Technology

In thermodynamic terms the GREC is a closed system with a moving boundary where the GREC converts heat energy to kinetic energy. The GREC heats up and cools down its internal large sliced WGV efficiently, fast and repetitively, resulting in internal pressure changes.
These internal pressure changes are used by its moving boundary to generate kinetic energy. You may think of the GREC as a revolving Carnot heat engine controlled by computer logic. Please find the theoretical presentation of the GREC on this link:
GREC Theory Presentation

The GREC is a new technological solution to tackle climate change and luckily there are three groups at Linköping University this spring that thrive on the challenge of a transition to fossil free energy systems. They will construct and build the GREC Lab Model v.3 as a step in a climate positive project that will need several research projects over time...
Please feel free to call or email:

Contact information at nilsinside AB
Nils Karlberg, tel +33 608 53 15 93, theory & technical questions
Sophia Karlberg , strategy & admin questions

The GREC Project