The SBO project ORCNext aimed at developing knowledge and design tools for the next generation of Organic Rankine Cycles (ORC). The focus was the implementation of ORC-technology in waste heat valorization. The project , funded by IWT, ran from February 2012 to January 2016. The project was a partnership between Ghent University, University of Antwerp, University of Liège and Atlas Copco.
During the last couple of years, a lot of knowledge and expertise has been gained.The project showed that the overall technical target of increasing efficiency with 20 to 25% can be met through appropriate cycle selection, efficient expanders, appropriate control and less oversizing of the heat exchangers.
Below are the links to the different fact sheets, each explaining a technology and the gained knowledge concerning that technology. It is also an overview of the services knowledge partners can offer to the industry regarding Organic Rankine Cycles.
Cycle Design – Thermal Energy Systems
Cycle Design – Simulation Tools and Thermocycle Coolprop
Component Design – CFD Analyses
Component Design – Heat Exchangers
Control Design – Classical Control Strategies
Control Design – Advanced Control Strategies
Today process industry (cement, glass, paper, plastic, chemical, …) has to deal with an enormous amount of waste heat. Experts assume that the annual unused industrial waste heat potential amounts to 140TWh in Europe alone, implying a CO2 reduction potential of about 14M ton of CO2 per annum. This waste heat is typically available at a low(er) temperature and can be recovered in the form of electrical power with Organic Rankine Cycles (ORC) technology. Hence, ORC technology has a big economical potential and helps to realise the EU ’20-20-20’ goals.
Several companies offer ORC for waste heat recovery. There is not only a lot of interest in this type of technology, there is still a big amount of waste heat in industry for which ORCs could be used. This is up till now not the case. Analysis shows that investments in these cycles are often not favourable if pay back time or IRR is considered.
To the opinion of the consortium this has to do with two main technical reasons.
Firstly the efficiencies of the cycles are too low for low temperature waste heat sources, resulting in too low energy production. Secondly, the current ORC’s on the market aim at a too high waste energy flow. First research will be aimed at new cycle architectures raising efficiency. One promising step is going towards supercritical cycles, using supercritical fluids. This is a trend also seen in refrigeration systems and chillers. The progress will be realised through thermodynamic modelling and experimental validation. An improvement of about a factor of 20-25%, which is similar to steam cycle improvements, should be envisaged.
Secondly the aim is to investigate efficient systems for smaller power ranges. Aiming at opening the potential for a lot of small scale systems on the market. Therefore specific expander technology has to be developed, by means of advanced CFD algorithms. This development will be done in close cooperation with an industrial research partner.
Two other important factors are also influencing the potential application of these systems.
First it is of great importance to develop smart control algorithms which can take care of varying load. The project results will open again more possibilities for these cycles as a lot of heat sources have a strong variable character.
Secondly, financial and economical constraints and possibilities have to be clearly understood. In previous studies the combined effort of economists and engineers has proven to give fruitful research results. Therefore the whole project will not only be benchmarked to technical possibilities but also to financial and economical benefits.
This project is supported by the IWT SBO program for the period February 2012 – January 2016.