13 October 2020

Clean technologies developed by Horizon 2020 funded projects for reducing the impact of energy intensive industrial processes are helping Europe to transform into a sustainable, competitive economy and address environmental and climate-related challenges. One of the cutting-edge EU projects is the trilateral flash cycle (TFC) system, which benefits from the use of HFC-245fa or HCFO-1233zd(E).

The EU-funded I-ThERM project set out to develop innovative plug-and-play waste heat recovery and conversion solutions with energy recovery potential across the temperature spectrum from 70 to 1000 °C. The trilateral flash cycle (TFC) system is suitable for heat-to-power conversion from low-temperature waste heat streams (70-200 °C), particularly in the food and drink, pulp and paper, petrochemical and metal industries, improving energy efficiency in process industries. The TFC system enables higher heat recovery potential and higher power output per unit heat input than conventional organic Rankine cycle systems.

Early simulations found that the HCFO, R-1233zd(E) is the best candidate for the TFC technology at the temperature levels selected, a hot source is a water stream at 90 °C, due to its technical performance and ultra- low GWP. However, the HFC, R-245fa provided almost identical performance and was the working fluid selected for a pilot test rig. As part of the I-ThERM project a demonstration plant was constructed.

The TFC technology is completely new, currently without direct competition and has been recognized by the European Commission’s Innovation Radar as having high market potential. The project has already led to significant interest in the TFC technology in Europe.

Explanatory note: In a TFC system, heat gain is achieved without phase change of the organic working fluid, and the expansion process therefore starts from the saturated liquid state rather than a vapor phase. As the working fluid is not evaporated in the heater, the mass flow rate is comparatively high compared to other cycles, and the work of the refrigerant feed pump is therefore considerable. Due to its low vapor pressure, R-245fa or the HCFO, R-1233zd(E) demands relatively low pumping power, and as such the parasitic losses associated with pumping liquid refrigerant are reduced, reducing the payback time of the system.

For further information about Horizon 2020 Waste Heat Valorization: Improving energy efficiency in process industries see
For more information about the trilateral flash cycle (TFC), see for example: