18 October 2021
DryFiciency project - Industrial heat pumps for greener European industry - From lab to reality

 

Autumn 2021


As part of the EU milestone to make leaps in energy efficiency savings and near zero emissions by 2050, a five-year Innovation Action project funded by Horizon2020, DryFiciency has advanced on research and demonstration of high temperature heat pumps (HTHP) that are able to supply process heat up to 160°C.

The Horizon2020 DryFiciency high temperature project demonstrations are the first-ever tests in industrial settings of waste heat upgrade of up to 160°C using technology developed by a consortium led by AIT, the Austrian Institute of Technology.

Most people are familiar with heat pump technologies in residential buildings, but less so in industry. The uptake of this technology in industry is in its early phase of market diffusion, due to the technical complexities of using heat pumps to generate high-temperature heat for industrial use, as for example for drying of starch, bricks and bio sludge.

The challenge is to design and construct a heat pump that is capable to provide high temperatures. "Compared to conventional gas boilers, heat pumps have the potential to increase energy efficiency by up to 80%, reduce CO2 emissions by up to 80% and also cause up to 20% less productions costs," says Veronika Wilk, Senior Research Engineer at AIT and coordinator of the project.

"The technologies we have developed here can be used in many industrial sectors, from paper, food and beverages to textile and other chemical industries, and they can be integrated into existing plants or for greenfield applications," she added.

Specifically, the consortium of 13 partners is addressing the challenge of the Resource and Energy Intensive Industries sectors that produce significant amounts of waste heat currently being lost.

Recapturing lost energy, which normally would be expelled, for drying processes in industrial settings eventually could substitute or complement fossil fuels, such as gas.

Capturing this energy would not only afford a massive energy saving by re-using it as a substitute fuel for firing, but also would dramatically reduce climate damaging CO2 emissions which are expelled in factory processing. Energy and fuels represent between 20% and 40% of the production costs in several of these industries and also produce large amounts of CO2 emissions.

Within DryFiciency three demonstrations in industrial drying have been pioneered as the drying processes are very energy intensive and offer huge potential for energy efficiency.

The first of two closed loop heat pumps under the coordination of the (AIT), with a heating capacity of up to 400 kW has been integrated at Wienerberger, the world’s largest producer of bricks in Uttendorf, Austria.

In a continuous dryer clay bricks with a moisture content of around 30% are dried to 2 to 4%, the drying air is heated by a heat exchanger supplied with hot water from a heat recovery cycle located inside the tunnel.

The heat pump demonstrator replaces a natural gas burner shown to lead to energy savings of up to 80% and reductions in CO2 emissions of about 80%. The heat pump provides hot water up to 160°C to heat the drying air. The hot air is fed into the outlet zone of the tunnel dryer, where the highest temperatures are required.

AGRANA, a global player in the three segments fruit, starch and sugar, specialized in processing and refining of top-quality agricultural raw materials is operating, the DryFiciency high-temperature closed loop heat pump demonstrator at the wheat starch plant in Pischelsdorf, Austria. With this innovative technology temperatures up to 160°C are possible, which are required to remove water in a wheat starch drying process. The DryFiciency Heat pump demonstrator has undergone some 5.000 operation hours with a maximum heat output ~350kW and a COP between 2-4 at varying source temperatures. While currently only contributing to a small part of the production process, internal calculation shows an annual CO2 savings up to 500 tonnes/year with the demonstrator.

Chief Technology Officer and Member of the Board of AGRANA Group Norbert Harringer said that "the DryFiciency project is an important step for reaching our climate goals which means climate neutral production by 2040".

The DryFiciency closed loop heat pump demonstrators include novel screw compressors developed by Bitzer, and piston compressors developed by Viking Heat Engines. Both are engineered to operate at very high pressures and internal temperatures. They are compatible with all common refrigerants of the 3rd and 4th generations e.g. HFOs like OpteonMZ (HFO 1336mzz-Z) from Chemours as used in the demonstrator. For its lubrication, the novel lubricant is provided by FUCHS.

The third demonstration under the coordination of SINTEF is an open loop heat pump system also known as Mechanical Vapour Recompression (MVR) system using water as refrigerant in steam drying processes. "With the technology developed for the open loop heat pump we are able to use water as refrigerant. Water or steam are already widely utilized by industry as heat carriers and the industrial acceptance for such technology is high. Water is surely also the saftest most abundant refrigerant on the planet" says Michael Bantle, Senior Research Scientist at SINTEF Energy Research.

In this demonstration Scanship is drying biomass at the Lindum waste management facility in Drammen, Norway. With the help of EPCON, an expert in mechanical vapour recompression, a number of modifications towards energy efficient Super Heated Steam (SHS) drying, including turbo compressors from the automotive industry developed by ROTREX have been accomplished.

This demonstration has shown improvements in efficiency and capacity of the dryer of more than 75% while reducing energy consumption by 70%. Over 100 tonnes of biomass has been dried using the system so far, now additional operational hours will be used to optimize and validate the system.

 


To learn more about the project, partners and results go to www.dry-f.eu