Heat pump drying – a cost effective and sustainable technology

• The 4th Nordic Baltic Drying Conference will be held at Q Hotel Plus Wrocław from the 7th-9th of September 2022.

Professor Odilio Alves-Filho is a renowned scientist, author of many articles, book chapters and books, and holds 16 patents on new drying systems that are applied to many production processes with the vision to enhance their quality, benefiting the environment and saving energy. Prof. Odilio Alves-Filho is also the founder of the Nordic Drying Conference series which he had expanded into the Nordic-Baltic Drying Conference series in 2012. He is also a former Dean of the Faculty of Mechanical-Electrical Engineering at the Norwegian University of Science and Technology in Trondheim, Head of the Center of Excellence in Dewatering and CEO of Innovative Drying Tech.

– Drying is one of the oldest ways to preserve food. It’s commonly known that the Vikings dried fish on rocks by wind exposure. In winter it resembled modern “atmospheric freeze drying” and in summer it corresponded to solar drying. So, basically we still use the same methods as many centuries ago but with modern means and processes – says Prof. Alves-Filho. Norway, where the professor is from, is a northern country with long winters. This climate has always been suitable for drying cod and other fish which has been a traditional Norwegian product since Viking times, and today the country excels in drying cod and exports it all over the world. 

Norway also greatly supports research and development of green technologies, including heat pump (HP) drying, which Prof. Alves-Filho researches because this process is energy efficient, environmentally friendly and sustainable.

As Prof. Odilio Alves-Filho says, the idea to use heat pumps for drying is not new, although the common use for them is home heating. However, the design of heat pump dryers is complex and requires knowledge and competence in several fields such as drying, heat pumps, refrigeration, thermodynamics, fluid flow dynamics, as well as heat and mass transfer. Norway is a leader in this technology because the country has always been concerned with environmental protection and energy efficiency. Consequently, the application of heat pumps in drying and other processes has a promising future.  

– Heat pumps and heat pump drying systems help society to solve many challenges,  including energy and waste issues. Firstly, using a heat pump for home heating and cooling reduces monthly electricity bills. Secondly, applying heat pumps to heavy industries helps to reduce the use of fossil fuel, greenhouse gas emissions, consequently slowing down global warming – explains Prof. Alves-Filho, adding that a new use of heat pump drying allows to convert and recycle wet organic waste into valuable dried products such as fertilizers, fuel, animal feed and even ingredients for bakeries.  

This method of drying, when used in the food industry, preserves the product's nutritional values because heat pump dryers operate in a closed cycle with control of all operating conditions. This allows for manufacturing high quality dried food. It means that nutrients, vitamins, proteins and all other important compounds are preserved in the product.  

Heat pump drying is not only a versatile but also sustainable technology. – Since it operates in a closed cycle it means that there is no emission of polluting gasses and dust. Also, the water vapor is condensed, recovered, and reused again and again in the process. New heat pump dryers are even designed to work with natural fluids which means that there is no ozone depletion or global warming potential compared to traditional drying systems – the scientist explains.

This drying technology is patented and licensed to industrial use. However, it’s still not widely used because in many countries there are no strict regulations, and for most industries it is easier to discard waste to landfills. – Society should create instruments to influence industries to properly treat waste instead of simply throwing it away.  Regarding the use of a heat pump dryer in the food industry, it certainly reduces food prices due to decreasing energy consumption at least twofold – explains the scientist.  

4th Nordic Baltic Drying Conference

During the 4th Nordic Baltic Drying Conference Prof. Alves-Filho will give a lecture on how to convert wet organic waste into valuable dried products. – I will show how our drying technology is applied to dry waste in food-catering hotels, breweries and the aquaculture sector – he says.

The conference will be held by the Wrocław University of Environmental and Life Sciences. Prof. Adam Figiel, Prof. Agnieszka Kita and Prof. Anna Michalska-Ciechanowska are responsible for organizing the conference on the Polish side. – Our partnership started in the early 2000’s when I worked with Prof. Adam Figiel and guided Dr. Anna Michalska-Ciechanowska during her research fellowship at my university in Norway. They are very competent and highly professional experts – says Prof. Alves-Filho adding that building partnerships with Polish universities is important, because Poland and Norway not only share the same sea, but also share the same planet. – Taking care of the environment is our common duty. As we can see from the name, Wrocław University of Environmental and Life Sciences focuses specifically on technology and processes in relation to their impact on the environment. And this is exactly what we all should do: create new processes and technologies that have a minimal impact on the world around us – he says. 

– Wrocław University of Environmental and Life Sciences and other Polish universities, for example Łódz University of Technology, University of Warmia and Mazury in Olsztyn, Warsaw University of Life Sciences have a strong potential and powerful research groups in the field of drying because a lot of young researchers are part of the teams. Also, there are many interesting and important projects going on. I really think that today, the Polish research group is one of the strongest in Europe in the field of drying – says the professor.

The 4th Nordic Baltic Drying Conference, where people from 16 countries from around Europe, America and Asia are participating provides a great opportunity to expand one's horizons, to see what problems scientists from other universities and countries are working on and to find interesting topics for joint work and new projects. – It’s also  wonderful to see how many students are participating in the conference now! I think Poland has a bright future in drying technologies and processes – sums up Prof. Alves-Filho.

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