Thanks to her participation in the NAWA project,  University Professor Sabina Rosiek-Pawłowska, PhD, DSc, Eng. has returned to Poland. The researcher worked for 15 years at the University of Almeria and Solar Energy Research Center. At our university, she has just started a four-year project aiming to develop a new cooling method for the dairy industry.

Professor Rosiek-Pawłowska started working at the Faculty of Mechanical and Power Engineering at our university a few months ago. Previously, she had worked for 15 years in Almeria, Spain, at the local university and at the prestigious Solar Energy Research Center (CIESOL), which is part of Platforma Solar de Almería. PSA is the largest European centre and one of the two largest research and testing centres in the world whose activity focuses on solar technologies.

NAEA made it possible to come back

In Almeria, Professor Rosiek-Pawłowska (first as a doctoral student and then as a member of the research staff) participated in nine research projects, on some of which in a managerial or executive capacity. There, she cooperated with many Spanish companies and foreign institutions, organised international conferences, and prepared numerous international and interdisciplinary research and implementation projects under scientific-industrial consortia.

- I gained extensive experience and learned a lot. It was an intensive time, which allowed me to develop and gain valuable contacts - says the researcher. - However, for personal reasons, I wanted to come back to Poland. I also noticed that in our country the topics related to renewable energy sources or, in particular, alternative cooling, which I dealt with, are still developing. I think I can be useful here. I have many ideas for research we can do at our university.

The professor came back to Poland thanks to the National Academic Exchange Agency programme. The institution offers grants to Polish scientists working in foreign scientific institutions who want to use their knowledge and experience in Poland by creating their own research group or joining projects conducted in already existing research teams.

The important problem of cows’ stress

 At the newly established Department of Thermodynamics and Renewable Energy Sources, Professor Rosiek-Pawłowska has started a four-year research project named "RadMAT: Radiative Water Mattress", for which she obtained a 1.6 million PLN grant as head of the project, financed by the National Academic Exchange Agency under the Polish Returns Programme 2018. She selected (by means of competition) graduates of our university’s Faculty of Mechanical and Power Engineering: Jagoda Błotny and Kamila Gębarowska. They will later describe their research under the project in their doctoral theses, written under the supervision of Professor Rosiek-Pawłowska. The team intends to develop and test a new cooling system that will help to reduce heat stress in cows.

- In our country, we’re still convinced that the most important thing is to provide heating due to the climatic conditions in which we live. Meanwhile, air conditioning is becoming equally important because in summer we must face the effects of prolonged periods of very high temperatures. This affects many aspects of our lives and economy, including the agricultural sector. Developing effective cooling systems (based on environmentally friendly technologies) for agriculture is certainly one of the particularly future-oriented research directions - explains Professor Rosiek-Pawłowska.

The project with water mattresses is the result of talks between the researcher and a company hailing from the energy sector. A few years ago, the company approached Professor Jacek Kasperski from the Department of Mechanical Engineering, Machinery, Instrumentation, and Energy Processes at the Faculty of Mechanical and Power Engineering, and the professor passed the contact on to Professor Rosiek-Pawłowska. - We established short cooperation, during which the company pointed out a big problem with temperature adjustment at dairy cow farms. Later, I began to explore the subject of cooling such spaces, which due to their design are difficult to air-condition – says the researcher.

Nowadays, traditional methods such as sprinklers, fog nozzles, and fans are used to cool the space used by animals. These methods consume a lot of electricity and water, which increases operating costs. None the less, cooling is very important in that it helps reduce heat stress in cows.

- It has serious consequences for these animals and therefore also for the dairy industry –stresses Professor Rosiek-Pawłowska. - Extreme weather conditions in summer are no longer an exceptional situation. Now they’re something almost certain. During a heatwave like this, cows get too hot and when it gets colder, the animals even need a few days to recover. All the more so if at night the temperature doesn’t fall below 20 degrees C, because even then they can’t rest.

The metabolic changes in cows and the conversion of nutrients into milk are exothermic processes. When an animal starts to give off more heat than it can passively give to its environment, it experiences heat stress. A cow begins to sweat intensely and breathe faster, which allows it to release more heat to the environment through the evaporation of water. It also takes up a standing position more often, as this makes the airflow easier, thus increasing heat exchange through convection.

To reduce the amount of heat given off in metabolic processes, the animal also starts to eat less forage and at the same its energy demand increases. As a result, it produces 10 to 25 per cent less milk. A cow then chooses the most substantial elements of the forage, avoiding the less caloric ones, and this leads to acidification of its body (so-called summer acidosis) and unbalanced microelements management.

- All of this results in hormonal changes and inhibition of reproduction – says Professor Rosiek-Pawłowska. - The quality of milk, which has a lower than usual fat and protein content, also deteriorates. An important health effect for a cow is also a decrease in its immunity. For a milk producer, this whole situation means long-term financial consequences.

Water to take away the heat

The optimum ambient temperature for cows is between 8 and 16 degrees C – depending on humidity and airflow. Body reactions related to thermoregulation start at 20 degrees C. So, how to keep the temperature lower while not generating high cooling costs?

The solution can be cooling water mattresses. Professor Rosiek-Pawłowska emphasises that the mattresses themselves are nothing new in the breeding sector. They have been used in cowsheds for years, because they provide comfort for cows, which are more likely to lie on these soft surfaces, adapting to their shape, than on straw-covered beds. Temperature reduction is a new feature. So far, only one company in the world - in France - has tried to develop such a mattress. However, our researchers want to develop their own solution, focusing on intensifying heat exchange processes and finding the optimal design solution to cater to the animals’ needs.

Professor Rosiek-Pawłowska’s team intends to use the existing product, in the shape of a water mattress (they will choose one that is best suited for expansion), with a view to creating a prototype of their solution. It will combine the water mattress with a closed water-based cooling system. Due to the temperature difference, heat will flow between the cow and the liquid circulating in the system, which will alleviate heat stress in the animal.

First simulations, then experiments

However, before this happens, the researchers will create a numerical model of the water mattress and simulate its performance under different conditions.

- Analysis of the results will give us information about the amount of heat exchanged between the cow and the surrounding environment - explains Professor Rosiek-Pawłowska. - Using this information, we will already build a laboratory test stand with a mattress modified so that it caters to our needs. We will carry out several experiments allowing us to determine the effectiveness and safety of our solution. Only then will we proceed to test the prototype at a dairy farm. We will place four cows in a climatically controlled barn. Two will be able to rest on cooling water mattresses, and two other ones will be lying on the same mattresses without the heat-reducing solution. We will control their milk yield, dry forage intake, temperature, and breathing rate. Analysis of this data and observation of the cows - whether they are keen to lie on the mattresses and how much time they spend on them - will allow us to modify the mattresses to best suit their needs.

The researcher points out that ensuring the animals’ safety is an important aspect of their design – so that the cow does not get cold and develop udder inflammation, which is very painful for the animal, affecting its well-being and the quality of the milk it produces.

- This is an interdisciplinary and high-risk project, as we’re going to work with living organisms, whose reactions are unpredictable, but it’ll lead to important discoveries in the livestock sector – she stresses.

At the final stage, the team will find the best source of coolness for the system, so that it can receive heat from the mattresses in a barn with up to several hundred cows. At the first stages of the project, the researchers will use a small standard chiller for the prototype installation. Later, they will look for a more environmentally friendly and cost-effective solution.

- We’re only just beginning our project, but we can already see great interest in it, both from mattress producers and the dairy industry - says Professor Rosiek-Pawłowska. - This confirms how challenging it is to ensure that cows are kept at a temperature that’s comfortable for them.