The first stage of building the prototype of a freeze dryer equipped with microwaves began at FrostX. The rear wall of the chamber has holes for the magnetrons and the fan motor.
The walls of the chamber were reinforced with fins.
Final tests of the freeze dryer equipped with microwaves will be carried out in labs of SINTEF. For safety reasons the freeze dryer will placed inside protection sleeve equipped with sealing and quick release lock.
The protection sleeve will also be equipped with a side extraction and ventilation duct where gasses can be evacuated.
On Wednesday, September 6, our PhD candidate Edyta Piechnik, had the pleasure of presenting paper "Numerical Analysis of Food Freezing and Airflow Distribution in a Home-Scale Freeze Dryer" at the 14th International Conference on Computational Heat and Mass Transfer (ICCHMT 2023), which took place in Düsseldorf, Germany. The conference was held by Düsseldorf University of Applied Sciences
FrostWave project at the ICR2023 Refrigeration Congress organized by IIFIIR - International Institute of Refrigeration!❄
Project representatives participated in the ICR2023 Refrigeration Congress, where our PhD candidate Edyta Piechnik gave a presentation entitled "Prototype of domestic-scale freeze-dryer with natural working fluid-based refrigeration system and microwave heating system". Both experimental and numerical activities that led to the creation of the concept of a prototype freeze dryer, which is currently under construction, were discussed.
We are pleased to present the final concept of a prototype freeze dryer equipped with a microwave heating system and a refrigeration system based on a natural refrigerant. Several months of numerical analysis of microwave distribution, structural and air flow, as well as experimental activities on the new refrigeration system, led the FrostWave team to the following chamber design.
Another important aspect that was taken into account when designing a prototype freeze dryer equipped with microwaves was to ensure even air distribution over each of the shelves filled with food products. For this purpose, flow analyzes were performed using a CFD model that was created in the first stages of the project. Several configurations of the position of fans and air guides were considered. The final design allowed for equalizing the air velocity fields in such a way that a velocity > 1 m/s was achieved over each shelf.
One of the key aspect during design procedure of the freeze-drying unit is to ensure safe operation of the device in terms of mechanical and thermal stresses, especially during the vacuum conditions. Therefore, the structural analysis of the prototype unit was performed to define the number and position of additional fins for deformation reduction.
According to the results, the similar deformation range was achieved when compared to the reference unit despite the additional equipments of the microwave heating system.
In July 2022, the WP3 package leader changed - Dr. Michael Bantle left SINTEF, and Dr. Krzysztof Banasiak took his place.
The numerical analyses of the electromagnetic field distribution proved that the most promising of the analysed variants for the microwave heating system is the one with a freeze dryer chamber equipped with a mixer - a rotary element used to change the distribution of microwave radiation during the freeze-drying of food products.
Last week in Trondheim the 15 th IIR-Gustav Lorentzen Conference on natural refrigerants took place. It was a pleasure to listen to the presentations on refrigeration, cooling, and heating and participate in inspiring discussions.
Our Ph.D. candidate, Edyta Piechnik, gave a presentation on the development of the natural working fluid-based refrigeration system for domestic scale freeze dryer. This topic is carried out as part of her PhD project under the FrostWave project.