Structural analysis

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.

WP3 package leader changed

In July 2022, the WP3 package leader changed - Dr. Michael Bantle left SINTEF, and Dr. Krzysztof Banasiak took his place.

Numerical analyses of the microwave system

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. 

15 th IIR-Gustav Lorentzen Conference

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.

First tests of the new device at NTNU

We are pleased to announce that the prototype of the freeze dryer with a new cooling system and chamber geometry has been successfully launched. Nevertheless, the system requires further calibration, so there is still some work ahead of us. We hope to share the results soon!

Development of a new refrigeration system at NTNU

Good news from the laboratory at NTNU! Work has begun on a prototype freeze dryer whose cooling system will be based on a natural refrigerant - R290. For this purpose, the type of evaporator and compressor have been changed.

Norsk Kjøleteknisk Møte 2022

This week, our PhD student Edyta Piechnik, together with Norwegian supervisors, prof. Ignat Tolstorebrov and prof. Trygve M. Eikevik, participated in the annual event Norsk Kjøleteknisk Møte 2022, organized in the far north of Norway, Tromsø. These were two intense days full of presentations on, among others, natural refrigerants, refrigeration systems and heat pumps. During the event, Edyta presented a poster devoted to the concepts of development of a refrigeration system based on a natural refrigerant in the prototype of a freeze dryer carried out as part of the FrostWave project.

Analysis of a new heating system

The next steps towards changing the heating system in our device have been made. The currently used heating system is based on the conduction of heat through a shelf under which a heating mat is placed to the product. In the prototype device, the product drying process will be based on the application of heat by means of microwaves. Below we present the preliminary numerical results of a freeze dryer equipped with three magnetrons emitting microwaves towards the product. The magnetrons were placed on three sides of the chamber, namely the upper and side walls.

Development of the microwave system

Intensive work is carried out to select an appropriate microwave system that will adequately provide heat to food products in the freeze-drying process. It is crucial to ensure even distribution of heat generation to minimize "cold spots" and "hot spots", which will minimise the risk of underheating or overheating food during freeze-drying. 

Concept of a new device - step 3

Recently, the activities of the project team have focused on developing the concept of a prototype of a freeze dryer equipped with microwaves and a new cooling system.
The proposed ideas for a new device geometry are based on the following modifications:
- internal evaporator with microwave membrane
- the use of the position of the zigzag-shaped shelves