Thermal analysis for home vacuum packing

Abstract

Food preservation techniques are among the main enablers of civilization. Every day, lives are saved as a result of our growing understanding of the processes of food deterioration. The present study is motivated by the theoretical study of the development of a homemade vacuum sealer as cheap and efficient as possible. In order to reach the goals of the present work, we developed a thermal system and numerically calculated the results with a script provided in the annexes. Most of the physical principles relating to thermal analysis are herein considered and explained. Several analyses were made, and the results are explained, which, along with the script, gives the reader the possibility to take tests on their own and have an understanding of their results. Furthermore, a sensitivity analysis is performed for all parameters considerations, defining which ones are relevant, and which are not. E.g., the influence of the geometrical dimensions, it was found that only the wire diameter is relevant since a larger wire help melting more quickly but enhances the battery consumption. We noticed that since this is a fairly rapid procedure, and the surface’s area of the components are small, the heat loss through convection and radiation are not significant, less than 0.3%. Mainly, the energy that is not heating nor melting the bag is rising the temperatures of the wire and the plate. Another relevant input, and the most important one, is the electrical voltage, the higher it is, the faster the material melts. Regarding the environmental properties, we observed that alterations barely change the results, meaning that the device work everywhere, at any weather or in any season. We found an optimal system that can melt a common low density polyethylene bag in 2 seconds with a maximum system temperature rising up to just 120.3 C by using a simple 1.5 V AAA alkaline battery. Even with the achieved results, more studies must be done in relation to the vacuum system, the casting, and the electrical system.