Solar Dehydrator with PCM storage system and IoT

What it does

The main objective of this solar dehydrator is the extension of the useful life of food by the dehydration of it, thus reducing waste, the advantages of dried food is the reduction of weight and volume of food facilitating its packing, transport and storage.

Your inspiration

This project was born from a class in my career, where we were studying phase change materials and their application as a thermal storage system. I developed the idea after finding a report of 1 ton per day of organic waste in a city market, after products such as fruits and vegetables were not sold and were close to decompose, with this in mind, I made the design for the first prototype, the teacher selected my project for participation in a state science fair, with the awards obtained I decided to make a second prototype more aesthetic and with improvements that were observed in the first to have a functional prototype of food grade.

How it works

The solar dehydrator has two main parts the collector and the drying chamber, the collector is made up with a steel plate with several rectangular sections filled with phase change material (PCM), and it is covered with a glass to generate a greenhouse effect to heat the air passing between the plate and the rectangular sections while loading the storage system consisting of a PCM, This material absorbs the thermal energy as it melts until the sun's rays stop hitting the plate, then all the latent heat of fusion begins to be released until the PCM solidifies, this process lasts from 2 to 3 hours, which allows us to heat the air that enters the drying chamber for a longer period of time without the use of electricity, the system is controlled and monitored by a circuit with internet of things (IoT), which makes this solar dehydrator the first of its kind, and above all, environmentally friendly unlike the electric or gas dehydrators.

Design process

For the first prototype, I thought of a functional design, leaving aside the aesthetic aspect, making it with inexpensive materials, this prototype was thought only in order to see the performance of the storage system with phase change materials, as well as the feasibility of using this system. For the second design I contemplated more the aesthetics but still with the use of accessible materials, the incorporation of the internet of things system, in addition to solving problems that arose in the first prototype, also improving the storage system with the shape of the containers in a zigzag pattern improving heat exchange. The third prototype was designed with more resistant materials and improved aesthetics, now with a semi-industrial design, the materials used are aluminum for the structure, polycarbonate sheet for the exterior, extruded polystyrene as insulation for the collector and wood for the interior of the drying chamber, the trays were also improved using aluminum frames and food grade plastic mesh. The capacity has also been increased in order to be able to test with a larger amount of fruits and with this, have the first base prototype for the manufacturing of the following commercial models.

How it is different

The innovation incorporated in this solar dehydrator is its thermal storage system with phase change materials, which allows us to increase the useful dehydration time of 2 to 3 hours more depending on the solar resource, by storing the thermal energy during the day and discharging it as soon as the sun goes down and giving a total time of dehydration of 7 to 8 hours per day. This extra dehydration time per day allows us to have a faster production compared to conventional solar dehydrators, because conventional solar dehydrators take 3 to 5 days to dehydrate the food, while with my dehydrator we can have productions in 2 to 3 days, without the use of electricity, making this an environmentally friendly food dehydrator. Another highlight is the incorporation of an IoT system developed especially for this dehydrator with which you have control of the temperature and can visualise both the temperature and humidity.

Future plans

In the next three months I plan to have the patent for the solar dehydrator and participate in the international competition that will take place in Portugal, after this I plan to design and build 3 models of different capacities for commercial use, in 6 months it is projected to have a business plan and verify the standards and comply with the necessary certifications, within a year or a year and a half to be starting a brand to market the first dehydrators and thus, within 5 years, to have an established brand.

Awards

this project has won a state science fair called "Expociencias", then a national "Expociencias" where it won a participation in the Younth Science metting event in Portugal, in addition to the above it also participated in the "Feria Mexicana de ciencias e Ingeniería" where it obtained the first place in its category.