Solar powered freezer prototype works where there is no electricity

A research team from the University of Coimbra (UC) has developed a set of efficient, low-cost prototypes for refrigeration – refrigerators and freezers – powered by solar energy (photovoltaic panels), for areas where there is no access to electricity, writes the Portuguese university in a press release.

The prototypes were developed over the last two years in the scope of the project “Energy-Efficient Off-Grid Refrigerators for Africa Rural Electrification”, led by researchers from the Institute for Systems and Robotics (ISR) of the UC and funded by the Efficiency for Access Coalition (UK Aid, UK Government) and the IKEA Foundation, after being selected in an international competition.

Consuming as less energy as possible

The team is also developing an intelligent controller that monitors and regulates the temperatures inside the equipment, as well as the variable speed of the compressor and the energy flows consumed by the system and generated by the solar panels, aiming for a stable internal temperature, so as to consume the least amount of energy possible.

This project specifically intends to implement these results in Sub-Saharan Africa, considering that, “in this part of the African continent, about 600 million people have no access to electricity, which directly impacts on these people’s quality of life. The refrigeration systems are essential to minimise food waste and to improve the population nutrition, while the vaccine refrigeration guarantees the necessary immunisation of communities, especially in rural areas”, explains Evandro Garcia, the project’s principal investigator and PhD student, supervised by full professor Aníbal Traça de Almeida.

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Solar modules as thermal batteries

Considering that developing regions are mostly in tropical areas, the abundance of solar radiation “makes the use of photovoltaic panels the best way to generate electricity. The use of solar energy in refrigerators adapted for these regions allowed the team to integrate cooling system modules. These modules were designed and manufactured through 3D printing systems and work as “thermal batteries”, adds Evandro Garcia.

According to the researcher, “during the day, the prototype uses the energy generated by the photovoltaic solar system to cool its interior and to accumulate cold in modules. At night the temperature is maintained due to the release of the cold accumulated in the modules, and the cycle restarts everyday”.