Off-Grid Vaccine Cooling

Published by Nick Barrowclough on

Coolar vaccine refrigerator

20 years ago a joint program with Greenpeace and the United Nations a solar powered vaccine chiller was developed. it used isobutane refrigerant. Around 100,000 units have been installed world wide at off-grid locations.

Coolar logo

Now, a German startup company, Coolar, based in Berlin, have taken a new approach to off-grid vaccine storage with a solar powered refrigerator that uses only water and adsorption technology to achieve stable cooling for vaccines in off-grid rural locations.

In a conventional refrigerator the evaporation of coolant creates the low temperatures. In Römer’s solar-powered vaccine refrigerator, the evaporating liquid is water. Her system uses silica gel to attract water after evaporation. A solar panel generates heat that causes the gel to dry, then the water evaporates and is returned to circulation. The solar chiller needs almost no maintenance and is easy to dispose of since it doesn’t contain any polluting substances.

Coolar refrigerator - off-grid vaccine storage

Coolar will run pilot tests of their off-grid vaccine cooling refrigerator in Kenya later in 2020. It is hoped that a COVID-19 vaccine will soon be made available, meaning the timing of such an innovation is perfect to meet the upcoming demand. If the trials go well Coolar will ask the World Health Organization (WHO) for approval of it’s technology for use as vaccine storage.

The founder and CEO of Coolar, Julia Römer had the idea for the product in 2014 while studying for a degree in Industrial Engineering at the Berlin Institute of Technology. In her thesis paper she examined the theoretical possibilities of down scaling industrial-sized adsorption systems to something the size of a refrigerator that would be suitable for vaccine storage. This would make the ideal product for use where electricity is scarce, remote and rural locations which are off-grid or have unreliable power. Her thesis concluded it was possible, and Coolar was born from there.

The first functioning prototype was built in 2015. It was a single-cycle mini-bar refrigerator and it won her second prize in the Darboven Idee Competition for women with promising business concepts.

Since then the team at Coolar has improved the prototypes with further testing they have demonstrated the ability for the system to work with outside ambient temperatures of up to 43°C (109.4°F)

In the spring of 2019 an in-field test was successfully carried out in the Canary Islands, and some final tweaks were made. The vaccine refrigerator will now be tested in the summer of 2020 in Berlin and later test units will be sent to Kenya once the worldwide COVID-19 travel bans are lifted.

An important criteria when thinking about vaccine storage is that the temperature is kept stable between 2°C and 8°C. if vaccines get too warm they will deteriorate, loosing potency and effectiveness. If they are kept too cold and they freeze, it kills the vaccine completely and you can not use them at all. Normal refrigerators have evaporator temperatures under zero degrees, as low as -15°C to -20°C. This makes it all too easy to freeze vaccines or cool them too much. The Coolar system is naturally a freeze-free system.


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