Coolar Refrigeration

Coolar: using solar power to stay cool

Jul 28, 2017 - 2min read



The sun has existed for 4.5 billion years, but we are only now reaching the cusp of a solar revolution. We are seeing a far wider range of applications for solar power than ever before, with businesses increasingly working towards a more sustainable future.

Coolar is one such firm – a high-tech social enterprise developing a solar-powered refrigerator that contains no moving parts or environmentally-unfriendly cooling liquids. All it needs to run – besides sunlight – is water.

The Coolar refrigerator could be invaluable in developing countries with hot climates, enabling remote off-grid areas to keep medical vaccines cool – thereby vitally prolonging their shelf life.

The idea of using the heat from solar energy to create a cooling effect may seem oddly counter-intuitive, but the system makes sense of this apparent contradiction through an ingenious 4-step cycle.

1. Evaporation
Sunlight heats water within the low-pressure system, causing it to evaporate and cool the storage compartment – similar to the way sweat cools you when it evaporates from your body.

2. Adsorption
Coolar fridges contain an adsorbent – a solid material that attracts the vapour and binds it on its surface, so more water can evaporate. This increases the cooling effect even further.

3. Cooling
Cooling pauses temporarily once the adsorbent’s surface has filled with vapour, so it can dry in order to restart the process.

4. Condensation
The adsorbent is heated, releasing the vapour from its surface until it is dry. The vapour condenses and returns to the evaporator, which begins the cycle again.

Cooler Quote

Requiring no electricity whatsoever, the potential for Coolar is immense; nearly every vaccine in the world requires cooling. Once Coolar systems are being used for on-site refrigeration in remote areas, the next step would be to develop solar-powered mobile refrigeration for each step in the ‘cold chain’ – the journey any refrigerated item takes, from producer to end user.

This could make it possible to refrigerate food as well as medical supplies. An estimated 16% of the world’s population live without access to electricity. That means 1.2bn people have never been able to refrigerate food, and Coolar’s renewably-powered cooling system could be the solution.

Coolar’s founder and Lead Technological Developer Julia Römer is enthusiastic about the potential for technology and solar power to make a difference: “I’ve always wanted to be an agent for positive change in the world, rather than just a passive observer. The provision of warm water and electricity through solar power opens the door to a wide variety of possible applications – and the beauty of using renewable energy in this way is that people can benefit greatly while also actively helping the environment.”

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