Kilian Mähne (Co-Founder, Manufacturing), Julia Römer (Co-Founder, CEO), Roland Kühn (Co-Founder, Technology Development), and Christoph Göller (Co-Founder, Business Development) © Nils Lucas


Change the Way of Cooling

Founded in 2016
8 employees
Funding €200K

Coolar develops a radically new electricity-free refrigerator that is powered with solar hot water instead of electricity. It will be used to enable reliable cooling for medicine and vaccines for the >1.2B people living off-grid/with unreliable electricity. Its cycle is 100% water-based and the system is highly durable. As the Coolar system taps into abundant solar heat and avoids the use of hazardous cooling fluids, it holds great potential for making any cooling application more sustainable. Website

Interview with Coolar

What inspired you to found your startup?

Julia has a long track record in environmental advocacy (she is a board member of Germany’s largest environmental NGO BUND). During her studies at TU Berlin her interest in sustainability motivated her to learn everything she could about “green” technologies. Here Julia was inspired by and made herself an expert for the highly sustainable, not yet widely used principle of adsorption cooling. She then developed the concpet for the Coolar refrigerator during a summer school and in her thesis.

How do you define success for yourself and your company?

Making a lasting difference by leveraging technology to improve people’s lives and making human life on this planet more sustainable. Cooling is an essential human need. It is closely linked to conserving food or access to lifesaving medicine and vaccines. However, cooling causes about 10% of global emissions – over 4 times the amount of air travel. Coolar aims to make reliable cooling available to the people who need it most and to make cooling more ecologically sustainable in any application.

Is there anything you’d do differently if you could do it again?

As Coolar is developing a completely new cooling system, there have been many occasions on which the team has tested approaches that did not work as well as was intended right away. Doing it all over again, a lot of time could be saved by immediately jumping to the solution and skipping the iteration. However, doing something that has not been done before, the team is pretty good at making these mistakes in a smart and systematic way, with tests that make the learning curve as steep as possible.

What problem does your product solve?

Worldwide 1.2 billion people live without access to electricity. Where they live, about half of the health facilities have to operate off-grid. Here the most critical healthcare challenge is reliable cooling for lifesaving medicine and vaccines. Because of unsafe cooling, mainly due to unstable electricity, 75% of vaccines are at risk of damage, resulting in high humanitarian and economic costs. Coolar can solve this problem with its reliable, electricity-independent solar heat refrigerator.

Where do you see your company in 1/5/10 years?

1 yr: Coolar will have its refrigerator ready to enter into customer pilot testing and series production.
5 yrs: Coolar will be profitable and also deliver high social impact by supplying health organisations with electricity-independent refrigerators for medicine and vaccines. Plus first successess in agriculture and transport cooling.
10 yrs: Coolar’s technology will be the new standard in various applications as the > $235 bn global cold chain market has shifted towards sustainable cooling.

How are you different?

The Coolar system’s advantages for cooling vaccines off-grid are that it operates with:
– zero electricity – grid-independent & no need for costly fuel or batteries like current solutions
– zero rotating parts – no compressors or pumps; this makes the system more durable
– zero risk of freezing – increased safety
– zero running costs – it is powered with water heated up by the sun; solar heat is free
– zero CO2eq emissions – it contains no harmful refrigerants and uses carbon neutral solar heat

How often does your product/service show up in a user’s day or week?

Health workers at remote off-grid health facilities typically interact with their vaccine refrigerator twice a day. Once in the morning to move vaccine doses that will be needed during the day to an insulated container without active cooling, from which they will be retrieved during the immunisation activities. Once in the evening to return the doses that have not been used during the day. Between those instances the refrigerator is usually locked to prevent unauthorised access/improper handling

Impact: how are you doing good and building a better future?

One refrigerator can store between 4100 (i.e. polio, measles) and 625 (i.e. rotavirus) doses of vaccines, costing between $600 and $5000. This way it can help health workers serve thousands of people every year. If it fails, however, the vaccines spoil, resulting in a heavy financial loss and potentially the prolonged interruption of the high-impact immunisation activities. Coolar’s refrigerator ensures highly reliable, fail-safe cooling and can enable uninterrupted immunisation efforts.

How has the startup scene in Berlin changed?

It is diversifying and thereby transcending the image that came with the big success stories in e-commerce and consumer-facing online service businesses (and their sometimes fairly ruthless business practices). Now there also is a burgeoining social entrepreneurship and cleantech start-up scene, where already well established accelerators like Impact Hub, Social Impact Lab or EIT Climate-KIC serve as hubs to this exciting new mission-driven subsection of the Berlin startup ecosystem.

What are the pros and cons of launching your startup from Berlin?

Launching Coolar in Berlin was not so much a deliberate decision for the Coolar team. All of the co-founders except Christoph studied at TU Berlin. A close relationship with TU Berlin helps the team until today. Berlin is Germany’s start-up capital and home to social enterprise and cleantech incubators and accelerators that greatly benefited Coolar.
Compared to London, New York or Silicon Valley, Berlin is still not as rich in venture capital. The gap seems to be closing gradually, though.

Bonus Question: Anything else that we need to know about you?

Coolar was featured in “The Hundert Vol. 10 – Startups of Berlin“, October 2017.

The picture above was taken at:

TU Berlin

The TU Berlin has over 33.000 students enrolled, 20% of which are foreign nationals. The university prides itself on being family-friendly, equal opportunity, and offering great workplace health policies.

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