The Coolar system is a medical refrigerator that uses warm water generated through solar energy to provide an affordable, durable, and sustainable solution for vaccine, medicine, and food storage in regions with unreliable or expensive electricity. Coolar is currently in a prototype stage.
SDG 3: Good Health and Well-Being
Target Users (Target Impact Group)
Public Sector Agencies, NGOs
Distributors / Implementing Organizations
This product is a prototype as of June 2017 and no distributors or implementors have been established, although Coolar is in the process of teaming up with industry partners and developmental organizations like Doctor's Without Borders to bring the solution to market. Coolar is supported by Bayer cares foundation, Expo 2020 Dubai UAE and others
Direct competitors include Sure Chill Vaccine Refrigerator BLF100 DC.
The product is still in the prototyping stage
Intellectural Property Type
User Provision Model
The product is not yet commercially available
Distributions to Date Status
Gross storage capacity (L)
Holding Temp (°C)
Above 0 degrees C
Holdover Time (days)
Number of Shelves
Vaccine storage capacity (Liters)
180 and 200 liters
The Coolar system uses warm water through solar energy. The system does not require batteries or electronic components, nor rotating parts. It does not use any hazardous refrigerants or lubricants. Coolar is designed to be economical, durable, and a sustainable solution for vaccines, medicine, and food storage in regions with unreliable or expensive electricity. It also produces 10x low carbon emissions How it works The absorption cooling cycle Evaporation Part of the water evaporates in the evaporator due to low pressure in the system. The resulting evaporation cooling effect cools the storage compartment. Absorption The absorbent attracts vapour, binds it on its surface and frees up space in the evaporator. In that space more water evaporates, so multiplying the cooling effect. Drying Once the absorbent’s surface is filled with vapour, the cooling is paused temporarily. In order for the process to be repeated the absorbent must be dried. Condensation By heating, the absorbent is then dried and all of the vapour is released from its surface. The vapour then condenses and flows back into the evaporators. This completes the cycle.
Provided by the manufacturer
Manufacturer Specified Performance Parameters
The manufacturers performance parameters are :
Powered by solar thermal energy it operates independent from electricity.
Long-lasting & Robust
System requires no short-lived batteries and contains no easy to break electronics or rotating parts.
No running costs as it is powered by hot water from abundant solar heat.
CO2 emissions are 10 x lower compared to conventional fridges.
Uses no hazardous materials, which makes it unproblematic upon disposal.
Enables reliable cooling for people without access to stable electricity.
Vetted Performance Status
In the spring of 2019, The company successfully installed and operated its Coolar refrigerator prototype on the island Tenerife. During the field test, the refrigerator operated completely independent from the electricity grid and managed to reliably cool the storage compartment inside the refrigerator cabinet to below 8°C, even as outside temperatures reached up to 36°C. This is the first successful field test of a refrigerator operating with a solar heat-powered continuous adsorption cooling system that only uses water as the refrigerant.
In developing nations, up to 75% of vaccines are damaged due to storage at too high or too low a temperature. Delivering damaged vaccines does not effectively influence disease control according to Coolar website
Complementary Technical Systems
Academic Research and References
Kühn, R., Göller, C., Goerdten, P., Mähne, K., Römer, J. and Schrecker, S., 2020. Performance evaluation of a double-lift concept for an adsorption refrigerator for high ambient temperatures. ISHPC 2021 Proceedings, p.69.
Hess, Jan, “Climate-KIC showcases Coolar, Prosumergy, MotionTag, Pendula and Orkess at ECO16 Berlin“, ECOSUMMIT, 2016
Coolar, “Coolar Field Test on Tenerife successful“, 2019
Compliance with regulations
Coolar has won various awards including Global Innovator by Expo 2020 Dubai’s Expo Live programme