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Current vaccine programmes in developing countries do not meet the international standards for temperature safe vaccine distribution which leads to vaccine freezing and losing potency. Isobar maintains stable temperature control (2-8 ˚C) up to 30-days.

  • Isobar cooling unit

  • Isobar - Mobile Vaccine Delivery

    Isobar - Mobile Vaccine Delivery

  • Isobar inside an insulated backpack

  • Sketch Development

  • Electronic feedback system

  • Propane recharging

What it does

Current vaccine programmes in developing countries do not meet the international standards for temperature safe vaccine distribution which leads to vaccine freezing and losing potency. Isobar maintains stable temperature control (2-8 ˚C) up to 30-days.

Your inspiration

A book called ‘from the killing fields to the healing fields’ highlighted major issues in vaccine transportation that have not been changed in 30 years. I came up with my solution while camping in Mexico. My friends bought 13kg of ice with them and I thought that there must be a better system of cooling than this. I saw that we had 4 propane stoves and wondered if you could make a cooling effect by heating it. I discovered a 1929 forgotten cooling invention called ‘Icyball’ that had no moving parts and provided rural farmers access to off the grid refrigeration. I refined the cast iron technology for use as a portable, controllable cooling device.

How it works

The core principal of Isobar is long-term, controlled cooling effect that is rechargeable anywhere in the world. 2-phase ammonia-water absorption refrigeration invented by Einstein in 1906 is fundamentally the simplest and most powerful cooling technology for its size. It relies upon heat to separate the ammonia into an upper chamber. Ammonia is hydroscopic, meaning it is naturally drawn to water. When a valve opens, Ammonia evaporates into the original chamber and gives a powerful cooling effect. Isobars key innovation lies in the way this effect is controlled and recharged. It is controlled using an automated valve that monitors the internal temperature of the insulated vaccine backpack and recharged using either an internal electric heating element or propane burner. This allows for a system that is adaptable to logistical problems such as transport or infrastructure breakdowns that would lead to vaccine loosing potency.

Design process

The initial design phase involved extensive research into absorption refrigeration and the thermodynamic properties of a scaled down absorption cycle based on declassified military units and hobbyist units. From this I worked closely with vaccine nurses to turn an engineered unit into a device that is simple and easy to use by the people on the front line. We analysed load carriages to design an insulated backpack that was suitable for rural trips. I used the maximum load carriage for how many vaccines a small women from India can carry (8kg) to design a 1.6L unit that is capable of delivering 330x4ml (2,460 0.5ml doses) of vaccine over 6-days without the need to recharge. It can be sustainably recharged in an hour using a 900w heating element for day-to-day use and a propane burner that can be recharged on-the-go in case of emergency for up to 30-days. The propane burner and pressure unit was designed to limit the energy input to meet international safety standards. Each ergonomic attribute of the cooling device and the backpack was built, tested and improved in a cyclical feedback loop with the nurses. A detailed amortisation business model and manufacture costings was developed to justify the introduction of a unit capable of safe last-mile transit for vaccine.

How it is different

The principal technology has been developed by hobbyists since introduction in 1929 as a commercial cooling unit. Since then the technology has been widely forgotten due to the COP (coefficient of performance) of modern mains electric refrigerators. Absorption refrigeration requires no fans, pumps or moving parts to work. It is the simple transfer of energy to and from the internal chemistry. Original Icyball units are known to be working well 85 years after their introduction. There are no recorded ammonia-water micro absorption refrigerators on the market with my valve system to regulate temperature. The idea is a fundamental shift in the way we carry valuable vaccine in locations where the system is failing all around them. Instead of pumping money into more vaccines, Isobar can pay for itself very quickly by ensuring vaccine arrives safely (see business plan on request).

Future plans

I already have a small shed/lab set up to develop the mechanical proof of principal unit further. I plan on progressing the project to present to the Bill & Melinda Gates foundation or WHO to run a pilot study for the effectiveness of the unit. I have contacts in social enterprise from the McKinsey venture Academy that can help to build a team of engineers and business facing to support further development. Loughborough University has helped market the device and has offered its further support to aid in development for the foreseeable future.


- McKinsey Venture Academy 2nd place winner - Awarded a zero ties grant to peruse the development further. A solo effort against 100 teams of 6, top 10 were PhD students from Oxford and Cambridge University. A detailed business plan was created to win 2nd place for Isobar. - JDF bursary. - New Designers exhibitor.

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