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.