A SDD and PCM solution for vaccine storage and outreach

摘要

In responding to the demand for vaccine outreach solutions in remote off-grid areas in developing countries, Intellectual Ventures Global Good developed a highly-efficient vaccine storage and PCM (Phase Change Material) freezing device prototype, called Arktek SDD (Solar Direct Drive). A final design and product, which may differ in certain details from the prototype, will be developed by Global Good's commercial partner Aucma, a leading manufacturer of refrigeration and cold chain equipment. The prototype device consists of two parts: a SDD cooling system as an add-on to an Arktek PSD (Passive vaccine Storage Device). The active-cooling system employs thermoelectric cooling technology, which maintains inside temperature of a 10L vaccine compartment from 2 to 8°C. Two removable PCM packs can be fully frozen inside the device, and then put into WHO standard vaccine carriers for outreach. Five prototype devices were built and tested inside an environmental chamber. The test results showed that the performance met or exceeded WHO verification protocol for combined SDD refrigerator and freezer. For example, the devices achieved 8 days holdover time vs 20 hours as WHO requires. Four devices were then taken to 4 remote health posts in west Senegal for field tests. The test results demonstrated that the devices met all the relevant requirements under real world conditions and use cases. The devices maintained the vaccine temperature within 3-5°C all the time; and a 100W solar panel is sufficient to power the system with ample margin. Routine vaccine-retrievals and PCM pack's insertion / freezing did not adversely impact vaccine temperature range.