This project developed and deployed a portable medical-grade refrigerator that can maintain any pre-set temperature for over 15 hours through its battery powered by a 100 W solar panel. This product (“Emvolio”) has been effectively deployed in remote regions with intermittent power supply. It has helped keep primary health centres operational and maintain the cold chain for medicine supplies during extreme weather events (e.g., during the floods in Assam between 2020-2023). The product is currently deployed in 14 states in India, and the deployment of 100 units has commenced in Kenya. 

The underlying refrigeration mechanism is solid-state cooling, which ensures accurate temperature control without the danger of harmful refrigerant leaks or cross-contamination. Additionally, it includes a portable solar unit, increasing cooling capacity and promoting renewable, sustainable energy use. 

PATH India facilitated the designing and field testing of the product. The following stakeholders were involved during deployment: hospitals (Government and private); non-profit healthcare and livelihood organizations (SELCO Foundation, CINI, TATA Trusts, and Venture Center); the National Health Mission; and Indian state health departments.   

After deployment, the team conducted on-site training sessions, familiarising health care workers with the need for  precise temperature control in vaccine distribution, correct cold-chain handling, and the role of data monitoring for enhancing vaccine supply chains. Additionally, regular assessments were conducted  to gauge the device performance, community acceptability, and its impact on the system in comparison to traditional ice-based vaccine carriers. 

Major funding sources for the projects included grants from the Government of India (DBT BIRAC, Govt of India) and USAID, and impact investments (Venture Center, Social Alpha, Qualcomm, Manipal Foundation). The developer of the technology, Blackfrog, has been able to mobilize more than USD $700,000 in grants and investments. 

Solar-powered refrigerators have been facilitating last-mile delivery of effective vaccines, servicing key population groups such as  pregnant women and children. The portable backpack design helped reach remote areas, especially in the mountainous areas of North-East India, where community centres are often a half-day journey from major roads.  

Field doctors reported that with the device’s battery performance, they are now able to immunize twice as many children in remote regions, as well as increase routine immunization time. 

This technology has been used to administer more than 150,000 vaccination (routine and COVID-19) doses in hard-to-reach areas. Over 800 health centres are now equipped with the device , and around 1,000 health workers were trained in vaccine storage and transport at the optimal temperature.

The capital cost of the device is an initial investment that has a return on investment (ROI) indirectly within one year. This ROI is directly linked to the vaccine wastage averted. The government or donor agency procures the units to strengthen the last-mile cold chain delivery. One device costs USD 1,600, a cost the end-user recovers from savings on routine vaccine waste reduction. The SVYM Hospital in Mysore (Karnataka), which has been using two devices since 2019, has reported saving INR 13,000 (USD 160) every month as a direct consequence of not discarding unused vaccines at the end of the day’s field trip. With solar-powered units, they are carrying the unused vaccines back to a health-facility.  

The technology is adaptable to multiple healthcare and geographic settings, with the potential for optimizing the vaccine delivery process globally. Any country can  improve immunization efforts without requiring policy amendments. Upon approval, the project begins device manufacturing and deployment, and ends once the innovation is assimilated with the national public health system.