Photovoltaic-Thermoelectric Power for Sustainable Cold Chains Needed for Covid-19 Vaccine Delivery and Use in Niger

In areas where the access to an off-grid electricity is not possible or not reliable, the transport and conservation of vaccine and medicines is not possible. Nevertheless, these areas need and have right to access medicine. This need is much more critical nowadays since preservation of COVID-19 vaccines require cold-chain at some level of degree. Solar energy can be used to power the refrigerator destined to keep the medicines and vaccines cool. Even tough stand-alone photovoltaic (PV) is already used to power these coolers, our work shows that the use of a Photovoltaic-Thermoelectric hybrid generators could allow a great improvement of the autonomy. The output power of the PV alone and the hybrid are investigated under Niger meteorological conditions. These two systems coupled with a medical cooler are investigated. The results show that the hybrid system produces considerably more power to be stored in the battery, indicating much longer autonomy. Under the same conditions, when the PV reached its lowest efficiency of 12.24% , the hybrid was at his efficiency peak 19.62%. Thus, a rise of 5.88% was achieved. Our work presented here is important for giving a message to the international organizations that sustainable cold chains needed for equitable COVID-19 vaccine distribution is clearly possible with solar PV/TE driven DC refrigerators.