Many of the negative impacts of poverty – poor health and lower life expectancy – can be avoided if medicines and vaccines for diseases such as polio and measles are made widely available. Many countries are aware of the importance of vaccinating against these diseases and have created programs to promote vaccination, such as the synchronized national polio immunization campaign begun in 19 countries in West and Central Africa this March, targeted at 85 million children under the age of 5.
However, many vaccines and medicines, such as the vaccine for polio, require refrigeration during transport and storage, making them difficult to distribute to rural areas where there is no access to an electric grid. This is a critical point to consider in Sub-Saharan Africa, for instance, where, according to the UN-Energy publication “The Energy Challenge for Achieving the Millennium Development Goals”, only 8% of the rural population has access to electricity. Worldwide, the report claims that “at least 1.6 billion people do not have access to electricity”, highlighting the importance of developing vaccine and medicine distribution systems which do not require electricity from a grid. Solar-powered refrigerators can be part of the solution to this problem, enabling vaccines and medicines which must be refrigerated to be made widely available in regions where electricity is not.
There are three main types of solar-powered refrigeration systems currently available:
- Systems with batteries and solar panels – Solar panels produce electricity which charges a battery. A standard refrigerator is then run from the battery.
- Systems with solar panels but without batteries – Solar panels produce electricity and are directly connected to a variable-speed vapor compression cooling system which uses a phase-change material and a microprocessor-based control system. The NASA-spinoff SunDanzer, shown below, is an example of this type of system. One advantage of this system is that it removes the environmental threat of improper battery disposal.
- Systems with neither solar panels nor batteries – An example of this system is the EcoFridge, displayed below, which uses cooling from evaporation to extract heat from a refrigerator’s cooled compartment. This system is advantageous because it is simple to make and can be constructed from local materials. However, it requires water to operate, which is disadvantageous in arid climates.
Further information on the history of different types of solar-powered refrigerators as well as comparisons of these devices can be found here.
Currently, solar-powered refrigerators are beginning to be used for vaccine distribution in remote areas. For instance, one of the finalist projects in the 2007 World Bank Development Marketplace competition entitled Integrated Mobile Health Clinics for Remote Communities in Kenya uses camels with solar-powered refrigeration systems to transport vaccines to nomadic communities in Kenya’s Laikipia and Samburu districts. Hopefully, solar-powered refrigerators will be made widely available, enabling the distribution of refrigerated vaccine and medicine in regions of the world that lack electricity access.