REFRIGERATION OF VACCINES
Extensive immunisation programmes are in progress throughout the developing world in the fight
against the common communicable diseases. To be effective these programmes must provide
immunisation services to rural areas.
Solar radiation tends to be high in climates that have great needs for cooling, a great deal of effort
has been directed to develop solar powered refrigerators. Although some solar absorption
(thermal) refrigerators have been developed only solar photovoltaic (electric) refrigerators have so
far proved reliable.
Solar photovoltaic power for refrigerators has great potential for lower running costs, greater
reliability and a longer working life than kerosene refrigerators or diesel generators, which have
been generally used in remote areas. Over the past five years, at least 3000 photovoltaic medical
refrigerators have been installed.
All vaccines have to be kept within a limited temperature range throughout transportation and
storage. The provision of refrigeration for this, known as the Vaccine 'Cold Chain', is a major
logistical undertaking in areas where electricity supplies are non-existent or erratic. The
performance of refrigerators fuelled by kerosene and bottled gas is often inadequate. Diesel
powered systems frequently suffer fuel supply problems. Solar power is therefore of great
importance to health care.
Relative merits of using photovoltaic refrigerators
Compared to kerosene or bottled gas fuelled refrigerators, photovoltaic systems have the following
Improved vaccine storage facilities as a result of:
• elimination of fuel supply problems
• elimination of fuel quality problems
• greater refrigerator reliability
• better refrigerator performance (and temperature control).
Reduced running costs as a result of:
• elimination of kerosene fuel costs
• elimination of kerosene transportation costs
• reduced vaccine losses
• lower refrigerator maintenance costs
• reduced needs for back-up refrigerators where there are fuel supply or repair
Cold chain management benefits due to:
• longer equipment life (photovoltaic array 15 years, battery 5 years refrigerator 10
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