Lessons learned from testing, photovoltaic vaccine refrigerators

Side-by-side testing of vaccine refrigeration systems began in March 1987 at the Florida Solar Energy Center. By December 1987, three photovoltaic (PV) powered vapor compression vaccine refrigerators were installed and operating. A kerosene-powered absorption refrigerator began operation in June 1988. The authors present observations, conclusions, and recommendations derived from testing the four vaccine refrigeration systems. Refrigerators, photovoltaic arrays, battery subsystems, charge controllers, and user training requirements are considered. It is concluded that all of the refrigerators which have been tested have their advantages and disadvantages, depending on the needs, capabilities, and resources of the user. In general, for the PV-powered units, the arrays are stable and the refrigerators are reliable. The long-term limitation for these systems appears to be a gradual decline in battery capacity, while the short-term problem is the periodic unwarranted refrigerator cutoffs due to the system controller reacting to surge voltages. For the kerosene unit, besides always having to maintain an available supply of fuel, its biggest problem is the generation of toxic fumes