Vaccine refrigeration technologies and power sources

Unfortunately, the areas in most urgent need of effective immunization programs are often distant from reliable refrigerated storage facilities or energy services. Selection of an appropriate energy supply and/or refrigeration technology has been seen as a limiting factor in effective immunization programs. In response to this problem, this report provides information on refrigeration technologies and energy sources currently employed in the vaccine cold chain and discusses possible responses to a variety of energy-related problems, including intermittent or unreliable electric service, and unreliable supply, unavailability, or poor quality of fuels for refrigerators in health centers not served by the electric power grid. Selection of appropriate vaccine refrigerators is relatively straightforward for clinics served by grid electricity. Equipment selection becomes somewhat more complex for off-grid clinics where absorption refrigeration is working satisfactorily, and becomes most complex for off-grid clinics where refrigeration costs are excessive or refrigerator reliability and performance are poor. The decision tools used in this report enable the reader to estimate, very roughly, lifecycle costs for various refrigerator systems, at different fuel costs. In addition to system cost, consideration must be given to how refrigerator reliability and performance may effect cost-effectiveness or appropriateness. A decision chart, and information in the text, indicate the types of situations where certain technologies can or cannot function effectively. Where reliable or fairly reliable grid-electric power is available, compression refrigeration is the most reliable and cost-effective technology for vaccine cold chain use. If electric service is reliable, but there are planned outages daily, or short unplanned outages are common, ice-lining refrigerators are recommended, assuming at least 8 hours of electricity per day. In areas where grid-electric service is not available, or where it is often unavailable for long periods, a choice will have to be made between kerosene and gas absorption systems, solar or photovoltaic (PV) systems, or cold-box outreach. Photovoltaic (PV) systems can play a valuable role in immunization programs. In some cases, PV refrigeration appears to be the most cost-effective alternative; in other cases, PV systems may be the only type that can be effectively supported in the field. At present system costs, PV systems will be most cost-effective or programmatically justifiable in locations that are subject to poor fuel availability or quality, high fuel costs, severe logistical problems, and high vaccine spoilage rates. Bottled gas or kerosene refrigerators will often be the most cost-effective option for offgrid health clinics, if the fuel supply is reliable, of high quality, and reasonably priced. If both kerosene and gas are available, gas is generally highly preferable, even if fuel costs are higher. Provided that kerosene is of acceptable quality and kerosene refrigerators have functioned effectively for the Expanded Program on Immunization in that region in the past, kerosene systems can be a cost- effective option. The material is organized as follows. Part I contains a general discussion of the vaccine cold chain, addressing both equipment needs and various cold chain constraints. Refrigeration equipment recommendations for different conditions and advice on how to proceed with equipment selection is contained in Part II. Part III consists of a more detailed discussion of technology selection, including region- and site-specific factors that must be taken into account; performance, reliability, and cost information on each of the technologies and power sources; and a description of the operation of each technology. (Author abstract)