Powering Health
Electrification Options for Developing Country Health Facilities
Cold Chain and Refrigeration
This solar powered vaccine refrigerator installed by the World Health Organization at Port Salut in Haiti has worked well for two years. (Photo: Jeff Haeni)
Health facilities in developing countrie need to maintain the cold chains to ensure that critical medicines, vaccines and supplies can reach those in need.
Vaccines are sensitive to both heat and cold and so need to be kept between 2° and 8°C from the point of manufacture to the point of use. The recent global push to deliver anti retroviral drugs and services to HIV-positive patients worldwide has introduced new cold chain requirements. Blood, HIV rapid test kits, pediatric ARV drugs, and a variety of testing reagents all must be stored in climate controlled conditions. Properly refrigerated and stored blood is critical to HIV treatment efforts in developing countries. In order to keep blood useable, blood bank refrigerators need to keep internal temperatures between 2° to 6°C all day, every day.
The system for keeping these critical supplies at the proper temperature is called the cold chain. For years, health professionals have struggled to develop the cold chain in developing countries to ensure that critical medicines and vaccines could reach those in need. Lack of access to electricity and intermittent power supply greatly complicate establishing a cold chain in many developing countries with traditional electric refrigeration.
A variety of different refrigeration technologies have been developed in order to extend the cold chain to areas with limited energy services including, 12 V electric, LPG, gas electric hybrid, and kerosene powered models. A cold box can also help keep vaccines at the required temperature for between two and seven days and is needed in case of interrupted power supply, equipment maintenance. They can also be used to supply health posts without refrigeration, provided the vaccine is to be used immediately.
Each of these refrigeration technologies has advantages and disadvantages and there is a healthy debate among health professionals concerning the most reliable technology. Evaluation of in several countries has highlighted the following observations:
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Footnote: 1. WHO/UNICEF supported solar powered vaccine refrigerators are typically the most successful example of solar power application in rural health facilities. While solar/PV powered refrigerators still suffer from all the challenges detailed on this site – they can be very effective when installed as part of a nationwide cold chain program with associated support mechanisms. These systems are typically more sustainable than standard clinic-wide solar/PV systems for the following reasons:
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| Compression | Compression refrigerators and freezers require a source of electricity to run a compressor, and can be powered either by AC or DC power. AC refrigerators can be operated by grid power or by battery power through an inverter. DC refrigerators can be powered directly by batteries. Compression refrigerators for medical use are heavily insulated, and include cooling fans and temperature monitoring equipment. Some medical refrigerators have two compressors to provide redundancy in case one compressor fails. Compression refrigerators are the best option when there is a high quality electricity supply, either from the grid or an on-site energy supply system specifically designed to meet refrigeration loads. |
| Solar | Solar electric refrigerators are a type of compression refrigerator. They are self-powered units that typically include a top-opening refrigerator with no internal fans or lights; solar panels, and batteries. Solar refrigerators require careful study of the refrigeration requirement, number of sunlight hours, and a specification of the number of days of storage for cloudy periods. Solar refrigerators also require the use of high-quality batteries and battery charge control equipment, properly sized electrical wires, and a supply of spare parts. Solar refrigerators are an excellent option for remote facilities without access to reliable electricity or fuel supplies if all the conditions for maintaining and sustaining the solar systems are also in place.1 |
| Standard Domestic | Domestic refrigerators are not as reliable or efficient as medical refrigerators, but are often more easily available and less costly. They may be of the compression or absorption type, and are typically front-opening with poorly insulated magnetic seals. Because domestic refrigerators are usually poorly insulated, internal temperatures can rise quickly during failures and result in uneven temperature distribution, including cold spots in some parts of the unit. Domestic refrigerators are a suitable option when high-quality AC power is available and reliability is not critical. |
| Absorption | Absorption refrigerators require a heat source, which is typically either a kerosene or propane burner, but can also be supplied by an electric resistive heater. Kerosene refrigerators are more difficult to control than propane refrigerators, and electric absorption refrigerators are typically less efficient. Absorption refrigerators are an excellent option for areas with no power but access to fuel and funds to purchase the fuel can be a serious constraint. |
| Hybrid | Hybrid absorption/compression refrigerators can operate on either electricity or gas. These refrigerators offer the flexibility of operating on whichever energy source is available at the lowest cost. They are a good option for any type of small facility with inconsistent electrical power. Supply of fuel is still an issue, however, as hospital staff often consider it a “back-up” and do not prioritize refilling canisters. |
Some refrigerators are designed for intermittent electricity supply and maintain storage temperatures using an ice lining. Some designs can maintain storage temperatures for up to five days. Refrigerators typically have a ten-year lifetime when properly operated and maintained. A refrigerator’s useful life depends on climate, power quality, and operating procedures. The World Health Organization provides good resources for choosing and maintaining refrigerators for medical use. Refer to the References section at the end of this manual.
Blood Bank Refrigeration
Types of Refrigerators
Descriptions of standard electric and solar powered refrigerators for blood banks are provided here.
Considerations when Choosing a Blood Bank Refrigerator
Issues to consider when choosing a blood bank refrigerator are described here, such as temperature zones, vaccine storage capacity, daily icepack freezing capacity, performance at extreme external temperatures, power source/variability, reliability and price.
Additional Resources
These are links to external publications and Web sites that have information on issues related to providing reliable electricity and energy services at health facilities. USAID and Powering Health make no warrantee or guarantee regarding these external resources, and the organizations hosting these resources are solely responsible for their content.
The Blood Cold Chain: Guide to the Selection and Procurement of Equipment and Accessories, World Health Organization, Nov 2002 (PDF 792K)
This is the first WHO publication dedicated to assisting managers of blood programmes to select and procure equipment and devices for the blood cold chain. This publication also aims to provide basic information on the blood cold chain and guidelines on its management.
Product Information Sheets, World Health Organization, Jun 2000 (PDF 1,350K)
This publication provides general information on the choice of equipment, together with specific technical and purchasing data for individual selected items. Please take note of these specific sections:
- A1 & A2 – Equipment for Acute Respiratory Infections
- B4 – Cold Boxes and Carriers for Blood Transport
- EC – Equipment for Emergency Campaigns
- P7 & P8 – Syringes, Needles and Accessories for Primary Health Care
SolarChill Vaccine Refrigerator, CREATE: Center for Renewable Energy, Appropriate Technology and Environment.
The SolarChill is a small vaccine refrigerator that operates directly from solar photovoltaic panels without batteries or a charge controller. When the sun is shining, DC power generated by the solar panels operates the variable voltage DC compressor which freezes ice-packs used in an ice bank.
Care and Repair of Refrigerators for Vaccine Storage
This page contains PDF training modules for refrigerator technicians produced by WHO between 1985 and 1988 including handbooks on different types of refrigerators and materials from a ten-day course for compression and solar refrigerator repair technicians.
Evaluation of Alternative Refrigerator Models for Primary Health Facilities, Indonesia Ministry of Health and PATH, Apr 2006 (DOC 951K).
The Ministry of Health in collaboration with PATH conducted monitoring on several refrigerators that are currently in use or can become candidates for use at the health center level. Several parameters that should be respected in order to maintain a stable temperature were noted and reported, while an operating cost efficiency based on electricity/fuel consumption per liter capacity of each refrigerator was calculated.
Solar Photovoltaic Refrigeration of Vaccines, Intermediate Technology Development Group, Jul 2002 (PDF 131K).
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. 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.
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Last updated: September 28, 2011
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