The operational needs are basically determined by the type of service aimed to be covered and the capacity of storage required. Because of the level of investment and the strategic importance of the cold chain, it is important to apply a long-term vision and plan the needs for the next 5-10 years.
It is important to determine the function of the storage facility within the whole vaccine supply chain and to decide whether or not the site will need to produce coolant packs for outreach, mass vaccination campaigns or recurrent vaccines delivery to other sites. This is mainly because coolant packs should not be stored in the same compartment as vaccines. Therefore, in case coolant packs are to be regularly managed, facilities should use either dual compartment devices, or two separate devices – one for storing vaccines and one for storing coolant packs. In this last scenario, small front-opening refrigerators or refrigerator/freezer combinations are best used at health facilities, where easy access to vaccine and a separate freezing compartment for ice packs are needed. The chosen refrigeration solution should have the capacity to store the required number of vaccines and produce the required amount of coolant packs.
Check the information above about Estimating the required storage capacity to determine the needs and then, the right device size for a facility.
Keep in mind that the capacity of refrigerators ranges approximately between 30L and 200L of net vaccine storage volume. For storage facilities with required capacity exceeding a considerable number of refrigerators, a cold room could be less flexible but a more efficient solution. Walk-in cold rooms (WIC) and walk-in freezer rooms (WIF) are refrigerated enclosures accessible via at least one door and large enough for a person to walk into, housed within existing buildings. Consider that WICs and WIFs are compression type refrigerators and require reliable power supply.
WICs and WIFs are an important storage point in the temperature-controlled supply chain and usually used at the central or national level or near shipping ports used for import/export of vaccines. For comprehensive information on how to choose the correct Walk-in cold rooms (WIC) and walk-in freezer rooms (WIF), refer to UNICEF Procurement Guidelines for Walk-In Cold Rooms And Freezer Rooms.
Top-opening refrigerators and freezers (also known as chest refrigerators and freezers) are the first choice for bulk vaccine storage in places where cold rooms or freezer rooms are not justified.
Context and Available Infrastructure
The context of use and the available infrastructure will influence the access to different power sources, the possibility to use solar devices and the available space and conditions to locate the cold chain equipment.
Accessible Power Sources
It is of key importance to ensure the reliability of the power source for the active cold chain: mains, solar, kerosene or butane. Having access to reliable electricity will back the use of electricity-powered devices – such as ILRs and on-grid freezers – since they have a lower Total Cost of Ownership than solar or passive devices for the same amount of storage.
Off-grid facilities should use devices that can generate their own power (such as SDDs), devices that can keep vaccines cold for long periods of time without power (such as long-term passive devices) or absorption type refrigerators (such as butane or kerosene refrigerators). These devices often cost much more to purchase than on-grid devices, and their operational and maintenance costs tend to be higher than for the electricity-powered devices. Therefore, it is of key importance to ensure ongoing funding in place for the lifespan of the equipment.
The choice of devices should correspond to the number of hours of electricity that a facility can access per day, and the length of electricity outages it experiences. WHO and UNICEF recommend that all primary vaccine stores should be fitted with a generator with automatic start up, regardless of the reliability of the mains power supply.
Solar devices are suitable for those facilities with sufficient solar energy available at installation locations: basically, strong enough sunlight all year round and clear surroundings without buildings or trees. Be aware that mountainous areas and coastal regions may have micro-climates with prolonged cloud cover. In these cases, the choice of solar technology will be limited and its implementation will require careful design to ensure adequate performance. In addition, it is advised to have a solar service provider able to deliver all necessary services, including site assessments, equipment installation, training, corrective maintenance, and repair.
The following figure, taken from WHO, Introducing Solar-Powered Vaccine Refrigerator And Freezer Systems, A Guide For Managers In National Immunisation Programmes, provides a decision tree to guide in the selection of the most appropriate energy source for vaccine refrigeration:
Cold Rooms are bulky items and require considering if the model ordered will fit into the allocated room (including height), allowing for enough space for access and ventilation. Some are prefabricated, allowing to be assembled in any pattern and to any size, with quick and easy installation which can be applied to any context. For further instructions on the installation and pre-operation of Cold Rooms and Freezer Rooms, follow UNICEF Procurement Guidelines for Walk-In Cold Rooms and Freezer Rooms,
Refrigerators and freezers are available in several shapes and sizes. Top-opening refrigerators and freezers, although are the first choice for bulk vaccine storage, occupy more floor space per litre of vaccine than front-opening models. Front-opening refrigerators or refrigerator/freezer combinations are easier to accommodate in reduced spaces and offer an easier access to vaccine.
Operating Temperature Range
It is important to take into account, as part of the environment criteria, the ambient operating temperature range where the refrigerator or freezer performs. This information should be provided by the manufacturer. Though a standard is a range between +5°C and +43°C, some models have a maximum ambient operating temperature of +32°C.
Support and Standardisation
As a general rule, when possible and if reviews show that the cold chain is well managed and that temperature monitoring procedures are reliable, select cold chain equipment similar in technology to the one already in place. This has obvious operational advantages.
It is important for the sustainability of the storage facilities to have access to professional in-country installation and maintenance support, including availability of spare parts. In this sense, the device's warranty and after-sales support from the supplier are fundamental.
Environmental criteria should also be considered when choosing the cold chain equipment. Compression type refrigerators are loaded with a coolant fluid agent (refrigerant). Manufacturers select refrigerants to suit the specified operating temperatures. The type of refrigerant used has evolved together with the growing environmental concerns. Until recently, the use of chlorofluorocarbons (CFCs) was widespread, but in 1987 the Montreal Protocol restricted its use due to its effect on the ozone layer. CFCs were replaced by hydrofluorocarbons (HFCs), like R134a, a popular refrigerant currently in use but still having a high Global Warming Potential (GWP). There is an expected cut-down in the use of HFCs and progressively new production of cooling instruments will probably be limited to Hydrocarbon (HC) refrigerants. HC refrigerants, like R600 or R600a, known as green or natural gases, have a GWP value roughly on the same level as CO2 but are extremely flammable.
Total Cost of Ownership (TCO)
Any vaccine storage site will require a considerable level of investment for its acquisition, installation, operation, maintenance, renewal and decommissioning. Understanding the costs of purchasing and maintaining cold chain equipment over time is basic for the planning and the sustainability of the vaccine storage facilities. To make the proper decision in the selection of equipment, the Total Cost of Ownership for Cold Chain Equipment must be considered.
Domestic appliances, though cheaper and locally available, are considered unsuitable for vaccine storage, particularly in hot climates. WHO recommendations on this matter are as follows:
- Standard domestic refrigerators should only be used for vaccine at the peripheral level, and then only if water bottles are used to improve temperature stability. This is especially true in hot climates. Domestic refrigerators are unsuitable for vaccine storage because they are not designed to maintain the temperature range required and they warm up quickly when the electricity fails.
- Domestic chest freezers should not be used to store vaccines but may be suitable for freezing ice packs.
Other technical reasons to avoid using domestic refrigerators to store thermo-sensitive pharmaceutical products are: its lighter insulation and imprecise regulation of the temperature, the heterogeneity of the temperatures at different areas inside the container and the variations in temperatures in case of automatic defrosting.
The concept of total cost of ownership (TCO) refers to all costs associated with owning and operating a unit of equipment over its useful life expectancy. It helps to evaluate a purchasing decision based on the comprehensive costs of owning and operating a piece of equipment over its useful life or a set period of time. TCO is calculated adding the capital costs and the operating expenses.
Capital costs are one-time costs incurred at the time of purchase. It includes: the costs of the equipment, recommended spare parts, in-country transport, installation kit, and installation labour.
Operating expenses are the recurring costs over the useful life of the equipment. This includes cost of energy (electricity, gas, kerosene), maintenance, repairs and decommissioning plus the costs of operation and training of staff.
Taking in consideration that devices that can generate their own power such as SDDs often cost much more to purchase than on-grid devices and that absorption type refrigerators tend to have higher operation costs, a first step in the process is comparing the costs of the different technologies suitable for the site.
Once a decision on the technology has been taken, a comparison of models will be pertinent. Compare the unit price, useful life, frequency of maintenance required and technical individual device characteristics such as:
- Holdover time for ILRs based on a facility’s power reliability.
- Autonomy time for SDD devices based on regional climate factors.
- Freezer capacity for ice pack production.
- Ease of use, including:
- Readability of control panels and displays by a standing health worker
- Use of internal storage racks, boxes or drawers to help organise vaccines and separate other medicines that are stored in the device.
- Voltage stabiliser integration.
To evaluate the cold chain equipment options from a cost perspective, it is advised to use the “PATH Total Cost of Ownership tool”. The tool allows users to explore the capital and operating costs associated across various cold chain equipment technology categories, as well as to compare costs for specific models within a technology category or across multiple technologies.
For further information on how to choose the correct cold chain equipment, please refer to GAVI’s Cold Chain Equipment Technology Guide.