by Kien Vu and Hai Le, PATH
In many developing countries, vaccine storage in refrigerators is very costly for immunization programs. For years, solar refrigeration has helped those countries increase cold chain capacity and decrease energy costs and consumption. However, problems with battery maintenance have made solar refrigeration a challenge in many low-resource settings. To address the battery problem, refrigerator manufacturers have created a new category of solar refrigeration that eliminates the need for an energy-storage battery. Vietnam is piloting this battery-free solar refrigeration system to evaluate it as a vaccine storage solution, especially in areas where electricity is limited.
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As part of project Optimize’s collaboration with Vietnam, the National Expanded Programme on Immunization (NEPI) has been piloting two Sure Chill™ refrigerators (Sure Chill is a registered trademark of True Energy) for vaccine storage at the district level in Vietnam. The selected districts were Thanh Ba district in Phu Tho province (representing the North) and Thanh Phu district in Ben Tre province (representing the South). With technical support from True Energy, the refrigerators have been installed and PATH and NEPI have conducted stabilization testing to ensure appropriate refrigerator temperature for vaccine storage. During this time, bottled water was used to mimic the presence of vaccine in the refrigerator. Ten data loggers were placed in different positions inside and outside the refrigerator, inside and outside vaccine store, and near the solar panels to record the temperature and amount of solar energy produced and used. Health workers have been testing the refrigerators as if vaccines were actually being stored inside them, including monitoring the temperature daily and opening the refrigerator to simulate vaccine receiving and distribution on a particular schedule.
Data downloaded from the temperature data loggers show both refrigerators performed very well, with the temperature inside the solar refrigerator at a stable temperature as 4.3°C in Ben Tre province (see Figure 1) and 4.6°C in Phu Tho province.
Figure 1. Temperature inside a Sure Chill refrigerator in Thanh Phu district, Ben Tre province.
The project team is conducting ongoing interviews on user experience with the refrigerators throughout the study. At the first monitoring visit, users agreed that the Sure Chill refrigerators worked well and were easy to use on a regular basis. The one complaint from health care workers was regarding the noise generated by the compressor. However, health workers expressed their readiness to store vaccine in the refrigerator once they receive permission from NEPI. Based on positive results from the pilot period, NEPI has requested that Ben Tre Preventive Medicine Centre guide Thanh Phu district health center in using the Sure Chill refrigerator for storing EPI vaccines starting in September 2011. The goal is that Phu Tho province will also start using the Sure Chill for vaccine storage in their district health center by November 2011 when their pilot period is completed. (The pilot period is longer in the northern district where there is a more marked difference in weather patterns from summer to winter. In the north, it is important to observe how the refrigerator performs as winter begins, and frequent clouds are expected to impact the amount of solar energy available on a daily basis.)
This early success is encouraging as it may enable the government to increase vaccine storage capacity in Vietnam’s NEPI. If successful and accepted, battery-free solar refrigerators could not only ensure the required temperature range for vaccine storage, but also reduce energy costs for the health facilities. In that case, the Vietnam Ministry of Health may consider scaling up such vaccine storage systems widely in the future. Vietnam has the potential to become a model for other developing countries in using solar refrigerators to help improve the immunization logistics and supply systems.
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Click to enlarge.
As part of project Optimize’s collaboration with Vietnam, the National Expanded Programme on Immunization (NEPI) has been piloting two Sure Chill™ refrigerators (Sure Chill is a registered trademark of True Energy) for vaccine storage at the district level in Vietnam. The selected districts were Thanh Ba district in Phu Tho province (representing the North) and Thanh Phu district in Ben Tre province (representing the South). With technical support from True Energy, the refrigerators have been installed and PATH and NEPI have conducted stabilization testing to ensure appropriate refrigerator temperature for vaccine storage. During this time, bottled water was used to mimic the presence of vaccine in the refrigerator. Ten data loggers were placed in different positions inside and outside the refrigerator, inside and outside vaccine store, and near the solar panels to record the temperature and amount of solar energy produced and used. Health workers have been testing the refrigerators as if vaccines were actually being stored inside them, including monitoring the temperature daily and opening the refrigerator to simulate vaccine receiving and distribution on a particular schedule.
Data downloaded from the temperature data loggers show both refrigerators performed very well, with the temperature inside the solar refrigerator at a stable temperature as 4.3°C in Ben Tre province (see Figure 1) and 4.6°C in Phu Tho province.
Figure 1. Temperature inside a Sure Chill refrigerator in Thanh Phu district, Ben Tre province.
The project team is conducting ongoing interviews on user experience with the refrigerators throughout the study. At the first monitoring visit, users agreed that the Sure Chill refrigerators worked well and were easy to use on a regular basis. The one complaint from health care workers was regarding the noise generated by the compressor. However, health workers expressed their readiness to store vaccine in the refrigerator once they receive permission from NEPI. Based on positive results from the pilot period, NEPI has requested that Ben Tre Preventive Medicine Centre guide Thanh Phu district health center in using the Sure Chill refrigerator for storing EPI vaccines starting in September 2011. The goal is that Phu Tho province will also start using the Sure Chill for vaccine storage in their district health center by November 2011 when their pilot period is completed. (The pilot period is longer in the northern district where there is a more marked difference in weather patterns from summer to winter. In the north, it is important to observe how the refrigerator performs as winter begins, and frequent clouds are expected to impact the amount of solar energy available on a daily basis.)
This early success is encouraging as it may enable the government to increase vaccine storage capacity in Vietnam’s NEPI. If successful and accepted, battery-free solar refrigerators could not only ensure the required temperature range for vaccine storage, but also reduce energy costs for the health facilities. In that case, the Vietnam Ministry of Health may consider scaling up such vaccine storage systems widely in the future. Vietnam has the potential to become a model for other developing countries in using solar refrigerators to help improve the immunization logistics and supply systems.
To comment or reply to this article, click “reply.” 
Thanks for sharing some results of this interesting work.
Related to the usage of solar fridges, is the question of buying and operating solar arrays.
Could you share some insights from Vietnam about
the size of the solar arrays required for the fridges you tested,
the cost of the material and the cost of labor for the installation of the fridge and array
the operational challenges to address to successfully install and operate such installation
Thanks,
Yann
Hi Yann,
Thanks for your interest in our project.
Regarding the design of the solar array, there are many who are much more qualified to answer this than I, but the important thing is to have a qualified solar supplier design the system that will go with your refrigerator. It must take into account the solar and temperature conditions at the location of installation, the specific power needs of the refrigerator, and may include an overage factor (though I think this overage is generally more critical for systems with batteries). We were quoted for the complete system, including solar array, hardware, and refrigerator, so I can’t respond well on the topic of cost of the arrays, but you might be able to find some useful info on the web if you can calculate the approximate peak watt power you will need based on the refrigerator consumption data in PQS.
Regarding installation, we hired a local installation company in Vietnam, and paid somewhere between 5 and 8 percent of the total cost of 2 systems for the installation, including material and labor. We were lucky to have the refrigerator manufacturer also heavily involved in installation, which I think contributed to success. Regular maintenance should be planned for the system in order to ensure longevity. For battery-free systems, this involves regular cleaning of the solar panels, checking cables and connections, and of course responding to any breakdowns. Wherever possible, a local resource for maintenance should be arranged.
Joanie Robertson
PATH Vietnam
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