TechNet-21 - Forum

Ce forum est un lieu d'échange où les membres peuvent poser des questions, partager leurs expériences, coordonner des activités, et discuter les récentes avancées en matière de vaccination.
  1. Dan Brigden
  2. équipement de la chaîne du froid
  3. mercredi 31 août 2016

Dear TechNet members, I'm putting together a document on the performance of solar direct-drive (SDD) vaccine refrigerators and would like to request your assistance. If you have experience of SDD projects in the field I would be very grateful if you could share your thoughts on how well they have performed (particularly in relation to other types of vaccine refrigerator), problems that were encountered, solutions identified, and any other observations you might have.

More than 20 SDDs are now WHO PQS-prequalified, and many of these are eligible for funding as part of the GaviCold Chain Equipment Optimisation Platform. It's an exciting technology that has the potential to be a "game-changer" for immunization programs, as iteliminates the need for expensive/problematic energy storage batteries used to power solar refrigerators. However, with all new technologies it is uncertain how well suited it is for use in "the real world" outside of the laboratory.

As part of Project Optimize, PATH and WHO worked with ministries of health in in Vietnam and Senegal toconduct some SDD pilot studies, but this was five years ago. I've also heard that CHAI have been doing some work in this area, but don't think they have yet published their experiences. I wonder if TechNet members can share any more recent experiences with these devices? Both good and bad!

Many thanks.

Alain Claude BILOA Réponse acceptée

I am very happy to read this subject. Cameroon is going to acquire this kind of equipements next year. We will continue to follow the discussion in order to know if this issue will be sold by the first semester, as we will start the installation at the en d of the year.

Thank you


Shahrzad Yavari Réponse acceptée

Dear Dan and Technet-21 members,

Attached please find a set of slides on 2 solar direct-drive (SDD) vaccine refrigerators performance in the field. If you need more informaiton or have any questions, please contact me at

I hope you find these analytics helpful.

Warm regards,


Pièces jointes
Lars Gorzelak Réponse acceptée

Dear TechNet readers,

I can confirm that we have had some incidents in the market with the VLS054SDD. The failure cause has been identified and corrective action has already been implemented in our production. Right now we are in dialog with UNICEF and MOH to solve the problem on units already installed, that is effected by this fault. In case you need further information or technical support please feel free to contact me.

Best regards

Lars Gorzelak
Head Of Product In.& Concept

A/S Vestfrost

Falkevej 12

DK-6705 Esbjerg Ø


+45 79142551


+45 21413551



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Moussa Valle Réponse acceptée
Dear Moderator, Malawi procured 120 solar direct drive (SDD) refrigerators in November 2015. Sixty were TCW2000 SDDs and the remaining 60 were VLS 054. These two models were installed in February/March 2016 with technical assistance provided by a Technician who was engaged by UNICEF country office. A week after installation we started receiving information that some VLS 054 SDDs were not functioning and by July, 2016 we had 11 SDDs that developed faults. In September UNICEF engaged a technician within MoH who also participated in the training and installation of the SDD as a supervisor. He visited all the sites whose VLS 054 refrigerators developed faults. His findings were that all the 11 VLS 054 had a common fault of burnt electronic thermostat XR20CX, item number 7020274. The contributing factor to burning of the electronic thermostats is the moisture that comes out of the pipe through which sensors of the thermostat and the thermometer enter into the cabinet. This could be due to insufficient application of sealant to fill up the hole. Due to limited spare parts only five were repaired and six are up to now not functioning. The other model TCW2000 has not developed any fault up to now. We are still monitoring the performance of the SDDs in the country and the only challenge now is the lack of spare parts to maintain the VLS 054 SDDs. Thanks. Moussa Valle National EPI Logistics Officer Ministry of Health, P.O. Box 303787, Lilongwe 3 Malawi
Wudu Ayalew Melaku Réponse acceptée

Dear Douglas,

Thanks a lot for your interest on details.

The average temperature recorded from two refrigerators is 4.2oC and 4.6oC. I did not record room temperature at SDD installation sites. In case if it helps I have also conducted temperature monitoring study in vaccine supply chain in parallel with SDD Installation at 10 representative health facilities and maximum room temperature recorded was 35oC, minimum room temperature reading was 17.5oC.Rwanda is land locked country with 24,949 sq Km land area.

Based on Meterological data Rwanda gets approximately equal to 5kWh/m2/day and peak sun hours of approximately 5 hours per day.

The SDD refrigerator that I have installed is Dometic TCW3000SDD.

Many Thanks,


Mukwaya Douglas Réponse acceptée

Dear Wudu,

Thanks for the update however since we are looking for performance i would appreciate to have more information on average temperature range of the equipment, minimum and maximum temperature during normal working/ running hours as well as ambient temperature of the location (HF) coupled with average sun hours a day. Secondly, it would also be good to know which type of fridge you are refering to because SDD is a common factor. With such information, performance can then be clearly determined which can also guide us in equipment selection.



Wudu Ayalew Melaku Réponse acceptée

Dear Technet-21 members,

I would like to share my experience on performance of SDD refrigerator that I have in Rwanda.

I have been working in Rwanda from January to May 2016 and one of my assignment was to install SDD refrigerators, train end users and technicians, conduct temperature monitoring study and cold and freezer room mapping. The main objective of the SDD refrigerator installation was to check suitability of technology in Rwanda and to expand in places where there is no grid electricity. I have installed two SDD refrigerators out of six in Kaduha  and Munini hospital on April 2016. After Installation I have placed FridgeTag 2 and Logtag Trix8 to monitor the temperature before storing vaccines. After 41 and 42 days of installation I have visited the sites and extracted data from LogTag Trix 8 and FridgeTag2. Data shows very good performance. There were no temperature records below +2oC and above +8oC. The only above +8oC reading at Kaduha hospital was on the first 48hours before refrigerator stabilizes temperature. In case if you need more information please contact me on or



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