TechNet-21 - Forum

This forum provides a place for members to ask questions, share experiences, coordinate activities, and discuss recent developments in immunization.

Discussions tagged Refrigerator / freezer

SDD freezers that maintain -10C and below

Hello, I am brand new to TechNet-21 so this will be my first posting.  I am trying to find an SDD (Solar Direct Drive) freezer which will maintain -10C and below. The product I need to store in Nigeria is surfactant (injected into the lungs of premature babies with collapsed lungs to give them life) which must be kept at that cold temperature to maintain a shelf life of 3 years. The electricity supply throughout the country in Nigeria is erratic and undependable, thus I would like to install an SDD freezer with a distributer (in Lagos) which would be independent of grid power. Surfactant is a very high value and low volume product so a smaller (50-100 liters) SDD freezer would be ideal. My understanding is the freezers designed for freezing ice packs may not maintain -10C and colder thoughout a 24 hour cycle which includes night. The only other solar option I am aware of is to revert back to older technology that relies on solar charged batteries to either operate a 12 or 24 volt DC freezer of use an inverter to power an AC powered freezer. I was hoping to eliminate the weak link in the system, the battery. To date I have not been able to identify an SDD freezer among the mainline manufacturers -- Dulas, SunDanzer, SureChill, Vestfrost, Haier. Thanks for any advice! Dave

UNICEF/WHO guidance on Decommissioning and safe disposal of CCE now available in ARABIC and RUSSIAN

Dear TechNet-21 community, Further to the publication of the English and French versions of the Decommissioning and safe disposal of cold chain equipment guidance earlier this year (available here, we are glad to share with you that the Arabic and Russian versions of the document are now available in the TechNet-21 Resource Library. To access these documents, please click on the following links:
1. For the Arabic version:
2. For the Russian version: On behalf of UNICEF and WHO, I wish you an insightful reading and look forward to interesting and fruitful discussions with the TechNet-21 community! Michelle Seidel, Cold Chain Specialist - Immunization Supply Chain, UNICEF Programme Division (UN City Copenhagen)  

Live-Tweeting from the PQS Manufacturer Consultation on Tuesday, July 10th!

Dear TechNet-21 Colleagues, WHO PQS will be engaging with a selected group of PQS product manufacturers on Tuesday, July 10th to discuss and agree on a path forward for some significant proposed changes to immunization cold chain equipment standards. Although this is a closed event, the PQS Team and TechNet-21 are partnering to bring you exclusive insights from the meeting and I will be guest tweeting from the TechNet-21 Twitter account, sharing highlights and pictures from this first-of-its-kind event. All you have to do is follow the TechNet-21 Twitter account and check it on Tuesday, July 10th. If you don’t already follow TechNet-21 on Twitter (@TechNet21Mod) this is a great opportunity to start doing so! Looking forward to your virtual participation! Best wishes, Denise, on behalf of the PQS Team

Powering Auxiliary Loads in SDD Systems – Energy Harvesting: Is It the Best Alternative?

One of the beneficial features of SDD refrigerators is its relative simplicity. Electrically two wires from the solar array are directly connected to the compressor. This simplicity minimizes problems in the field and simplifies repairs. Energy harvesting technology introduces a great deal of electronic complexity and the complexity increases as a larger percent of the available energy is harvested. In the US the primary mode of failure of new refrigerators is the electronic circuitry. In the field there will be different types of energy harvesting devices coupled to different brands of refrigerators and the loads connected to the device will be of varying types, ie batteries, resistive loads, pumps etc. these factors will complicate the determination of  a cause of failure and will also complicate training of the repair person. If the energy harvesting device does fail there may not be the power necessary to call a repair person. If a USB charging port is created it is desirable to provide power throughout daylight hours so devices such as smart phones and I pads can get fully charged. The simpler harvesting technologies only provide auxiliary power when the refrigerator is not running and the more complex technologies could provide a USB port throughout the day if there is sufficient excess power when the refrigerator is running.    A simpler strategy to supply energy for auxiliary loads may be to add a small stand alone power system. A 100 watt $100 solar module could typically provide 500 watt hrs of continuously available reliable power. A USB charging station can be powered by a panel between 6 and 20 watts, the cost of the system would be between $15 and $50, and these systems do not require a battery. Although the idea of energy harvesting is intriguing it may not be the most reliable and cost effective way to supply power for auxiliary loads.

SPOTLIGHT: Installation of SDD Refrigerators in Colombia

Dear TechNet-21 communty, I would like share with you some pictures of the installation process of 37 SDD that we are doing in Colombia. Best regards.

Total Cost of Ownership (TCO) tool for cold chain equipment version 1.5 now available

We are happy to announce the latest version of the Total Cost of Ownership tool for cold chain equipment (v1.5) is now available to download and use. If you have been using an earlier version of the tool, please download the latest version from the link below.   Version 1.5 includes options to add Service Bundle quotes for CCEOP procurement which will overwrite installation cost assumptions.  Version 1.5 also features enhanced warranty comparisons that reflect the value of standard warranties from suppliers over time.  The latest version of the TCO tool contains PQS pre-qualified equipment as of May 2018. Please download the latest version (in English or French) for the most up to date products and pricing.  If you have any questions or would like any training/demos please email Matt Morio

Off-Grid Portable Vaccine Refrigeration

I am developing an off-grid backpack with an inbuilt removal battery powered (8hrs) portable refrigerator that is approx 1.5 litre in size and can transport 2 blood bags. The off-grid backpack has 48hrs of battery supply to the portable refrigerator, however, it is designed to be recharged daily. Our vision is to provide a waterproof backpack that has in-built refrigeration that can provide additional electricity for lighting and other appliances that maybe be useful in the field and that can also provide continuous electricity supply to vaccines refrigeration. What I am trying to identify is if the 1.5 litre is large enough for daily vaccines missions and what other equipment can be used such as lighting, charging phones and laptops, providing power to smart devices to record data and if, needed, bring back blood samples under refrigeration is a benefit? Also is 4g temperature monitoring and temperature control of the refrigerator a workable solution in most locations? My questions are: 1. What size refrigerator is required for daily vaccine missions? 2. Is there a requirement to bring samples back from the mission under refrigeration? 3. Is there ever a requirment to stay overnight during a daily mission? 4. What is the maximum amount of hours required for vaccine missions? 5. What other electricial equipment can be utilised if continuous electricity is availble? 6. Is GPS tracking of benefit? Is there anyone who can assist me with the above information or provide any other information I may require to complete the development of system. If you wish to email me directly, please contact me on 

Temperature monitoring devices and Thermostat for vaccine refrigeration system

Dear Technet members, I would like to share my thoughts on the temperature monitoring devices and thermostal for vaccine refrigeration system. In the early days of EPI, temperature of the refrigerator was measured and displayed by a simple analogue thermometer which was either a bi-metal or stem type alcohol thermometer.  Twice daily the health worker records these temperature on the temperature monitoring sheet and posted on the door of the fridge.  Filled temperature records are collected, kept on the file at the end of each month and replaced by a new one.  Temperature recorded was the temperature obtained during that time when it was read.  There was no information on the temperatures during the night or between the time interval when temperatures were obtained.  These old thermometers need to be calibrated more often which was a big challenge at the remote health facility. To rectify the problem an electronic thermometer that could continuously record and display the temperature of the fridge was developed.  It does not need calibration till its lifetime of 2-3 years when it has to be replaced.  Average temperature readings could be read for the past 30 days.  The device was further developed to include a usb connector and with temperature alarm alert and temperature data could be downloaded for record and review purposes. The latest temperature monitoring and recording device has a temperature sensor placed inside the fridge and could send the temperature readings on a computer/cellphone and could further be accessed via cloud etc. All of the above temperature monitoring and recording devices are passive devices, in the sense that it does not take any corrective action if temperature excursions are encountered.  It is simply used to inform or alert the health worker that something is wrong with the fridge.  Corrective actions at health facility level relies on the health worker who is alone and frequently busy and not specifically trained to do the job of diagnosing the cause of the problem.  With shortage of the technical staff at the national/provincial/distric level, it is not expected to rectify the problem as early as it is needed thus causing potency problem to the vaccines, missed vaccine sessions and increase unopened vial vaccine wastage. Allow me to give information to each one who are not familiar with refrigeration system, that every vaccine refrigerator/freezer (with the exception of the absorption kerosene refrigerator) has a temperature control which is commonly called a “Thermostat”.  Thermostat is an active device (compared to a thermometer which is a passive device) which is connected in the electrical circuit component of the refrigerator.  Its main job is to regulate or control the temperature of the refrigerator according the temperature setting by the user.  The old thermostat control switch is numbered starting from 0 to say 5.  Each number has a corresponding cut-in and cut- out temperature. How does thermostat work? The purpose of all refrigeration system is to lower the temperature of the confined space below that of its immediate surrounding.  The confined space of the refrigerator is the vaccine storage compartment. The refrigerant compressor of the refrigeration system once connected to the grid or solar panel will continuously run to lower the temperature of the vaccine storage compartment thus putting the freeze-sensitive vaccines at risk.   Running compressor motor can be stopped by any of the following actions:  a) if power from the grid is manually disconnected by the user or accidental power shutdown; b) the overload protector of the compressor is automatically activated due to extreme heat and voltage fluctuation; and c) the thermostat which was set at a desired temperature is automatically activated. Please note that once the compressor is stopped by either of the above ways the temperature inside the vaccine storage compartment will continue to rise.  Operation of the refrigerator will commence again if either the refrigerator is manually connected to the grid, the overload protector cools down and voltage is back to the normal range or the thermostat automatically reach its cut-in set point.  Therefore, THERMOSTAT is an active device that automatically regulates the temperature between the cut-in temperature of +8°C and the cut-out temperature of +2°C of the vaccine storage compartment.  Cut-in temperature of +8°C is the temperature when refrigerator compressor motor will start and cut-out temperature of +2°C is the temperature when refrigerator compressor motor will stop to protect freeze sensitive vaccines from freezing. It is therefore very important call to action for the refrigeration system equipment manufacturer to further conduct a very thorough study to equip the vaccine refrigerator with a very accurate and precise thermostat control device that will work at various conditions in the field. WHO PQS has introduced new standards for refrigerators to have a sealed thermostat. This effort is highly appreciated hoping to reduce unopened vaccine vial wastage due to freezing temperature in the refrigerator.  If thermostat is not sealed untrained staff as in the previous refrigeration units will try to adjust the temperature setting of the thermostat thus placing the both freeze sensitive and not freeze sensitive vaccines at risk.  Electronic sealed thermostats are now used by equipment manufacturer.  Temperature settings of these thermostat can only be altered by a manufacturer trained technician. Recently, countries are receiving refrigeration equipment under the GAVI CCEOP project.  Equipment are laboratory tested and PQS compliant, however their performance could actually be tested at different and difficult environment and situations in the field.   To be able to assist the equipment manufacturer to develop a more accurate and precise thermostat, country’s EPI national program should monitor equipment performance and share feedback to TechNet for follow up actions. Hope this helps. Alejo H  Bejemino Consultant Medical Physics and Health Physics Services, Inc Philippines    

Total Cost of Ownership (TCO) tool version 1.4 available now

We are happy to announce the latest version of the Total Cost of Ownership tool for cold chain equipment (v1.4) is now available to download and use. If you have been using an earlier version of the tool, please download the latest version from the link below.   Version 1.4 includes filters for CCEOP eligible equipment, as well as filters for refrigerator/freezer combination devices.  The latest version of the TCO tool contains PQS pre-qualified equipment as of May 2017. Please download the latest version (in English or French) for the most up to date products and pricing.  If you have any questions or would like any training/demos please email Matt Morio

“VaccineSafe” Vs Conventional Ice-Lined Refrigerator (ILR).

Dear viewers - sharing the following for needful Universally it is very well known that vaccination is one of the most cost effective public health programme from control to eradication of Vaccine Preventable diseases. Public sector is provided with proper cold chain equipments, periodic training blended with monitoring & supportive supervision. National Immunization Schedule (NIS) is expanding; included IPV, Rota, MR, JE and Pneumococcal is the next candidate vaccine. Vaccines of NIS have Vaccine Vial Monitor (VVM). Optional vaccines applicable to our country [Meningococcal, Seasonal Influenza, Hepatitis A, Varicella, Typhoid, HPV for females] without VVM are easily available and accessible to the affordable. Availability of vaccines in various combinations: [Triple / Quadri / Penta….]; no uniform Immunization schedule created confusion among parents. Service providers in the tertiary care centers also have confusion / difference of opinion. Pilot study conducted among Medicos [undergraduate students / post graduates / faculties] revealed dangerously low operational knowledge about routine immunization. Absence of regular monitoring / supportive supervision; periodic training of private service providers have further accentuated the quality of vaccination service; e.g. Hepatitis B birth dose vaccine is yet to be started in some of the reputed pioneer Medical Colleges and in private clinics / hospitals. To address some of these issues, COMBOCARD was developed and shared, communicated with Govt, IAP and other stakeholders. Withdrawal of current IAP schedule by the IAP President [Ref:TOI] and assurance of issuing revised schedule is a welcome step provided the entire country will follow uniform schedule compatible with NIS. Sustaining >85% coverage of optional vaccines solely by the private sector is impossible without which community may not benefit “herd immunity”. The study also revealed that administering vaccine with known potency is not the task responsibility of private service provider. To create more awareness, simplified PPT on 8 rights before vaccine administration based on CDC guidelines and GoI guidelines was shared with the stakeholders. Proper cold chain equipment has an extremely important role in administering vaccines in potent condition which is seriously lacking in the private sector in India including private Medical Colleges. For solving this issue, “VaccineSafe” is designed and developed for the private service providers. Very few units are in use in Karnataka since 2005 due to lack of bulk manufacturer. Manufacturing locally in sufficient number incurs low cost and can solve the problem of private practitioners. With this in view, “VaccineSafe” Vs Conventional ILR with illustrations in 2 pages is attached for needful by the policymakers / global RI players / manufacturers of ILR / Pharmaceutical fridge.

When to consider solar, based on hours of mains/generator electricity available each day

I’ve been reading with great interest the most recent issue of Vaccine, which is dedicated to “Building Next-Generation Immunization Supply Chains”. I particularly enjoyed the following article but was surprised to read that the authors identified a discrepancy between WHO PQS and Gavi Cold Chain Equipment Optimization Platform guidance relating to solar refrigerators and under what conditions (how many hours of mains/generator electricity are available each day on average) they should be considered for vaccine storage. 'When are solar refrigerators less costly than on-grid refrigerators: A simulation modeling study' The article states: "To effectively maintain an adequate supply of life-saving vaccines in low and middle income countries, where electricity supplies can be capricious [1], the World Health Organization (WHO) currently recommends solar refrigerators for regions with less than four hours of electricity per day, on average, and electric mains-powered ice-lined refrigerators (ILRs) for areas with more reliable electricity [2]. Gavi recommends solar refrigerators for locations with fewer than eight hours of electricity per day or power outages that last more than 48 h [3].
[2] World Health Organization Department of Immunization, Vaccines and Biologicals Quality, Standards and Safety. PQS devices catalogue: prequalified
equipment for the Expanded Programme on Immunization (EPI); 2016 March 11.
[3] Gavi. Cold chain equipment optimisation platform technology guide; February 2016." I went back to the PQS Catalogue and the “Selecting a suitable energy source” graphic on page 35 (this also appears in the WHO-UNICEF solar guidance document). My understanding is that the guidance offered here is in fact the same as Gavi's, in other words solar - in addition to other solutions - should be considered at locations with fewer than eight hours of electricity per day (if the answer to the question "On average, how many hours a day is mains/generator electricity available?" is between 0 and 7). After some thought, I realised that the confusion has probably arisen from the way that solar is presented under the 0-3 box. Under 4-7 it is stated: “Use ice-lined refrigerator* rated 4 hours electricity a day, or consider solar”. However, it seems the “or consider solar” has (understandably) been missed by the authors of the journal article. I don't think this impacts the findings of the article in any way; however, it is worth calling out the discrepancy, as it’s clear that Platform and PQS guidance should be closely aligned if possible (and I think they are). It may be worthwhile to create a new, clearer version of the PQS graphic. I am in discussion with the PQS team in relation to this and hope to update members in future if a new graphic is developed. In summary, for a location with 0 to 7 hours of mains/generator electricity available each day, solar, long-term passive, or liquid petroleum gas solutions should all be considered. And for locations with 4 to 7hours of mains/generator electricity, ice-lined refrigerators rated 4 hours electricity a day should also be considered. Refer to the PQS Devices Catalogue for more information.

New reports on harvesting unused energy from SDD installations

To ensure that solar direct drive (SDD) appliances can keep vaccines at acceptable temperatures continuously, the installed photovoltaic array often produces excess power that is not used by the primary cooling load and this excess power generally goes unutilized. If this power is to be used, the primary SDD appliance load must be prioritized above any other load. WHO and other organizations have been working to define how this can be done safely and reliably. In support of WHO/PQS, PATH has recently posted results from lab testing of a couple of prototype devices intended to do just this. The Solar Electric Light Fund (SELF), organized and provided the prototypes and also carried out initial field tests on this energy harvesting control (EHC) technology. You can access the report here: Additionally, the recently posted PQS specification and verification protocol are available on the WHO website: I would be interested to know - what do people think of this approach with the intent to safely access excess power through EHCs? What do you think could be the most important uses for this power in remote health settings? Thank you, Steven P. Diesburg Product Development Engineer PATH, Seattle, WA, USA

Ice-Lined Refrigerator & Freezer

Dear Colleagues, As known that Ice-lined refrigerators are the best choice wherever there is at least 8 hours electricity a day, but what about producing ice-packs for immunization session (e.g. outreach sessions) under the same supply of electricity (=< 8hrs)? What will be the better decision to make here? maybe consider the combined icelined refrigerator/ freezer (not many options are available on WHO PQS devices catalogue) , or consider a stand- alone deep freezer for ice production (even though the holdover time for the most modules is about 3 hrs) ! Best regards,

New case studies on SDD vaccine refrigeration projects

WHO and UNICEF have just published a new evidence brief on solar direct-drive (SDD) vaccine refrigerators and freezers. It includes case studies from Tanzania, Colombia and Kenya, as well as an overview of SDD technology and how to make sure that SDD technology is the right choice. Here's the link: This is the document summary: “Solar direct-drive (SDD) refrigerators and freezers can be a good option for vaccine storage in areas without reliable electricity, and many models are now WHO-prequalified. But with little information on SDD field performance currently available, making a case for investing in this new technology can be problematic. This evidence brief provides supply chain managers in low- and middle-income countries with a summary of how recent SDD projects have performed, highlighting problems encountered and the steps that were taken to resolve them. An overview of how SDD technology works, and how to make sure that SDD technology is the right choice, is also provided.” It provides a nice overview of SDD projects, but for those looking for more detailed guidance on how to implement successful solar-powered vaccine refrigerator and freezer systems, I would also recommend the following much longer WHO-UNICEF publication: “Introducing solar-powered vaccine refrigerator and freezer systems - A guide for managers in national immunization programmes” I would be interested to hear the thoughts of other members on the new evidence brief. PS. If you’re looking for more information on other SDD projects, check out at the following forum discussion, which includes contributions from members regarding SDD projects in Somalia, Ethiopia, Malawi, and Rwanda.

What is the distance refrigerator should be from wall?

Dear Technet Followers: Is there a universal recommendation for the distance a refrigerator should be from the wall. I have seen 1 foot, 10cm, 300mm, and 50mm on different documents from different partners. Thanks, Carla

CCE Total Cost of Ownership (TCO) tool version 1.3 available now

Happy new year all, We are happy to announce that the latest version of the Total Cost of Ownership tool for cold chain equipment (v1.3) is now available to download and use. The latest version has a few minor changes to the presentation of data as well as the latest PQS pre-qualified equipment as of December 2016. Please download the latest version (in English or French) for the most up to date products and pricing. If you have any questions or would like any training/demos please email Matt Morio

Measurement of Condensation

We are working with ILRs. While daily operations, it was found that there is formation of water droplets inside the device. We want to measure the amount of condensation taking place inside the device in a day. We also tried to calculate the Dew Point Temperature but not much useful. Kindly suggest some method or way to measure the condensation. Regards Akhil

RCW50EG field perfomance problems

At B Medical Systems we have received lately more and more complaints about RCW50EG, absorption type vaccine refrigerator / ice pack freezer, that stopped working or never started working correctly. The largest complaint came from the EPI in Kenya with 200 X RCW50EG not working. The RCW50EG and the smaller version of it, the RCW42EG, have always been known as excellent equipment in the cold chain, and never had any issues, therefore initialy we thought it must just have been wrong use, settings or similar issues. Seen the claims we have started investigating where that huge and systematic problem might have come from, and here are the results : during the calendar year of 2011, our supplier of absorption cooling units did change the interior boiler layout of the cooling system in order to increase the efficiency. That would mean as a result less electrical power consumption and as well less gas consumption. It means as well that the cooling system is now more sensitive to the heat applied to the boiler through either the electrical heating element or the gas burner. Therefore, I am explaining hereafter the effects on the different types of operation, and this is valid for every RCW50EG produced as of 2012. You can identify the year of manufacturing with the help of the serial number that is composed by 7 digits, where the first digit is the year- and the 2nd and 3rd are the week of manufacturing: example 2503456 : produced in week 50 in year 2012 1) Operation on LP Gas : The new cooling units will not work properly and mostly not at all with the original burner jet 32, that is producing too much heat. This jet has to be replaced by a jet size 26. This change makes sure the cooling unit operates well on gas. 2) Operation on electricity : We deliver the RCW50EG in a 220V version with a 220V/120W heating element. This setting works well for voltages of 210-230VAC. If the voltage goes higher, it won't work. I am currently in Kenya and we measure constant voltages of 250VAC. In such a case the heater has too much power and overheats the absorption cooling system. We have replaced the heaters in Kenya on several refrigerators with a 240V / 120W version, and now they perfectly well. If you have come around similar problems wih your RCW50EGs, please contact us immediately so that we can help you to solve the problems asap. There are solutions that can be implemented quickly, and B Medical Systems will fully support those activities. In such a case please contact me directly through : Please make sure to report as much details on the problem as you can. If the issue is on electrical operation, please give as much as possible details on the voltage level. PS : we have not heard of any issues with the kerosene version as on these the heat can be adjusted through the flame setting. If anyways you would know about issues on those, please let us know as well. Thanks for letting know and forwarding this message to any of your colleagues or network that may need to get this information. Best Regards Gilles for the B Medical Systems Team

High temperature freezers

Knowing the problem of vaccines being frozen because of too cold ice-packs. What about freezers that does not get colder that minus 5'C

Looking for more information on SDD vaccine refrigerator performance in the field

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.

Experience about solarchill in Colombia

I like to share with you in this space a video about the instalation, basic maintenance and operation of one of the solar equipments with PQS that are installed in my country (Colombia), nowadays we have 300 equipments in operation.
Best regards

Vaccine Storage in Cold Climates

Most ice-lined refrigerators in India are fully functional at 5 - 45 degrees Celsius (ie, they are able to maintain an internal temperature of 2-8 degrees Celsius when the external temperatures are between 5 and 45 degrees Celsius). Some states of India have an extremely cold climate during winters (for example, the areas of Jammu and Kashmir, Uttarakhand, Sikkim that are in the Himalayas) and so they are prone to high rates of vaccine freezing.
I am sure this is a problem experienced by program managers of Russia, Canada, Greenland, Iceland, northern Europe, Alaska, etc and would be extremely grateful if they could share how they have managed to tackle this in their respective countries/regions.
The only resource that I have been able to find till now after an extensive search is "The Warm Chain", which suggests the use of a low ambient temperature refrigerature which provides protection upto -5 degrees Celsius.Does WHO have any guidelines regarding this?
A related question would be - how do we arrange for outreach immunization in such cold climates? What sort of ice packs should be used in such a scenario?
Warm Regards,
Dr. Tapas Sadasivan Nair

Two collections of WHO equipment maintenance resources (user and technician)

Thanks to the flexibility of the TechNet-21 website, I can share two older (circa 1985) collections of densely technical and highly practical equipment maintenance documents developed by WHO using the TechNet Resource Library (TRL). Once only available in hardcopy or in a digital corner of the online PATH Vaccine Resource Library, these materials are now available in two TRL collections:
WHO User's Handbooks for Refrigerators and Cold Stores
A series of booklets to help refrigerator and cold store users look after their equipment better. Developed in 1983, includes user handbooks on compression, kerosene and electric, and gas and electric refrigerators, as well as cold stores. Contents in all booklets include: actions on receipt, parts list, starting process, periodic attention needs, fault-finding, and maintenance and repair tasks.
WHO Technician's Handbook for Compression Refrigerators
Technician's Handbook for Compression Refrigerators materials were produced in 1985 by WHO EPI to improve the standards of refrigerator and cold room maintenance and repair. These were course materials to support a 10 working day course for repair technicians.
Please take a moment to look at these unique materials and other great finds in the TRL.

Best regards,

Cold Chain Equipment Optimization Platform - Technology Guide

Dear friends, Gavi, the Vaccine Alliance is very pleased to present the Cold Chain Equipment ‘Technology Guide’, to support the appropriate selection of modern, efficient and reliable technologies. Download the guide here.
Identifying the most appropriate equipment choices for each health facility is key to help ensure more facilities have adequate cold chain capacity, and that more facilities also have higher performing equipment that stays functional for longer periods of time. This in turn will help increase access to immunisation as well as greater vaccine safety and potency, and contribute to improvements in immunisation coverage and equity.
Developed by technical assistance providers, the Technology Guide offers comprehensive and regularly up-dated information on cold chain equipment and technologies and how to choose the solutions that meet the needs of each health facility. The Technology Guide covers the range of optimised on-grid and off-grid refrigerators and freezers. It also covers other new technologies such as new passive cooling devices and temperature monitoring solutions. The Guide provides clear advice and structured approach to CCE decision-making is intended in particular for use in health facilities and at lower levels of the cold chain.
The Technology Guide is also available as part of the TechNet ‘Cold Chain Equipment Management - Technical Resources’ page here.
The Technology Guide also explains which devices comply with the requirements of the recently launched Gavi Cold Chain Equipment Optimisation Platform. Platform eligible equipment and technologies include innovation that has been achieved via quality assurance provided by WHO Performance, Quality and Safety (PQS) specifications and additionally establishing target product profiles (TPPs) designed to ensure manufacturers also bring the next generation of equipment needed by countries. Click here for more information on the Platform, which is a new form of support to countries to improve access to appropriate and high-performing cold chain equipment.

Uganda Equipment Failure Investigation Report

In cooperation with the Uganda Ministry of Health, PATH recently conducted a pilot study to document equipment failures in the Uganda National Expanded Programme on Immunization cold chain. Due to our use of purposeful sampling to locate a subset of failed cold chain equipment in Uganda, conclusions about predicted failures cannot be drawn from our study report. However, after learning of the failures, one manufacturer (B. Medical) has agreed to replace the equipment assessed. The full report can be accessed here: Information from this report has also been added tothe Dulas VC65F revew here:

Remote Temperature Monitoring Data for Cold Chain Maintenance

Dear TechNet Colleagues,   I would like to share with you a report on our latest cold chain maintenance investigation in Mozambique: "Why Fridges Fail Part 2: RTM Data for Maintenance". We are beginning to document how remote temperature monitoring data and dashboards can be used by maintenance technicians to significantly improve cold chain performance. This assessment follows up on the randomized control trial conducted in 2014-2015 with Village Reach, PATH, and the Ministry of Health in Mozambique which aimed to evaluate the impact of remote temperature monitoring (RTM) on vaccine cold chain equipment performance at the health facility level. That study showed that RTM with SMS alerts increased fridge uptime and reduced freezing (See Appendix I of the report for more details.)

However, even some fridges in the RTM intervention group had chronic problems and failed to achieve 95% uptime.

We launched this follow-up investigation to answer the question: Can maintenance + RTM lead to 95% uptime?

We were very happy to work with Soren Spanner, a global cold chain expert with decades of experience. Soren traveled to Mozambique from September 24 until October 14, 2015. He used ColdTrace data to identify 27 fridges that were failing and worked with the Ministry of Health maintenance technician to visit or remotely diagnose and fix as many fridges as possible. Soren remained active in fridge fixes, phone calls and follow-ups through the end of November.

Perhaps the most interesting finding was that distinct patterns in the RTM data (which we call “temperature data signatures”) can be used to remotely diagnose problems and enable remote fixes via phone calls to nurses in clinics. For the improperly adjusted fridges in this investigation, thermostat adjustments increased uptime by 30%. Today, the MOH technician continues to use the dashboard data to diagnose problems, call clinics to address the issues, and verify fixes by monitoring subsequent temperature data. We also learned that, without access to key spare parts/tools, even an expert technician cannot get all fridges to 95%: flat batteries on solar fridges were one such problem that Soren did not have the resources to fix. With RTM data, however, those responsible for cold chain maintenance can identify which fridges need help and determine where to focus resources.

This report features all causes of fridge failure that the Technicians encountered, several key screenshots from the ColdTrace web dashboard, and critical recommendations for how to procure for and improve cold chain maintenance capacity at every level of the health system moving forward. We hope you’ll find these results approachable and easy to understand. I would greatly appreciate your feedback on the report and I hope we can start a discussion here on how temperature monitoring data could improve maintenance. Thank you. Regards,

Universal, hybrid refrigerator for vaccines?

Among the TECHNET postings on cold-chain equipment there are embedded remarks pointing towards the need to make vaccine refrigeration simpler and less expensive to procure, more responsive to energy changes and easier to use and maintain. For example, to choose a refrigerator now current WHO, UNICEF and GAVI guides require that you make equipment choices according to energy availability and quality conditions. But in practice, energy availability and quality are changing, they do not remain static over the life of the equipment. The grid may arrive, or it may deteriorate; you may need a standalone refrigerator or one included in solar energy providing for a whole health facility. Solar direct drive refrigerators and Ice-lined refrigerators are starting to share the same design, both using an ‘energy buffer’. Opportunity exists to merge these two refrigerator types in a single model able to run with electrical grid electricity or solar energy or both linked together. Advantages of this hybrid include flexibility for the same refrigerator to adapt to any energy situation, greater production quantities will reduce excessive price differences between the two types and refrigerators are likely to adopt front door opening as the most usable, more compact installed and more efficient at avoiding freezing. Your opinions will be much appreciated to continue this reasoning!

Performance evaluation of solar adsorption cooling systems for vaccine preservation in Sub-Saharan Africa

In case this new article published in Applied Energy is of interest Abstract
An intermittent solar adsorption refrigerator can supply cold needed in third world countries, especially for vaccine and medicine preservation. This paper investigated theoretically the potential of solar adsorption refrigerators in Sub-Saharan Africa. The dynamic behavior of the system and its performance were assessed using real climatic conditions of four Sub-Saharan African sites. A refrigerator operating with activated carbon/methanol as a working pair was simulated using a 1-D mathematical model to investigate its dynamic optimization. The results showed that the best solar coefficient of performance (SCOP) was predicted in Garoua (Cameroon) and Beitbridge (Zimbabwe). The maximum specific cooling power (SCP) was achieved in Beitbridge (Zimbabwe). Under the climate of Lamu (Kenya), the system presented the lowest performance indices.

Error in suggested sizing method for SDD systems

I was recently looking at the “System Sizing tool 3/3” in a 2DI3 “Technical evaluation and Methodology” a unicef publication. The publication originated from a 2DI3 SDD industry meeting. The sizing method prescribed is based on the premise that “the daily potential solar energy supply is calculated as the number of sunshine hours 1000 W/m2 multiplied with the corrected power output.” The compressor of an SDD refrigerator requires about 70 watts to run and start. When the output of the solar array is below 70 watts no useable energy is collected. If for example the refrigerator is connected to a solar array with an actual output (corrected for dust and other losses) of 300 watts the output of the array may not go above 70 watts for a 1.5 hour solar day. From the method in section 3/3 the calculated useable energy collected will be 300 watts x 1.5hr or 450 watt hrs. This result would be correct for a battery based system however zero useable energy would be collected for an SDD system with this sizing method the errors are particularly large when sizing is most critical, during periods of low insolation. Manufacturers apparently know about the failure in this sizing method because the arrays they are incorporating are about 3x larger than the arrays suggested by this method. If any one knows if there is a sizing method for SDD systems currently being suggested by WHO please let me know.

Reorganizing Nigeria’s vaccine supply chain reduces need for additional storage facilities, but more storage is required

Interesting paper on system design in Nigeria from Health Affairs. Abstract One of the major problems facing Nigeria’s vaccine supply chain is the lack of adequate vaccine storage facilities. Despite the introduction of solar-powered refrigerators and the use of new tools to monitor supply levels, this problem persists. Using data on vaccine supply for 2011–14 from Nigeria’s National Primary Health Care Development Agency, we created a simulation model to explore the effects of variance in supply and demand on storage capacity requirements. We focused on the segment of the supply chain that moves vaccines inside Nigeria. Our findings suggest that 55percent more vaccine storage capacity is needed than is currently available. We found that reorganizing the supply chain as proposed by the National Primary Health Care Development Agency could reduce that need to 30percent more storage. Storage requirements varied by region of the country and vaccine type. The Nigerian government may want to consider the differences in storage requirements by region and vaccine type in its proposed reorganization efforts.
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