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 SDD

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 ...

WHO PQS Manufacturer Consultation Report

Dear TechNet Community, On Tuesday 10th July 2018, the WHO Performance, Quality and Safety (PQS) Working Group conducted its first face-to-face technical consultation with manufacturers of PQS prequalified immunization products and devices from the E003 (Refrigerators and freezers) and E006 (Temperature Monitoring Devices) equipment categories - some of you may also have followed the event in real time via the TechNet-21 Twitter account. Thirty industry representatives took pa...

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 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. Pleas...

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, P...

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: http://www.who.int/immunization/documents/general/WHO_IVB_17.01 This is the document summary: “...

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 ...

La version française de l’outil de calcul du Coût Total de Possession (CTP) d’équipements de la chaîne du froid est maintenant disponible.

Outil de calcul du Coût Total de Possession d’équipements de la chaîne du froid
L’outil de calcul du Coût Total de Possession (CTP) d’équipements de la chaîne du froid a été développé afin d’assister les utilisateurs dans leur compréhension du coût d’achat et de maintenance des équipements de la chaîne du froid. L’outil peut être personnalisé pays par pays et calcule les dépenses en capital et en coûts d’opération pour les équipements préqualifié par le département Qualité ...

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 s...

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...

PATH’s cold chain equipment Total Cost of Ownership tool now available

PATH’s Total Cost of Ownership (TCO) tool for cold chain equipment is now available for download and use. The TCO tool is designed to help countries compare and understand the costs associated with the purchase, installation, and ongoing operation of cold chain equipment. The tool currently covers 82 cold chain equipment devices including all 72 PQS (Performance, Quality and Safety) prequalified devices from the E001 (cold rooms and freezer rooms), E003 (refrigerators and freezers), a...

Solar vaccine fridges and freezers - new guidance available

WHO and UNICEF have just released a new joint publication on solar fridges and freezers that is intended to provide managers in national immunization programmes with guidance on how to implement successful solar-powered vaccine refrigerator and freezer systems. It takes into account new developments in refrigerator technology like solar direct-drive (SDD) refrigerators and water-pack freezers, as well as containers with passive cooling, and is based on lessons learned during the 30 years sinc...

Considering a Max/Min range for Vaccine Storage Capacity in refrigerators

The percent difference between the gross refrigerator (ILRs and SDDs) volumes quoted in the PQS Catalogue and the net vaccine storage volume varies from 29.6% to 88.6 %. This is a wide variation for front opening fridges, due to space for air-circulation. Increasingly, new models of ILR and SDD are emerging with cooled internal walls and cooled ceilings. Some of these models maintain a satisfactory internal temperature distribution whether they are packed according to the test procedu...

A New Solar Hybrid Refrigerator/Freezer

Sun Frost developed a hybrid refrigerator/ice pack freezer, the FRH-3. The Sun Frost FRH-3 has a SDD freezer and a battery powered refrigerator. The SDD freezer is the same size as our F-1 (http://www.sunfrost.com/batteryless_direct_drive_freezer.html) and incorporates the same t...

Are SDD refrigerators solutions or challenge in solution for the low resources countries?

The decision of a National Immunization Programme to use Solar Direct Driven (SDD) Refrigerators instead of Solar Panels to run refrigerators I think is like presenting challenges in the so called expected “better and sustainable solution” especially for the low resources countries. It is true that, SDD are compressor powered directly from the sunlight (they are really environmental friendly) and therefore does not need additional running costs for batteries which in other way these batteries ...

SDD Ice Pack Freezer: High Demand – Successfully Field Tested – Unavailable

Two solar direct drive ice pack freezers have been successfully tested for seven months in Columbia. The F-1 was manufactured by Sun Frost and a second freezer was produced by Sun Danzer. The freezers were tested by Steve McCarney of SELF and the project was supported by BMGF grant. The tests results were highly successful: To quote Denis Marie the performance of the units was “beyond user expectations”. F-1 Runs at Low Light Levels The Sun Frost F-1 incorporates some unique technology ...

PQS sheets: Solar refrigeration

The data given for solar-powered refrigerators in the PQS sheets is not given consistently enough so that comparisons of various models can be made. The data needed for a fair comparison most often is energy consumption at 32 deg C without ice making, energy use with ice making and quantity of ice made. It would also be useful to know the number of days of autonomy time for direct-drive refrigerators. Looking at the PQS sheets it is not always clear how to obtain total energy consumption when...

Direct-drive freezer operates at low levels of isolation

Sun Frost has been building vaccine storage refrigerators for the past 20 years. Sun Frost is now building a direct-drive ice pack freezer. Some new technologies incorporated into the design allows the freezer to run even at very low light levels. On a cloudy day if the output of the PV array is less than about 60 watts the compressor in a direct drive system will not start. The Sun Frost F-1 will run on cloudy days even if the output of the solar array is minimal. On a sunny day the number of r...

Approach for extensive field monitoring of solar generator

Hi, I would greatly appreciate your expert opinion on a technical question regarding extensive field monitoring of solar generator. The objective is to carry out a long-term, rather in-depth field monitoring of solar (DD) fridge installations for their long-term performance evaluation and programmatic learning about their operations- hence only a subset of all solar units would be monitored. To monitor and evaluate a solar generator, the basic set up should probably track the solar exposure ...

Implementing the solar cool chain successfully

With many thanks to John Lloyd for this post. Countries that currently use absorption refrigeration (gas, electric or kerosene-powered) are facing increasing pressure to switch to solar photovoltaic-powered refrigeration for vaccine as manufacture of absorption equipment shrinks. We have a substantial evidence from the field on the success of solar refrigeration systems that point to a few critical success factors: ? Systems designed rigorously to match climatic and irradiation, site-...

Refrigerator/Ice Pack Freezer or Refrigerator Only

Recently, I have seen a number of relatively large RFQ’s for direct drive refrigerators. These refrigerators do not have an ice pack freezer. From past feed back from our customers and WHO we have heard that ice packs are necessary to distribute vaccines to more remote areas. We are concerned that these remote clinics may not be getting a refrigerator, which fits all their needs. We would like to get feed back on this point....

The Battery-Free Solar Refrigerator Challenge

by Joanie Robertson, Technical Officer, PATH

In March 2009, six companies submitted designs to PATH in response to its Battery-Free Solar Refrigerator Challenge. Product designs that meet desired specifications will receive financial assistance to cover the cost of third-party testing required for consideration under the World Health Organization's
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