I have been working on solar electric cooking systems which are appropriate for the developing. The system I think has the most promise is a solar direct system,no batteries. Thermal storage allows hot food to be eaten 5 hours after sunset. A  single 280 watt PV module would supply al...

Join us for a free, non-commercial presentation on the past, present and possible future(s) for solar vaccine refrigeration.  Led by Steve McCarney, Director of Sunny Day LLC, this interactive webinar will takplace once on August 5, 2020.  More details are found at the non profit Solar Ene...

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 lif...

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....

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 p...

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: ...

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 CCE...

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 pe...

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...

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...

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...

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...

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...

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 technology which allo...

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 result...

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 ic...

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 les...

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 programma...

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 substa...

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 ...