Dave Klassen

Hello Steven,

This is all very helpful. I have spent the last month doing research and have spoken with engineers from B Medical Systems, Dulas and Vestfrost. I've had conversation wtih Africa Solar and Ian from Sure Chill. All of these individuals have given me very helpful advice. Essentially an SDD freezer that can meet the demands of a constant -10C or colder is not available at the moment. Dulas offered to build one for me and I encouraged them to do so, but that research and design work does not fit into my timeline. 

I have finally decided to go back to the more "conventional" solar panels and battery system. I have ordered a Steca PF 166H (at the recommendation of Ian from Sure Chill) and will be pairing it with a system of Deka batteries and Canadian solar panels, both of which are available in Lagos. The Steca is supposed to be a very efficient freezer that runs on DC power, either 12 or 24 volts. If you want to know more about the Steca, their web page has a significant amount of information and specifications on this unit in the way of downloads.

What I have learned is that SDD freezers are essentially designed to freeze ice packs. Even the volumes of those SDD freezers that are available, are defined in terms of the number of ice packs they can hold. Many are set up to "condition" the ice packs so they are just at 0 degrees C by the morning when they will be used. Even the B Medical Systems TFW 40 SDD, which was the closest to what we needed has a set point of -5 C and an autonomy (through the night) that would drop it to -3 C IF the unit was filled with ice packs. They made that last point very clear to me.

As I indicated earlier, the product we want to keep frozen is high value and low volume, so we cannot risk being exposed to several days of cloudy weather; the system must be more fool proof with resiliency and autonomy built in. I believe that a well designed and quality solar PV with battery power supply system will do that. 

The industry is not yet there but I believe in a few years it will be.

Thanks again for the input, feedback and advice!

...Dave