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Dave Klassen replied to a discussion, SDD freezers that maintain -10C and belowHello 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...
MoreHello 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
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Dave Klassen replied to a discussion, SDD freezers that maintain -10C and below
Update: I believe I have found an SDD freezer which will work -- the B Medical Systems TFW 40 SDD. I am trying to verify its set point temperature with the company. It would be great if there were anyone out there who could testify to their experience with this unit.
...Dave
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Dave Klassen started a new discussion, 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...
MoreHello,
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
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