Monthly Archives: February 2016

Part 4 – What do we know about the hardware of the system, and can we increase efficiency and lower costs?

Electric_Rice_Cooker_in_ShowroomOvens (enclosed heating devices) – the advantage of an oven is that it is often insulated, so heat loss can be made minimal.  The disadvantage is that only certain types of food can be cooked.  A hob can in theory boil, fry, simmer.  However it cannot bake bread.

We have explored regular low powered ovens, and alternatives like halogen ovens, bread makers, slow cookers and rice cookers.  The latter deices tend to have an insulated chamber and electrically heat, generally quite slowly and at low power.  Again, colleagues have suggested this would work well with solar reducing the total energy required – indeed even cooking slowly during the day, reducing the need for storage. Read more…

Part 3 – What do we know about the hardware of the system, and can we increase efficiency and lower costs?

Light_Label_Electric_tabletop_burner_KCK-L103Discharge controller/inverter – now we approach the components that started this blog.  Getting the energy out the storage and into the food.  To invert or not invert?  When we started the first experiments we found that cooking rings at 12V were just not available.  We could have commissioned such a ring, but were persuaded by various colleagues to just invert for the moment and use commercially available hobs.  Since then we have found 12V heating elements (500W for dumping surplus energy from a solar panel to water), but have not really pursued the non-invertion option.

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Part 2 – What do we know about the hardware of the system, and can we increase efficiency and lower costs?

Gamos_Infographic_Elements-26Batteries (energy storage) – Ok, so I could write a lot about this.  Batteries and their changing chemistries and emerging opportunities, and reduction in price were recently the subject of a report by Slade (2015) as a part of the DFID evidence based checking of this proposition.  There will be many and myriad opportunities for choosing the right chemistry, the right configuration, the right lifetime/price point.

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Part 1 – What do we know about the hardware of the system, and can we increase efficiency and lower costs?

Gamos_Infographic_Elements-21As I said in a previous blog, with the publication of the report, I have had many emails asking if induction hobs are the way forward.  I had yet another ‘induction’ email this morning from a colleague.  Once again the suggestion was attached to the efficiency
savings of induction stoves.

So in this blog I would like to outline some of what we know about the major components and document where we might save energy and make system efficiency improvements.

 

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Induction hobs??

8088871849_bb55aa2110_bOne of the great frustrations to us, is that we haven’t been able to confirm whether Induction hobs will work with a pure sine wave inverter.

Induction hobs are more efficient than hot plates.  In discussion we think this is mainly heat loss downwards on cheaper portable hot plates – it would be interesting to test an induction hob against a really expensive cooker with good thermal insulation below the heating ring (and a good fitting pan).

However, the point is that induction is recognised as more efficient, and cheap induction hob is a good 20% more efficient than cheap hot plate.

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THE report just came out

synthesis coverThe proposition begins to gain traction among the donors.  DFID wanted to check my numbers and so commissioned three evidence based reports.  However at the time of writing, these reports are not yet on the web.

What is on the web is the synthesis paper.   “SOLAR ELECTRIC COOKING IN AFRICA IN 2020. A SYNTHESIS OF THE POSSIBILITIES”.  Admittedly this is by myself, but it is based on the three other peer reviewed papers, and my synthesis itself was peer reviewed.

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