Currently, there is no wholesale discount available for Cardboard CooKits sourced from SCI in California. We generally recommend to African organizations that they craft their own CooKits for small quantities and then consider moving to local mass production (at costs of around US $5 per unit) when the demand for CooKits is substantial. One of our CooKits makes an ideal template that can be used to trace any number of cookers onto cardboard before cutting out the cardboard.
The HotPot by Solar Household Energy. This is a variation on the CooKit, usually made from polished or anodized aluminum sheeting and includes a specially made pot and glass pot container for trapping heat. The package retails for about US $119 in the US.
Global Sun Oven by Sun Ovens International are available unassembled in bulk quantities for assembly outside of the US. With the one-time purchase of an assembly package, GLOBAL SUN OVENSTM can be assembled in the country in which they will be used, dramatically reducing the cost of the ovens and shipping. Once an assembly plant has been established, using U.S. made components, Sun Ovens International provides the specifications allowing for the manufacture of any of the components (with the exception of one gasket) to be locally produced. Additional information can be found at: http://www.sunoven.com/around-the-world/entrepreneurs/local-assembly-plants
The SPORT solar box cooker by the Solar Oven Society. Retail price is about $125 without reflectors and about $141 with reflectors. The reflectors would have much less use value in Malawi than in places 30 or more degrees from the equator. The distributor’s price to SCI for SPORTs without reflectors is about $92. Like many producers of solar cookers in the western world, SOS is a non-profit association and may make better wholesale deals with particular groups in developing countries than the $92 price SCI gets.
The Rohitas Electronics company in India also markets box cookers under the Tulsi brand name, some with electrical back-up, and Rohitas may be the most aggressive box cooker maker in India when it comes to exports. However, their web-page is currently down.
Several companies in India produce variations on the German-designed SK parabolic cookers. Several years ago, the TinyTech company in India reported that it could deliver a version of the SK-14 parabolic cooker in batches of about 400 to African locations for a unit price.
There are many sources in India for box and parabolic cookers, and one could probably get a good range of prices by writing to the manufacturers listed on the website of India’s Ministry of Non-Conventional Energy Sources.
The Yancheng Sangli company in south eastern China may well be China’s most experienced and prolific producers. They sell a focusing type cooker of the two-reflector or “butter-fly” design that may be the most powerful domestic solar cooker in the world at 800 watts. They told me they will export it for a unit price of US $105 for orders of ten. They ship the parts—not assembled cookers, and they package 10 cookers in 3 boxes, so unless you get into substantially larger numbers, I think you have to purchase in units of 10. Shipping costs to Malawi would likely add roughly US $50 per unit to the cost. These are large cookers that weigh 50 kilograms, so they are best for situations where they can be safely left outside all the time.
There are also many suppliers in Europe, and most of them also seem to be non-profit organizations or something similar to non-profit organizations. I will just mention a few of the most famous.
EG-Solar of Germany is the source of a line of solar cookers such as SK-14, SK-10, etc. These are bowl-like parabolic cookers and have great reputations. The SK-14 has a 1.4 meter collector, the SK-10 has a one meter collector, the SK-12 has a 1.2 meter collector, etc. They have a tiny .35 meter collector that sells for 99 euros in Germany. The .70 meter version sells for 175 euros, and the 1.4 meter version sells for 335 euros and up. This is before shipping, which is a reasonable 9 euro service charge within the European Union but which I suspect is much higher for deliveries to Africa. However, EG-Solar is basically non-profit in outlook, and it helps bring the costs down by supporting the creation of assembly workshops. Their web site says they do have a workshop in Malawi—in Lilongwe. This should bring the price down tremendously, but I can’t really guess how much.
This NGO in France sells a variety of cookers including some of EG-Solar’s parabolic cookers at prices that seem better than EG-Solar’s. They also sell some box cookers and at least one kit for assembling a box cooker. Their web page shows retail prices for box cookers ranging from about 120 euros for a cardboard demonstration-model solar box cooker, to about 200 euros for their kit, to 240 to 580 euros for various size and quality box cookers. There is no indication of what wholesale prices would be.
These involve one or more extra-large to extremely large parabolic dishes that track the sun in such a way that the concentrated energy is always reflected to the same spot. Typically, this spot is a hole in the wall of a kitchen building and when the energy comes through the hole it strikes a vessel filled with liquid. The liquid heats up and then is circulated by pipes to deliver its heat to multiple cooking stations inside the kitchen. This is the most popular way I’ve heard of to do mass solar cooking. Smaller kitchens may produce a few hundred meals a day, while the large one at the Mt. Abu retreat center in India reportedly cooks 30,000 meals per day. The web site for this resource does not give cost figures, and it is logical to assume that cost would vary with each product based on location, resources available, volume of meals needed, and materials and skills available for building the kitchen, the piping, the support structures, etc. Based on EG-Solar’s prices for a 1.4 meter dish, I could imagine that a 5 meter dish reflector could run to US $3000 or more. The support structure and tracking apparatus could add a few thousand dollars more. The plumbing or piping for the heat distribution system would add hundreds or perhaps thousands of dollars, on top of the basic costs of the kitchen itself and the cooking stations and accessories. So I would guess (this is not just a rough guess, it is a wild guess) substantially more than US $5000 for a relatively small and rudimentary version of a Sheffler kitchen—not counting the costs of the building and work stations, etc—just for the reflector, tracking mechanism and the heat circulation plumbing. I would also think that the larger systems would be more economical in terms of cost per meal than trying to apply this concept on too small a scale.
One final thought about calculating relative costs. In general, parabolic cookers are bulkier for shipping purposes and are often heavier, adding to shipping costs. In addition, I think they almost always are delivered unassembled, and assembly takes time, care and patience—and often would go better with in-person instruction.
And a final general thought: if ordinary window glass is practical in your area, wooden box cookers can be produced by local craftsman. While it is not uncommon to hear of wooden box cookers costing US $50 to $60 to produce, I have heard from a Sri Lankan group a few years ago that they made one for about US $20. With wooden box cookers, one does have to worry some about glass breaking and about the cooker losing heat if the wood warps over time and creates gaps in the construction. However, if these potential problems can be worked through, locally crafted wooden box cookers could be a good answer to supplying cookers that are more affordable than imports, while also increasing Malawian “ownership” of cookers, while also providing meaningful employment in the local economy.
Please remember that the figures and ideas given in these notes are a rough approximation based on prior experience but far too little current research.
[Original text for this article taken from notes by Ramon Coyle 12 Oct. 2006]