Here’s an interesting simple, low-maintenance technology:
“Elephant Pumps” that were introduced to rural areas in Zimbabwe and Malawi during the last few years. These rather simple, enhanced rope pumps (based on an ancient Chinese technology) where designed for use in rural areas, where the supply of readymade spare parts isn’t that easy.
Now, what makes the Elephant Pump so different from the other popular low-maintenance pump “Afripump” is that it’s locally assembled and maintainable by the local community. Both systems – Afripump and Elephant Pump – may have their pro & cons (80-100m depth, high durability, low-maintenance vs. <40m depth, simple design, cheaper), but I especially like the “bicycle option” added to pumps which were built for schools:
On school pumps Pump Aid often incorporates a “bicycle” system onto the Elephant Pump since this has proved enormously popular with children. Most children in Zimbabwe have never had the chance to ride a bicycle so can even come to school early to “play” on the pump thereby helping to fill the school water tanks. The job of collecting water, once a tiresome chore, becomes fun and children no longer have to leave their classrooms to walk miles carrying buckets of water on their heads from a distant muddy pool.
The British Charity Org “Pump Aid“, which has in the past introduced and promoted these systems in Zimbabwe and Malawi for the costs of GBP 250 (~ USD 460, EUR 310) each, also created a very informative video on how the technology actually works:
“The Elephant Pump yields about one litre of clean water every second for an average well depth of 20 metres.”
Bush camping is one of the greatest pleasures of living in Kenya – only if you have the right equipment. On a recent hastily planned trip to Lake Magadi hot springs we discovered too late that we’d forgotten the jiko (charcoal cooking stove). Stopping in Magadi town which serves only one industry, the Magadi Soda Company, we had one made for us right there and then in a very active jua kali workshop.
I always wondered where the metal for jiko’s came from – In this the many discarded gas cylinders are chopped into segments to make up the body of the jiko.
There seems to be no power shortage here, a mess of electric cables and metal and wooden waste remnants from the soda company is an active business for about 20 artisans making furniture, gates, and jikos for the staff of the soda company.
A ten minute job turned out into a one hour event and a thousand shillings later ($20) we take off proudly with our extremely heavy stove. That’s when we discover that there is no charcoal to be had in this part of the world anyway. We ended up with a 3 stone fire.
At dinner time we realized that we’d forgotten most of the food anyway (camping note to Paula: don’t believe him when he says “I already put it in the car” ).
Nevertheless, the hot springs were fabulous.
The Jiko came home and has not yet been used – and thinking about it now … should I be worrying about cooking on something made from gas cylinders? Is it just iron or could there be lead in this?
Or How to get your camel milk to market in 40 degree C climate.
My brother Dominic Wanjihia invented this gadget which he calls Fine Lined Evaporative Cooler, for rural application in Somalia – the cooling of camels milk for transportation . He was working on a project for VETAID, Somali Pastoral Dairy Development Program – SPDDP,in Burao, Somalia June 2008. All this content belongs to Dominic who has allowed me to post it here- please seek his permission to use this content elsewhere dwanjihia@yahoo.com
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Evaporative cooling technology
The evaporative cooling concept has been used for centuries in countless applications. Cooling occurs when a fluid changes state from liquid to vapor. Put simply, evaporation. In order to evaporate, the liquid requires energy or heat. It acquires this heat energy from its immediate surrounding. As the surrounding gives up this heat, it lowers in temperature or cools.
The rate at which evaporation occurs depends largely on two main factors, the amount of heat available and the humidity in the air.
The cooler must also be shaded from direct sunlight otherwise the surfaces absorb UV heat and warms up, becoming ineffective as a cooler.
In short
Evaporative cooling devices work most efficiently in windy, dry and shaded conditions
Charcoal cooler
Everyone knows how to make charcoal fridges. After carrying out extensive tests on evaporative coolers in hot arid Burao, Somaliland, with day temperatures as high as 36OC in the shade, the charcoal would absorb ambient heat from the air and as opposed to cooling, would warm up the interior compartment.
Imagine wearing a wet thick winter jacket under the palms at a breezy beach. The jacket acts as a wetsuit and will insulate your body preventing heat from escaping.
Fine lined cooler
However, imagine wearing a wet skintight t-shirt in similar conditions. The water evaporates quite rapidly and cools your body.
I applied this concept to the cooler prototype pictured and achieved startling results. The cooler would drop as low as 15.5OC at night when temperatures averaged 25OC and maintain under 17OC during the day at average temps of + 32OC.
Construction
An elevated metal box is lined interior and exterior with a fabric. In this case I used locally available corrugated galvanized iron sheets for the container and sisal sacking fabric for lining. The upper ends of the fabric overhang in a water trough that rings the top of the cooler. Capillary action causes the water to slowly trickle over the inner and outer surfaces. A small vent keeps the interior air circulating and wind guides or tunnels direct air flow over the exterior surfaces. A low speed small solar powered fan can be incorporated in areas where there is not a constant breeze.
How it works
The circulating air in the interior causes evaporation on the wet surfaces. The necessary energy is acquired from the contents hence cooling them and is transfers to the iron sides.
Wind guides or tunnels direct an airflow over the external sides. The evaporation that occurs acquires energy from the sides causing further cooling of the interior.
Construction design
Cool-box with water-bath interior for rapid milk cooling application– Collection Point Cooler
Walk-in cold-room for vegetable storage
Vehicle mounted for long distance transporters
Features (Comparison to conventional charcoal coolers)
Very simple construction
Corrugated galvanized iron or GI sheets increase the surface area
Wind tunnels guide air flow efficiently over evaporation surfaces
Air flow coolers at tunnel entrances
Being galvanized, the sheets are long lasting
GI sheets are affordable and available in most rural areas
Secondhand sacking fabric is available in virtually every vegetable market
The simple capillary action dripping system replaces more complicated dripping apparatus
Convection current system to increase water-bath cooling efficiency
In hot arid regions, cooling the warm ambient air before it reaches the wet evaporation surfaces increase efficiency. Note. Setup for airflow from either direction
For further information and other rural development concepts and innovative designs, Dom can be reached on
Ruud Elmendorp, a video journalist living in East Africa, has done a more in depth interview with the young Morris Mbetsa who we recently talked about with his mobile phone-based car security system.
“You don’t need a computer, you don’t need a monthly subscription fee, you just need your mobile phone.”
He’s now looking to start a company that manufactures and installs these systems in Kenya.
On a recent trip to the worlds greatest natural wonder (well, ok, one of!), the wilderbeeste migration in the Masai Mara, we had the pleasure of discovering an extraordinary bush vehicle repair outfitters in the lovely slum village of Talek, after our extortionately expensive rental car suffered from not one, but three flat tyres.
If you haven’t been to the Mara during the spectacular migration, then you might find it hard to imagine our frustration – try rousing 5 kids and 4 adults at 5 am, pack them and lunch and head off to the Mara River to witness for the first time in our lives, the crossing of thousands of wilderbeeste, zebra, gazelles, lions, – images of crocodiles leaping for the bleating calves … adrenaline racing with anticipation…..and then “poof”, a flat, right at the edge of the Mara reserve.
No big deal right – just change the tyre and continue. Five minutes delay? No, 3 hours later, we’re screaming at the rental agent because the key for the spare tyre’s lock does not work! Aaarrrggghhhh
With second car we head to Talek hardly expecting to find an outfitter who can repair tubeless tyres.
This is what we found.
A modified wheel barrow full of silty water and a bit of detergent to find the holes. We stopped counting a 15 – it was very depressing! I don’t even remember going over a thorn bush either!Should have been my first warning – these tyres were seriously worn and thin.
The air compressor system comprised a tank and engine and a compressor unit – the last part was an adaptation from an airconditioning unit off a vehicle! Very creative.
In the end we had to opt for converting a tubeless tyre into a tube tyre – and this is the gizmo that was used to remove the tyre. It was completely home made and very effective. We found an old inner tube with just about the right dimensions at one of the tented camps, 350 shillings and 3 hours later we were on the road again!
It was well worth the hell to get to the crossing point – and of course this is where we experienced puncture no. 2! Crazy place for a puncture as you aren’t allowed to step out of your car while animals are crossing. Hours later It was back to Talek jua kali puncture repair for us!
After 3 days of stunning experiences we headed back to Nairobi on what may easily be described as the worlds worst road. That was where the new tubed tyre went totally bezerk on us and exploded ripping the tube completely in half! Turns out the tyres were so worn that the wires in the tyre simply ripped the tube open. Nice one!
We discovered that the spare lock could be opened with a good whack! with a tyre spanner and off the lock fell. Away we went.
Words of advice to anyone renting a 4×4 to go on a major trek to Mara or anywhere in Kenya – check everything before you go, take rental company managers personal cell no with and make sure you have credit and full phone charge, take a second car if you can, and a fundi (without my brother I’d probably still be on the road side – thanks a million Dom!). Despite the annoying hassles of the rental car and the unbelievable road, the trip was well worth it. I refused to pay for the lost day and was so glad to see the back of that damn rental car – the agency didn’t quarrel. Gonna buy my own safari car now.
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