1. How much water do you need per day?
and
2. What is the pressure your pump must deliver?
Each pump sales person should ask these questions. In most cases, your first estimated answer will be way off. As a result, the pump you are buying is too expensive.
1. According to WHO (2010) a person needs between 50 and 100 litres of water per day. In reality, the average African uses 20 litres per day (that is showering for 1.5 minutes in a developed country to give an idea).
Anyway, when you want to buy a pump you want enough water so let us say your family of 6 needs 600 litres in a day plus 10 buckets for the garden makes 800 litre a day. The sun shines 5 hours a day, than the pump must deliver 800/5 = 160 litre/hour = 2.7 litre/minute.
2. The pressure needed is the difference in height between water level and outlet plus a little friction in the pipes. This differs from place to place. In Eastern Zambia, it is often not more than 10m.
At this moment, the smallest common solar driven pump available on the market in Zambia is about ½ horse power, which delivers 2600 litre/hour @10m. That is 16x times too much for our example. The pump will only pump for 18 minutes. The rest of the day, your expensive equipment is idle!
Inspired by John Demarco and Henk Holtslag, Jacana has been and still is testing several small solar powered pumps.
Pumps being tested, good and bad
Our criteria are:
- Affordability of the pump and panel.
- The pump must be powered direct by a solar panel without the need of controllers or batteries. Not only to reduce costs, but also to reduce point of failure and maintenance.
- Durability. Pumps must run day in – day out, for at least a full year without switching it off.
- Scalability to reduce initial investment and allow expansion.
We measure output (litre/minute) at several pressure levels to match customer needs and costs.
Smaller pumps are also better for the well or borehole since they put less stress on it. Small pumps can be a solution for wells in slow aquifers (soil structures where water passes slowly).
Durability test
There are good affordable solar powered pumps, which produce more than enough water for most households and small gardens. A good solar driven pump with panel is already much cheaper than a common hand pump (India Mark II or Afridev) and deliver in many places more water (depending on water level) and are more durable when installed correctly.
Affordable solar power sprinkler
Installation of solar powered pump in a manually drilled borehole
We believe that a new era has started.
It normally takes time for people to get used to new concepts.
Thanks to Marie-Stella-Maris foundation, Jacana is able to introduce these concepts.
Want to know more?
Learn how to select the best pump for your situation, get to know good international suppliers and learn how to scale up you affordable pump installation. Download the manual:
“Electrical pump selection and installation”
