This page details answers to frequently asked questions relating to the Poldaw Windpump design.
How Much Water Do The Poldaws Produce?
The performance of the Poldaw Windpumps depend on pumping head (i.e. total lift required) and windspeeds. The two most popular models are the 3.5m machine (the diameter of the rotor is 3.5 metres) and the 5m machine. For a moderate pumping head of 20m, in a medium wind speed of 4m/s, outputs are:
- Poldaw 3.5 m: 21,000 litres per day
- Poldaw 5.0 m: 43,000 litres per day
There are also smaller models, 2.2m and 1.8m, with correspondingly smaller outputs.
The 3.5 metre machine can pump from depths of up to 90m, whilst the 5 metre machine can pump from 140m, now extended to 200m max by means of a spring counterbalance system.
Are There Siting or Wind Condition Constraints?
The Poldaw can start up under load in the lightest of breezes and operates in wind speeds as low as 3 metres per second (approx. 7 mph). A simple test with an anemometer will confirm local wind speed conditions.
A range of tower heights is available, selected to suit local topography and wind conditions, for example a sheltered site may require a tall tower. If there is doubt about the suitability of a site for a windpump, Poldaw and/or its local licensees will advise.
Cost effectiveness of the Poldaw Windpump:
The Poldaw Windpumps costs 30% less to manufacture than other similarly sized windpumps and, being made with local materials and labour, have no import duties.
The initial purchase cost of a community water supply system using a Poldaw Windpump varies from country to country, but generally compares well with other powered pumping systems.
Running costs are negligible due to no fuel and minimal straightforward maintenance.
Who Manufactures Poldaw Windpumps?
The Poldaw is a modern appropriate technology windpump design, which can be made easily in any country using readily available materials with basic engineering tools and equipment.
The preferred approach is to licence the design to local manufacturers who make, sell, install and maintain the windpumps as required. As part of the licence agreement, Neale Consulting Engineers provide on-site training, transfer of know-how and ongoing technical support to the manufacturer.
Poldaw Windpumps are currently manufactured in the UK and in a number of countries in Africa, Asia and South America. Click here for list.
How Easy Are Poldaw Windpumps to Maintain?
Poldaw Windpumps have been designed to need very little maintenance. All that is required is the greasing of bearings once a year, with a general inspection of other components. The principal wearing parts of the whole system are the leather sealing washers in the pump piston, which are replaced on average every 2 to 3 years.
Routine maintenance and pump washer replacement can easily be carried out with the tower standing. To simplify installation, and for any major borehole or windpump maintenance, the tower has been designed to hinge on two of its three feet so that the whole machine can be laid down by use of a winch.
Local mechanics can be trained in one to two days to carry out these procedures or the local manufacturer can provide support under an ongoing contract. The skill level required is much less than for diesel engine maintenance and attention is only needed once per year.
What Happens When the Wind Doesn’t Blow?
Windpumps are suitable for any location with an average wind speed of 2.5 m/s or more and with no prolonged windless periods.
In such locations, on most days there is sufficient wind for the windpump to operate for at least part of the day. However, to provide against windless days, the Poldaw Windpump is usually installed with a water tank or reservoir. Generally a tank with three days of water supply is adequate.
What Happens When There is a Storm?
The Poldaw Windpump is designed, through the use of a hinged tail vane, to turn (or “furl”) automatically to minimise the area facing into the wind. By means of this mechanism it will withstand storms of up to 180 kilometres per hour (= 50 m/s, 110 miles/hr).