Solar Water Pumping Module 4

Solar Water Pumping System Applications | Benefits and Effectiveness of Solar Water Pumping Systems | Purchasing a Solar Water Pumping System |

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Solar Water Pumping System Applications

Where are solar water pumps most cost effective? The Figure below is an indicative diagram showing the most common pumping heads that are suited to different technologies (the head is shown in metres and is an indication only). Solar water pumps can still work in the higher sections of the chart, but are not cost effective with windmills or diesel engine pumps unless of course wind resources are poor or fuel costs are prohibitive – life span and noise and pollution are a consideration also when comparing solar with diesel pumps.

 

Benefits and Effectiveness of Solar Water Pumping Systems ( SWP’s)

Because there are so many variables in the process of designing and installing an SWP, it is often difficult to clearly identify actual savings over time. However anecdotal evidence suggests that in many cases, a solar water pump operating in a particular region can cost less than an equivalent pumping system to achieve the same task. It also has been shown that an SWP is more reliable than other types of pumping systems with solar consistency in the region. The warranty periods for the SWP system is generally higher than systems based on other technologies, particularly PV modules ( 25 years) than other pump types.

Maintenance is generally far less than other types of systems – and all maintenance is usually at a safe working level height, however when either the electronics or “exotic” submersible pumps do break down, the cost of repairs is high. However the modularity of SWP's allows easy replacement of major components in case of breakdowns. Most SWP’s can withstand excessive weather conditions often better than other types of pumps. SWP’s are quiet and non polluting with minimal moving parts. In general, SWP's are quite portable and can be relocated with no special trade skills.

Many suppliers of SWP’s have a standard range of proven product and sufficient history to  be able to guarantee performance under the client’s conditions and application.

 

Purchasing a Solar Water Pumping System

Points to consider when working with suppliers and clients:

The Buyer

• Be sure of your daily water demand – add in a factor for expansion – keep a copy of your calculations for later reference

• Measure as accurately as possible the site topography – record both the methods used and the results – have another person check your work

• Be sure of your facts when advising of water resource capacities – if you must estimate, be conservative – it is an embarrassment to have the pump fail  because of poor drawdown  data – do a measurement then a test (known rate) pump to confirm – also note if the water resource changes with the seasons.

• Be aware if the water resource area is among trees or bushes that shading of the array may be a problem, or else longer and more expensive cable runs may be required to move the array into open sun.

• Be prepared to protect the pumping system from damage by animals or vandals.

• Advise the supplier if you have a budget – often systems can be upgraded at a later date, and this can be built into the original design. This will result in lower initial system cost but with the flexibility of later expansion.).

• Carefully compare different pumps system styles and models offered for the task.

•  Finally, be truthful in all dealings – exaggerating the old windmill’s performance is of no help to the supplier who wishes to give you value for money with a solar pump , but still provide for your water needs.

 

The Seller

• Should assist you with methods of measurements and check your calculations

• Should give you a detailed quotation , detailing the type of equipment offered and including a proposed installation date

• Should give you a guarantee of performance based on correct information given by you

• Should provide full documentation and warranties including service and maintenance needs

• Should arrange for the installation to  meet all relevant standards and use all new components

• Should arrange for commissioning and  user training after installation

• Should provide details of any rebate programs and assist you with applications  if applicable

 

This is the end of Module 4.