T.E.(Terry) Manning Schoener 50 1771 ED Wieringerwerf The Netherlands Tel/fax 0031-227-604128 Homepage: http://www.flowman.nl E-mail:pumps@flowman.nl

FLOWMAN

ADVANCED PUMP TECHNOLOGIES

Edition 05: 08 March, 2002

SOLAR SPRING SOLAR PUMPS

INSTALLATION

The following pages refer to the orientation of photovoltaic (PV) panels, the support structure for the panels and its resistance to winds and shock. A schematic drawing of a typical installation is also given. If you are more interested in other aspects concerning installation, please return to INSTALLATION INDEX

Orientation of PV panels and tracking systems

Photovoltaic systems are pointed North if placed in the Southern hemisphere, and South if placed in the Northern hemisphere. The daily and global performance of PV panels depends on the amount of energy they are able to collect, so they are best if oriented seasonally (thus vertically, in accordance with height of the sun with respect to the horizon) and hourly (thus moving east to west, in accordance with the position of the sun during the day). In isolated locations, systematic manual adjustments will rarely be feasible. The user must then choose either to install an automatic tracking system, or point the panels in a fixed position so as to obtain the best possible average daily power input. With an automatic tracking system, the initial investment costs for the panel support structure, and in some cases, long term maintenance costs, will be higher, but on the other hand fewer PV panels may be required, and more water will be pumped over a long term for each peak watt installed. With a fixed system, a larger PV panel array will increase PV panel costs, the initial investment in the tracking system will be eliminated, and slightly less water will be pumped for each peak watt installed, but security of water supply is improved and long term maintenance costs are reduced. There is no general agreement amongst experts as to which alternative should be adopted. We believe that safety of water supply must take precedence over all other aspects and recommend that users adopt a fixed system in isolated locations, while for rural villages we recommend that a three point manual tracking system without any moving parts which can get lost, be used. The adoption of automatic non-manual tracking systems is therefore the responsibility of the end-user.

Tilting of panels

Panels should be seasonally tilted according to the latitude of the installation site. Your solar dealer may have monthly tilting charts for your area. Choose the correct tilt for your design month. However, if you live near the equator, NEVER set the array in a horizontal position, as dust and debris will not wash off. Make sure the tilt is sufficient to enable the panels to self-clean themselves when it rains. In areas of low rainfall and in the presence of dust, it may be necessary to wipe the panel surfaces periodically.

Fixed systems

Panels are fixed pointing due South/North. This means that they will tend towards peak performance in the middle of the day, but will not deliver much current earlier in the morning or later in the afternoon. However, fixed systems are INHERENTLY SAFE as they cannot get "stuck" pointing either East or West. They represent a compromise solution : global power generation is lower than it might otherwise be, but the installation does not need any attention. They are particularly suited to sites which are rarely visited and/or where the costs of making regular visits greatly outweigh the benefits of extra power generation deriving from the use of tracking systems. Fixed systems may or may not be seasonally tiltable. If there is certainty that the installation will be visited for a control three or four times a year, it is sensible to tilt the panels according to the season. If no visits are foreseen, it is better to tilt for the DESIGN MONTH you have chosen. An alternative is to allow a little surplus power in your array, and tilt the array one angle away from DESIGN MONTH optimum.
We believe that with small, highly efficient, systems such as those using Solar Spring pumps, it is wiser to invest capital in a slightly larger fixed array than in purchasing a tracking system.

Hand tracking systems

Extremely robust three point manual tracking supports without moving parts which can get lost are available. Daily orientation can considerably extend the amount of energy collected by the panels across the day, and therefore substantially increase the amount of water pumped, although such benefits are not so important with Solar Spring piston pumps as they are with traditional technologies. Any user may change the orientation of the panels at any time, so as to attain the most benefit in terms of water supply. In some cases, a village may nominate a pump caretaker, and in such case, periodic orientation of the panels during the day could fall amongst the caretaker's duties. The use of the manual tracking systems is particularly indicated where installations are sited in villages, or where people are regularly available to change the orientation of the panels as required.

Electronically driven or gas filled tracking systems

A number of fairly reliable automatic tracking systems have come on the market in recent years. Their inherent weakness is that if they fail, the panels may be locked to the extreme East or to the West, which would be disastrous to the success of the installation. We think it is better (eventually) to invest in the purchase of one or more extra PV panels rather than purchase an automatic tracking system. In any case, automatic tracking systems are used AT THE SOLE RISK AND DISCRETION OF THE END USER.

Schematic drawing of installation

LAYOUT OF INSTALLATION

Panel support

You can place your PV panels practically anywhere you wish, provided they are pointing South if you live in the Northern hemisphere and North if you live in the Southern hemisphere. They should,where possible, be inclined as recommended in array tilt tables for the latitude in question, where available.

Some examples for the siting of PV panels are:

On the roof of your house or other building, close to the water source
Mobile, on a trailer or similar, positioned close to the water source
Mobile but grounded, on a stable metallic structure, placed close to the water source
On a pole or trellis structure, close, wherever possible, to the water source.

Positioning close to the water source has been emphasised because the shorter the electric cable, the lower the current loss. It is seldom, however, critical, and where necessary the PV array can be placed as far away from the water source as is necessary to obtain the best possible insolation.

The panels must generally be free towards the South (if you live in the Northern hemisphere) or towards the North (if you live in the Southern hemisphere) from obstacles such as buildings, trees, and the like which may obstruct the sun's rays. It is still better if obstructions to the east and west are also avoided, as this will enable your PV panels to capture the sun's rays over much of the day, thereby extending the number of hours the pump can work each day, and therefore the amount of water pumped. Make sure the array is going to remain free from growing weeds and from snow, rain or mud spatter which could shade one or more panels and seriously reduce the capacity or your array. For this reason, the bottom of the panels should always at least 1 meter from the ground.
In some areas risk of theft of PV panels and structures may be a major issue. In others risk of damage by vandalism or sabotage or damage by animals persons or things. Please remember to take such factors into account when siting your array.

You may wish to use your Solar Spring pump and accompanying array as mobile equipment which can be moved from place to place according to your requirements from time to time.

Fixed support structures should in any case be firmly anchored in concrete and such as to be able to withstand the worst weather conditions ever recorded at the site. The support structure should have been installed several days BEFORE the installation of the pump, so as the ensure that the concrete used has had time to set.

ASSEMBLY OF MOUNTING RACKS AND PANELS

Please follow the instructions given by the respective manufacturers.

WARNING! THE PUMP SUPPLIER IS NOT LIABLE FOR FAILURE TO USE ADEQUATE SUPPORT STRUCTURES OR FOR FAILURE TO PLACE THEM SAFELY OR CORRECTLY

Correct installation of panel supports is the responsibility of the end use and/or of the installer he has nominated. No liability for damage whether direct or indirect to persons or things howsoever caused by failure of the support structure to withstand winds atmospheric conditions generally or shock shall attach to the pump supplier.

Subject to the above limitation as to liability, a 76mm diameter hot dip galvanised mild steel support pole is usually considered sufficient. The pole should be anchored (where possible, as stated above, in a concrete bedding) at least one metre below ground level, and should project at least 2 metres above the ground. Height is not critical, but higher structures may be better suited to capturing the sun's rays earlier in the day and later in the evening.

WARNING! : THE SUPPORT STRUCTURE MUST BE RESISTANT TO FORESEEABLE HIGH WINDS AND SHOCK!

WARNING! : TAKE INTO ACCOUNT RISK OF THEFT OF OR DAMAGE TO YOUR PANELS!

FOR MORE INFORMATION ON THE SOLAR SPRING PUMP PLEASE GO TO:

SOLAR SPRING COVER PAGE.
INSTALLATION INDEX

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PRODUCTS OFFERED

If you cannot find the information you require on these pages, please contact Terry Manning by e-mail on : pumps@flowman.nl or telephone or fax him at 0031-227-604128.

E-mail Terry Manning