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
ADVANCED PUMP TECHNOLOGIES
Edition 03 : 01 March, 2002
SOLAR SPRING
FAQ - Frequently asked questions and answers
QUESTIONS AND ANSWERS CONCERNING SOLAR HORIZONTAL AXIS SUBMERSIBLE PISTON PUMPS.
The following "questions and answers" have been prepared by Windy Dankoff, of Dankoff Solar Products, Santa Fe (NM) in the United States. Mr Dankoff is one of the world's solar pumping experts and a pioneer in the field of solar water pumping. He is the exclusive agent for solar horizontal axis submersible piston pumps in the United States. "SunRise" is the registered trade name used by Dankoff Solar in the United States and in the following material to describe these pumps. Operators in other markets use their own trade names. This material is re-produced by kind permission of Dankoff Solar Products and may be freely copied without alteration by third parties as required on condition that both author and source are duly cited. For further information, contact : Australian Sun Power Corp, Unit 4/204 Balcatta Road, Balcatta 6021, West Australia. Tel. 0061-8-92402992. Fax 92402993. E-mail: pump@iinet.net.au
Questions & Answers about SunRise(tm) Solar Pumps
by Windy Dankoff, Dankoff Solar Products, Inc. Santa Fe, NM (USA), 1997.
Who is Dankoff Solar Products?
Dankoff Solar is a solar pump manufacturer and distributor. In 1983, we developed the "Solar Slowpump". It was the first commercialized solar pump that could push water up hundreds of vertical feet at a system cost of under $3000. We now have a wide line of solar pumps, with thousands sold worldwide. For deep wells, we consider SunRise to be the development of the decade. We are the exclusive U.S.A. importer. We market our products through solar and water well distributors and dealers nationwide. We are a small company with a high degree of competence and enthusiasm.
Who makes SunRise?
SunRise is made by Fluxinos Italia, a 25-year old manufacturer in Italy. (Most of the world's high pressure water pumps are made in Italy.) In the early 80's, Fluxinos invented a revolutionary hand pump, for African foreign aid. SunRise evolved from that effort. It is a complete reinvention of the submersible pump. We visited Fluxinos and were impressed by the quality of their products, the facility, and the people. We maintain regular contact with their technical staff so that they benefit from our experiences in the field.
Why is solar pumping so great?
Solar pumps operate anywhere that the sun shines, and the longer it shines, the more they produce. When the weather is cloudy they produce less water, but then you need less. So, the sun is the natural source of energy for independent water supply. Photovoltaic (PV) panels have no moving parts and last for undetermined decades. A well-engineered solar pump can run for years at a time without trouble.
Isn't it expensive?
No! If your water source is far from a power line, add up your long-term costs of feeding and fixing generators, repairing windmills, etc., including time and transportation to well sites. Now consider the savings with a pump that runs on sunshine and only needs attention every 5 to 10 years.
Why isn't solar pumping more popular?
It's a new, emerging technology. A photovoltaic array produces direct current (DC) that varies with the sunshine. Solar pumps must therefore use a different electrical system from conventional pumps. Low-power solar pumps like SunRise require also require a different mechanism from the conventional (centrifugal) submersibles. It has taken many years to develop the technology, and to overcome early problems with solar pumps.
Solar pumps have also been difficult to sell. To quote a price to a customer, a dealer might study five different product lines, often to find each one to be either too powerful, too weak, too peculiar, or just too expensive. SunRise now fills a great gap in the range of available products. A pump supplier can fulfill a wide range of needs by stocking only SunRise pumps. We think that the growth of solar pumping will be exponential.
Is SunRise reliable?
Is SunRise reliable?
Prototypes of SunRise has been working in southern Africa since late '93. Pumps pulled have shown measurable wear only at the motor brushes, which is slow and predictable. We began selling SunRise in July 1996. We have excellent results, flawless factory support, and all customers satisfied!
What about parts and service?
SunRise is a simple machine that may be repaired by any skilled mechanic. Parts and service are supplied by Dankoff Solar, the U.S.A. importer. The only normally wearing parts are the brushes used in the DC motor. To replace them requires one wrench and 10 minutes. A quick inspection will reveal their state of wear, from which their life expectancy may be predicted. The life expectancy of other parts is indefinite in most cases.
Will SunRise tolerate sand in our well?
Yes. In such a case, we recommend inspection and possible replacement rubber valves and gasketswhenever the brushes are changed. Because of SunRise's low flow rate and its tolerance for running dry, it may be placed higher in the well than a conventional pump. Thus it will have less tendency to draw sand in the first place!
What is the pump controller? Is it reliable?
A controller is required to start our pump, and to prevent stalling in low sunlight conditions. Our controller is simple and robust. Failures are rare. The controller is easily accessible, above ground.
I've never even seen a solar pump. How do we install it?
Installation requires nuts and bolts assembly and simple wiring. It can be installed using the same technique as a conventional AC pump, or it can be installed by hand with sufficient manpower. Our instruction manual covers all aspects of installation (Spanish version is available). We have shipped hundreds of solar submersibles to pump dealers, ranchers and homeowners. Sometimes they call us to ask a question or two, and sometimes they only call to order more!
Who else produces solar pumps, and how does SunRise fit in?
The first low power submersible diaphragm pumps were introduced starting in 1987 by Solarjack, followed by Shurflo and others. These inexpensive pumps are seriously limited in lifting range and longevity. Grundfos, McDonald, and Solarjack also produce centrifugal type solar pumps, that resemble conventional AC pumps. They are only efficient at much higher flow rates, requiring much more power. SunRise fills a range of needs in between these extremes. Its sealed piston mechanism is much more durable than the diaphragm pumps, and much more efficient than the centrifugals for low volume needs.
What makes SunRise different from other solar submersibles?
There are two families of pumps, positive displacement and centrifugal. A positive displacement pump draws water into a chamber, then squeezes it upward using either diaphragm or piston action. A centrifugal pump spins the water to force it outward and then upward, through one or more impellers. Conventional AC submersible pumps, and larger solar pumps work that way. SunRise is a positive displacement pump.
Positive displacement pumps work best for high-lift systems that produce less than 6 GPM. In this range, centrifugal pumps have much lower energy efficiency. Furthermore, during periods of low sunlight, a centrifugal pump loses its ability to build full pressure. Thus at half-sun intensity, it may bring little or no water to the surface, while a positive displacement pump will still produce half-flow.
In low power diaphragm pumps (ie. Shurflo, Solarjack) a flexible diaphragm carries the full work load, and doesn't last more than 3 to 5 years. Diaphragm failures cause water to flood and ruin the motor. SunRise uses pistons that run in oil, on roller bearings. Flexible gaskets separate water from the oil, without bearing the work load. This sealed-piston system can last for 10 to 20 years under most circumstances (duration may be reduced by lift exceeding 450 ft, or by sandy water). The motor is sealed from the oil bath, to protect it from any possible water leakage. To date, we have seen NO failures due to water entering the mechanism or the motor. The pump is fully rebuildable.
What maintenance does a SunRise system require?
PV Array: Photovoltaic panels need no preventive maintenance. Adjusting the tilt angle twice a year is optional, to optimize year-round performance. Most PV racks allow this adjustment.
Pump: Our DC motor uses brushes. These are graphite rods that conduct current to the spinning part of the motor. They wear down after 5 to 10 years, causing the motor to stop. Brush replacement can be done in the field, requiring only the removal of four nuts to loosen the motor shroud.
Other wearing parts will generally last until the second change of brushes.
Why don't we use a brushless motor?
Because they are too complicated. Brushless motors are used in centrifugal solar pumps that use high-speed motors. They use complex electronics that can fail by surprise. Our pumps use a slower speed motor, so brush wear is slow, and predictable. Brushes are inexpensive and easy to replace in the field. We have used only simple brush-type motors in the thousands of solar pumps that we have produced since 1983. The brushes routinely last 5 to 10 years, and the motors far longer.
Do I need a solar tracker?
Tracking the sun is optional. The SunRise system performs well in low light conditions, so it will work through most of the day without a tracker. Use our performance charts to determine daily yield. If that is not sufficient, a tracker may be used to increase the yield primarily during the summer.
I need lots of water. Can I use storage batteries to pump all night?
Yes, but batteries lose 15% of the energy stored, and need to be recharged the next day using a correspondingly larger solar array. Electronic controls are required to prevent overcharge and over discharge. Batteries need watering, protection from severe cold, and finally, replacement every few years. We recommend that you choose a pumping system that is large enough to satisfy your needs without the use of batteries. If SunRise cannot produce enough water that way, consider installing two of them in
one well or consider a larger system from another manufacturer, whichever
is more economical. A two-pump system has the advantage of redundancy. If one system fails, you will still have half of your supply.
I need less water than SunRise produces. Can I run it slower?
In some cases, you may install it with a half-sized array (2 panels, 24 volt). It will produce half the rated flow. If you decide to expand the system later, you can add 2 more panels (48V) to speed it up to full flow.
I have a solar diaphragm pump. After two costly repairs, I am ready for something better. Can I use my existing solar array to power SunRise?
Yes! The Model 5218 SunRise can directly replace a smaller 24V diaphragm pump, and run from the same solar array. Its performance will be comparable. But, because it is a stronger machine running at half-speed, parts should last about five times as long. You will need to replace your controller also.
We have very weak wells. Is SunRise appropriate?
Yes, extremely!
(2) SunRise tolerates running dry, unlike conventional pumps.
(3) SunRise can tolerates great submergence (150 Ft.+). This allows use in wells with a high fluctuation or drawdown.
Can I pressurize water using SunRise?
Yes, within limits. 43 PSI (average house pressure) is equivalent to 100 feet of lift added to the vertical lift from the well. So, for example, model 5230 can produce this pressure in addition to lifting 175 feet (see the performance chart). Using a 48 volt battery bank, you can use it to nearly full flow. With a 24V system, it will produce half of that. A small family, using a large pressure tank (80 gallons min.) can obtain adequate water supply from a pumping rate of less than 2 GPM, if they understand that a quick 30 gallon discharge will result in a recovery period of 15 minutes. The 5226 and 5218 models produce greater lift/pressure, but at lower flow rates.
Most pressurizing systems utilize a storage tank to accumulate the day's water production, plus a second pump for pressuring. For highest efficiency and economy, use a DC pressurizing pump such as Flowlight® Booster Pump or Solar Force Piston Pump. These are made by Dankoff Solar Products and are available from your SunRise dealer. If you do install SunRise to pressurize, you can expand your system, by adding a storage tank and a pressurizing pump later.
I have a solar power system for my home. It produces AC power. Why shouldn't I use an ordinary AC well pump that costs much less?
That is the expensive way! A conventional pump will use 2 to 3 times the energy per gallon, so you will need to purchase a larger power system, including a large power inverter that cannot be repaired locally if it fails. The more water you need, and the deeper your well, the more you will benefit by using a good DC pump. SunRise can run from a 24 or 48V home power system, eliminating the need for a separate solar array.
Can I use SunRise in a shady area (canyon or forest)?
Yes! By using properly sized wire you can locate the solar array hundreds of feet from the pump, in order to gain solar exposure. Our 48 volt system minimizes power loss in the wire. Follow the wire sizing chart on the SunRise specification sheet.
How far can I run a pipeline from the pump to my tank?
Ranchers in the Western states use our pumps to push through MILES of pipeline! By sizing your pipe diameter properly, you can minimize friction loss. The low flow rate of SunRise allows long distance piping using small, inexpensive pipe.
Does it matter what brand of PV (photovoltaic) panels I use?
Any of today's high quality PV modules will run the SunRise pump. It is difficult to obtain comparisons of longevity and of low-light performance, so it is best to use a well reputed, top quality brand.
How long do PV panels last?
Estimates are well beyond 30 years. Most have twenty year warranty!
How can SunRise replace a windmill that produces twice the GPM?
A solar pump works more consistently, in most locations. Its production corresponds closely to the need for water, during the sunniest weather. Its production is slower than the highest flow from a windmill, but it won't let you down on hot still summer days, or in mid-winter when wind is typically low. Some ranchers have observed that their solar pumps are as effective as windmills that pump 3 times the peak flow. And, because its production corresponds to the demand for water, you can use a much smaller storage tank.7
Will the system operate automatically?
Yes! It can run for long periods of time, unattended. Our float switch accessory will stop the pump when the tank fills, then reset when the level drops. This conserves ground water, prevents overflow, and eliminates unnecessary wear. To reduce stagnation in a stock tank (or to help prevent freezing) install a valve just below the reset level, and set it to allow a slow leak. Our controller allows the use of very small wire to the float switch, even a long distance away.
How does it work in the winter?
Fine! Photovoltaics produce power from the sun's light, not from heat. In the fall, tilt the panels to face the lower sun angle. In cold country, you may install a "pitless adapter" available from your local well supplier, to place your piping below frost line.
Must I use the polyethylene PE) pipe that you recommend?
Yes! The pump produces a pulsating flow. Flexible (black) PE pipe absorbs this pulsation like a shock absorber. If rigid PVC pipe is to be used (for machine installation) we can supply a 50-foot "Damping Line" made of poly pipe, to meet the damping requirement.
How can I learn more about water wells, solar power, and solar water pumping?
Ask for the Glossary of Solar Water Pumping Terminology, and other publications from Dankoff Solar Products. These may be transmitted by E-mail if you prefer. We also have an instructional video for sale ($30 US).
TESTIMONY
"The small new generation [SunRise] pumps are efficient units which are now produced industrially to international standards. ... The pump is already an economically feasible solution for little water demand, high head irrigation applications. [It demonstrates] improved hydraulic energy cost compared to conventional [centrifugal submersible] solar pumping systems....[SunRise] pumps offer an economically attractive solution to the end user." Comparative evaluation of SunRise® and Grundfos® systems by the Centre for Renewable Energy Sources (Athens, Greece) for European Union's AVICENNE research program on small solar pumps, June 1997
"This is our third SunRise. We're real happy with them." MW, Alternative Solar Products, Temecula, CA
"Solar pumps are much more dependable than windmills. They work in the hot dry time of the summer when the wind isn't blowing. In some cases we can now sell a solar pump for less than a windmill installation." Matt Williams, Williams Windmills (SunRise dealer) Socorro, NM
"We've been running our SunRise model 5226 pump for a year now. It supplies four families, 20 to 30 trees and some animals. It's a good deal and I thank you." RF, Nevada City, CA
"Yours is the finest instruction manual that I have ever had the pleasure of using, and I am a heating, ventilating and air conditioning technician. Your staff is wonderful to work with." JH, Pecos, NM
Source
Written by Windy Dankoff, Feb. 1998
FOR MORE INFORMATION ON THE SOLAR SPRING PUMPS PLEASE GO TO:
GENERAL FILE FOR THE SOLAR SPRING PUMPS
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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