Demonstration of Solar Water Pumping Systems for New York State Agriculture

3. Overview Introduction to stand-alone, photovoltaic-powered water pumping systems PV and pumps Application to grazing Performance and cost System sizing Hands-on demonstration GOAL: Provide New York State farmers with cost-effective and reliable options for watering remotely pastured livestock and small scale irrigation.

4. Uses for Solar Water Pumps in New York Solar pumps are very cost-effective for remote applications (where utility interconnect costs more than $5000). Off-grid homes and cabins Livestock watering: pond and stream protection, rotational grazing, remote pasturing Aquaculture: aeration, circulation, and de-icing. Irrigation: best for small scale applications

5. Other Remote Watering Options Diesel/gas pumps- high fuel, maintenance and labor costs. Potential noise and pollution issues Windmill- Very site specific. Does not work as well in the summer due to lower wind speeds Gravity feed- very site specific…often impractical. Works well when used with a solar pumping system Ram pump- requires moving water for operation Hauling water- The lowest cost option. Very labor intensive for livestock watering….frequently replaced by a solar water pumping system!

6. Pros and Cons of Solar Water Pumping Reliable and long life Produces water during sunny weather when it’s needed most Low labor and maintenance costs No fuel costs Easy to remove, transport, and store Non-polluting Potentially high initial system cost Decreased water production in cloudy weather Water storage and/ or battery needed for providing full time water Must have good sun exposure between 9 am and 3 pm

7. Introduction to Photovoltaics Solar (photovoltaic or PV) modules produce DC electricity directly from sunlight with no moving parts. Solar modules have been around for over 50 years and in mass production since 1979. The reliability of PV is such that 20 to 25 year power warranties are typical, with life expectancies beyond 30 years.

8. Photovoltaic Panels

9. PV-Powered Pumps Solar powered pumps have been in mass production since 1983, providing an alternative to high maintenance fuel-burning engines, windmills and labor intensive hand pumps. Thousands of systems are at work around the world, providing water for remote homes, villages, livestock, medical clinics and more.

10. Solar Water Pumps…NOT your average pump! Solar water pumps are designed to use DC power directly from the solar modules. They are much more efficient than an equivalent AC powered pump. The pump controller acts as an automatic transmission between the solar modules and the pump, optimizing low light operation. Some newer versions use a variable frequency AC motor driven by a 3 phase pump controller which is powered by the solar modules.

11. Solar charge controller and LVD in an outdoor rated enclosure

12. Surface pumps

14. Side view of a helical rotor submersible

15. Floating pumpsOn a stream In an improved spring

16. Submersible Pump System at ASC Tech Farm

18. Cost Example - Well Systems 212 ft. well $5,000 labor $1,100 - $1,500

19. Does Solar Water Pumping Work in NY? The answer is YES! We have several systems in operation to prove it! In 2001 we installed 2 solar water pumping systems at the Alfred State College Tech Farm. In 2002 we installed 6 more systems in Steuben, Tioga and Tompkins County, NY. 11 more are scheduled for Chemung, Schuyler, Steuben and Yates Counties through the “Solar Powered Livestock Watering Project” sponsored by the Finger Lakes RC&D and funded by NYSERDA. All 8 existing systems are doing well, meeting or exceeding projected daily water production.

20. Think Small The sizing philosophy for PV water pumping is to move a small volume over an extended time. Just the opposite of their energy hungry AC powered counterparts. Example: One brand of surface pump, utilizing 150 watts of PV, can push 3.8 gallons per minute to a height of 120 feet. On a sunny June or July day, this adds up to about 1600 gallons. That’s enough for several families or over 50 head of cattle! Example: One brand of submersible pump, with 300 watts of PV, can produce over 1100 gallons per day from a 150’ drilled well. The equivalent ¾ HP 240 VAC pump would require 2 kilowatts of PV, an inverter and batteries to do the same amount of work.

21. Site Evaluation- The proposed pump site must be examined to determine it’s suitability for the installation. The solar panels require a south facing location. Locations must be found for the water pump (surface), controllers, storage tank and other system components. The solar array should be as close to the pump as possible to minimize wire size and installation cost. If batteries are to be used, they must be in a reasonably dry/ temperature controlled location with proper venting. If year round water is required, freeze proofing issues must be addressed. A heated area is preferred for water storage and pressure tanks. Basic System Sizing

22. Aerial view of proposed solar pump and gravity feed system

23. Basic System Sizing Site Evaluation- Solar Insolation Get published data/maps Determine full sun hours per day; the average for the most of NY State is 2.5 hours in the winter, 5.5 hours in the summer, 4 hours average for the year Multiply array wattage by this number to get a rough estimate of daily power available at the site.

24. Basic System Sizing Determine your daily water requirements: Household- 50 gallons per day per person (average) Cattle and Horses- 10-15 gallons per day per head Dairy Cows- 20-30 gallons per day Sheep and goats- 2 gallons per day Small Animals- ¼ gallon per day per 25lb body weight Poultry- 6-12 gallons per day per 100 birds Young Trees- 15 gallons per day in dry weather

25. Basic System Sizing Water Source Information: Surface water: Pond, stream or improved spring? Well: Drilled or dug? Static water level? Water depth: Seasonal variations? Recovery rate: Sufficient for your daily needs? Water Quality: Colloidal clay, sand, silt or other debris present? Determine Pump Type: Surface type pump for ponds, springs and streams. Must be close to the water source as the suction lift on this type is 20 feet or less. Capable of pushing water over 400’ vertically. Submersible type pump for wells to 650’ in depth. Submersible pumps are also used for some surface water applications where high volume and/ or high lift is required.

26. Basic System Sizing Estimate the total dynamic head (TDH): TDH is the sum of all losses in the system the vertical distance from the static water level to the storage tank The addition of a pressure tank is the equivalent of increasing vertical head friction losses from pipes and fittings

27. Basic System Sizing Sizing the pump: we can now take all this data and, using the manufacturer’s specification chart, find the proper pump for our application. Sizing the solar array: this same manufacturer’s chart will also give us the recommended solar array needed to power this pump. Standard procedure is to increase the array wattage by 25% to compensate for power losses due to high heat, dust, aging, etc.

29. Open Tank Water Storage The most common method of water storage is the food grade poly tank. This works well for seasonal, gravity fed pasture and drip irrigation applications. A float switch is installed inside the tank to control the pump according to water level. The float method works well for other non-pressurized storage methods.

30. Water storage with float switch

31. Pressurized Water Systems A properly sized solar pump may be used in a pressurized water system much the same as a standard AC powered pump. If full time water is needed, the pressure tank can be oversized to provide sufficient water to get through the night. Storage batteries may also be used to provide a continuous power source. The solar array is used for battery charging purposes, recharging each day what was used during the night. A charge controller and low voltage disconnect are needed in this type of system.

32. 560 watt solar/ battery pump system pumping 3500 GPD to an insulated 4200 gallon storage tank. This gravity feeds through 1.5” water line to 16 - 200 gallon stock tanks with float valves.

33. DC powered booster pump assembly

34. Conclusions To date, the systems installed on NYS farms have proven to be cost effective for: rotational grazing with remote water source primary water source for off-grid livestock barn

35. Future Work demonstrate use in small-scale irrigation pond aeration