5 Tips for Using a Solar Irrigation Pump
Using a solar irrigation pump saves time, increases production, and is more economically sustainable than any other irrigation method. Whether you have acres of crops, a small backyard garden, or have a desire to live off-grid and supply your own water, using a solar irrigation pump is an investment that will pay off for years to come. Follow this article to save time in choosing the right type of pump, how to set it up, protect it, and even how to get a tax credit.
1- Choosing the Right Solar Irrigation Pump
There are two basic types of solar water pumps, surface and submersible. Surface pumps are used when you have a water source, such as a river, stream, or lake nearby. These pumps will use a series of pipes to bring the water from the water source either directly to your point of use, or a storage tank. But, for the vast majority of users a submersible solar pump is the best option. The pump itself is submerged in a well or underground water source up to 1000 feet deep. The pump is attached to the solar power relay and the water is pumped upwards and water is stored for use in a storage tank, or a pressure tank is used.
2- How to Choose the Best Type of System for Your Pump
Once you have determined the right type of Solar Pump for you, your next step is to determine the type of system you will use with that pump. There are 3 main types of Solar Water Pump Systems. The first is Array Direct to Elevated Storage. This system uses a large elevated water storage tank (able to hold 1200 gallons), similar to a water tower to provide the necessary amount of water pressure for your use. If you want to use the pump to provide household water you need to set the tank at least 100 feet higher than it's point of use. The tank stores water for days that are cloudy and water use at night. This way the pump only runs when it is actually pulling water into the tank.
If a large, elevated storage tank is not an option, you can use an Array Direct to Storage Tank with Pressure Pump. In this system the storage tank is not elevated and you attach a pressure pump so the outgoing water has enough pressure for your use. The tank will still allow for storage for cloudy days and the pressure pump will only run when the water is being used.
If a storage tank of any sort will not work for you, you can use a Pump to Pressure Tank system. This system only needs a 40 to 60 gallon water tank and a pressure regulator senses when the pressure inside the tank needs to be adjusted up or down. Compared to the other systems this one has the lowest up-front component costs. But the downside is that the pump will need to come on every time you need water and that will drain the solar batteries at night and on cloudy days. You may reach a point of the battery dying before the sun can recharge it, leaving you without water.
3- Choose the Right Site
Now that you have your system figured out, make sure you place the solar array in the best area possible. For the best performance the array should be free from shade the entire day and face as close to true South as possible. For most residential users the array will be set at a fixed tilt. For users that need more water during the summer for irrigation, installing a sun-tracking PV Module is a good option. This way the array will follow the sun across the sky and you will get the most power available. A sun-tracking module can provide 20 percent to 40 percent more power on summer days than a fixed array.
4- Prevent Pump Damage
After investing all of this money into you Solar Irrigation Pump you need to take steps to prevent the pump from being damaged. First off, there needs to be a water level sensor installed inside your tank so that the pump knows when to shutoff. Some pumps come with this already, so double check with your manufacturer. It is also important that your system is properly grounded. Some manufacturer's warranties will even require a lightning arrestor. If you have your system properly grounded, your pump should be well enough protected even if the array takes a direct lightning hit.
5- Don't Forget Your Tax Credit
Tax credits are available for installing solar irrigation pump systems. You can deduct up to 30 percent of the cost of your system. This credit was extended for an additional 8 years in 2008. Besides this generous tax credit, the money that a solar irrigation system will save you will pay for itself many times over.