Rural Water Pumping

 

What if we could create a local photovoltaic industry in rural communities?

 

Robert G. Hockaday

 

Our engineering company, Energy Related Devices, has developed and patented inventions to be incorporated into the home: solar water pumping, solar skylights, attic vents and insect repellants. In December 2011, because of an invitation from the city, we moved from Los Alamos to Tucumcari, New Mexico to get closer to our customers: ranchers and farmers.

Ranching and farming in NM, because of the 13-plus -year drought, has been devastating. Our community needs to adapt and diversify. This may seem like an economic development dream, but we need to establish an industry that can utilize our plentiful local resources, use little water for product production and support our community.

For our company to make an impact we thought we should get out of the ivory tower and live and work with our customers and products. So we purchased a rural house with a deep water well and three acres of land to test and demonstrate our products.

Our first of these inventions, installed in the field at the end of September, is a photovoltaic (PV) power system for water-well pumping. A critical need in a drought is to provide a steady source of water for livestock. Ranchers have fine windmill-powered pumps from as early as 1854, but the problem is that the leather (or urethane) pump valves in these systems wear out due to the abrasion of sliding with sand in the well tubes. They need to be replaced periodically, which means pulling up the steel sucker rods, replacing the “leathers,” and sliding them back into the wells. This chore can be as frequent as every six months, so it is a pesky and expensive problem. Even with regular maintenance, wind-powered pumps can still fall behind demand if there is little wind in the summer.

Solar PV well-water pumping is a new, alternative way to pump wells that could alleviate these problems. The electric submersible pumps can run without servicing for over 10 years. Solar-powered pumping systems tend to follow the water demand by producing more water on sunny days. The current PV systems on the market typically use aluminum racking and concrete footers. These are nice systems and have worked well for some, but there are things we can do locally to make solar water pumping an even a better fit for the ranchers. Particular complaints that we have heard: solar pumping systems are not capable of deep well pumping, are too expensive, can run dry and damage themselves, need monitoring to see if they are running, and they need to be moveable by a single rancher.

Our company is customizing the PV panels for local conditions with four new technologies:

Reinforcing—We are reinforcing the back of the PV panels and replacing the frames with galvanized steel beams. Galvanized steel is roughly three times the strength of and many times less expensive than aluminum. Ranchers need tough panels if they are going to be moving the water pumping system with the herd. This reinforcing also permits the option of bolting panels directly to existing windmill towers. Our reinforcement of the PV panels is enough to withstand even hurricanes.

Cooling—We are building in cooling fins, which we call BlackTip, on the back of the PV panels to keep them cool, strengthen them to withstand wind and hail, and cool the panels for better performance and longevity in the hot NM sun. Our first prototype averaged over 3 percent better performance than a conventional PV panel by keeping them on average 10°F cooler.

Tire Mounts—We use discarded truck tires for ground-mounts. Discarded truck tires are plentiful at many local repair shops due to the heavy transportation flow across our state. These tires have sufficient mass and area to make an effective ground-mount for NM wind conditions, even without filling the tires. They can be rolled in and out of a pickup truck by a single person on-site. If the tires are filled with dirt, the system can even withstand hurricanes. The soft, wide base of a truck tire enables us to be ”brownfield ready,” meaning we can place solar panel systems on the ground with little to no ground penetration. They can be placed on landfills or available vacant land with minimal disturbance. This new use for discarded rubber tires makes up by weight (without dirt) 70 to 80 percent of the total mass of the system. Their biggest benefit is in saving the time and energy required to prepare the site with concrete footers or ground penetrations, which are required for conventional mounts.

Smart Pumps—The fourth technology we have added is the new pumping systems that use electronics to sense whether or not there is water to pump. They can also optimize the pumping speed to match what the PV panels can deliver. These submersible pumps can pump wells as deep as 820 feet at flow rates of 4.5 gallons per minute. For a deep well this translates to water service for 57 cow-calf pairs. These new water-pumping systems come with a radio transmitter to allow the rancher to remotely monitor the performance of the well pump.

The Bottom Line—We can produce a solar water pumping system for ranchers modified with local materials to be more robust and portable, for about 30 percent less than conventional systems.

 

Robert G. Hockaday is president of Energy Related Devices, Inc., based in Tucumcari, NM. www.energyrelateddevices.com