Designing a solar powered system can be done quite easily. For example, a pasture dugout of 2,400,000 litres (1.9 acre foot or 635,000 gallons) ) can be aerated with a minimum of 0.5-1.0 CFM (cubic feet per minute) at 3-6 feet of water depth. For proper system design, the compressor size and power requirements must be calculated for sufficient aeration. Once calculated, the number of solar panels and batteries can be determined.
The following formula is used to determine the number of solar panels required.
Volts × Amps × Hrs running × Battery Efficiency Factor = Watts/hr Required
Example: (based on summer use)
An average summer day will provide about 6.0-6.5 hours of charging time equalling our 12-volt compressor rated load of 3.8 amps (45.6 W) per hour. To determine the number of panels using the formula, the following is calculated.
12v × 3.8amps × 24hr × 1.1bf = 1,204 Watt/hrs
Based on this calculation, three solar panels are required. This assumes use of 64-watt panels, which produce (64 watts × 6 hrs) 384 Watt-hrs per day. Therefore, (1,204 ÷ 384) = 3.1, round to three panels.
When installing a solar powered system, one should determine the number of batteries needed or calculate how much battery power is required during cloudy periods or if the panels are disconnected. This calculation will depend on how often the system is inspected. PFRA recommends a battery storage capacity of three to five days.
In this example, if four days of storage is required and a twelve -volt 220-amp hour battery is used, then calculate the number of batteries needed using the following formula:
Load × Duty Cycle × Run Time = Reserve Capacity
Load: volts multiplied by amps (Watts)
Duty cycle: running time percent
Run time: length of time required
To determine the number of batteries using the formula, the following is calculated:
45.6w × 1.0 × 96 hours = 4377.6 Watt/hrs
The number of 220 A/hr batteries required is 1.6 , rounded up to two.
This is achieved because a 220 A/hr battery holds (220 A/hr × 12v) 2640 Watt/hrs, which, when divided into reserve capacity equals 1.6 batteries to get four days of reserve capacity.
To summarize according to the Canadian Water Environment study, to continuously aerate 2 acre foot of dugout you need a minimum of two 12 volt batteries, three 64 watt solar panels, and 46 watts of air pumps to get 0.5 to 1.0 cubic foot of diffused air into the pond at a 3-6 foot depth at a cost of +$8500.00.
OR you can buy 1 of our EKBS-20 Solar Aerators at $2195.00 and provide 0.5 to 1.0 cfm @ 3-6 foot of water depth. Use our draft tubes to aerate at any depth.
OR you can buy 2 of our EKBS-15 Solar Aerators at $2584.00 and provide 0.6 to 1.2 cfm @ 3-6 foot of water depth. Use our draft tubes to aerate at any depth.
Cost of Solar Aeration
Depending on the system components used, dugout solar aeration can vary from as low as $1,200 (with no battery storage) to $2,500 - $8,500 for 24-hour aeration.
The following table indicates the approximate component costs for a solar powered aeration system.
Component Approximate cost
64-watt solar panel $600
220-amp hour 6-volt battery $130
Air compressor $300
Control regulator and LVD $250
1/2 inch air line (weighted) $30-$100 depending on length
Air diffuser $25-$150
Mountings for panels, enclosures for batteries and compressor can be purchased from a local dealer or built at the farm. A system can be permanently located at the site or mounted on a trailer for easy relocation.
The Big Picture
Dugouts are an important water source on the Prairies. Water quality is very important to livestock health and potential weight gains. Therefore, it is important to maintain the best water quality possible in your dugout. Solar aeration is an ideal method to keep pasture dugouts healthy.