All aeration systems require a power source. If the reservoir is close to available electricity, that will be the likely choice. If no electrical power is in close to proximity to the dugout, another power source will be necessary. Popular choices are wind-power and solar power.
Solar-Powered Dugout Aeration
Solar powered aeration systems are similar to electrical powered systems. The main benefit of solar-powered aeration systems is that they can be used in remote dugouts where access to an Alternating Current (AC) grid is not practical.
Solar Powered systems (also known as photovoltaic systems) consist of solar arrays (solar panels) that convert sunlight into Direct Current (DC) electricity, which can be used directly or stored in batteries for use at night or on cloudy days.
Invertors can be used to convert the DC to AC.
A solar aeration system consists of:
- Solar panels (sized to supply enough power for calculated consumption)
- Deep cycle batteries to store excess power
- A control board with regulator (charge controller)
- Compressor
- Weighted feeder hose
- Air diffuser
Illustration of Solar Aeration System
Description - Illustration of Solar Aeration System
Cross-sectional illustration of a pond. The sun is shining on a solar panel that is charging a storage battery. The battery is powering a compressor that is forcing air through a diffuser at the bottom of the pond. Arrows in the pond indicate the movement of air throughout the entire volume of water.Solar Aeration System Design
Designing a solar powered system can be done quite easily. For example, a pasture dugout of 2,400,000 litres can be aerated with a minimum of 0.5-1.0 cubic feet per minute. 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.
Number of Solar Panels Required
The following formula is used to determine the number of solar panels required.
Volts (v) × amperes (amps) × Hours running (hr) × Battery Efficiency Factor (bf) = Watts/hour (W/hrs) Required
Example: (based on summer use)
An average summer day will provide about 6.0-6.5 hours of charging time equaling a 12-volt compressor rated load of 3.8 amps (45.6 watts (W)) per hour. To determine the number of panels using the formula, the following is calculated.
12v × 3.8amps × 24hr × 1.1bf = 1,204 W/hrs
Based on this calculation, three solar panels are required. This assumes use of 64-watt panels, which produce (64 W × 6 hrs) 384 Watt-hrs per day. Therefore, (1,204 ÷ 384) = 3.1, round to three panels.
Number of Batteries Required
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 when the panels are disconnected. This calculation will depend on how often the system is inspected. Battery storage capacity of three to five days is recommended.
Load × Duty Cycle × Run Time = Reserve Capacity
- Load: volts multiplied by amps (Watts)
- Duty cycle: running time percent
- Run time: length of time required
Example:
If four days of storage is required and a six-volt 220-amp hour battery is used, then calculate the number of batteries needed using the following formula:
To determine the number of batteries using the formula, the following is calculated:
45.6W × 1.0 × 96 hours = 4377.6 W/hrs
The number of 220 amperes per hour (A/hr) batteries required is 3.32, rounded up to four.
This is achieved because a 220 A/hr battery holds (220 A/hr × 6v) 1320 Watt/hrs, which, when divided into reserve capacity equals 3.32 batteries to get four days of reserve capacity.
Most DC systems are 6, 12 or 24 volts. 6-volt batteries are recommended because they provide the best storage life.
For a 12-volt system, the batteries must be used in increments of two in series equaling 12 volts; and for a 24-volt system, increments of four in series that equal 24 volts are required.
Cost of Solar Aeration
Depending on the system components used, dugout solar aeration can vary from as low as $1,200 for systems with no battery storage up to $2,500 - $8,500 for 24-hour aeration.
Solar panels consist of silicon cells, which have no moving parts. They are durable and have a life expectancy of 25 years or more. Most solar arrays begin delivering power or charging batteries with as little as 10 per cent of sunlight with each cell of the array converting approximately 14 per cent of the available energy to DC power.
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 | $140 |
| Air compressor | $350 |
| Control regulator and low voltage differential (LVD) | $325 |
| 1/2 inch air line (weighted) | $30-$100 (depending on length) |
| Air diffuser | $35-$175 |
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.