Quick Answer
Adapt existing AC units for off-grid use by installing a DC-to-AC inverter, upgrading the unit's control board to a high-efficiency design, and sizing a solar panel array to meet the unit's power requirements.
Upgrading AC Units for Off-Grid Use
Upgrading existing AC units for off-grid use involves replacing the control board with a high-efficiency design that allows the unit to run more efficiently on DC power. Look for AC units with a high SEER (Seasonal Energy Efficiency Ratio) rating, typically above 16, as these will consume less energy and provide better performance. The control board can be upgraded with a high-efficiency model, such as the Lennox iComfort, which is specifically designed for off-grid use.
Sizing a Solar Panel Array
To size a solar panel array for an AC unit, calculate the unit’s power requirements in watts. A typical 5-ton AC unit consumes around 4,000-5,000 watts of power. Consider adding a 10-20% margin for peak sun hours and efficiency losses. For example, a 5-ton AC unit might require a 4.5 kW to 5.5 kW solar panel array, depending on the location and efficiency of the panels. Use a solar panel efficiency of 0.2-0.3 watts per panel to determine the number of panels needed.
Installing a DC-to-AC Inverter
Installing a DC-to-AC inverter is a crucial step in adapting an AC unit for off-grid use. Look for inverters with a high efficiency rating, typically above 95%, and a high surge capacity to handle the unit’s startup power requirements. Consider using a string inverter, such as the SolarEdge SE5000, which can handle high power requirements and provide real-time monitoring and control.
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