Quick Answer
The size of the solar array needed for air conditioning depends on several factors, including the type and size of the AC unit, the amount of energy it consumes, and the local solar irradiance. A typical 5-ton DC inverter AC unit requires a solar array of around 10-15 kilowatts (kW) to meet its peak demand. This can vary depending on the unit's efficiency and the desired level of backup power.
Calculating AC Power Requirements
To determine the required solar array size, we need to calculate the AC unit’s power requirements. A 5-ton DC inverter AC unit typically consumes around 5,000-6,000 watts (W) at its peak demand. However, this value can vary depending on the unit’s efficiency, which is usually around 2.5-3.5 kilowatt-hours (kWh) per ton per hour. To account for this variation, we can use a safety factor of 1.2-1.5. For a 5-ton unit, this would result in a required solar array size of around 10-14 kW.
DC to AC Inverter Efficiency
DC inverter AC units have an efficiency of around 85-90%. This means that for every kilowatt-hour (kWh) of DC power produced, the inverter will output around 0.85-0.9 kWh of AC power. To account for this efficiency loss, we can multiply the required AC power by 1.11-1.14. For a 10-14 kW solar array, this would result in a required DC power of around 11.1-15.96 kW.
Solar Array Sizing Guidelines
The National Electrical Code (NEC) recommends that the solar array size be at least 25% larger than the required AC power to account for startup and peak demand. Based on the calculations above, the required solar array size would be around 12.75-17.45 kW. To account for the NEC recommendation, we can increase this value to around 15.9-22.13 kW. This will ensure that the solar array can meet the AC unit’s power requirements and provide a buffer for startup and peak demand.
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