Question

Suppose an older 4-ton central air conditioning unit draws 23.8 Amps of electricity at 200 volts. Assume the unit runs an average of 6 hours a day for 60 days. If ComEd charges 11 cents per Kwh, how much does it cost to run the central AC unit? Show all work.

Answer 1

To determine the cost of running the central AC unit, you multiply the energy consumption in kWh (calculated using current, voltage, and time) by the cost per kWh. For this unit, it costs approximately $188.50 to run for 6 hours a day over 60 days at a rate of 11 cents per kWh.

Step-by-step explanation:

To calculate the cost of running the central AC unit, we'll need to first determine the total energy consumption and then multiply it by the cost per kWh. The energy consumed (in kWh) can be calculated using the formula: Energy (kWh) = Power (kW) × Time (h).

First, we need to calculate the power in kilowatts (kW):

Power (kW) = (Current (Amps) × Voltage (Volts)) / 1000 = (23.8 A × 200 V) / 1000 = 4.76 kW

Next, we calculate the total energy consumption for 60 days:

Total Energy (kWh) = Power (kW) × Time (h/day) × Number of days = 4.76 kW × 6 h/day × 60 days = 1713.6 kWh

Finally, we find the total cost:

Total Cost = Total Energy (kWh) × Cost per kWh = 1713.6 kWh × $0.11/kWh = $188.496