Calculating the Annual Electricity Cost of a Compressor

Understanding the Calculation Process

Given Data:

Power of compressor: 75 hp

Operating time: 2500 hours/year

Efficiency of electric motor: 93%

Unit cost of electricity: $0.11/kWh

Step-by-Step Calculation:

1. Calculate Energy Consumption:

First, convert the power of the motor from horsepower (hp) to watts:

1 hp = 746 watts

Power in watts = 75 hp x 746 = 55,950 watts

Now, find the energy consumption using the formula:

Energy Consumption = Power x Time

Energy Consumption = 55,950 watts x 2500 hours = 139,875,000 watt-hours

Convert the energy consumption to kilowatt-hours (kWh):

1 kWh = 1000 watt-hours

Energy Consumption in kWh = 139,875,000 watt-hours / 1000 = 139,875 kWh

2. Calculate Annual Electricity Cost:

Finally, multiply the energy consumption by the unit cost of electricity:

Annual Electricity Cost = 139,875 kWh x $0.11/kWh = $15,386.25

Therefore, the annual electricity cost of this compressor is $15,386.25.