Energy Consumption and Cost Calculation for Home Refrigeration Unit
What is the electric energy consumption rate of the three motors in an average-sized home refrigeration unit?
(a) All three motors use electric energy at what rate?
What is the cost of running the unit per hour based on the electricity cost?
(b) If electricity costs $0.17/kWh, what is the cost of running the unit per hour?
How much does it cost to run the unit 12 hours a day for a 30-day month?
(c) What is the cost for running the unit 12 hours a day for a 30-day month? (Round final answer to the nearest cent.)
Answers:
(a) The three motors use electric energy at a rate of 3.154 kW.
(b) The cost of running the unit per hour is $0.536.
(c) The cost for running the unit 12 hours a day for a 30-day month is $192.96.
To calculate the electric energy used by each motor, we need to multiply the power rating of each motor by the time it operates. The power rating of the 1/3-hp fan motor is 1/3 hp, which is equivalent to approximately 0.248 kW. The power rating of the 1/6-hp fan motor is 1/6 hp, equivalent to approximately 0.124 kW. And the power rating of the compressor motor is 3.75 hp, equivalent to approximately 2.79 kW.
(a) Electric Energy Consumption Rate: To find the electric energy used by all three motors, we add up their power ratings. So, the total electric energy used is approximately 0.248 kW + 0.124 kW + 2.79 kW = 3.154 kW.
(b) Cost Per Hour: The cost of running the unit per hour can be found by multiplying the total electric energy used by the cost of electricity per kilowatt-hour. Given that electricity costs $0.17/kWh, the cost of running the unit per hour is approximately 3.154 kW * $0.17/kWh = $0.536 per hour.
(c) Cost for 30-Day Month: To find the cost for running the unit 12 hours a day for a 30-day month, we multiply the cost per hour by the total number of hours. So, the cost for running the unit for 12 hours a day is approximately $0.536/hour * 12 hours = $6.432 per day. Multiplying this by 30 days, we get the cost for running the unit for a 30-day month as approximately $6.432/day * 30 days = $192.96.