Answer :
Final answer:
The power input required by a 4-ton air conditioner with an EER of 12.0 is calculated by dividing the heat removed in BTU/hr (48,000) by the EER, resulting in 4 kW. The closest answer from the options is 4.2 kW (Option B).
Explanation:
To determine the power input required by an air conditioner with a specified energy efficiency rating (EER), we can use the definition of EER, which is the number of British thermal units of heat transfer from a cold environment per hour divided by the power input in watts. Given that a 4-ton air conditioner removes 48,000 BTU from a cold environment in 1 hour and has an EER of 12.0, we can calculate the required power input using the following formula:
Power input (W) = Heat removed (BTU/hr) / EER
Thus, the power input in watts is:
Power input (W) = 48,000 BTU/hr / 12.0 = 4,000 W
Converting this into kilowatts (since 1 kW = 1,000 W), we get:
Power input (kW) = 4,000 W / 1,000 = 4 kW
Therefore, the closest option for the power input required by the air conditioner from the given choices is B) 4.2 kW.
To address part (b) mentioned in the reference, such as calculating the cost of operating this air conditioner, you would multiply the power input by the cost per kilowatt-hour. For instance:
Cost = Power input (kW) * Hours of operation * Cost per kilowatt-hour
This calculation helps determine the running cost over a specified period.
