15.5 Exercise 14

A 4-ton air conditioner removes $5 . \text{06} \times \text{10}^{7} \text{ J}$ (48,000 British thermal units) from a cold environment in 1.00 h. (a) What energy input in joules is necessary to do this if the air conditioner has an energy efficiency rating ($\text{EER}$) of 12.0? (b) What is the cost of doing this if the work costs 10.0 cents per $3 . \text{60} \times \text{10}^{6} \text{ J}$ (one kilowatt-hour)? (c) Discuss whether this cost seems realistic. Note that the energy efficiency rating ($\text{EER}$) of an air conditioner or refrigerator is defined to be the number of British thermal units of heat transfer from a cold environment per hour divided by the watts of power input.