In: Electrical Engineering
For this question, you are a construction partner in a managing firm in Kuala Lumpar. The skyscraper you are working in has 12 air conditioners that use 30 amps and operate 33% during the year. You will be installing 3 new, compatible air conditioners that are the same size for identical installation spaces in each unit. Each new unit will use 25 amps operating 40% during the year. If both units function at 135 volts each, what will the difference in 30-day energy cost be if the price for electricity is $0.15kWhr from the mandate?
Annual energy requirement for 12 air conditioners
= 12 x 30 A x 135 V x 365 x 24 hr x 33% [ 30A is operating
current and 135 V is operating voltagge of each AC, 33% is
the time each AC unit is operational each year. 1 year = 365 days,
1 day = 24 hours]
= 140492880 Whr
140493 kWhr
Annual energy cost for 12 air conditioners
= 140493 kWhr x $0.15/kWhr
= $21073.95
30-day energy cost = ($21073.95/36)x30 = $1732.1
If 3 new units are installed with 25 A operating current, 135 V operating voltage and 40% operating period, then annual energy requirement for 12 air conditioners
= 3 x 25 A x 135 V x 365 x 24 hr x 40% + 9 x 30 A x 135 V x 365 x 24 hr x 33% [3 new and 9 old AC units]
= 175970880 Whr
175971 kWhr
Annual energy cost for 12 air conditioners after installing the 3 new ones
= 175970 kWhr x $0.15/kWhr
= $21127.2
30-day energy cost = ($21127.2/365)x30 $1736.5
Difference in 30-day energy after installing 3 new units
= $1736.5 - $1732.1
= $4.4