Solution :
Given :
The power of the air‐conditioning (AC) unit is , W = 0.434 kW
The coefficient of performance or the COP of the air‐conditioning (AC) unit is given by = 6.22
Therefore he heat removed is given by ,
Now if the electricity is valued at 0.10 dollar per kW hour, then the operating cost of the air conditioning unit in 24 hours is given by = 0.10 x 2.7 x 24
= 6.48
Therefore the operating cost = $ 6.48 for 24 hours.
The size conductor that should be used to supply each motor is 12 AWG and the size conductor that should be used for the feeder conductor is 1/0AWG.
<h3>Size conductor</h3>
a. Using NEC table 430.250
Running connect for 150HP connected to 460V = 21 A
Conductor size=25% current to 125% current (Increase)
Increase current=21×125/100
Increase current=26.25 A
Nearest standard conductor size using NEC table 310.15(B)(16)=25 A
Since the motor contain NEMA design code the conductor will be choosing from 75° column which means that the size conductor that should be used to supply each motor is 12AWG copper conductors.
b. Feeder conductor
Using NEC section 430.24 plus ampere rating of other motors
Running current
Using NEC Table 430.250
Running current=26.25+21+21+21+21+21
Running current=131.25 A
The value that is greater than 131.25 A under 75° column of NEC Table 310 (B)(16) is 150 A which means that the size conductor that should be used for the feeder conductor is 1/0 AWG conductors.
Therefore the size conductor that should be used to supply each motor is 12 AWG and the size conductor that should be used for the feeder conductor is 1/0AWG.
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Answer:
The claim is false and violate the zeroth law of thermodynamics.
Explanation:
Zeroth law of thermodynamics refers to thermal equilibrium among elements. It states that elements which different temperatures will reach the same temperature at the endgame if they are close enough to interact each other. This temperaure is called <em>equilibrium temperature and it is always a intermediate value between the element with highest temperature and the element with the lowest one. So there is no way </em> a cup of cold coffee on a table can warm up to 80°C picking up energy from the surrounding air at 25°C because the cup can only reach a temperature closer to the surrounding air temperature which will be the equilimbrium temperature for that case.