" 65 Degrees F is the “target” outside temperature. If the average temperature is 75, then we are 10 degrees “off target”. For 365 days, the Cooling Degree Days would be:
(10)(365)
=3,650 CDD per year"
An appropriately loaded motor typically operates at 90% efficiency.
Induction of Alternating Current The most common form of motor used in buildings is a motor.
Power input divided by Powermoved is the Coefficient of Performance. This machine can move 250 tons of cooling using a 250 ton chiller, hence the power input would be:
In this problem, we are given A and must find P. Logically, for this project to have a positive NPV, we know the P (from the positive cash flows) must be at least equal to the Cost. Thus, let's find the P and then that is the maximum we can pay for the installed cost. The PV of the Annual Savings of $1,000,000 per year:
= $1,000,000/year (P/AIN Factor)
= $1,000,000/year (2.8021)
= $ 2,802,100
Thus, we can pay $2,802,100 for the Waste Heat Exchanger and still have a positive NPV.
Use the “Fan Laws” HP2=HP1 (RPM2/RPM1)3. Therefore, if the new speed (RPM2) is 80% of the old speed (RPM1), the new power load (HP2) will be:
HP2=HP1 (.8)3
HP2=200HP (0.512)
HP2=102.4 HP
