This article breaks down the key mathematical calculations used in air-saver nozzle savings calculator.
To calculate the savings for an air-saver nozzle system, start by determining the average compressed air consumption. This value provides the basis for understanding how much air is typically used and is calculated with the following equation:
$$ Cavg = 8.835 \times D^2 \times (P + 14.7) \times N $$
Here,
- $D$ is the nozzle diameter in inches,
- $P$ is the system pressure in psig,
- $N$ is the number of openings, and
- $8.835$ is a conversion factor that brings the units into balance.
Once the average consumption is known, the next step is to calculate the reduction in air consumption when using a more efficient nozzle. This reduction, denoted as $CAR$, subtracts the air delivered by the new nozzle design from the average air consumption:
$$ CAR = Cavg - (N \times FN) $$
In this formula, $FN$ represents the rated flow of the new nozzle. The result, $CAR$, quantifies how much compressed air is saved.
The power reduction resulting from the decreased air consumption can then be estimated by converting the saved air volume into a change in horsepower (and further into kilowatts). The calculation is performed as follows:
$$ P = \frac{CAR}{CAO} \times 0.746 \times \frac{(1 - FP0)}{Em} $$
Where:
- $CAO$ is the nominal compressed air output,
- $0.746$ converts horsepower to kilowatts,
- $FP0$ is the fraction of power at no production, and
- $Em$ is the motor efficiency.
With the power reduction $P$ in kilowatts determined, the annual energy savings, $ES$, are calculated simply by multiplying $P$ with the operating hours per year ($HPY$):
$$ ES = P \times HPY $$
This energy saving, measured in kilowatt-hours per year, directly ties into cost savings when multiplied by the electricity cost per kilowatt-hour ($CE$):
$$ ElectricityCostSavings = ES \times CE $$
For a glimpse at the environmental benefit, the carbon emission reduction is computed next. Using the carbon intensity of electricity ($CIE$) in pounds of CO₂ per kWh, the savings in emissions (converted to tonnes) is given by:
$$ CO2Savings = \frac{ES \times CIE}{2205} $$
(The divisor 2205 converts pounds to tonnes.)
Finally, to understand the financial return on investment, the simple payback period (in months) can be calculated if the implementation cost is known. This is done by dividing the implementation cost by the annual electricity cost savings and then converting the result to months:
$$ SimplePPayback = \left(\frac{ImplementationCost}{ElectricityCostSavings}\right) \times 12 $$