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MEASUR-Tools-Suite v1.0.11
The MEASUR Tools Suite is a collection of industrial efficiency calculations written in C++ and with bindings for compilation to WebAssembly.
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This calculator estimates annual compressed air consumption and associated energy use and cost for compressed airflow reduction measures identified during an energy treasure hunt or efficiency assessment. It supports four measurement methods for determining airflow or consumption, and two utility types for translating consumption into a monetary cost.
The calculation follows these steps for each measure:
Relevant formulas and symbol definitions are documented below.
Annual compressed air consumption derived from a flow meter reading.
An installed flow meter provides an instantaneous flow rate reading. This is multiplied by the annual operating time, a unit conversion factor of 60 (to convert hours to minutes), and the quantity multiplier to obtain total annual consumption in standard cubic feet.
\begin{equation}\label{eq:compressed-air-reduction-flow-meter-consumption} C = Q_{meter} \cdot t_{op} \cdot 60 \cdot n\end{equation}
| \(C\) | Annual compressed air consumption \([\unit{ \cubic\foot\per\year}]\) |
| \(Q_{meter}\) | Flow rate reading from the installed meter \([\unit{ \cubic\foot\per\minute}]\) |
| \(t_{op}\) | Annual operating hours \([\unit{ \hour\per\year}]\) |
| \(60\) | Unit conversion factor (minutes per hour) \([\unit{ \minute\per\hour}]\) |
| \(n\) | Quantity multiplier (number of identical measures) \([\unit{ \unitless}]\) |
Compressed airflow rate and annual consumption estimated using the bag method.
The bag method estimates flow rate by measuring how long it takes to fill a known-volume bag with compressed air from a leak or equipment vent. Dividing the bag volume by the fill time (converted to minutes) gives the instantaneous flow rate in scfm. Annual consumption is then computed from the flow rate, operating hours.
\begin{equation}\label{eq:compressed-air-reduction-bag-flow-rate} Q_{bag} = \frac{V_{bag}}{t_{fill} / 60}\end{equation}
\begin{equation}\label{eq:compressed-air-reduction-bag-consumption} C = Q_{bag} \cdot t_{op} \cdot 60 \cdot n\end{equation}
| \(Q_{bag}\) | Estimated compressed airflow rate \([\unit{ \cubic\foot\per\minute}]\) |
| \(V_{bag}\) | Internal volume of the bag \([\unit{ \cubic\foot}]\) |
| \(t_{fill}\) | Time to fill the bag with compressed air \([\unit{ \second}]\) |
| \(60\) | Unit conversion factor (seconds per minute) \([\unit{ \second\per\minute}]\) |
| \(C\) | Annual compressed air consumption \([\unit{ \cubic\foot\per\year}]\) |
| \(t_{op}\) | Annual operating hours \([\unit{ \hour\per\year}]\) |
| \(n\) | Outer quantity multiplier (number of identical measures) \([\unit{ \unitless}]\) |
Compressed airflow rate estimated from nozzle type and supply pressure.
The orifice/pressure method estimates flow rate using a quadratic equation fit to empirical flow-versus-pressure data for 12 standard nozzle types (indices 0–11). Each nozzle type has a distinct set of coefficients \(a\), \(b\), and \(c\) from the lookup table in Nozzle Coefficient Lookup Table. The single-nozzle flow rate is computed from the supply pressure; total flow rate and annual consumption then scale with the number of nozzles.
\begin{equation}\label{eq:compressed-air-reduction-pressure-flow-rate} Q_{nozzle} = a \cdot P^2 + b \cdot P + c\end{equation}
\begin{equation}\label{eq:compressed-air-reduction-pressure-total-flow} Q_{total} = Q_{nozzle} \cdot N_{nozzles}\end{equation}
\begin{equation}\label{eq:compressed-air-reduction-pressure-consumption} C = Q_{total} \cdot t_{op} \cdot 60\end{equation}
| \(Q_{nozzle}\) | Flow rate per individual nozzle \([\unit{ \cubic\foot\per\minute}]\) |
| \(a, b, c\) | Nozzle-type-specific quadratic coefficients (from lookup table) \([\unit{ \unitless}]\) |
| \(P\) | Compressed air supply pressure \([\unit{ \psi}]\) |
| \(Q_{total}\) | Total compressed airflow rate \([\unit{ \cubic\foot\per\minute}]\) |
| \(N_{nozzles}\) | Number of nozzles in the system \([\unit{ \unitless}]\) |
| \(C\) | Annual compressed air consumption \([\unit{ \cubic\foot\per\year}]\) |
| \(t_{op}\) | Annual operating hours \([\unit{ \hour\per\year}]\) |
| \(60\) | Unit conversion factor (minutes per hour) \([\unit{ \minute\per\hour}]\) |
Annual electrical energy use derived from compressed air consumption, compressor specific power, and control adjustment.
When the electricity utility type is selected, the annual compressed air consumption is converted to electrical energy use using the compressor specific power scaled by the compressor control adjustment factor. The control adjustment is expressed as a percentage (0–100) and is divided by 100 to obtain a dimensionless multiplier. Dividing by 60 converts the per-minute basis of the specific power to a per-hour basis consistent with the consumption units.
\begin{equation}\label{eq:compressed-air-reduction-electricity} E = \frac{P_{specific} \cdot \frac{f_{control}}{100}}{60} \cdot C\end{equation}
| \(E\) | Annual electrical energy use \([\unit{ \kilo\watt\hour\per\year}]\) |
| \(P_{specific}\) | Compressor specific power (electrical power per 100 scfm) \([\unit{ \kilo\watt\per\cubic\foot\per\minute}]\) |
| \(f_{control}\) | Compressor control adjustment factor \([\unit{ \percent}]\) |
| \(100\) | Percentage-to-fraction conversion \([\unit{ \unitless}]\) |
| \(60\) | Unit conversion factor (minutes per hour) \([\unit{ \minute\per\hour}]\) |
| \(C\) | Annual compressed air consumption \([\unit{ \cubic\foot\per\year}]\) |
Annual energy cost calculated from consumption or energy use and the applicable cost rate.
The cost calculation depends on the selected utility type. For the compressed air utility type, annual cost is the product of consumption and the cost rate per unit volume. For the electricity utility type, annual cost is the product of the electrical energy use and the electricity cost rate.
\begin{equation}\label{eq:compressed-air-reduction-cost-air} C_{cost} = r_{air} \cdot C\end{equation}
\begin{equation}\label{eq:compressed-air-reduction-cost-electricity} C_{cost} = r_{elec} \cdot E\end{equation}
| \(C_{cost}\) | Annual energy cost \([\unit{ \dollar\per\year}]\) |
| \(r_{air}\) | Compressed air cost rate \([\unit{ \dollar\per\cubic\foot}]\) |
| \(C\) | Annual compressed air consumption \([\unit{ \cubic\foot\per\year}]\) |
| \(r_{elec}\) | Electricity cost rate \([\unit{ \dollar\per\kilo\watt\hour}]\) |
| \(E\) | Annual electrical energy use \([\unit{ \kilo\watt\hour\per\year}]\) |
The following table lists the empirical quadratic coefficients \(a\), \(b\), and \(c\) for each of the 12 supported nozzle types. Select the row whose index matches the nozzle_type field of compressed_air_reduction::PressureMethodData.
| Index | Nozzle Type | \(a\) \([\unit{\scfm\per\psi\squared}]\) | \(b\) \([\unit{\scfm\per\psi}]\) | \(c\) \([\unit{\scfm}]\) |
|---|---|---|---|---|
| 0 | 1.0 mm nozzle | \(-2.200 \times 10^{-7}\) | 0.018893 | 0.268476 |
| 1 | 1.5 mm nozzle | \(-2.800 \times 10^{-5}\) | 0.038377 | 1.061905 |
| 2 | 1/4" pipe, open | \f$-7.600 \times 10^{-5}\f$ | 1.537424 | 14.300000 |
| 3 | 1/4" tubing | \f$-2.200 \times 10^{-5}\f$ | 0.345931 | 5.780952 |
| 4 | 1/8" pipe, open | \f$6.820 \times 10^{-4}\f$ | 0.643182 | 13.833330 |
| 5 | 1/8" tubing | \f$5.410 \times 10^{-6}\f$ | 0.228851 | 2.968095 |
| 6 | 2.0 mm nozzle | \(-2.100 \times 10^{-6}\) | 0.075463 | 1.089857 |
| 7 | 2.5 mm nozzle | \(-2.800 \times 10^{-5}\) | 0.148710 | 1.841905 |
| 8 | 3/8" pipe, open | \f$2.652 \times 10^{-3}\f$ | 2.250152 | 46.566670 |
| 9 | 3/8" tubing | \f$7.470 \times 10^{-4}\f$ | 0.842056 | 15.957140 |
| 10 | 5/16" tubing | \f$4.110 \times 10^{-4}\f$ | 0.560649 | 10.161900 |
| 11 | Air Knife | \(9.350 \times 10^{-4}\) | 0.130792 | 4.429524 |
Modules | |
| Nozzle Coefficient Lookup Table | |
| Pre-calibrated quadratic coefficients for 12 standard compressed air nozzle types used in the orifice/pressure measurement method. | |
| Flow Meter Consumption Formula | |
| Annual compressed air consumption derived from a flow meter reading. | |
| Bag Method Flow Rate and Consumption Formula | |
| Compressed airflow rate and annual consumption estimated using the bag method. | |
| Orifice/Pressure Method Flow Rate Formula | |
| Compressed airflow rate estimated from nozzle type and supply pressure. | |
| Electricity Energy Use Formula | |
| Annual electrical energy use derived from compressed air consumption, compressor specific power, and control adjustment. | |
| Energy Cost Formula | |
| Annual energy cost calculated from consumption or energy use and the applicable cost rate. | |
Files | |
| file | compressed_air_reduction.h |
| Declares structs, enums, and functions for the Compressed Air Reduction Calculator.Calculates annual compressed air consumption, energy use, and cost for compressed airflow reduction measures. | |
Namespaces | |
| namespace | compressed_air_reduction |
| Compressed air reduction calculations for treasure hunt measures. | |
Classes | |
| struct | compressed_air_reduction::FlowMeterMethodData |
| Input data for the flow meter measurement method. More... | |
| struct | compressed_air_reduction::BagMethodData |
| Input data for the bag measurement method. More... | |
| struct | compressed_air_reduction::PressureMethodData |
| Input data for the orifice/pressure measurement method. More... | |
| struct | compressed_air_reduction::OtherMethodData |
| Input data for the other (direct consumption) measurement method. More... | |
| struct | compressed_air_reduction::CompressedAirReductionInput |
| Input data for a single compressed air reduction measure. More... | |
| struct | compressed_air_reduction::CompressedAirReductionOutput |
| Output data for a compressed air reduction calculation. More... | |
Functions | |
| CompressedAirReductionOutput | compressed_air_reduction::compressedAirReduction (const std::vector< CompressedAirReductionInput > &input_vec) |
| Calculates total annual compressed air consumption, energy use, and cost for a collection of measures. | |
| CompressedAirReductionOutput | compressed_air_reduction::flowMeterReduction (const FlowMeterMethodData &data, int hours_per_year, int units) |
| Calculates annual compressed air consumption and flow rate using the flow meter method. | |
| CompressedAirReductionOutput | compressed_air_reduction::bagMethodReduction (const BagMethodData &data, int hours_per_year, int units) |
| Calculates annual compressed air consumption and flow rate using the bag method. | |
| CompressedAirReductionOutput | compressed_air_reduction::pressureMethodReduction (const PressureMethodData &data, int hours_per_year) |
| Calculates annual compressed air consumption and flow rate using the orifice/pressure method. | |
| CompressedAirReductionOutput | compressed_air_reduction::otherMethodReduction (const OtherMethodData &data) |
| Returns a partial result with consumption set from a directly supplied value. | |
| CompressedAirReductionOutput compressed_air_reduction::bagMethodReduction | ( | const BagMethodData & | data, |
| int | hours_per_year, | ||
| int | units | ||
| ) |
Flow rate is derived from the bag volume and fill time. Annual consumption is computed from the flow rate, annual operating hours, and both quantity multipliers (bags and units). Energy use and energy cost are zero; call compressedAirReduction for a full result.
| [in] | data | BagMethodData with bag geometry, fill time, and number of bags. |
| [in] | hours_per_year | Annual operating hours \([\unit{\hour\per\year}]\). |
| [in] | units | Outer quantity multiplier (number of identical leak points or equipment pieces). |
| CompressedAirReductionOutput compressed_air_reduction::compressedAirReduction | ( | const std::vector< CompressedAirReductionInput > & | input_vec | ) |
Iterates over input_vec, dispatches each measure to the appropriate single-method helper (flow meter, bag, pressure, or other), applies the utility-type cost calculation, and accumulates the results.
| [in] | input_vec | Vector of CompressedAirReductionInput structs, one per measure. |
| CompressedAirReductionOutput compressed_air_reduction::flowMeterReduction | ( | const FlowMeterMethodData & | data, |
| int | hours_per_year, | ||
| int | units | ||
| ) |
Computes annual consumption as the product of the meter reading, annual operating hours, units multiplier, and a factor of 60 to convert from per-minute to per-hour. Energy use and energy cost are zero; call compressedAirReduction for a full result.
| [in] | data | FlowMeterMethodData with the flow meter reading \([\unit{\cubic\foot\per\minute}]\). |
| [in] | hours_per_year | Annual operating hours \([\unit{\hour\per\year}]\). |
| [in] | units | Quantity multiplier (number of identical measures). |
| CompressedAirReductionOutput compressed_air_reduction::otherMethodReduction | ( | const OtherMethodData & | data | ) |
No flow-rate or energy calculation is performed. The supplied consumption value is used directly as the annual compressed air consumption. Energy use, energy cost, and flow rate are zero; call compressedAirReduction for a full result.
| [in] | data | OtherMethodData with the annual consumption \([\unit{\cubic\foot\per\year}]\). |
| CompressedAirReductionOutput compressed_air_reduction::pressureMethodReduction | ( | const PressureMethodData & | data, |
| int | hours_per_year | ||
| ) |
Single-nozzle flow rate is computed from a quadratic function of supply pressure using pre-calibrated coefficients for the selected nozzle type. Total flow rate scales with the number of nozzles. The outer units multiplier is not applied in this method. Energy use and energy cost are zero; call compressedAirReduction for a full result.
| [in] | data | PressureMethodData with nozzle type, number of nozzles, and supply pressure \([\unit{\psi}]\). |
| [in] | hours_per_year | Annual operating hours \([\unit{\hour\per\year}]\). |
1.9.8