Factors and functions for unit conversions.

Functions
constexpr double	fahrenheitToKelvin (double fahrenheit)
	Convert Fahrenheit to Kelvin.

constexpr double	psigToMPa (const double psig)
	convert psig to MPa.

constexpr double	fahrenheitToRankine (double fahrenheit)
	Convert Fahrenheit to Rankine.

constexpr double	fahrenheitToCelsius (double fahrenheit)
	Convert Fahrenheit to Celsius.

constexpr double	mmbtuPerHrToKW (double mmbtu_per_hr)
	Converts power from MMBtu/hr to kW.

constexpr double	kWToMMBtuPerHr (double kw)
	Converts power from kW to MMBtu/hr.

Variables
constexpr double	kBtuPerLbFToKJPerKgK = 4.1868
	Conversion factor from Btu/(lb·°F) to kJ/(kg·K).

constexpr double	kM3PerKgToFt3PerLb = 16.0185
	convert m3/kg -> ft3/lb.

constexpr double	kFt3ToIn3 = 1728
	convert ft3 -> in3.

constexpr double	kKJPerKgToBtuPerLb = 0.429923
	convert kJ/kg -> btu/lb.

constexpr double	kWaterSurfacePressure = 14.6
	Surface pressure exerted by water @ sea level lb/in2.

constexpr double	kFahrenheitToRankineOffset = 459.67
	Offset to convert Fahrenheit to Rankine.

constexpr double	kHoursPerDay = 24.0
	Number of hours in a day.

constexpr double	kMinutesPerHour = 60.0
	Number of minutes in an hour.

constexpr double	kSecondsPerMinute = 60.0
	Number of seconds in a minute.

constexpr double	kIn2PerFt2 = 144.0
	Conversion factor: square inches per square foot \([\unit{\inch\squared\per\squareFoot}]\).

constexpr double	kKilowattToBtuPerHour = 3412.136247820839
	Conversion factor from kilowatts to BTU/hr \([\unit{\btu\per\hour\per\kilowatt}]\).

constexpr double	kKgPerM3ToLbPerGal = 0.0083454
	Conversion factor from kilograms per cubic meter to pounds per gallon \([\unit{\pound\per\gallon\per\kilogram\per\meter\cubed}]\).

constexpr double	kMMBtuToBtu = 1'000'000.0
	Conversion factor: 1 MMBtu = 1,000,000 Btu.

constexpr double	kLbPerFt3ToKgPerM3 = 16.018463
	Conversion factor: 1 pound per cubic foot = 16.018463 kilograms per cubic meter \([\unit{\kilogram\per\meter\cubed\per\pound\per\foot\cubed}]\).

constexpr double	kBhpToKw = 0.746
	Conversion factor from brake horsepower to kilowatts \([\unit{\kilowatt\per\bhp}]\).

constexpr double	kBtuPerTonRefrigeration = 12000.0
	BTU per ton of refrigeration \([\unit{Btu/Ton}]\).

Function Documentation

◆ fahrenheitToCelsius()

constexpr double physics::conversions::fahrenheitToCelsius ( double fahrenheit )

constexpr

Converts a temperature from degrees Fahrenheit to degrees Celsius:

Relation: \begin{equation}\label{eq:fahrenheit-to-celsius} T_C = \frac{5}{9}(T_F - 32)\end{equation}

Symbols

\(T_C\)	Temperature in degrees Celsius \([\unit{ \degreeCelsius}]\)
\(T_F\)	Temperature in degrees Fahrenheit \([\unit{ \degreeFahrenheit}]\)

Parameters

[in] fahrenheit Temperature in degrees Fahrenheit \([\unit{\degreeFahrenheit}]\)

Returns: Temperature in degrees Celsius \([\unit{\degreeCelsius}]\)

Definition at line 282 of file constants.h.

◆ fahrenheitToKelvin()

constexpr double physics::conversions::fahrenheitToKelvin ( double fahrenheit )

inlineconstexpr

Converts a temperature from degrees Fahrenheit to Kelvin:

Relation: \begin{equation}\label{eq:fahrenheit-to-kelvin} T_K = (T_F - 32) / 1.8 + 273.15\end{equation}

Symbols

\(T_K\)	Temperature in Kelvin \([\unit{ \kelvin}]\)
\(T_F\)	Temperature in degrees Fahrenheit \([\unit{ \degreeFahrenheit}]\)

Parameters

[in] fahrenheit Temperature in degrees Fahrenheit \([\unit{\degreeFahrenheit}]\)

Returns: Temperature in Kelvin \([\unit{\kelvin}]\)

Definition at line 197 of file constants.h.

◆ fahrenheitToRankine()

constexpr double physics::conversions::fahrenheitToRankine ( double fahrenheit )

constexpr

Converts a temperature from degrees Fahrenheit to degrees Rankine:

Relation: \begin{equation}\label{eq:fahrenheit-to-rankine} T_R = T_F + 459.67\end{equation}

Symbols

\(T_R\)	Temperature in degrees Rankine \([\unit{ \degreeRankine}]\)
\(T_F\)	Temperature in degrees Fahrenheit \([\unit{ \degreeFahrenheit}]\)

Parameters

[in] fahrenheit Temperature in degrees Fahrenheit \([\unit{\degreeFahrenheit}]\)

Returns: Temperature in degrees Rankine \([\unit{\degreeRankine}]\)

Definition at line 264 of file constants.h.

◆ kWToMMBtuPerHr()

constexpr double physics::conversions::kWToMMBtuPerHr ( double kw )

constexpr

1 kW = 0.003412142 MMBtu/hr.

Relation: \begin{equation}\label{eq:kw-to-mmbtu-per-hr} P_\mathrm{MMBtu/hr} = P_\mathrm{kW} \times 0.003412142\end{equation}

Symbols

\(P_\mathrm{MMBtu/hr}\)	Power in MMBtu/hr \([\unit{ \mega\btu\per\hour}]\)
\(P_\mathrm{kW}\)	Power in kilowatts \([\unit{ \kilo\watt}]\)

Parameters

[in] kw Power in kilowatts (kW) \([\unit{\kilo\watt}]\)

Returns: Power in MMBtu/hr \([\unit{\mega\btu\per\hour}]\)

Definition at line 341 of file constants.h.

◆ mmbtuPerHrToKW()

constexpr double physics::conversions::mmbtuPerHrToKW ( double mmbtu_per_hr )

constexpr

1 MMBtu/hr = 293.07107 kW.

Relation: \begin{equation}\label{eq:mmbtu-per-hr-to-kw} P_\mathrm{kW} = P_\mathrm{MMBtu/hr} \times 293.07107\end{equation}

Symbols

\(P_\mathrm{kW}\)	Power in kilowatts \([\unit{ \kilo\watt}]\)
\(P_\mathrm{MMBtu/hr}\)	Power in MMBtu/hr \([\unit{ \mega\btu\per\hour}]\)

Parameters

[in] mmbtu_per_hr Power in MMBtu/hr \([\unit{\mega\btu\per\hour}]\)

Returns: Power in kilowatts (kW) \([\unit{\kilo\watt}]\)

Definition at line 323 of file constants.h.

◆ psigToMPa()

constexpr double physics::conversions::psigToMPa ( const double psig )

inlineconstexpr

Definition at line 200 of file constants.h.

Variable Documentation

◆ kBhpToKw

constexpr double physics::conversions::kBhpToKw = 0.746

inlineconstexpr

1 mechanical horsepower = 0.746 kW (standard rounded value). Used to convert compressor shaft power from bhp to kW for electricity cost calculations.

Definition at line 299 of file constants.h.

◆ kBtuPerLbFToKJPerKgK

constexpr double physics::conversions::kBtuPerLbFToKJPerKgK = 4.1868

inlineconstexpr

1 Btu/(lb·°F) = 4.1868 kJ/(kg·K)

Definition at line 182 of file constants.h.

◆ kBtuPerTonRefrigeration

constexpr double physics::conversions::kBtuPerTonRefrigeration = 12000.0

constexpr

Used for refrigeration capacity calculations. Source: ASHRAE Handbook.

Definition at line 305 of file constants.h.

◆ kFahrenheitToRankineOffset

constexpr double physics::conversions::kFahrenheitToRankineOffset = 459.67

inlineconstexpr

Definition at line 217 of file constants.h.

◆ kFt3ToIn3

constexpr double physics::conversions::kFt3ToIn3 = 1728

inlineconstexpr

Definition at line 208 of file constants.h.

◆ kHoursPerDay

constexpr double physics::conversions::kHoursPerDay = 24.0

inlineconstexpr

Definition at line 220 of file constants.h.

◆ kIn2PerFt2

constexpr double physics::conversions::kIn2PerFt2 = 144.0

inlineconstexpr

1 ft² = 144 in². Used when converting pipe cross-sectional areas between square feet and square inches in U.S. customary piping calculations.

Definition at line 233 of file constants.h.

◆ kKgPerM3ToLbPerGal

constexpr double physics::conversions::kKgPerM3ToLbPerGal = 0.0083454

inlineconstexpr

Multiplies water density in kg/m^3 to obtain lb/gal. Source: NIST, CRC Handbook of Chemistry and Physics.

Definition at line 246 of file constants.h.

◆ kKilowattToBtuPerHour

constexpr double physics::conversions::kKilowattToBtuPerHour = 3412.136247820839

inlineconstexpr

Source: NIST, Perry's Chemical Engineers' Handbook

Definition at line 239 of file constants.h.

◆ kKJPerKgToBtuPerLb

constexpr double physics::conversions::kKJPerKgToBtuPerLb = 0.429923

inlineconstexpr

Definition at line 211 of file constants.h.

◆ kLbPerFt3ToKgPerM3

constexpr double physics::conversions::kLbPerFt3ToKgPerM3 = 16.018463

inlineconstexpr

Use this to convert a mass density from lb/ft^3 to kg/m^3.

Definition at line 292 of file constants.h.

◆ kM3PerKgToFt3PerLb

constexpr double physics::conversions::kM3PerKgToFt3PerLb = 16.0185

inlineconstexpr

Definition at line 205 of file constants.h.

◆ kMinutesPerHour

constexpr double physics::conversions::kMinutesPerHour = 60.0

inlineconstexpr

Definition at line 223 of file constants.h.

◆ kMMBtuToBtu

constexpr double physics::conversions::kMMBtuToBtu = 1'000'000.0

inlineconstexpr

Definition at line 285 of file constants.h.

◆ kSecondsPerMinute

constexpr double physics::conversions::kSecondsPerMinute = 60.0

inlineconstexpr

Definition at line 226 of file constants.h.

◆ kWaterSurfacePressure

constexpr double physics::conversions::kWaterSurfacePressure = 14.6

inlineconstexpr

Definition at line 214 of file constants.h.

Functions

Variables

Function Documentation

◆ fahrenheitToCelsius()

◆ fahrenheitToKelvin()

◆ fahrenheitToRankine()

◆ kWToMMBtuPerHr()

◆ mmbtuPerHrToKW()

◆ psigToMPa()

Variable Documentation

◆ kBhpToKw

◆ kBtuPerLbFToKJPerKgK

◆ kBtuPerTonRefrigeration

◆ kFahrenheitToRankineOffset

◆ kFt3ToIn3

◆ kHoursPerDay

◆ kIn2PerFt2

◆ kKgPerM3ToLbPerGal

◆ kKilowattToBtuPerHour

◆ kKJPerKgToBtuPerLb

◆ kLbPerFt3ToKgPerM3

◆ kM3PerKgToFt3PerLb

◆ kMinutesPerHour

◆ kMMBtuToBtu

◆ kSecondsPerMinute

◆ kWaterSurfacePressure