PsychroLib 2.3.0 (#47)

Adds inverse methods for temperature conversions (GetTFahrenheitFromTRankine and GetTCelsiusFromTKelvin) and GetTDryBulbFromMoistAirVolumeAndHumRatio to calculate dry-bulb temperature given moist air specific volume, humidity ratio, and pressure. This PR also adds two new constants ZERO_FAHRENHEIT_AS_RANKINE and ZERO_CELSIUS_AS_KELVIN used by the temperature conversion functions.
psychrometrics · Nov 21, 2019 · bd71cdd · bd71cdd
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diff --git a/CHANGELOG.txt b/CHANGELOG.txt
@@ -1,3 +1,8 @@
+2.3.0
+- Add `GetTDryBulbFromMoistAirVolumeAndHumRatio`.
+- Add `GetTFahrenheitFromTRankine` and `GetTCelsiusFromTKelvin`.
+- Define `ZERO_FAHRENHEIT_AS_RANKINE` and `ZERO_CELSIUS_AS_KELVIN`.
+
 2.2.0
 - Add C# support with .NET Standard 1.0 (.NET Core >= 1.0 & .NET Framework >= 4.5).
 

diff --git a/DEVELOP.md b/DEVELOP.md
@@ -20,7 +20,7 @@ This project uses [semantic versioning](https://semver.org/).
 We use two branches to record the history of the project. The `master` branch stores the official release history while the `develop` branch serves as an integration branch for features and bug fixes. All new releases are tagged with a version number in `master`.
 
 
-## How to create and upload a new version to PiPy
+## How to create and upload a new version to Pypi
 
 From the command prompt, navigate to `src/python`. Then you can create and upload a new release with the following commands:
 

diff --git a/docs/overview.md b/docs/overview.md
@@ -22,7 +22,9 @@ The following psychrometric functions are currently available across all the sup
 |Function Name|Description|
 |-------------|-----------|
 |`GetTRankineFromTFahrenheit`|Utility function to convert temperature to degree Rankine given temperature in degree Fahrenheit.|
+|`GetTFahrenheitFromTRankine`|Utility function to convert temperature to degree Fahrenheit given temperature in degree Rankine.|
 |`GetTKelvinFromTCelsius`|Utility function to convert temperature to Kelvin given temperature in degree Celsius.|
+|`GetTCelsiusFromTKelvin`|Utility function to convert temperature to degree Celsius given temperature in Kelvin.|
 |`GetTWetBulbFromTDewPoint`|Return wet-bulb temperature given dry-bulb temperature, dew-point temperature, and pressure.|
 |`GetTWetBulbFromRelHum`|Return wet-bulb temperature given dry-bulb temperature, relative humidity, and pressure.|
 |`GetRelHumFromTDewPoint`|Return relative humidity given dry-bulb temperature and dew-point temperature.|
@@ -53,6 +55,7 @@ The following psychrometric functions are currently available across all the sup
 |`GetDegreeOfSaturation`|Return the degree of saturation (i.e humidity ratio of the air / humidity ratio of the air at saturation at the same temperature and pressure) given dry-bulb temperature, humidity ratio, and atmospheric pressure.|
 |`GetMoistAirEnthalpy`|Return moist air enthalpy given dry-bulb temperature and humidity ratio.|
 |`GetMoistAirVolume`|Return moist air specific volume given dry-bulb temperature, humidity ratio, and pressure.|
+|`GetTDryBulbFromMoistAirVolumeAndHumRatio`|Return dry-bulb temperature given moist air specific volume, humidity ratio, and pressure.|
 |`GetMoistAirDensity`|Return moist air density given humidity ratio, dry bulb temperature, and pressure.|
 |`GetStandardAtmPressure`|Return standard atmosphere barometric pressure, given the elevation (altitude).|
 |`GetStandardAtmTemperature`|Return standard atmosphere temperature, given the elevation (altitude).|

diff --git a/src/c/psychrolib.c b/src/c/psychrolib.c
@@ -1,5 +1,5 @@
 /**
- * PsychroLib (version 2.2.0) (https://github.com/psychrometrics/psychrolib)
+ * PsychroLib (version 2.3.0) (https://github.com/psychrometrics/psychrolib)
  * Copyright (c) 2018 D. Thevenard and D. Meyer for the current library implementation
  * Copyright (c) 2017 ASHRAE Handbook — Fundamentals for ASHRAE equations and coefficients
  * Licensed under the MIT License.
@@ -53,10 +53,18 @@
  * Global constants
  *****************************************************************************************************/
 
+# define ZERO_FAHRENHEIT_AS_RANKINE 459.67  // Zero degree Fahrenheit (°F) expressed as degree Rankine (°R).
+                                            // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 39.
+
+# define ZERO_CELSIUS_AS_KELVIN 273.15      // Zero degree Celsius (°C) expressed as Kelvin (K).
+                                            // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 39.
+
 #define R_DA_IP 53.350                  // Universal gas constant for dry air (IP version) in ft∙lbf/lb_da/R.
                                         // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1.
+
 #define R_DA_SI 287.042                 // Universal gas constant for dry air (SI version) in J/kg_da/K.
                                         // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1.
+
 #define INVALID -99999                  // Invalid value.
 
 #define MAX_ITER_COUNT 100              // Maximum number of iterations before exiting while loops.
@@ -162,12 +170,22 @@ int isIP                    // (o) 1 if IP, 0 if SI, error otherwise
 // Utility function to convert temperature to degree Rankine (°R)
 // given temperature in degree Fahrenheit (°F).
 // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
-double GetTRankineFromTFahrenheit(double T_F) { return T_F + 459.67; }         /* exact */
+double GetTRankineFromTFahrenheit(double T_F) { return T_F + ZERO_FAHRENHEIT_AS_RANKINE; }         /* exact */
+
+// Utility function to convert temperature to degree Fahrenheit (°F)
+// given temperature in degree Rankine (°R).
+// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
+double GetTFahrenheitFromTRankine(double T_R) { return T_R - ZERO_FAHRENHEIT_AS_RANKINE; }        /* exact */
 
 // Utility function to convert temperature to Kelvin (K)
 // given temperature in degree Celsius (°C).
 // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
-double GetTKelvinFromTCelsius(double T_C) { return T_C + 273.15; }            /* exact */
+double GetTKelvinFromTCelsius(double T_C) { return T_C + ZERO_CELSIUS_AS_KELVIN; }                /* exact */
+
+// Utility function to convert temperature to degree Celsius (°C)
+// given temperature in Kelvin (K).
+// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
+double GetTCelsiusFromTKelvin(double T_K) { return T_K - ZERO_CELSIUS_AS_KELVIN; }                /* exact */
 
 
 /******************************************************************************************************
@@ -865,6 +883,30 @@ double GetMoistAirVolume        // (o) Specific Volume ft³ lb⁻¹ [IP] or in m
     return R_DA_SI * GetTKelvinFromTCelsius(TDryBulb) * (1. + 1.607858 * BoundedHumRatio) / Pressure;
 }
 
+// Return dry-bulb temperature given moist air specific volume, humidity ratio, and pressure.
+// Reference:
+// ASHRAE Handbook - Fundamentals (2017) ch. 1 eqn 26
+// Notes:
+// In IP units, R_DA_IP / 144 equals 0.370486 which is the coefficient appearing in eqn 26
+// The factor 144 is for the conversion of Psi = lb in⁻² to lb ft⁻².
+// Based on the `GetMoistAirVolume` function, rearranged for dry-bulb temperature.
+double GetTDryBulbFromMoistAirVolumeAndHumRatio   // (o) Dry-bulb temperature in °F [IP] or °C [SI]
+  ( double MoistAirVolume                         // (i) Specific volume of moist air in ft³ lb⁻¹ of dry air [IP] or in m³ kg⁻¹ of dry air [SI]
+  , double HumRatio                               // (i) Humidity ratio in lb_H₂O lb_Air⁻¹ [IP] or kg_H₂O kg_Air⁻¹ [SI]
+  , double Pressure                               // (i) Atmospheric pressure in Psi [IP] or Pa [SI]
+  )
+{
+  double BoundedHumRatio;
+
+  ASSERT (HumRatio >= 0., "Humidity ratio is negative")
+  BoundedHumRatio = max(HumRatio, MIN_HUM_RATIO);
+
+  if (isIP())
+    return GetTFahrenheitFromTRankine(MoistAirVolume * (144 * Pressure) / (R_DA_IP * (1 + 1.607858 * BoundedHumRatio)));
+  else
+    return  GetTCelsiusFromTKelvin(MoistAirVolume * Pressure / (R_DA_SI * (1 + 1.607858 * BoundedHumRatio)));
+}
+
 // Return moist air density given humidity ratio, dry bulb temperature, and pressure.
 // Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 eqn. 11
 double GetMoistAirDensity       // (o) Moist air density in lb ft⁻³ [IP] or kg m⁻³ [SI]

diff --git a/src/c/psychrolib.h b/src/c/psychrolib.h
@@ -1,4 +1,4 @@
-// PsychroLib (version 2.2.0) (https://github.com/psychrometrics/psychrolib)
+// PsychroLib (version 2.3.0) (https://github.com/psychrometrics/psychrolib)
 // Copyright(c) 2018 D.Thevenard and D.Meyer. Licensed under the MIT License.
 
 /******************************************************************************************************
@@ -22,8 +22,12 @@ enum UnitSystem GetUnitSystem  // (o) System of units (SI or IP)
 
 double GetTRankineFromTFahrenheit(double T_F);
 
+double GetTFahrenheitFromTRankine(double T_R);
+
 double GetTKelvinFromTCelsius(double T_C);
 
+double GetTCelsiusFromTKelvin(double T_K);
+
 
 /******************************************************************************************************
  * Conversions between dew point, wet bulb, and relative humidity
@@ -230,6 +234,12 @@ double GetMoistAirVolume        // (o) Specific Volume ft³ lb⁻¹ [IP] or in m
   , double Pressure             // (i) Atmospheric pressure in Psi [IP] or Pa [SI]
   );
 
+double GetTDryBulbFromMoistAirVolumeAndHumRatio   // (o) Dry-bulb temperature in °F [IP] or °C [SI]
+  ( double MoistAirVolume                         // (i) Specific volume of moist air in ft³ lb⁻¹ of dry air [IP] or in m³ kg⁻¹ of dry air [SI]
+  , double HumRatio                               // (i) Humidity ratio in lb_H₂O lb_Air⁻¹ [IP] or kg_H₂O kg_Air⁻¹ [SI]
+  , double Pressure                               // (i) Atmospheric pressure in Psi [IP] or Pa [SI]
+  );
+
 double GetMoistAirDensity       // (o) Moist air density in lb ft⁻³ [IP] or kg m⁻³ [SI]
   ( double TDryBulb             // (i) Dry bulb temperature in °F [IP] or °C [SI]
   , double HumRatio             // (i) Humidity ratio in lb_H₂O lb_Air⁻¹ [IP] or kg_H₂O kg_Air⁻¹ [SI]

diff --git a/src/c_sharp/PsychroLib/PsychroLib.csproj b/src/c_sharp/PsychroLib/PsychroLib.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>netstandard1.0</TargetFramework>
-    <Version>2.2.0</Version>
+    <Version>2.3.0</Version>
     <PackageProjectUrl>https://github.com/psychrometrics/psychrolib</PackageProjectUrl>
     <RepositoryUrl>https://github.com/psychrometrics/psychrolib</RepositoryUrl>
     <PackageIcon>psychrolib_logo_64.png</PackageIcon>
@@ -12,8 +12,8 @@
     <Company>PsychroLib</Company>
     <PackageTags>net,standard,core</PackageTags>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-    <AssemblyVersion>2.2.0.0</AssemblyVersion>
-    <FileVersion>2.2.0.0</FileVersion>
+    <AssemblyVersion>2.3.0</AssemblyVersion>
+    <FileVersion>2.3.0</FileVersion>
   </PropertyGroup>
   <ItemGroup>
   <None Include="$(SolutionDir)../../assets/psychrolib_logo_64.png">

diff --git a/src/c_sharp/PsychroLib/psychrolib.cs b/src/c_sharp/PsychroLib/psychrolib.cs
@@ -1,5 +1,5 @@
 /*
- * PsychroLib (version 2.2.0) (https://github.com/psychrometrics/psychrolib)
+ * PsychroLib (version 2.3.0) (https://github.com/psychrometrics/psychrolib)
  * Copyright (c) 2018 D. Thevenard and D. Meyer, D. Gosnell for the current library implementation
  * Copyright (c) 2017 ASHRAE Handbook — Fundamentals for ASHRAE equations and coefficients
  * Ported to C# by https://github.com/DJGosnell
@@ -19,6 +19,18 @@ public class Psychrometrics
          * Global constants
          *****************************************************************************************************/
 
+        /// <summary>
+        /// Zero degree Fahrenheit (°F) expressed as degree Rankine (°R).
+        /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 39.
+        /// </summary>
+        private const double ZERO_FAHRENHEIT_AS_RANKINE = 459.67;
+
+        /// <summary>
+        /// Zero degree Celsius (°C) expressed as Kelvin (K).
+        /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 39.
+        /// </summary>
+        private const double ZERO_CELSIUS_AS_KELVIN = 273.15;
+
         /// <summary>
         /// Universal gas constant for dry air (IP version) in ft lb_Force lb_DryAir⁻¹ R⁻¹.
         /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1.
@@ -102,14 +114,26 @@ public Psychrometrics(UnitSystem unitSystem)
 
         /// <summary>
         /// Utility function to convert temperature to degree Rankine (°R)
-        /// given temperature in degree Fahrenheit(°F).
-        /// Reference: ASHRAE Handbook - Fundamentals(2017) ch. 1 section 3
+        /// given temperature in degree Fahrenheit (°F).
+        /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
         /// </summary>
         /// <param name="tF">Temperature in Fahrenheit (°F)</param>
         /// <returns>Rankine (°R)</returns>
         public double GetTRankineFromTFahrenheit(double tF)
         {
-            return tF + 459.67; /* exact */
+            return tF + ZERO_FAHRENHEIT_AS_RANKINE; /* exact */
+        }
+
+        /// <summary>
+        /// Utility function to convert temperature to degree Fahrenheit (°F)
+        /// given temperature in degree Rankine (°R).
+        /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
+        /// </summary>
+        /// <param name="tR">Temperature in Rankine (°R)</param>
+        /// <returns>Fahrenheit (°F)</returns>
+        public double GetTFahrenheitFromTRankine(double tR)
+        {
+            return tR - ZERO_FAHRENHEIT_AS_RANKINE; /* exact */
         }
 
         /// <summary>
@@ -121,7 +145,19 @@ public double GetTRankineFromTFahrenheit(double tF)
         /// <returns>Rankine (°R)</returns>
         public double GetTKelvinFromTCelsius(double tC)
         {
-            return tC + 273.15; /* exact */
+            return tC + ZERO_CELSIUS_AS_KELVIN; /* exact */
+        }
+
+        /// <summary>
+        /// Utility function to convert temperature to degree Celsius (°C)
+        /// given temperature in Kelvin (K).
+        /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 section 3
+        /// </summary>
+        /// <param name="tK">Temperature in Rankine (°R)</param>
+        /// <returns>Celsius (°C)</returns>
+        public double GetTCelsiusFromTKelvin(double tK)
+        {
+            return tK - ZERO_CELSIUS_AS_KELVIN; /* exact */
         }
 
 
@@ -890,6 +926,32 @@ public double GetMoistAirVolume(double tDryBulb, double humRatio, double pressur
         }
 
 
+        /// <summary>
+        /// Return dry-bulb temperature given moist air specific volume, humidity ratio, and pressure.
+        /// Reference:
+        /// ASHRAE Handbook - Fundamentals (2017) ch. 1 eqn 26
+        /// Notes:
+        /// In IP units, R_DA_IP / 144 equals 0.370486 which is the coefficient appearing in eqn 26
+        /// The factor 144 is for the conversion of Psi = lb in⁻² to lb ft⁻².
+        /// Based on the `GetMoistAirVolume` function, rearranged for dry-bulb temperature.
+        /// </summary>
+        /// <param name="MoistAirVolume">Specific volume of moist air in ft³ lb⁻¹ of dry air [IP] or in m³ kg⁻¹ of dry air [SI]</param>
+        /// <param name="humRatio">Humidity ratio in lb_H₂O lb_Air⁻¹ [IP] or kg_H₂O kg_Air⁻¹ [SI]</param>
+        /// <param name="pressure">Atmospheric pressure in Psi [IP] or Pa [SI]</param>
+        /// <returns>Dry-bulb temperature in °F [IP] or °C [SI]</returns>
+        public double GetTDryBulbFromMoistAirVolumeAndHumRatio(double MoistAirVolume, double humRatio, double pressure)
+        {
+            if (!(humRatio >= 0.0))
+                throw new InvalidOperationException("Humidity ratio is negative");
+            var boundedHumRatio = Math.Max(humRatio, MIN_HUM_RATIO);
+
+            if (UnitSystem == UnitSystem.IP)
+                return  GetTFahrenheitFromTRankine(MoistAirVolume * (144 * pressure) / (R_DA_IP * (1 + 1.607858 * boundedHumRatio)));
+
+            return GetTCelsiusFromTKelvin(MoistAirVolume * pressure / (R_DA_SI * (1 + 1.607858 * boundedHumRatio)));
+        }
+
+
         /// <summary>
         /// Return moist air density given humidity ratio, dry bulb temperature, and pressure.
         /// Reference: ASHRAE Handbook - Fundamentals (2017) ch. 1 eqn. 11