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## Buildings.UsersGuide.ReleaseNotes

Release notes

### Information

This section summarizes the changes that have been performed on the Buildings library.

- Version 2.0.0(May 4, 2015)
- Version 1.6 build1(June 19, 2014)
- Version 1.5 build3(February 12, 2014)
- Version 1.5 build2(December 13, 2013)
- Version 1.5 build1(October 24, 2013)
- Version 1.4 build1(May 15, 2013)
- Version 1.3 build1(January 8, 2013)
- Version 1.2 build1(July 26, 2012)
- Version 1.1 build1(February 29, 2012)
- Version 1.0 build2(December 8, 2011)
- Version 1.0 build1(November 4, 2011)
- Version 0.12.0 (May 6, 2011)
- Version 0.11.0 (March 17, 2011)
- Version 0.10.0 (July 30, 2010)
- Version 0.9.1 (June 24, 2010)
- Version 0.9.0 (June 11, 2010)
- Version 0.8.0 (February 6, 2010)
- Version 0.7.0 (September 29, 2009)
- Version 0.6.0 (May 15, 2009)
- Version 0.5.0 (February 19, 2009)
- Version 0.4.0 (October 31, 2008)
- Version 0.3.0 (September 30, 2008)
- Version 0.2.0 (June 17, 2008)
- Version 0.1.0 (May 27, 2008)

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Package Content

Name | Description
--- | ---
Version_2_0_0 | Version 2.0.0
Version_1_6_build1 | Version 1.6 build 1
Version_1_5_build3 | Version 1.5 build 3
Version_1_5_build2 | Version 1.5 build 2
Version_1_5_build1 | Version 1.5 build 1
Version_1_4_build1 | Version 1.4 build 1
Version_1_3_build1 | Version 1.3 build 1
Version_1_2_build1 | Version 1.2 build 1
Version_1_1_build1 | Version 1.1 build 1
Version_1_0_build2 | Version 1.0 build 2
Version_1_0_build1 | Version 1.0 build 1
Version_0_12_0 | Version 0.12.0
Version_0_11_0 | Version 0.11.0
Version_0_10_0 | Version 0.10.0
Version_0_9_1 | Version 0.9.1
Version_0_9_0 | Version 0.9.0
Version_0_8_0 | Version 0.8.0
Version_0_7_0 | Version 0.7.0
Version_0_6_0 | Version 0.6.0
Version_0_5_0 | Version 0.5.0
Version_0_4_0 | Version 0.4.0
Version_0_3_0 | Version 0.3.0
Version_0_2_0 | Version 0.2.0
Version_0_1_0 | Version 0.1.0

## Buildings.UsersGuide.ReleaseNotes.Version_2_0_0

Version 2.0.0

### Information

Version 2.0.0 is a major release that contains various new packages, models and improvements.

The following major additions have been done in version 2.0:

- A CFD model that is embedded in a thermal zone has been added. This model is implemented in Buildings.Rooms.CFD. The CFD model is an implementation of the Fast Fluid Dynamics code that allows three-dimensional CFD inside a thermal zone, coupled to building heat transfer, HVAC components and feedback control loops.
- A new package Buildings.Electrical has been added. This package allows studying buildings to electrical grid integration. It includes models for loads, transformers, cables, batteries, PV and wind turbines. Models exist for DC and AC systems with two- or three-phase that can be balanced and unbalanced. The models compute voltage, current, active and reactive power based on the quasi-stationary assumption or using the dynamic phasorial representation.
- The new package Buildings.Controls.DemandResponse contains models for demand response simulation.
- The new package Buildings.Controls.Predictors contains a data-driven model that predicts the electrical load of a building. The prediction can be done either using an average baseline or a linear regression with respect to outside temperature. For both, optionally a day-of adjustment can be made.

The tables below give more detailed information to the revisions of this library compared to the previous release 1.6 build 1.

The following new libraries have been added:

Buildings.Electrical | Library for electrical grid simulation that allows to study building to electrical grid integration. The library contains models of loads, generation and transmission for DC and AC systems.
Buildings.Controls.DemandResponse | Library with a model for demand response prediction.
Buildings.Controls.Predictors | Library with a data-driven model that predicts the electrical load of a building. The prediction can be done either using an average baseline or a linear regression with respect to outside temperature. For both, optionally a day-of adjustment can be made.

The following new components have been added to existing libraries:

Buildings.Fluid
Buildings.Fluid.Actuators.Valves.TwoWayPressureIndependent | Model of a pressure-independent two way valve.
Buildings.Fluid.HeatExchangers.HeaterCooler_T | Model of a heater or cooler that takes as an input the set point for the temperature of the fluid that leaves the component. The set point is tracked exactly if the component has sufficient capacity. Optionally, the component can be configured to compute a dynamic rather than a steady-state response.
Buildings.Utilities
Buildings.Utilities.Psychrometrics.Phi_pTX Buildings.Utilities.Psychrometrics.Functions.phi_pTX | Block and function that computes the relative humidity for given pressure, temperature and water vapor mass fraction.
Buildings.Rooms
Buildings.Rooms.CFD | Room model that computes the room air flow using computational fluid dynamics (CFD). The CFD simulation is coupled to the thermal simulation of the room and, through the fluid port, to the air conditioning system. Currently, the supported CFD program is the Fast Fluid Dynamics (FFD) program. See Buildings.Rooms.UsersGuide.CFD for detailed explanations.

The following existing components have been improved in a backward compatible way:

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Added option to obtain the black body sky temperature from a parameter or an input signal rather than computing it in the weather data reader. Removed redundant connection `connect(conHorRad.HOut, cheHorRad.HIn);`.
Buildings.Fluid
Buildings.Chillers.ElectricEIR Buildings.Chillers.ElectricReformulatedEIR | Changed implementation so that the model is continuously differentiable. This is for issue 373.
Buildings.Fluid.HeatExchangers.DryCoilCounterFlow | Changed assignment of `T_m` to avoid using the conditionally enabled model `ele[:].mas.T`, which is only valid in a connect statement. Moved assignments of `Q1_flow`, `Q2_flow`, `T1`, `T2` and `T_m` outside of equation section to avoid mixing graphical and textual modeling within the same model.
Buildings.Fluid.HeatExchangers.DryCoilDiscretized | Removed parameter `m1_flow_nominal`, as this parameter is already declared in its base class Buildings.Fluid.Interfaces.PartialFourPortInterface. This change avoids an error in OpenModelica as the two declarations had a different value for the `min` attribute, which is not valid in Modelica.
Buildings.Fluid.HeatExchangers.BaseClasses.CoilRegister Buildings.Fluid.HeatExchangers.BaseClasses.DuctManifoldDistributor | Reformulated the multiple iterators in the `sum` function as this language construct is not supported in OpenModelica.
Buildings.Fluid.HeatExchangers.RadiantSlabs.SingleCircuitSlab | Set start value for `hPip(fluid(T))` to avoid a warning about conflicting start values.
Buildings.Fluid.Movers.SpeedControlled_y Buildings.Fluid.Movers.SpeedControlled_Nrpm Buildings.Fluid.Movers.FlowControlled_dp Buildings.Fluid.Movers.FlowControlled_m_flow | For the parameter setting `use_powerCharacteristic=true`, changed the computation of the power consumption at reduced speed to properly account for the affinity laws. This is in response to #202.
Buildings.Fluid.SolarCollectors.ASHRAE93 Buildings.Fluid.SolarCollectors.EN12975 | Reformulated the model to avoid an translation error if glycol is used. Propagated parameters for initialization in base class `Buildings.Fluid.SolarCollectors.BaseClasses.PartialSolarCollector` and set `prescribedHeatFlowRate=true`.
Buildings.Fluid.Storage.StratifiedEnhancedInternalHex | Replaced the `abs()` function in the assignment of the parameter `nSegHexTan` as the return value of `abs()` is a `Real` which causes a type error during model check.
Buildings.HeatTransfer
Buildings.HeatTransfer.Conduction.MultiLayer | Changed the assignment of `_T_a_start`, `_T_b_start` and `RTot` to be in the initial equation section as opposed to the parameter declaration. This is needed to avoid an error during model check and translation in Dymola 2015 FD01 beta1.
Buildings.HeatTransfer.Windows.InteriorHeatTransferConvective | Changed model to allow a temperature dependent convective heat transfer on the room side. This is for issue 52.
Buildings.Media
Buildings.Media.Interfaces.PartialSimpleIdealGasMedium Buildings.Media.Interfaces.PartialSimpleMedium | Set `T(start=T_default)` and `p(start=p_default)` in the `ThermodynamicState` record. Setting the start value for `T` is required to avoid an error due to conflicting start values when translating Buildings.Examples.VAVReheat.ClosedLoop in pedantic mode.
Buildings.Rooms
Buildings.Rooms.MixedAir | Changed model to allow a temperature dependent convective heat transfer on the room side for windows. This is for issue 52.
Rooms.BaseClasses.ExteriorBoundaryConditionsWithWindow | Conditionally removed the shade model if no shade is present. This corrects #234.

The following existing components have been improved in a non-backward compatible way:

Buildings.Airflow
Buildings.Airflow.Multizone.ZonalFlow_ACS Buildings.Airflow.Multizone.ZonalFlow_m_flow | Removed parameter `forceErrorControlOnFlow` as it was not used. For Dymola, the conversion script will automatically update existing models.
Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Changed the following signals for compatibility with OpenModelica: `weaBus.sol.zen` to `weaBus.solZen`. `weaBus.sol.dec` to `weaBus.solDec`. `weaBus.sol.alt` to `weaBus.solAlt`. `weaBus.sol.solHouAng` to `weaBus.solHouAng`. For Dymola, the conversion script will automatically update existing models.
Buildings.Examples
Buildings.Examples.VAVReheat.Controls.IntegerSum | Removed block as it is not used in any model. Models that require an integer sum can use `Modelica.Blocks.MathInteger.Sum`.
Buildings.Examples.VAVReheat.Controls.UnoccupiedOn | Removed block as it is not used in any model.
Buildings.HeatTransfer
Buildings.HeatTransfer.Data.GlazingSystems.Generic | Removed parameter `nLay` as OpenModelica could not assign it during translation. For Dymola, the conversion script will automatically update existing models.
Buildings.HeatTransfer.Conduction.BaseClasses.der_temperature_u | Changed the input argument for this function from type `Buildings.HeatTransfer.Data.BaseClasses.Material` to the elements of this type as OpenModelica fails to translate the model if the input to this function is a record.
Buildings.HeatTransfer.Types.Azimuth Buildings.HeatTransfer.Types.Tilt | Moved these types from `Buildings.HeatTransfer` to the top-level package `Buildings` because they are used in `Buildings.BoundaryConditions`, `Buildings.HeatTransfer` and `Buildings.Rooms`. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid
Buildings.Fluid.FixedResistances.Pipe Buildings.Fluid.FixedResistances.BaseClasses.Pipe Buildings.Fluid.HeatExchangers.RadiantSlabs.SingleCircuitSlab | Renamed pressure drop from `res` to `preDro` to use the same name as in other models. This corrects #271. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.HeatExchangers.DryCoilDiscretized Buildings.Fluid.HeatExchangers.WetCoilDiscretized | Reformulated flow splitter in the model to reduce the dimension of the coupled linear or nonlinear system of equations. With this revision, the optional control volume in the duct inlet has been removed as it is no longer needed. Therefore, the parameter `dl` has also been removed. Replaced the parameters `energyDynamics1` and `energyDynamics2` with `energyDynamics`. Removed the parameter `ductConnectionDynamics`. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.HeatExchangers.HeaterCoolerPrescribed | Renamed the model to `HeaterCooler_u` due to the introduction of the new model `HeaterCooler_T`. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.HeatExchangers.RadiantSlabs.SingleCircuitSlab Buildings.Fluid.HeatExchangers.RadiantSlabs.ParallelCircuitsSlab | Changed the models to use by default an ε-NTU approach for the heat transfer between the fluid and the slab rather than a finite difference scheme along the flow path. Optionally, the finite difference scheme can also be used as this is needed for some control design applications. The new ε-NTU formulation has shown to lead to about five times faster computation on several test cases including the models in Buildings.Rooms.FLEXLAB.Rooms.Examples. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.HeatExchangers.BaseClasses.DuctManifoldFixedResistance | Reformulated flow splitter in the model to reduce the dimension of the coupled linear or nonlinear system of equations. With this revision, the optional control volume in the duct inlet has been removed as it is no longer needed. Therefore, the parameters `dl` and `energyDynamics` have also been removed. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.HeatExchangers.BaseClasses.CoilRegister | Replaced the parameters `energyDynamics1` and `energyDynamics2` with the new parameter `energyDynamics`. Removed the parameters `steadyState_1` and `steadyState_2` as this information is already contained in `energyDynamics`. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.MassExchangers.HumidifierPrescribed | Renamed the model to `Humidifier_u` due to the introduction of the new model `HeaterCooler_T` and to use the same naming pattern as `HeaterCooler_u`. For Dymola, the conversion script will automatically update existing models.
Buildings.Fluid.Movers | This package has been redesigned. The models have been renamed as follows: `Buildings.Fluid.Movers.FlowMachine_dp` is now called `Buildings.Fluid.Movers.FlowControlled_dp`. `Buildings.Fluid.Movers.FlowMachine_m_flow` is now called `Buildings.Fluid.Movers.FlowControlled_m_flow`. `Buildings.Fluid.Movers.FlowMachine_Nrpm` is now called `Buildings.Fluid.Movers.SpeedControlled_Nrpm`. `Buildings.Fluid.Movers.FlowMachine_y` is now called `Buildings.Fluid.Movers.SpeedControlled_y`. In addition, the performance data of all movers are now stored in a record. These records are in Buildings.Fluid.Movers.Data. For most existing instances, it should be sufficient to enclose the existing performance data in a record called `per`. For example, `Buildings.Fluid.Movers.FlowMachine_y fan( redeclare package Medium = Medium, pressure( V_flow={0,m_flow_nominal,2*m_flow_nominal}/1.2, dp={2*dp_nominal,dp_nominal,0})));` becomes `Buildings.Fluid.Movers.SpeedControlled_y fan( redeclare package Medium = Medium, per( pressure( V_flow={0,m_flow_nominal,2*m_flow_nominal}/1.2, dp={2*dp_nominal,dp_nominal,0})));` See the User's Guide for more information about these records. For Dymola, the conversion script will update existing models to use the old implementations which are now in the package `Buildings.Obsolete.Fluid.Movers`.
Buildings.Media
Buildings.Media | Renamed all media to simplify the media selection. For typical building energy simulation, Buildings.Media.Air and Buildings.Media.Water should be used. The following changes were made. Renamed `Buildings.Media.GasesPTDecoupled.MoistAirUnsaturated` to `Buildings.Media.Air`. Renamed `Buildings.Media.ConstantPropertyLiquidWater` to `Buildings.Media.Water`. Renamed `Buildings.Media.PerfectGases.MoistAir` to `Buildings.Obsolete.Media.PerfectGases.MoistAir`. Renamed `Buildings.Media.GasesConstantDensity.MoistAirUnsaturated` to `Buildings.Obsolete.Media.GasesConstantDensity.MoistAirUnsaturated`. Renamed `Buildings.Media.GasesConstantDensity.MoistAir` to `Buildings.Obsolete.Media.GasesConstantDensity.MoistAir`. Renamed `Buildings.Media.GasesConstantDensity.SimpleAir` to `Buildings.Obsolete.Media.GasesConstantDensity.SimpleAir`. Renamed `Buildings.Media.IdealGases.SimpleAir` to `Buildings.Obsolete.Media.IdealGases.SimpleAir`. Renamed `Buildings.Media.GasesPTDecoupled.MoistAir` to `Buildings.Obsolete.Media.GasesPTDecoupled.MoistAir`. Renamed `Buildings.Media.GasesPTDecoupled.SimpleAir` to `Buildings.Obsolete.Media.GasesPTDecoupled.SimpleAir`. For Dymola, the conversion script will update existing models according to the above list.
Buildings.Media.Water | Removed option to model water as a compressible medium as this option was not useful.
Buildings.Rooms
Buildings.Rooms.BaseClasses.ParameterConstructionWithWindow | Removed the keyword `replaceable` for the parameters `ove` and `sidFin`. Models that instantiate `Buildings.Rooms.MixedAir` are not affected by this change.
Buildings.Rooms.Examples.BESTEST | Moved the package to `Buildings.Rooms.Validation.BESTEST`.
Buildings.Utilities
Buildings.Utilities.SimulationTime | Moved the block `Buildings.Utilities.SimulationTime` to `Buildings.Utilities.Time.ModelTime`. For Dymola, the conversion script will update existing models according to the above list.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Corrected error that led the total and opaque sky cover to be ten times too low if its value was obtained from the parameter or the input connector. For the standard configuration in which the sky cover is obtained from the weather data file, the model was correct. This error only affected the other two possible configurations.
Buildings.Fluid
Buildings.Fluid.Data.Pipes | Corrected wrong entries for inner and outer diameter of PEX pipes.
Buildings.Fluid.HeatExchangers.Boreholes.BaseClasses.singleUTubeResistances | Corrected error in function that used `beta` before it was assigned a value.
Buildings.Fluid.Storage.Stratified Buildings.Fluid.Storage.StratifiedEnhanced Buildings.Fluid.Storage.StratifiedEnhancedInternalHex | Replaced the use of `Medium.lambda_const` with `Medium.thermalConductivity(sta_default)` as `lambda_const` is not declared for all media. This avoids a translation error if certain media are used.
Buildings.Fluid.Storage.StratifiedEnhancedInternalHex | Corrected issue #271 which led to a compilation error if the heat exchanger and the tank had different media.
Buildings.HeatTransfer
Buildings.HeatTransfer.Windows.BaseClasses.GlassLayer | Corrected issue #304 that led to an error in the glass temperatures if the glass conductance is very small.
Buildings.Rooms
Buildings.Rooms.MixedAir | Added propagation of the parameter value `linearizeRadiation` to the window model. Prior to this change, the radiation was never linearized for computing the glass long-wave radiation.
Buildings.Rooms.FLEXLAB.Rooms.Examples.TestBedX3WithRadiantFloor Buildings.Rooms.FLEXLAB.Rooms.Examples.X3AWithRadiantFloor Buildings.Rooms.FLEXLAB.Rooms.Examples.X3BWithRadiantFloor | Corrected wrong entries for inner and outer diameter of PEX pipes.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings.Fluid
Buildings.Fluid.FixedResistances.FixedResistanceDpM | Corrected error in documentation of computation of `k`.
Buildings.HeatTransfer
Buildings.HeatTransfer.Windows.BaseClasses.GlassLayer | Changed type of `tauIR` from `Modelica.SIunits.Emissivity` to `Modelica.SIunits.TransmissionCoefficient`. This avoids a type error in OpenModelica.

Note:

With version 2.0, we start using semantic versioning as described at http://semver.org/.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_2_0_0 "Version 2.0.0" extends Modelica.Icons.ReleaseNotes; end Version_2_0_0;

## Buildings.UsersGuide.ReleaseNotes.Version_1_6_build1

Version 1.6 build 1

### Information

Version 1.6 build 1 updates the `Buildings` library to the Modelica Standard Library 3.2.1 and to `Modelica_StateGraph2` 2.0.2.

This is the first version of the `Buildings` library that contains models from the IEA EBC Annex 60 library, a Modelica library for building and community energy systems that is collaboratively developed within the project "New generation computational tools for building and community energy systems based on the Modelica and Functional Mockup Interface standards", a project that is conducted under the Energy in Buildings and Communities Programme (EBC) of the International Energy Agency (IEA).

The following new components have been added to existing libraries:

Buildings.Fluid
Buildings.Fluid.Actuators.Valves.TwoWayTable | Two way valve for which the opening characteristics is specified by a table.
Buildings.Utilities.Math
Buildings.Utilities.Math.Examples.Average Buildings.Utilities.Math.Examples.InverseXRegularized Buildings.Utilities.Math.Examples.Polynominal Buildings.Utilities.Math.Examples.PowerLinearized Buildings.Utilities.Math.Examples.QuadraticLinear Buildings.Utilities.Math.Examples.RegNonZeroPower Buildings.Utilities.Math.Examples.SmoothExponential Buildings.Utilities.Math.Functions.average Buildings.Utilities.Math.Functions.booleanReplicator Buildings.Utilities.Math.Functions.Examples.IsMonotonic Buildings.Utilities.Math.Functions.Examples.TrapezoidalIntegration Buildings.Utilities.Math.Functions.integerReplicator Buildings.Utilities.Math.InverseXRegularized Buildings.Utilities.Math.Polynominal Buildings.Utilities.Math.PowerLinearized Buildings.Utilities.Math.QuadraticLinear Buildings.Utilities.Math.RegNonZeroPower Buildings.Utilities.Math.SmoothExponential Buildings.Utilities.Math.TrapezoidalIntegration | Various functions and blocks for mathematical operations.
Buildings.Utilities.Psychrometrics
Buildings.Utilities.Psychrometrics.Examples.SaturationPressureLiquid Buildings.Utilities.Psychrometrics.Examples.SaturationPressure Buildings.Utilities.Psychrometrics.Examples.SublimationPressureIce Buildings.Utilities.Psychrometrics.Functions.BaseClasses.der_saturationPressureLiquid Buildings.Utilities.Psychrometrics.Functions.BaseClasses.der_sublimationPressureIce Buildings.Utilities.Psychrometrics.Functions.BaseClasses.Examples.SaturationPressureDerivativeCheck Buildings.Utilities.Psychrometrics.Functions.Examples.SaturationPressure Buildings.Utilities.Psychrometrics.Functions.saturationPressureLiquid Buildings.Utilities.Psychrometrics.Functions.saturationPressure Buildings.Utilities.Psychrometrics.Functions.sublimationPressureIce Buildings.Utilities.Psychrometrics.SaturationPressureLiquid Buildings.Utilities.Psychrometrics.SaturationPressure Buildings.Utilities.Psychrometrics.SublimationPressureIce | Various functions and blocks for psychrometric calculations.

The following existing components have been improved in a backward compatible way:

Buildings.Fluid
Buildings.Fluid.Interfaces.PartialTwoPortInterface Buildings.Fluid.Interfaces.PartialFourPortInterface | Removed call to homotopy function in the computation of the connector variables as these are conditionally enabled variables and therefore must not be used in any equation. They are only for output reporting.
Buildings.Fluid.Actuators.Dampers.Exponential | Improved documentation of the flow resistance.
Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Added the option to use a constant, an input signal or the weather file as the source for the ceiling height, the total sky cover, the opaque sky cover, the dew point temperature, and the infrared horizontal radiation `HInfHor`.

The following existing components have been improved in a non-backward compatible way:

Buildings.Fluid
Buildings.Fluid.Movers.FlowMachinePolynomial | Moved the model to the package `Buildings.Obsolete`, as this model is planned to be removed in future versions. The conversion script should update old instances of this model automatically in Dymola. Users should change their models to use a flow machine from the package `Buildings.Fluid.Movers`.
Buildings.Fluid.Storage.ExpansionVessel | Simplified the model to have a constant pressure. The following non-backward compatible changes have been made. The parameter `VTot` was renamed to `V_start`. The following parameters were removed: `VGas0`, `pMax`, `energyDynamics` and `massDynamics`. The conversion script should update old instances of this model automatically in Dymola.
Buildings.Fluid.Storage.StratifiedEnhancedInternalHex | Revised the model as the old version required the porta of the heat exchanger to be located higher than portb. This makes sense if the heat exchanger is used to heat up the tank, but not if it is used to cool down a tank, such as in a cooling plant. The following parameters were changed: Changed `hexTopHeight` to `hHex_a`. Changed `hexBotHeight` to `hHex_b`. Changed `topHexSeg` to `segHex_a`, and made it protected as this is deduced from `hHex_a`. Changed `botHexSeg` to `segHex_b`, and made it protected as this is deduced from `hHex_b`. The names of the following ports have been changed: Changed `port_a1` to `portHex_a`. Changed `port_b1` to `portHex_b`. The conversion script should update old instances of this model automatically in Dymola for all of the above changes.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Fluid
Buildings.Fluid.HeatExchangers.Boreholes.UTube | Reimplemented the resistor network inside the borehole as the old implementation led to too slow a transient response. This change also led to the removal of the parameters `B0` and `B1` as the new implementation does not require them.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings.Fluid
Buildings.Fluid.HeatExchangers.Boreholes.BaseClasses.HexInternalElement | Corrected error in documentation which stated a wrong default value for the pipe spacing.
Buildings.Fluid.HeatExchangers.BaseClasses.ntu_epsilonZ() | Added dummy argument to function call of `Internal.solve` to avoid a warning during model check in Dymola 2015.
Buildings.Fluid.HeatExchangers.DryEffectivenessNTU | Changed `assert` statement to avoid comparing enumeration with an integer, which triggers a warning in Dymola 2015.
Buildings.Rooms.Constructions.Examples.ExteriorWall Buildings.Rooms.Constructions.Examples.ExteriorWallWithWindow Buildings.Rooms.Constructions.Examples.ExteriorWallTwoWindows | Corrected wrong assignment of parameter in instance `bouConExt(conMod=...)` which was set to an interior instead of an exterior convection model.
Buildings.Utilities.Psychrometrics.Functions.TDewPoi_pW() | Added dummy argument to function call of `Internal.solve` to avoid a warning during model check in Dymola 2015.

The following issues have been fixed:

Buildings.Fluid
#196 | Change capacity location in borehole grout.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_6_build1 "Version 1.6 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_6_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_1_5_build3

Version 1.5 build 3

### Information

Version 1.5 build 3 is a maintenance release that corrects an error in Buildings.Fluid.MassExchangers.HumidifierPrescribed. It is fully compatible with version 1.5 build 2.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Fluid
Buildings.Fluid.MassExchangers.HumidifierPrescribed | Corrected the enthalpy balance, which caused the latent heat flow rate to be added twice to the fluid stream. This closes issue #197.

The following issues have been fixed:

HumidifierPrescribed accounts twice for latent heat gain
#197 | This issue has been addressed by correcting the latent heat added to the fluid stream.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_5_build3 "Version 1.5 build 3" extends Modelica.Icons.ReleaseNotes; end Version_1_5_build3;

## Buildings.UsersGuide.ReleaseNotes.Version_1_5_build2

Version 1.5 build 2

### Information

Version 1.5 build 2 is a maintenance release that corrects an error in Buildings.Fluid.HeatExchangers.DryCoilDiscretized and in Buildings.Fluid.HeatExchangers.WetCoilDiscretized. It is fully compatible with version 1.5 build 1.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Fluid
Buildings.Fluid.HeatExchangers.DryCoilDiscretized Buildings.Fluid.HeatExchangers.WetCoilDiscretized | Corrected wrong connect statements that caused the last register to have no liquid flow. This closes issue #194.

The following issues have been fixed:

DryCoilDiscretized model not using last register, liquid flow path
#194 | This issue has been addressed by correcting the connect statements.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_5_build2 "Version 1.5 build 2" extends Modelica.Icons.ReleaseNotes; end Version_1_5_build2;

## Buildings.UsersGuide.ReleaseNotes.Version_1_5_build1

Version 1.5 build 1

### Information

Version 1.5 build 1 is a major release that contains new packages with models for solar collectors and for the Facility for Low Energy Experiments (FLEXLAB) at the Lawrence Berkeley National Laboratory.

This release also contains a major revision of all info sections to correct invalid html syntax. The package `Buildings.HeatTransfer.Radiosity` has been revised to comply with the Modelica language specification. The package `Buildings.Rooms` has been revised to aid implementation of non-uniformly mixed room air models. This release also contains various corrections that avoid warnings during translation when used with Modelica 3.2.1. Various models have been revised to increase compatibility with OpenModelica. However, currently only a subset of the models work with OpenModelica.

The following new libraries have been added:

Buildings.Fluid.SolarCollectors | Library with solar collectors.
Buildings.Rooms.FLEXLAB | Package with models for test cells of LBNL's FLEXLAB (Facility for Low Energy Experiments in Buildings).
Buildings.Utilities.IO.FLEXLAB | Package that demonstrates two-way data exchange between Modelica and LBNL's FLEXLAB (Facility for Low Energy Experiments in Buildings).

The following new components have been added to existing libraries:

Buildings.Fluid.Storage
Buildings.Fluid.Storage.StratifiedEnhancedInternalHex | Added a model of a tank with built-in heat exchanger. This model may be used together with solar thermal plants.
Buildings.Resources
Buildings.Resources.Include | Added an `Include` folder and the `bcvtb.h` header file to it to fix compilation errors in BCVTB example files.

The following existing components have been improved in a backward compatible way:

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 Buildings.BoundaryConditions.WeatherData.BaseClasses.getAbsolutePath | Improved the algorithm that determines the absolute path of the file. Now weather files are searched in the path specified, and if not found, the urls `file://`, `modelica://` and `modelica://Buildings` are added in this order to search for the weather file. This allows using the data reader without having to specify an absolute path, as long as the `Buildings` library is on the `MODELICAPATH`.
Buildings.Fluid
Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation | Reformulated computation of outlet properties to avoid an event at zero mass flow rate.
Buildings.Fluid.HeatExchangers.CoolingTowers.YorkCalc | Simplified the implementation for the situation if `allowReverseFlow=false`. Avoided the use of the conditionally enabled variables `sta_a` and `sta_b` as this was not proper use of the Modelica syntax.
Buildings.Fluid.Interfaces.Examples.ReverseFlowHumidifier | Changed one instance of `Modelica.Fluid.Sources.MassFlowSource_T`, that was connected to the two fluid streams, to two instances, each having half the mass flow rate. This is required for the model to work with Modelica 3.2.1 due to the change introduced in ticket #739.
Buildings.Fluid.Sensors.EnthalpyFlowRate Buildings.Fluid.Sensors.SensibleEnthalpyFlowRate Buildings.Fluid.Sensors.LatentEnthalpyFlowRate Buildings.Fluid.Sensors.VolumeFlowRate | Removed default value `tau=0` as the base class already sets `tau=1`. This change was made so that all sensors use the same default value.
Buildings.Fluid.Sensors.TraceSubstancesTwoPort | Added default value `C_start=0`.
Buildings.HeatTransfer
Buildings.HeatTransfer.Data.OpaqueConstructions.Generic | Changed the annotation of the instance `material` from `Evaluate=true` to `Evaluate=false`. This is required to allow changing the material properties after compilation. Note, however, that the number of state variables in Buildings.HeatTransfer.Data.BaseClasses.Material are only computed when the model is translated, because the number of state variables is fixed at compilation time.
Buildings.Utilities
Buildings.Utilities.Diagnostics.AssertEquality Buildings.Utilities.Diagnostics.AssertInequality | Added `time` in print statement as OpenModelica, in its error message, does not output the time when the assert is triggered.

The following existing components have been improved in a non-backward compatible way:

Buildings.Airflow
Buildings.Airflow.Multizone.Orifice Buildings.Airflow.Multizone.EffectiveAirLeakageArea Buildings.Airflow.Multizone.ZonalFlow_ACS | Changed the parameter `useConstantDensity` to `useDefaultProperties` to use consistent names within this package. A conversion script in `Resources/Scripts/Dymola` can be used to update old models that use this parameter.
Buildings.Fluid
Buildings.Fluid.BaseClasses.IndexWater | Renamed class to `Buildings.Fluid.BaseClasses.IndexMassFraction` as it is applicable for all mass fraction sensors.
Buildings.Fluid.HeatExchangers.ConstantEffectiveness Buildings.Fluid.HeatExchangers.DryEffectivenessNTU Buildings.Fluid.Interfaces.ConservationEquation Buildings.Fluid.Interfaces.StaticFourPortHeatMassExchanger Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger Buildings.Fluid.MassExchangers.ConstantEffectiveness Buildings.Fluid.MassExchangers.HumidifierPrescribed Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolumeWaterPort Buildings.Fluid.MixingVolumes.MixingVolume Buildings.Fluid.MixingVolumes.MixingVolumeDryAir Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir Buildings.Fluid.Storage.ExpansionVessel | Changed the input connector `mXi_flow` (or `mXi1_flow` and `mXi2_flow`) to `mWat_flow` (or `mWat1_flow` and `mWat2_flow`). This change has been done as declaring `mXi_flow` is ambiguous because it does not specify what other species are added unless a mass flow rate `m_flow` is also known. To avoid this confusion, the connector variables have been renamed. The equations that were used were, however, correct. This addresses issue #165.
Buildings.Fluid.Storage.BaseClasses.IndirectTankHeatExchanger Buildings.Fluid.BaseClasses.PartialResistance Buildings.Fluid.FixedResistances.BaseClasses.Pipe Buildings.Fluid.FixedResistances.FixedResistanceDpM Buildings.Fluid.FixedResistances.LosslessPipe Buildings.Fluid.HeatExchangers.Boreholes.BaseClasses.BoreholeSegment Buildings.Fluid.HeatExchangers.Boreholes.UTube Buildings.Fluid.HeatExchangers.RadiantSlabs.ParallelCircuitsSlab Buildings.Fluid.Interfaces.FourPortHeatMassExchanger Buildings.Fluid.Interfaces.PartialFourPortInterface Buildings.Fluid.Interfaces.PartialTwoPortInterface Buildings.Fluid.Interfaces.StaticFourPortHeatMassExchanger Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolume Buildings.Fluid.Movers.BaseClasses.FlowControlled Buildings.Fluid.Movers.BaseClasses.IdealSource Buildings.Fluid.Movers.BaseClasses.PrescribedFlowMachine | Removed the computation of `V_flow` and removed the parameter `show_V_flow`. The reason is that the computation of `V_flow` required the use of `sta_a` (to compute the density), but `sta_a` is also a variable that is conditionally enabled. However, this was not correct Modelica syntax as conditional variables can only be used in a `connect` statement, not in an assignment. Dymola 2014 FD01 beta3 is checking for this incorrect syntax. Hence, `V_flow` was removed as its conditional implementation would require a rather cumbersome implementation that uses a new connector that carries the state of the medium.
Buildings.Fluid.MixingVolumes | Removed `Buildings.Fluid.MixingVolumes.MixingVolumeDryAir` as this model is no longer used. The model `Buildings.Fluid.MixingVolumes.MixingVolume` can be used instead of. Removed base class `Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolumeWaterPort` as this model is no longer used.
Buildings.Fluid.Sensors.Examples.TraceSubstances | Renamed example from `ExtraProperty` to `TraceSubstances` in order to use the same name as the sensor.
Buildings.Fluid.Sources.PrescribedExtraPropertyFlowRate | Renamed model to`TraceSubstancesFlowRate` to use the same terminology than the Modelica Standard Library. The conversion script updates existing models that instantiate this model.
Buildings.Fluid.Sources.Examples.PrescribedExtraPropertyFlow | Renamed example to`TraceSubstancesFlowRate` in order to use the same name as the source model.
Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolume Buildings.Fluid.FixedResistances.Pipe Buildings.Fluid.HeatExchangers.RadiantSlabs.ParallelCircuitsSlab Buildings.Fluid.HeatExchangers.RadiantSlabs.SingleCircuitSlab Buildings.Fluid.Movers.BaseClasses.FlowControlled | Renamed `X_nominal` to `X_default` or `X_start`, where `X` may be `state`, `rho`, or `mu`, depending on whether the medium default values or the start values are used in the computation of the state and derived quantities.
Buildings.HeatTransfer Buildings.Rooms
Buildings.HeatTransfer.Interfaces.RadiosityInflow Buildings.HeatTransfer.Interfaces.RadiosityOutflow Buildings.HeatTransfer.Radiosity.BaseClasses.ParametersTwoSurfaces Buildings.HeatTransfer.Radiosity.Constant Buildings.HeatTransfer.Radiosity.Examples.OpaqueSurface Buildings.HeatTransfer.Radiosity.Examples.OutdoorRadiosity Buildings.HeatTransfer.Radiosity.IndoorRadiosity Buildings.HeatTransfer.Radiosity.OpaqueSurface Buildings.HeatTransfer.Radiosity.OutdoorRadiosity Buildings.HeatTransfer.Radiosity.RadiositySplitter Buildings.HeatTransfer.Radiosity.package Buildings.HeatTransfer.Windows.BaseClasses.Examples.CenterOfGlass Buildings.HeatTransfer.Windows.BaseClasses.Examples.GlassLayer Buildings.HeatTransfer.Windows.BaseClasses.Examples.Shade Buildings.HeatTransfer.Windows.BaseClasses.GlassLayer Buildings.HeatTransfer.Windows.BaseClasses.Shade Buildings.HeatTransfer.Windows.Examples.BoundaryHeatTransfer Buildings.HeatTransfer.Windows.ExteriorHeatTransfer Buildings.HeatTransfer.Windows.InteriorHeatTransfer Buildings.Rooms.BaseClasses.InfraredRadiationExchange Buildings.Rooms.BaseClasses.InfraredRadiationGainDistribution Buildings.Rooms.BaseClasses.MixedAir Buildings.Rooms.BaseClasses.Overhang Buildings.Rooms.BaseClasses.SideFins | Changed the connectors for the radiosity model. The previous implemenation declared the radiosity as a `flow` variables, but the implementation did not use a potential variable. Therefore, the radiosity was the only variable in the connector, which is not allowed for `flow` variables. This change required a reformulation of models because with the new formulation, the incoming and outcoming radiosity are both non-negative values. This addresses issue #158.
Buildings.HeatTransfer Buildings.Rooms
Buildings.HeatTransfer.Windows.BaseClasses.PartialConvection Buildings.HeatTransfer.Windows.BaseClasses.PartialWindowBoundaryCondition Buildings.HeatTransfer.Windows.BaseClasses.Shade Buildings.HeatTransfer.Windows.BaseClasses.ShadeConvection Buildings.HeatTransfer.Windows.BaseClasses.ShadeRadiation Buildings.HeatTransfer.Windows.InteriorHeatTransfer Buildings.HeatTransfer.Windows.InteriorHeatTransferConvective Buildings.Rooms.ExteriorBoundaryConditionsWithWindow Buildings.Rooms.PartialSurfaceInterface Buildings.Rooms.InfraredRadiationExchange Buildings.Rooms.AirHeatMassBalanceMixed Buildings.Rooms.SolarRadiationExchange Buildings.Rooms.RadiationTemperature Buildings.Rooms.InfraredRadiationGainDistribution | Redesigned the implementation of the room model and its base classes. This redesign separates convection from radiation, and it provides one composite model for the convection and the heat and mass balance in the room. This change was done to allow an implementation of the room air heat and mass balance that does not assume uniformly mixed room air.
Buildings.HeatTransfer
Buildings.HeatTransfer.Convection.Functions.HeatFlux.rayleigh | Renamed function from `raleigh` to `rayleigh`.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Fluid
Buildings.Fluid.Sensors.SpecificEntropyTwoPort | Corrected wrong computation of the dynamics used for the sensor signal.
Buildings.HeatTransfer
Buildings.HeatTransfer.Data.GlazingSystems.DoubleClearAir13Clear | Corrected the glass layer thickness, which was 5.7 mm instead of 3 mm, as the documentation states.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings
Buildings.BoundaryConditions.SkyTemperature.BlackBody Buildings.BoundaryConditions.WeatherData.BaseClasses.CheckTemperature Buildings.BoundaryConditions.WeatherData.ReaderTMY3 Buildings.Controls.SetPoints.HotWaterTemperatureReset Buildings.Examples.ChillerPlant.BaseClasses.Controls.ChillerSwitch Buildings.Examples.ChillerPlant.BaseClasses.Controls.WSEControl Buildings.Fluid.Boilers.BoilerPolynomial Buildings.Fluid.HeatExchangers.BaseClasses.HexElement Buildings.Fluid.HeatExchangers.BaseClasses.MassExchange Buildings.Fluid.HeatExchangers.BaseClasses.MassExchangeDummy Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.ApparatusDewPoint Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.ApparatusDryPoint Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.CoolingCapacity Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.DXCooling Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.DryCoil Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.DryWetSelector Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.Evaporation Buildings.Fluid.HeatExchangers.DXCoils.BaseClasses.WetCoil Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolumeWaterPort Buildings.Fluid.Sensors.RelativeTemperature Buildings.Fluid.Sensors.Temperature Buildings.Fluid.Sensors.TemperatureTwoPort Buildings.Fluid.Sensors.TemperatureWetBulbTwoPort Buildings.Fluid.SolarCollectors.BaseClasses.PartialHeatLoss Buildings.Utilities.Comfort.Fanger Buildings.Utilities.IO.BCVTB.From_degC Buildings.Utilities.IO.BCVTB.To_degC Buildings.Utilities.Psychrometrics.TDewPoi_pW Buildings.Utilities.Psychrometrics.TWetBul_TDryBulPhi Buildings.Utilities.Psychrometrics.TWetBul_TDryBulXi Buildings.Utilities.Psychrometrics.WetBul_pTX Buildings.Utilities.Psychrometrics.pW_TDewPoi | Replaced wrong attribute `quantity="Temperature"` with `quantity="ThermodynamicTemperature"`.
Buildings.Fluid
Buildings.Fluid.Data.Fuels.Generic | Corrected wrong type for `mCO2`. It was declared as `Modelica.SIunits.MassFraction`, which is incorrect.
Buildings.Fluid.HeatExchangers.CoolingTowers.Correlations.BaseClasses.Bounds | Corrected wrong type for `FRWat_min`, `FRWat_max` and `liqGasRat_max`. They were declared as `Modelica.SIunits.MassFraction`, which is incorrect as, for example, `FRWat_max` can be larger than one.
Buildings.Fluid.HeatExchangers.ConstantEffectiveness Buildings.Fluid.MassExchangers.ConstantEffectiveness | Corrected error in the documentation that was not updated when the implementation of zero flow rate was revised.
Buildings.Fluid.Interfaces.ConservationEquation | Corrected the syntax error `Medium.ExtraProperty C[Medium.nC](each nominal=C_nominal)` to `Medium.ExtraProperty C[Medium.nC](nominal=C_nominal)` because `C_nominal` is a vector. This syntax error caused a compilation error in OpenModelica.
Buildings.Fluid.Sensors.SensibleEnthalpyFlowRate Buildings.Fluid.Sensors.LatentEnthalpyFlowRate Buildings.Fluid.Sensors.MassFraction Buildings.Fluid.Sensors.MassFractionTwoPort | Changed medium declaration in the `extends` statement to `replaceable` to avoid a translation error in OpenModelica.
Buildings.Fluid.Sensors.TraceSubstances Buildings.Fluid.Sensors.TraceSubstancesTwoPort | Corrected syntax errors in setting nominal value for output signal and for state variable. This eliminates a compilation error in OpenModelica.
Buildings.Fluid.Sources.TraceSubstancesFlowSource | Added missing `each` in declaration of `C_in_internal`. This eliminates a compilation error in OpenModelica.
Buildings.Utilities.Python27
Buildings.Utilities.IO.Python27.Functions.exchange | Corrected error in C code that lead to message `'module' object has no attribute 'argv'` when a python module accessed `sys.argv`.

The following issues have been fixed:

Verify mass and species balance
#165 | This issue has been addressed by renaming the connectors to avoid an ambiguity in the model equation. The equations were correct.
Remove flow attribute from radiosity connectors
#158 | This issue has been addressed by reformulating the radiosity models. With the new implementation, incoming and outgoing radiosity are non-negative quantities.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_5_build1 "Version 1.5 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_5_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_1_4_build1

Version 1.4 build 1

### Information

Version 1.4 build 1 contains the new package Buildings.Utilities.IO.Python27 that allows calling Python functions from Modelica. It also contains in the package Buildings.HeatTransfer.Conduction.SingleLayer a new model for heat conduction in phase change material. This model can be used as a layer of the room heat transfer model.

Non-backward compatible changes had to be introduced in the valve models Buildings.Fluid.Actuators.Valves to fully comply with the Modelica language specification, and in the models in the package Buildings.Utilities.Diagnostics as they used the `cardinality` function which is deprecated in the Modelica Language Specification.

See below for details.

The following new libraries have been added:

Buildings.Utilities.IO.Python27 | Package that contains blocks and functions that embed Python 2.7 in Modelica. Data can be sent to Python functions and received from Python functions. This allows for example data analysis in Python as part of a Modelica model, or data exchange as part of a hardware-in-the-loop simulation in which Python is used to communicate with hardware.

The following new components have been added to existing libraries:

Buildings.BoundaryConditions.WeatherData
Buildings.BoundaryConditions.WeatherData.BaseClasses.getAbsolutePath | This function is used by the weather data reader to set the path to the weather file relative to the root directory of the Buildings library.

The following existing components have been improved in a backward compatible way:

Buildings.Fluid
Buildings.Fluid.MixingVolumes.BaseClasses.PartialMixingVolume | Removed the check of multiple connections to the same element of a fluid port, as this check required the use of the deprecated `cardinality` function.
Buildings.HeatTransfer
Buildings.HeatTransfer.Conduction.SingleLayer | Added option to model layers with phase change material.
Buildings.Rooms
Buildings.Rooms.BaseClasses.InfraredRadiationExchange | Removed the use of the `cardinality` function as this function is deprecated in the Modelica Language Specification.

The following existing components have been improved in a non-backward compatible way:

Buildings.Fluid
Buildings.Fluid.Actuators.Valves | All valves now require the declaration of `dp_nominal` if the parameter assignment is `CvData = Buildings.Fluid.Types.CvTypes.OpPoint`. This change was needed because in the previous version, `dp_nominal` had a default value of 6000 Pascals. However, if `CvData >< Buildings.Fluid.Types.CvTypes.OpPoint`, then `dp_nominal` is computed in the initial algorithm section and hence providing a default value is not allowed according to the Modelica Language Specification. Hence, it had to be removed. As part of this change, we set `dp(nominal=6000)` for all valves, because the earlier formulation uses a value that is not known during compilation, and hence leads to an error in Dymola 2014.
Buildings.Fluid.MixingVolumes.MixingVolumeDryAir Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir | Removed the use of the deprecated `cardinality` function. Therefore, now all input signals must be connected..
Buildings.Utilities
Buildings.Utilities.Diagnostics.AssertEquality Buildings.Utilities.Diagnostics.AssertInequality | Removed the option to not connect input signals, as this required the use of the `cardinality` function which is deprecated in the MSL, and not correctly implemented in OpenModelica. Therefore, if using these models, both input signals must be connected.
Buildings.Utilities.Math.Functions.splineDerivatives | Removed the default value `input Boolean ensureMonotonicity=isMonotonic(y, strict=false)` as the Modelica language specification is not clear whether defaults can be computed or must be constants.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Controls
Buildings.Controls.SetPoints.HotWaterTemperatureReset | Corrected error that led to wrong results if the room air temperature is different from its nominal value `TRoo_nominal`. This fixes issue 74.
Buildings.HeatTransfer
Buildings.Fluid.HeatExchangers.RadiantSlabs.SingleCircuitSlab Buildings.Fluid.HeatExchangers.RadiantSlabs.ParallelCircuitSlab | Fixed bug in the assignment of the fictitious thermal resistance by replacing `RFic[nSeg](each G=A/Rx)` with `RFic[nSeg](each G=A/nSeg/Rx)`. This fixes issue 79.
Buildings.Utilities
Buildings.Utilities.Diagnostics.AssertEquality Buildings.Utilities.Diagnostics.AssertInequality | Replaced `when` test with `if` test as equations within a `when` section are only evaluated when the condition becomes true. This fixes issue 72.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings.Fluid
Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear Buildings.Fluid.Actuators.Valves.ThreeWayLinear | The documenation was Fraction Kv(port_1->port_2)/Kv(port_3->port_2) instead of Fraction Kv(port_3->port_2)/Kv(port_1->port_2). Because the parameter set correctly its attributes `min=0` and `max=1`, instances of these models used the correct value.
Buildings.Fluid.Actuators.BaseClasses.ValveParameters | Removed stray backslash in write statement.
Buildings.Fluid.Interfaces.ConservationEquation Buildings.Fluid.Interfaces.StaticTwoPortConservationEquation Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger | Removed wrong unit attribute of `COut`.
Buildings.Fluid.HeatExchangers.BaseClasses.HexElement | Changed the redeclaration of `vol2` to be replaceable, as `vol2` is replaced in some models.

The following issues have been fixed:

Add explanation of nStaRef.
#70 | Described in Buildings.HeatTransfer.Data.Solids how the parameter `nStaRef` is used to compute the spatial grid that is used for simulating transient heat conduction.
Assert statement does not fire.
#72 | The blocks `Buildings.Utilities.Diagnostics.AssertEquality` and `Buildings.Utilities.Diagnostics.AssertInequality` did not fire because the test on the time was in a `when` instead of an `if` statement. This was wrong because `when` sections are only evaluated when the condition becomes true.
`HotWaterTemperatureReset` computes wrong results if room temperature differs from nominal value.
#74 | The equation
    TSup = TRoo_in_internal
              + ((TSup_nominal+TRet_nominal)/2-TRoo_in_internal) * qRel^(1/m)
              + (TSup_nominal-TRet_nominal)/2 * qRel;
should be formulated as
    TSup = TRoo_in_internal
              + ((TSup_nominal+TRet_nominal)/2-TRoo_nominal) * qRel^(1/m)
              + (TSup_nominal-TRet_nominal)/2 * qRel;
Bug in `RadiantSlabs.SingleCircuitSlab` fictitious resistance RFic.
#79 | This bug has been fixed in the assignment of the fictitious thermal resistance by replacing `RFic[nSeg](each G=A/Rx)` with `RFic[nSeg](each G=A/nSeg/Rx)`. The bug also affected `RadiantSlabs.ParallelCircuitSlab`.

Note:

- This version contains various updates that allow the syntax of the example models to be checked in the pedantic mode in Dymola 2014.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_4_build1 "Version 1.4 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_4_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_1_3_build1

Version 1.3 build 1

### Information

In version 1.3 build 1, models for direct evaporative cooling coils with multiple stages or with a variable speed compressor have been added. This version also contains improvements to the fan and pump models to better treat zero mass flow rate. Various other improvements have been made to improve the numerics and to use consistent variable names. A detailed list of changes is shown below.

The following new libraries have been added:

Buildings.Fluid.HeatExchangers.DXCoils | Library with direct evaporative cooling coils.

The following new components have been added to existing libraries:

Buildings.Examples
Buildings.Examples.ChillerPlant.DataCenterContinuousTimeControl | Added chilled water plant model with continuous time control that replaces the discrete time control in `Buildings.Examples.ChillerPlant.DataCenterDiscreteTimeControl`.
Buildings.Utilities
Buildings.Utilities.Psychrometrics.Functions.X_pSatpphi | Function that computes moisture concentration based on saturation pressure, total pressure and relative humidity.
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulPhi | Block that computes the wet bulb temperature for given dry bulb temperature, relative humidity and atmospheric pressure.
Buildings.Utilities.Psychrometrics.WetBul_pTX | Block that computes the temperature and mass fraction at the wet bulb state for given dry bulb temperature, species concentration and atmospheric pressure.

The following existing components have been improved in a backward compatible way:

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Added computation of the wet bulb temperature. Computing the wet bulb temperature introduces a nonlinear equation. As we have not observed an increase in computing time because of computing the wet bulb temperature, it is computed by default. By setting the parameter `computeWetBulbTemperature=false`, the computation of the wet bulb temperature can be removed.
Buildings.Controls
Buildings.Controls.SetPoints.OccupancySchedule | Added `pre` operator and relaxed tolerance in `assert` statement.
Buildings.Fluid
Buildings.Fluid.Movers.FlowControlled_dp Buildings.Fluid.Movers.FlowControlled_m_flow Buildings.Fluid.Movers.SpeedControlled_Nrpm Buildings.Fluid.Movers.SpeedControlled_y | Reformulated implementation of efficiency model to avoid a division by zero at zero mass flow rate for models in which a user specifies a power instead of an efficiency performance curve.
Buildings.Utilities
Buildings.Utilities.Psychrometrics.TWetBul_TDryBulXi | Added option to approximate the wet bulb temperature using an explicit equation. Reformulated the original model to change the dimension of the nonlinear system of equations from two to one.

The following existing components have been improved in a non-backward compatible way:

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 Buildings.BoundaryConditions.Types | Improved the optional inputs for the radiation data global horizontal, diffuse horizontal and direct normal radiation. If a user specifies two of them, the third will be automatically calculated.
Buildings.BoundaryConditions.SkyTemperature.BlackBody | Renamed `radHor` to `radHorIR` to indicate that the radiation is in the infrared spectrum.
Buildings.Fluid
Buildings.Airflow.Multizone.BaseClasses.DoorDiscretized Buildings.Airflow.Multizone.DoorDiscretizedOpen Buildings.Airflow.Multizone.DoorDiscretizedOperable Buildings.Airflow.Multizone.Orifice Buildings.Airflow.Multizone.ZonalFlow_ACS Buildings.Fluid.Actuators.BaseClasses.PartialDamperExponential Buildings.Fluid.Actuators.Dampers.MixingBox Buildings.Fluid.Actuators.Dampers.VAVBoxExponential Buildings.Fluid.BaseClasses.PartialResistance Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger Buildings.Fluid.Movers.BaseClasses.PowerInterface Buildings.Fluid.Storage.BaseClasses.Buoyancy Buildings.Fluid.HeatExchangers.BaseClasses.MassExchange | Renamed protected parameters for consistency with the naming conventions. In previous releases, fluid properties had the suffix `0` or `_nominal` instead of `_default` when they where computed based on the medium default properties.
Buildings.Fluid.Sensors.SensibleEnthalpyFlowRate Buildings.Fluid.Sensors.LatentEnthalpyFlowRate | Moved computation of parameter `i_w` to new base class `Buildings.Fluid.BaseClasses.IndexWater` The value of this parameter is now assigned dynamically and does not require to be specified by the user.
Buildings.Fluid.Storage.BaseClasses.ThirdOrderStratifier | Removed unused protected parameters `sta0` and `cp0`.
Buildings.Examples
Buildings.Examples.ChillerPlant.DataCenterDiscreteTimeControl Buildings.Examples.ChillerPlant.BaseClasses.Controls.TrimAndRespond Buildings.Examples.ChillerPlant.BaseClasses.Controls.ZeroOrderHold | Re-implemented the controls for setpoint reset. Revised the model `TrimAndRespond` and deleted the model `ZeroOrderHold`. Improved the documentation.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Examples
Buildings.Examples.ChillerPlant.DataCenterDiscreteTimeControl | Fixed error in wet bulb temperature. The previous version used a model to compute the wet bulb temperature that takes as an input the relative humidity, but required mass fraction as an input.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 Buildings.BoundaryConditions.SkyTemperature.BlackBody | Renamed `radHor` to `radHorIR`.
Buildings.Fluid
Buildings.Fluid.BaseClasses.FlowModels.Examples.InverseFlowFunction | Fixed error in the documentation.
Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger | Fixed broken link in the documentation.
Buildings.Fluid.Movers.BaseClasses.Characteristics.powerParameters | Fixed wrong `displayUnit` and `max` attribute for power.
Buildings.Fluid.MixingVolumes | In documentation, removed reference to the parameter `use_HeatTransfer` which no longer exists.
Buildings.HeatTransfer
Buildings.HeatTransfer.Windows.Functions.glassPropertyUncoated | Improved the documentation for implementation and added comments for model limitations.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_3_build1 "Version 1.3 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_3_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_1_2_build1

Version 1.2 build 1

### Information

In version 1.2 build 1, models for radiant slabs and window overhangs and sidefins have been added. This version also contains various improvements to existing models. A detailed list of changes is shown below.

The following new libraries have been added:

Buildings.Fluid.HeatExchangers.RadiantSlabs | Package with models for radiant slabs with pipes or a capillary heat exchanger embedded in the construction.
Buildings.Fluid.Data.Pipes | Package with records for pipes.

The following new components have been added to existing libraries:

Buildings.HeatTransfer
Buildings.HeatTransfer.Windows.FixedShade Buildings.HeatTransfer.Windows.Overhang Buildings.HeatTransfer.Windows.SideFins | For windows with either an overhang or side fins, these blocks output the fraction of the area that is sun exposed.
Buildings.Rooms
Buildings.Rooms.Examples.BESTEST | Added BESTEST validation models for case 610, 620, 630, 640, 650FF, 650, 920, 940, 950FF, 950, and 960.

The following existing components have been improved in a backward compatible way:

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Removed assignment of `HGloHor_in` in its declaration, because this gives an overdetermined system if the input connector is used. Added new sub-bus that contains the solar position. This allows reusing the solar position in various other models.
Buildings.BoundaryConditions.SolarIrradiation.DiffuseIsotropic Buildings.BoundaryConditions.SolarIrradiation.DiffusePerez Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffuseIsotropic Buildings.BoundaryConditions.SolarIrradiation.BaseClasses.DiffusePerez | Added optional output of diffuse radiation from the sky and ground. This allows reusing the diffuse radiation in solar thermal collector.
Buildings.BoundaryConditions.SolarGeometry.BaseClasses.SolarAzimuth | Changed implementation to avoid an event at solar noon.
Buildings.HeatTransfer
Buildings.HeatTransfer.Data.BoreholeFillings | Renamed class to `BoreholeFillings` to be consistent with data records being plural.
Buildings.Media
Buildings.Media.GasesPTDecoupled.MoistAir Buildings.Media.Air Buildings.Media.PerfectGases.MoistAir Buildings.Media.PerfectGases.MoistAirUnsaturated Buildings.Media.GasesConstantDensity.MoistAir Buildings.Media.GasesConstantDensity.MoistAirUnsaturated | Added redeclaration of `ThermodynamicState` to avoid a warning during model check and translation.
Buildings.Rooms
Buildings.Rooms.MixedAir | Added a check that ensures that the number of surfaces are equal to the length of the parameter that contains the surface area, and added a check to ensure that no surface area is equal to zero. These checks help detecting erroneous declarations of the room model. The changes were done in `Buildings.Rooms.MixedAir.PartialSurfaceInterface`.

The following existing components have been improved in a non-backward compatible way:

Buildings.Rooms
Buildings.Rooms.MixedAir | Added optional modeling of window overhangs and side fins. The modeling of window overhangs and side fins required the introduction of the new parameters `hWin` for the window height and `wWin` for the window width, in addition to the parameters `ove` and `sidFin` which are used to declare the geometry of overhangs and side fins. The parameters `hWin` and `wWin` replace the previously used parameter `AWin` for the window area. Users need to manually replace `AWin` with `hWin` and `wWin` when updating models from a previous version of the library. See the information section in Buildings.Rooms.MixedAir for how to use these models.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Controls
Buildings.Controls.SetPoints.OccupancySchedule | Fixed a bug that caused an error in the schedule if the simulation start time was negative or equal to the first entry in the schedule.
Buildings.Fluid
Buildings.Fluid.Storage.BaseClass.ThirdOrderStratifier | Revised the implementation to reduce the temperature overshoot.
Buildings.HeatTransfer
Buildings.HeatTransfer.Windows.BaseClasses.GlassLayer | Fixed the bug in the temperature linearization and in the heat flow through the glass layer if the transmissivity of glass in the infrared regime is non-zero.
Buildings.HeatTransfer.Windows.BaseClasses.CenterOfGlass | Fixed a bug in the parameter assignment of the instance `glass`. Previously, the infrared emissivity of surface a was assigned to the surface b.
Buildings.Utilities
Buildings.Utilities.IO.BCVTB | Added a call to `Buildings.Utilities.IO.BCVTB.BaseClasses.exchangeReals` in the `initial algorithm` section. This is needed to propagate the initial condition to the server. It also leads to one more data exchange, which is correct and avoids the warning message in Ptolemy that says that the simulation reached its stop time one time step prior to the final time.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | Corrected the documentation of the unit requirement for input files, parameters and connectors.
Buildings.Fluid
Buildings.Fluid.Interfaces.PartialFourPortInterface Buildings.Fluid.Interfaces.PartialTwoPortInterface | Replaced the erroneous function call `Medium.density` with `Medium1.density` and `Medium2.density` in `PartialFourPortInterface`. Changed condition to remove `sta_a1` and `sta_a2` in `PartialFourPortInterface`, and `sta_a` in `PartialTwoPortInterface`, to also compute the state at the inlet port if `show_V_flow=true`. The previous implementation resulted in a translation error if `show_V_flow=true`, but worked correctly otherwise because the erroneous function call is removed if `show_V_flow=false`.
Buildings.Fluid.Chillers.Examples.BaseClasses.PartialElectric | Corrected the nominal mass flow rate used in the mass flow source.

The following issues have been fixed:

Heat transfer in glass layer
#56 | Fixed bug in heat flow through the glass layer if the infrared transmissivity is non-zero.
#57 | Fixed bug in temperature linearization of window glass.
Overshooting in enhanced stratified tank
#15 | Revised the implementation to reduce the temperature over-shoot.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_2_build1 "Version 1.2 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_2_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_1_1_build1

Version 1.1 build 1

### Information

Version 1.1 build 1 contains improvements to models that address numerical problems. In particular, flow machines and actuators now have an optional filter that converts step changes in the input signal to a smooth change in speed or actuator position. Also, ( Buildings.Examples.Tutorial) has been added to provide step-by-step instruction for how to build system models.

The following new libraries have been added:

Buildings.Examples.Tutorial | Tutorial with step by step instructions for how to build system models.

The following new components have been added to existing libraries:

Buildings.Fluid
Buildings.Fluid.FixedResistances.Pipe | Added a model for a pipe with transport delay and optional heat exchange with the environment.
Buildings.Fluid.Actuators.UsersGuide | Added a user's guide for actuator models.
Buildings.Fluid.Interfaces.ConservationEquation Buildings.Fluid.Interfaces.StaticConservationEquation | These base classes have been added to simplify the implementation of dynamic and steady-state thermofluid models.
Buildings.Fluid.Data.Fuels | Package with physical properties of fuels that are used by the boiler model.

The following existing components have been improved in a backward compatible way:

Buildings.Fluid
Buildings.Fluid.Actuators.Dampers.Exponential Buildings.Fluid.Actuators.Dampers.VAVBoxExponential Buildings.Fluid.Actuators.Dampers.MixingBox Buildings.Fluid.Actuators.Dampers.MixingBoxMinimumFlow Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear Buildings.Fluid.Actuators.Valves.ThreeWayLinear Buildings.Fluid.Actuators.Valves.TwoWayEqualPercentage Buildings.Fluid.Actuators.Valves.TwoWayLinear Buildings.Fluid.Actuators.Valves.TwoWayQuickOpening | Added an optional 2nd order lowpass filter for the input signal. The filter approximates the travel time of the actuators. It also makes the system of equations easier to solve because a step change in the input signal causes a gradual change in the actuator position. Note that this filter affects the time response of closed loop control. Therefore, enabling the filter may require retuning of control loops. See the user's guide of the Buildings.Fluid.Actuators package.
Buildings.Fluid.Boilers.BoilerPolynomial | Added computation of fuel usage and improved the documentation.
Buildings.Fluid.Movers.SpeedControlled_y Buildings.Fluid.Movers.SpeedControlled_Nrpm Buildings.Fluid.Movers.FlowControlled_dp Buildings.Fluid.Movers.FlowControlled_m_flow | Added a 2nd order lowpass filter to the input signal. The filter approximates the startup and shutdown transients of fans or pumps. It also makes the system of equations easier to solve because a step change in the input signal causes a gradual change in the mass flow rate. Note that this filter affects the time response of closed loop control. Therefore, enabling the filter may require retuning of control loops. See the user's guide of the Buildings.Fluid.Movers package.
Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger | Changed model to use graphical implementation of models for pressure drop and conservation equations.
Buildings.Fluid.BaseClasses.PartialResistance Buildings.Fluid.FixedResistances.FixedResistanceDpM Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve Buildings.Fluid.Actuators.BaseClasses.PartialDamperExponential | Revised base classes and models to simplify object inheritance tree. Set `m_flow_small` to `final` in Buildings.Fluid.BaseClasses.PartialResistance, and removed its assignment in the other classes.
Buildings.Fluid.FixedResistances.FixedResistanceDpM Buildings.Fluid.FixedResistances.SplitterFixedResistanceDpM | Improved documentation.
Buildings.HeatTransfer
Buildings.HeatTransfer.Windows.Functions.glassProperty | Added the function `glassPropertyUncoated` that calculates the property for uncoated glass.
Buildings.Rooms
Buildings.Rooms.MixedAir | Changed model to use new implementation of Buildings.HeatTransfer.Radiosity.OutdoorRadiosity in its base classes. This change leads to the use of the same equations for the radiative heat transfer between window and ambient as is used for the opaque constructions.

The following existing components have been improved in a non-backward compatible way:

Buildings.Fluid
Buildings.Fluid.Actuators.Valves.ThreeWayEqualPercentageLinear Buildings.Fluid.Actuators.Valves.ThreeWayLinear Buildings.Fluid.Actuators.Valves.TwoWayEqualPercentage Buildings.Fluid.Actuators.Valves.TwoWayLinear Buildings.Fluid.Actuators.Valves.TwoWayQuickOpening | Changed models to allow modeling of a fixed resistance that is within the controlled flow leg. This allows in some cases to avoid a nonlinear equation if a flow resistance is in series to the valve. This change required changing the parameter for the valve resistance `dp_nominal` to `dpValve_nominal`, and introducing the parameter `dpFixed_nominal`, with `dpFixed_nominal=0` as its default value. Previous models that instantiate these components need to change the assignment of `dp_nominal` to an assignment of `dpValve_nominal`. See also Buildings.Fluid.Actuators.UsersGuide.
Buildings.HeatTransfer
Buildings.HeatTransfer.Radiosity.OutdoorRadiosity Buildings.HeatTransfer.Windows.ExteriorHeatTransfer | Changed model to use new implementation of Buildings.HeatTransfer.Radiosity.OutdoorRadiosity. This change leads to the use of the same equations for the radiative heat transfer between window and ambient as is used for the opaque constructions.
Buildings.Controls
Buildings.Controls.SetPoints.OccupancySchedule | Changed model to fix a bug that caused the output of the block to be incorrect when the simulation started at a time different from zero. When fixing this bug, the parameter `startTime` was removed, and the parameter `endTime` was renamed to `period`. The period always starts at t=0 seconds.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.Controls
Buildings.Controls.SetPoints.OccupancySchedule | The output of the block was incorrect when the simulation started at a time different from zero.
Buildings.Fluid.HeatExchangers
Buildings.Fluid.HeatExchangers.DryCoilCounterFlow Buildings.Fluid.HeatExchangers.WetCoilCounterFlow | Corrected error in assignment of `dp2_nominal`. The previous assignment caused a pressure drop in all except one element, instead of the opposite. This caused too high a flow resistance of the heat exchanger.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, e.g., units are wrong or errors in documentation):

Buildings.BoundaryConditions
Buildings.BoundaryConditions.SkyTemperature.BlackBody | Fixed error in BlackBody model that was causing a translation error when `calTSky` was set to `Buildings.BoundaryConditions.Types.SkyTemperatureCalculation.HorizontalRadiation`.
Buildings.Fluid
Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger | Fixed wrong class reference in information section.
Buildings.Utilities
Buildings.Utilities.IO.BCVTB.Examples.MoistAir | Updated fan parameters, which were still for version 0.12 of the Buildings library and hence caused a translation error with version 1.0 or higher.

The following issues have been fixed:

Exterior longwave radiation exchange in window model
#51 | Changed model to use new implementation of Buildings.HeatTransfer.Radiosity.OutdoorRadiosity. This change leads to the use of the same equations for the radiative heat transfer between window and ambient as is used for the opaque constructions.
#53 | Fixed bug in Buildings.Controls.SetPoints.OccupancySchedule that led to wrong results when the simulation started at a time different from zero.

Note:

- The use of filters for actuator and flow machine input signals changes the dynamic response of feedback control loops. Therefore, control gains may need to be retuned. See Buildings.Fluid.Actuators.UsersGuide and Buildings.Fluid.Movers.UsersGuide for recommended control gains and further details.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_1_build1 "Version 1.1 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_1_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_1_0_build2

Version 1.0 build 2

### Information

Version 1.0 build 2 has been released to correct model errors that were present in version 1.0 build 1. Both versions are compatible. In addition, version 1.0 build 2 contains improved documentation of various example models.

The following existing components have been improved in a backward compatible way:

Buildings.Controls
Buildings.Controls.Continuous Buildings.Controls.Discrete Buildings.Controls.SetPoints | Improved documentation of models and of examples.
Buildings.Airflow.Multizone
Buildings.Airflow.Multizone.DoorDiscretizedOpen Buildings.Airflow.Multizone.DoorDiscretizedOperable | Changed the computation of the discharge coefficient to use the nominal density instead of the actual density. Computing `sqrt(2/rho)` sometimes causes warnings from the solver, as it seems to try negative values for the density during iterative solutions.
Buildings.Airflow.Multizone.Examples | Improved documentation of examples.
Buildings.Examples.DualFanDualDuct
Buildings.Examples.DualFanDualDuct.Controls.RoomMixingBox | Improved control of minimum air flow rate to avoid overheating.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.HeatTransfer
Buildings.HeatTransfer.Convection.Exterior | Fixed error in assignment of wind-based convection coefficient. The old implementation did not take into account the surface roughness.
Buildings.Rooms
Buildings.Rooms.BaseClasses.SolarRadiationExchange | In the previous version, the radiative properties of the long-wave spectrum instead of the solar spectrum have been used to compute the distribution of the solar radiation among the surfaces inside the room.
Buildings.Rooms.BaseClasses.MixedAir | Added missing connect statement between window frame surface and window frame convection model. Prior to this bug fix, no convective heat transfer was computed between window frame and room air.
Buildings.Rooms.BaseClasses.HeatGain | Fixed bug that caused convective heat gains to be removed from the room instead of added to the room.

The following issues have been fixed:

Buildings.Fluid.HeatExchangers.Boreholes
#45 | Dymola 2012 FD01 hangs when simulating a borehole heat exchanger. This was caused by a wrong release of memory in `freeArray.c`.
Buildings.Rooms
#46 | The convective internal heat gain has the wrong sign.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_0_build2 "Version 1.0 build 2" extends Modelica.Icons.ReleaseNotes; end Version_1_0_build2;

## Buildings.UsersGuide.ReleaseNotes.Version_1_0_build1

Version 1.0 build 1

### Information

Version 1.0 is the first official release of the `Buildings` library. Compared to the last pre-release, which is version 0.12, this version contains new models as well as significant improvements to the model formulation that leads to faster and more robust simulation. A detailed list of changes is shown below.

Version 1.0 is not backward compatible to version 0.12, i.e., models developed with versions 0.12 will require some changes in their parameters to work with version 1.0. The conversion script Buildings/Resources/Scripts/Dymola/ConvertBuildings_from_0.12_to_1.0.mos can help in converting old models to this version of the library.

The following new libraries have been added:

Buildings.Fluid.HeatExchangers.Boreholes | This is a library with a model for a borehole heat exchanger.

The following new components have been added to existing libraries:

Buildings.Airflow.Multizone
Buildings.Airflow.Multizone.BaseClasses.windPressureLowRise | Added a function that computes wind pressure on the facade of low-rise buildings.
Buildings.Examples
Buildings.Examples.ChillerPlant | Added an example for a chilled water plant model.
Buildings.Fluid.Interfaces
Buildings.Fluid.Interfaces.UsersGuide | Added a user's guide that describes the main functionality of all base classes.
Buildings.Fluid.Sources
Buildings.Fluid.Sources.Outside_Cp Buildings.Fluid.Sources.Outside_CpLowRise | Added models to compute wind pressure on building facades.
Buildings.HeatTransfer
Buildings.HeatTransfer.Conductor | Added a model for heat conduction in circular coordinates.
Buildings.Rooms.Examples
Buildings.Rooms.Examples.BESTEST | Added BESTEST validation models.
Buildings.Utilities.Math
Buildings.Utilities.Math.Functions.cubicHermiteLinearExtrapolation Buildings.Utilities.Math.Functions.splineDerivatives. | Added functions for cubic hermite spline interpolation, with option for monotone increasing (or decreasing) spline.

The following existing components have been improved in a backward compatible way:

Buildings.Airflow.Multizone
Buildings.Airflow.Multizone.BaseClasses.powerLaw | This function has been reimplemented to handle zero flow rate in a more robust and more efficient way. This change improves all components that model flow resistance in the package Buildings.Airflow.Multizone.
Buildings.BoundaryConditions.WeatherData
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 | This model has now the option of using a constant value, using the data from the weather file, or from an input connector for 7 variables, including atmospheric pressure, relative humidity, dry bulb temperature, global horizontal radiation, diffuse horizontal radiation, wind direction and wind speed.
Buildings.Fluid
Buildings.Fluid.Actuators.BaseClasses.PartialActuator Buildings.Fluid.Actuators.BaseClasses.PartialDamperExponential Buildings.Fluid.Actuators.BaseClasses.PartialTwoWayValve Buildings.Fluid.BaseClasses.PartialResistance Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_dp Buildings.Fluid.BaseClasses.FlowModels.basicFlowFunction_m_flow Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger | The computation of the linearized flow resistance has been moved from the functions to the model, i.e., into an equation section. If the linear implementation is in a function body, then a symbolic processor may not invert the equation. This can lead to systems of coupled equations in cases where an explicit solution is possible. In addition, the handling of zero flow rate has been improved for the nonlinear pressure drop model. These improvements affect all models in `Buildings.Fluid` that compute flow resistance.
Buildings.Fluid.HeatExchangers
Buildings.Fluid.HeatExchangers.HeaterCoolerPrescribed | This model can now be configured as a steady-state or dynamic model.
Buildings.Fluid.HeatExchangers.DryCoilCounterFlow Buildings.Fluid.HeatExchangers.WetCoilCounterFlow Buildings.Fluid.HeatExchangers.DryCoilDiscretized Buildings.Fluid.HeatExchangers.WetCoilDiscretized | The implementation for handling zero flow rate, if the models are used as steady-state models, have been improved.
Buildings.Fluid.HeatExchangers.BaseClasses.ntu_epsilonZ | Changed implementation to use `Modelica.Media.Common.OneNonLinearEquation` instead of `Buildings.Utilities.Math.BaseClasses.OneNonLinearEquation`, which was removed for this version of the library.
Buildings.Fluid.HeatExchangers.CoolingTowers
Buildings.Fluid.HeatExchangers.CoolingTowers.YorkCalc Buildings.Fluid.HeatExchangers.CoolingTowers.FixedApproach | These models are now based on a new base class `Buildings.Fluid.HeatExchangers.CoolingTowers.BaseClasses.CoolingTower`. This allows using the models as replaceable models without warning when checking the model.
Buildings.Fluid.HeatExchangers.CoolingTowers.YorkCalc | Changed implementation of performance curve to avoid division by zero.
Buildings.Fluid.MassExchangers
Buildings.Fluid.MassExchangers.HumidifierPrescribed | This model can now be configured as a steady-state or dynamic model.
Buildings.Fluid.Sensors
Buildings.Fluid.Sensors.*TwoPort | All sensors with two ports, except for the mass flow rate sensor, have been revised to add sensor dynamics. Adding sensor dynamics avoids numerical problems when mass flow rates are close to zero and the sensor is configured to allow flow reversal. See Buildings.Fluid.Sensors.UsersGuide for details.
Buildings.Fluid.Storage
Buildings.Fluid.Storage.Stratified Buildings.Fluid.Storage.StratifiedEnhanced | Changed the implementation of the model `Buoyancy` to make it differentiable in the temperatures.
Buildings.Media
Buildings.Media.Interfaces.PartialSimpleMedium Buildings.Media.Interfaces.PartialSimpleIdealGasMedium | Moved the assignment of the `stateSelect` attribute for the `BaseProperties` to the model `Buildings.Fluid.MixingVolumes.MixingVolume`. This allows to handle it differently for steady-state and dynamic models.
Buildings.Utilities.Psychrometrics
Buildings.Utilities.Psychrometrics.Functions.TDewPoi_pW | Changed implementation to use `Modelica.Media.Common.OneNonLinearEquation` instead of `Buildings.Utilities.Math.BaseClasses.OneNonLinearEquation`, which was removed for this version of the library.

The following existing components have been improved in a non-backward compatible way:

Buildings.Airflow.Multizone
Buildings.Airflow.Multizone.MediumColumnDynamic | The implementation has been changed to better handle mass flow rates near zero flow. This required the introduction of a new parameter `m_flow_nominal` that is used for the regularization near zero mass flow rate.
Buildings.Fluid
Buildings.Fluid.Storage.Examples.Stratified Buildings.Fluid.MixingVolumes | Removed the parameters `use_T_start` and `h_start`, as `T_start` is more convenient to use than `h_start` for building simulation.
Buildings.Fluid.Boilers
Buildings.Fluid.Boilers.BoilerPolynomial | The parameter `dT_nominal` has been removed as it can be computed from the parameter `m_flow_nominal`. This change was needed to avoid a non-literal value for the nominal attribute for the mass flow rate in the pressure drop model.
Buildings.Fluid.MixingVolumes
Buildings.Fluid.MixingVolumes.MixingVolume Buildings.Fluid.MixingVolumes.MixingVolumeDryAir Buildings.Fluid.MixingVolumes.MixingVolumeMoistAir | The implementation has been changed to better handle mass flow rates near zero flow if the components have exactly two fluid ports connected. This required the introduction of a new parameter `m_flow_nominal` that is used for the regularization near zero mass flow rate.
Buildings.Fluid.Movers
Buildings.Fluid.Movers.SpeedControlled_y Buildings.Fluid.Movers.SpeedControlled_Nrpm Buildings.Fluid.Movers.FlowControlled_dp Buildings.Fluid.Movers.FlowControlled_m_flow | The performance data are now defined through records and not through replaceable functions. The performance data now needs to be declared in the form
     pressure(V_flow_nominal={0,V_flow_nominal,2*V_flow_nominal},
              dp_nominal={2*dp_nominal,dp_nominal,0})
where `pressure` is an instance of a record. A similar declaration is used for power and efficiency. The parameter m_flow_nominal has been removed from FlowMachine_y and FlowMachine_Nrpm. The parameter m_flow_max has been replaced by m_flow_nominal in FlowMachine_m_flow. The implementation of the pressure drop computation as a function of speed and volume flow rate has been revised to avoid a singularity near zero volume flow rate and zero speed. The implementation has also been simplified to avoid using two different flow paths if the models are configured for steady-state or dynamic simulation.
Buildings.Fluid.Interfaces
Buildings.Fluid.Interfaces.FourPortHeatMassExchanger Buildings.Fluid.Interfaces.PartialDynamicStaticFourPortHeatMassExchanger Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger Buildings.Fluid.Interfaces.PartialDynamicStaticTwoPortHeatMassExchanger Buildings.Fluid.Interfaces.ConservationEquation | The implementation has been changed to better handle mass flow rates near zero flow if the components have exactly two fluid ports connected.
Buildings.Fluid.Sensors
Buildings.Fluid.Sensors.TemperatureTwoPortDynamic | This model has been deleted since the sensor Buildings.Fluid.Sensors.TemperatureTwoPort has been revised and can now also be used as a dynamic model of a sensor.
Buildings.Fluid.Interfaces
Buildings.Fluid.Interfaces.PartialStaticTwoPortInterface | Renamed to Buildings.Fluid.Interfaces.PartialTwoPortInterface
Buildings.Fluid.Interfaces.PartialStaticStaticTwoPortHeatMassExchanger | Renamed to Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger
Buildings.Fluid.Interfaces.PartialTwoPortHeatMassExchanger | Renamed to Buildings.Fluid.Interfaces.TwoPortHeatMassExchanger
Buildings.Fluid.Interfaces.PartialFourPort | Renamed to Buildings.Fluid.Interfaces.FourPort
Buildings.Fluid.Interfaces.PartialStaticStaticFourPortHeatMassExchanger | Renamed to Buildings.Fluid.Interfaces.StaticFourPortHeatMassExchanger
Buildings.Fluid.Interfaces.PartialStaticFourPortInterface | Renamed to Buildings.Fluid.Interfaces.PartialFourPortInterface
Buildings.Fluid.Interfaces.PartialFourPortHeatMassExchanger | Renamed to Buildings.Fluid.Interfaces.FourPortHeatMassExchanger
Buildings.Utilities.Math
Buildings.Utilities.Math.BaseClasses.OneNonLinearEquation | This package has been removed, and all functions have been revised to use Modelica.Media.Common.OneNonLinearEquation.
Buildings.Utilities.Reports
Buildings.Utilities.Reports.Printer Buildings.Utilities.Reports.printRealArray | Changed parameter `precision` to `significantDigits` and `minimumWidth` to `minimumLength` to use the same terminology as the Modelica Standard Library.

The following critical errors have been fixed (i.e., errors that can lead to wrong simulation results):

Buildings.BoundaryConditions
Buildings.BoundaryConditions.SkyTemperature.BlackBody | Fixed error in `if-then` statement that led to a selection of the wrong branch to compute the sky temperature.
Buildings.Media
Buildings.Media.PartialSimpleMedium Buildings.Media.GasesConstantDensity.SimpleAir | Fixed error in assignment of `singleState` parameter. This change can lead to different initial conditions if the density of water is modeled as a function of pressure, or if the medium model Buildings.Media.GasesConstantDensity.SimpleAir is used.
Buildings.Media.GasesConstantDensity Buildings.Media.GasesConstantDensity.MoistAir Buildings.Media.GasesConstantDensity.MoistAirUnsaturated Buildings.Media.GasesConstantDensity.SimpleAir | Fixed error in the function `density` which returned a non-constant density, and added a call to `ModelicaError(...)` in `setState_dTX` since this function cannot assign the medium pressure based on the density (as density is a constant in this model).
Buildings.Media.Interfaces.PartialSimpleIdealGasMedium | Updated package with a new copy from the Modelica Standard Library, since the Modelica Standard Library fixed a bug in computing the internal energy of the medium. This bug led to very fast temperature transients at the start of the simulation.
Buildings.Media.Interfaces.PartialSimpleMedium | Fixed bug in function density, which always returned `d_const`, regardless of the value of `constantDensity`.
Buildings.Media.GasesPTDecoupled | Fixed bug in `u=h-R*T`, which is only valid for ideal gases. For this medium, the function is `u=h-pStd/dStp`.
Buildings.Media.GasesConstantDensity | Fixed bug in `u=h-R*T`, which is only valid for ideal gases. For this medium, the function is `u=h-p/dStp`.
Buildings.Rooms
Buildings.Rooms.MixedAir Buildings.Rooms.BaseClasses.ExteriorBoundaryConditions | Fixed bug (issue 35) that leads to the wrong solar heat gain for roofs and for floors. Prior to this bug fix, the outside facing surface of a ceiling received solar irradiation as if it were a floor and vice versa.
Buildings.Rooms.MixedAir Buildings.Rooms.BaseClasses.ExteriorBoundaryConditionsWithWindow | Fixed bug (issue 36) that leads to too high a surface temperature of the window frame when it receives solar radiation. The previous version did not compute the infrared radiation exchange between the window frame and the sky.

The following uncritical errors have been fixed (i.e., errors that do not lead to wrong simulation results, but, e.g., units are wrong or errors in documentation):

Buildings.BoundaryConditions
Buildings.BoundaryConditions.WeatherData.BaseClasses.ConvertRadiation | Corrected wrong unit label.

The following issues have been fixed:

Buildings.BoundaryConditions
#8 | Add switches for new data.
#19 | Shift the time for the radiation data 30 min forth and output the local civil time in the data reader.
#41 | Using when-then sentences to reduce CPU time.
#43 | Add a ConvertRadiation to convert the unit of radiation from TMY3.
Buildings.Fluid
#28 | Move scripts to Buildings\Resources\Scripts\Dymola.
Buildings.HeatTransfer
#18 | Add a smooth interpolation function to avoid the event.
Buildings.Media
#30 | Removed non-required structurally incomplete annotation.
Buildings.Rooms
#35 | Wrong surface tilt for radiation at exterior surfaces of floors and ceilings.
#36 | High window frame temperatures.

Note:

- The version number scheme has been changed. It is now identical to the one used by the Modelica Standard Library. Versions are identified with two numbers `x.y` and a build number. The first official release of each version has the build number `1`. For each released bug fix, the build number is incremented. See Modelica.UsersGuide.ReleaseNotes.VersionManagement for details.
- To allow adding scripts for multiple simulation environments, all scripts have been moved to the directory `Buildings/Resources/Scripts/Dymola` and the annotation that generates the entry in the `Command` pull down menu has been changed to `__Dymola_Commands(file=...`

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_1_0_build1 "Version 1.0 build 1" extends Modelica.Icons.ReleaseNotes; end Version_1_0_build1;

## Buildings.UsersGuide.ReleaseNotes.Version_0_12_0

Version 0.12.0

### Information

Note: The packages whose name ends with `Beta` are still being validated.

The following critical error has been fixed (i.e. error that can lead to wrong simulation results):

Buildings.Rooms
Buildings.Rooms.BaseClasses.InfraredRadiationExchange | The model `Buildings.Rooms.BaseClasses.InfraredRadiationExchange` had an error in the view factor approximation. The error caused too much radiosity to flow from large to small surfaces because the law of reciprocity for view factors was not satisfied. This led to low surface temperatures if a surface had a large area compared to other surfaces. The bug has been fixed by rewriting the view factor calculation.

The following improvements and additions have been made:

- Updated library to Modelica 3.2.
- Added `homotopy` operator.
- Restructured package Buildings.HeatTransfer.
- Rewrote the models in Buildings.Fluid.Actuators to avoid having the flow coefficient `k` as an algebraic variable. This increases robustness.
- Rewrote energy, species and trace substance balance in Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger to better handle zero mass flow rate.
- Implemented functions `enthalpyOfCondensingGas` and `saturationPressure` in single substance media to allow use of the room model with media that do not contain water vapor.
- Revised Buildings.Fluid.Sources.Outside to allow use of the room model with media that do not contain water vapor.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_12_0 "Version 0.12.0" extends Modelica.Icons.ReleaseNotes; end Version_0_12_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_11_0

Version 0.11.0

### Information

Note: The packages whose name ends with `Beta` are still being validated.

- Added the package Buildings.Rooms to compute heat transfer in rooms and through the building envelope. Multiple instances of these models can be connected to create a multi-zone building model.
- Added the package Buildings.HeatTransfer.Windows to compute heat transfer (solar radiation, infrared radiation, convection and conduction) through glazing systems.
- In package Buildings.Fluid.Chillers, added the chiller models Buildings.Fluid.Chillers.ElectricReformulatedEIR and Buildings.Fluid.Cphillers.ElectricEIR, and added the package Buildings.Fluid.Chillers.Data that contains data sets of chiller performance data.
- Added package Buildings.BoundaryConditions with models to compute boundary conditions, such as solar irradiation and sky temperature.
- Added package Buildings.Utilities.IO.WeatherData with models to read weather data in the TMY3 format.
- Revised the package Buildings.Fluid.Sensors.
- Revised the package Buildings.Fluid.HeatExchangers.CoolingTowers.
- In Buildings.Fluid.Interfaces.StaticFourPortHeatMassExchanger and Buildings.Fluid.Interfaces.StaticFourPortHeatMassExchanger, fixed bug in energy and moisture balance that affected results if a component adds or removes moisture to the air stream. In the old implementation, the enthalpy and species outflow at `port_b` was multiplied with the mass flow rate at `port_a`. The old implementation led to small errors that were proportional to the amount of moisture change. For example, if the moisture added by the component was `0.005 kg/kg`, then the error was `0.5%`. Also, the results for forward flow and reverse flow differed by this amount. With the new implementation, the energy and moisture balance is exact.
- In Buildings.Fluid.Interfaces.ConservationEquation and in Buildings.Media.Interfaces.PartialSimpleMedium, set nominal attribute for medium to provide consistent normalization. Without this change, Dymola 7.4 uses different values for the nominal attribute based on the value of `Advanced.OutputModelicaCodeWithJacobians=true/false;` in the model Buildings.Examples.HydronicHeating.
- Fixed bug in energy balance of Buildings.Fluid.Chillers.Carnot.
- Fixed bug in efficiency curves in package Buildings.Fluid.Movers.BaseClasses.Characteristics.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_11_0 "Version 0.11.0" extends Modelica.Icons.ReleaseNotes; end Version_0_11_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_10_0

Version 0.10.0

### Information

- Added package Buildings.Airflow.Multizone with models for multizone airflow and contaminant transport.
- Added the model Buildings.Utilities.Comfort.Fanger for thermal comfort calculations.
- Rewrote Buildings.Fluid.Storage.BaseClasses.ThirdOrderStratifier, which is used in Buildings.Fluid.Storage.StratifiedEnhanced, to avoid state events when the flow reverses. This leads to faster and more robust simulation.
- In models of package Buildings.Fluid.MixingVolumes, added nominal value for `mC` to avoid wrong trajectory when concentration is around 1E-7. See also https://trac.modelica.org/Modelica/ticket/393.
- Fixed bug in fan and pump models that led to too small an enthalpy increase across the flow device.
- In model Buildings.Fluid.Movers.FlowControlled_dp, changed `assert(dp_in >= 0, ...)` to `assert(dp_in >= -0.1, ...)`. The former implementation triggered the assert if `dp_in` was solved for in a nonlinear equation since the solution can be slightly negative while still being within the solver tolerance.
- Added model Buildings.Controls.SetPoints.Table that allows the specification of a floating setpoint using a table of values.
- Revised model Buildings.Fluid.HeatExchangers.Radiators.RadiatorEN442_2. The new version has exactly the same nominal power during the simulation as specified by the parameters. This also required a change in the parameters.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_10_0 "Version 0.10.0" extends Modelica.Icons.ReleaseNotes; end Version_0_10_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_9_1

Version 0.9.1

### Information

The following critical error has been fixed (i.e. error that can lead to wrong simulation results):

Buildings.Fluid.Storage.
Buildings.Fluid.Storage.StratifiedEnhanced | The model `Buildings.Fluid.Storage.BaseClasses.Stratifier` had a sign error that lead to a wrong energy balance. The model that was affected by this error is Buildings.Fluid.Storage.StratifiedEnhanced. The model Buildings.Fluid.Storage.Stratified was not affected. The bug has been fixed by using the newly introduced model Buildings.Fluid.Storage.BaseClasses.ThirdOrderStratifier. This model uses a third-order upwind scheme to reduce the numerical dissipation instead of the correction term that was used in `Buildings.Fluid.Storage.BaseClasses.Stratifier`. The model `Buildings.Fluid.Storage.BaseClasses.Stratifier` has been removed since it also led to significant overshoot in temperatures when the stratification was pronounced.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_9_1 "Version 0.9.1" extends Modelica.Icons.ReleaseNotes; end Version_0_9_1;

## Buildings.UsersGuide.ReleaseNotes.Version_0_9_0

Version 0.9.0

### Information

- Added the following heat exchanger models
  - Buildings.Fluid.HeatExchangers.DryEffectivenessNTU for a sensible heat exchanger that uses the `epsilon-NTU` relations to compute the heat transfer.
  - Buildings.Fluid.HeatExchangers.DryCoilCounterFlow and Buildings.Fluid.HeatExchangers.WetCoilCounterFlow to model a coil without and with water vapor condensation. These models approximate the coil as a counterflow heat exchanger.
- Revised air damper Buildings.Fluid.Actuators.BaseClasses.exponentialDamper. The new implementation avoids warnings and leads to faster convergence since the solver does not attempt anymore to solve for a variable that needs to be strictly positive.
- Revised package Buildings.Fluid.Movers to allow zero flow for some pump or fan models. If the input to the model is the control signal `y`, then the flow is equal to zero if `y=0`. This change required rewriting the package to avoid division by the rotational speed.
- Revised package Buildings.HeatTransfer to include a model for a multi-layer construction, and to allow individual material layers to be computed steady-state or transient.
- In package Buildings.Fluid, changed models so that if the parameter `dp_nominal` is set to zero, then the pressure drop equation is removed. This allows, for example, to model a heating and a cooling coil in series, and lump there pressure drops into a single element, thereby reducing the dimension of the nonlinear system of equations.
- Added model Buildings.Controls.Continuous.LimPID, which is identical to Modelica.Blocks.Continuous.LimPID, except that it allows reverse control action. This simplifies use of the controller for cooling applications.
- Added model Buildings.Fluid.Actuators.Dampers.MixingBox for an outside air mixing box with air dampers.
- Changed implementation of flow resistance in Buildings.Fluid.Actuators.Dampers.MixingBoxMinimumFlow. Instead of using a fixed resistance and a damper model in series, only one model is used that internally adds these two resistances. This leads to smaller systems of nonlinear equations.
- Changed Buildings.Media.PerfectGases.MoistAir.T_phX (and by inheritance all other moist air medium models) to first compute `T` in closed form assuming no saturation. Then, a check is done to determine whether the state is in the fog region. If the state is in the fog region, then `Internal.solve` is called. This new implementation can lead to significantly shorter computing time in models that frequently call `T_phX`.
- Added package Buildings.Media.GasesConstantDensity which contains medium models for dry air and moist air. The use of a constant density avoids having pressure as a state variable in mixing volumes. Hence, fast transients introduced by a change in pressure are avoided. The drawback is that the dimensionality of the coupled nonlinear equation system is typically larger for flow networks.
- In Buildings.Fluid.Actuators.BaseClasses.PartialDamperExponential, added default value for parameter `A` to avoid compilation error if the parameter is disabled but not specified.
- Simplified the mixing volumes in Buildings.Fluid.MixingVolumes by removing the port velocity, pressure drop and height.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_9_0 "Version 0.9.0" extends Modelica.Icons.ReleaseNotes; end Version_0_9_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_8_0

Version 0.8.0

### Information

- In Buildings.Fluid.Interfaces.ConservationEquation, added to `Medium.BaseProperties` the initialization `X(start=X_start[1:Medium.nX])`. Previously, the initialization was only done for `Xi` but not for `X`, which caused the medium to be initialized to `reference_X`, ignoring the value of `X_start`.
- Renamed `Buildings.Media.PerfectGases.MoistAirNonSaturated` to Buildings.Media.PerfectGases.MoistAirUnsaturated and `Buildings.Media.GasesPTDecoupled.MoistAirNoLiquid` to Buildings.Media.Air, and added `assert` statements if saturation occurs.
- Added regularizaation near zero flow to Buildings.Fluid.HeatExchangers.ConstantEffectiveness and Buildings.Fluid.MassExchangers.ConstantEffectiveness.
- Fixed bug regarding temperature offset in Buildings.Media.PerfectGases.MoistAirUnsaturated.T_phX.
- Added implementation of function Buildings.Media.Air.enthalpyOfNonCondensingGas and its derivative.
- In Buildings.Media.PerfectGases.MoistAir, fixed bug in implementation of Buildings.Media.PerfectGases.MoistAir.T_phX. In the previous version, it computed the inverse of its parent class, which gave slightly different results.
- In Buildings.Utilities.IO.BCVTB.BCVTB, added parameter to specify the value to be sent to the BCVTB at the first data exchange, and added parameter that deactivates the interface. Deactivating the interface is sometimes useful during debugging.
- In Buildings.Media.GasesPTDecoupled.MoistAir and in Buildings.Media.PerfectGases.MoistAir, added function `enthalpyOfNonCondensingGas` and its derivative.
- In Buildings.Media, fixed bug in implementations of derivatives.
- Added model Buildings.Fluid.Storage.ExpansionVessel.
- Added Wrapper function Buildings.Fluid.Movers.BaseClasses.Characteristics.solve for Modelica.Math.Matrices.solve. This is currently needed since Modelica.Math.Matrices.solve does not specify a derivative.
- Fixed bug in Buildings.Fluid.Storage.Stratified. In the previous version, for computing the heat conduction between the top (or bottom) segment and the outside, the whole thickness of the water volume was used instead of only half the thickness.
- In Buildings.Media.ConstantPropertyLiquidWater, added the option to specify a compressibility. This can help reducing the size of the coupled nonlinear system of equations, at the expense of introducing stiffness. This change required to change the inheritance tree of the medium. Its base class is now Buildings.Media.Interfaces.PartialSimpleMedium, which contains the equation for the compressibility. The default setting will model the flow as incompressible.
- In Buildings.Controls.Continuous.Examples.PIDHysteresis and Buildings.Controls.Continuous.Examples.PIDHysteresisTimer, fixed error in default parameter `eOn`. Fixed error by introducing parameter `Td`, which used to be hard-wired in the PID controller.
- Added more models for fans and pumps to the package Buildings.Fluid.Movers. The models are similar to the ones in Modelica.Fluid.Machines but have been adapted for air-based systems, and to include more characteristic curves in Buildings.Fluid.Movers.BaseClasses.Characteristics. The new models are better suited than the existing fan model Buildings.Fluid.Movers.FlowMachinePolynomial for zero flow rate.
- Added an optional mixing volume to Buildings.Fluid.BaseClasses.PartialThreeWayResistance and hence to the flow splitter and to the three-way valves. This often breaks algebraic loops and provides a state for the temperature if the mass flow rate goes to zero.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_8_0 "Version 0.8.0" extends Modelica.Icons.ReleaseNotes; end Version_0_8_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_7_0

Version 0.7.0

### Information

- Updated library from Modelica_Fluid to Modelica.Fluid 1.0
- Merged sensor and source models from Modelica.Fluid to Buildings.Fluid.
- Added sensor for sensible and latent enthalpy flow rate, Buildings.Fluid.Sensors.SensibleEnthalpyFlowRate and Buildings.Fluid.Sensors.LatentEnthalpyFlowRate. These sensors are needed, for example, to interface air-conditioning systems that are modeled with Modelica with the Building Controls Virtual Test Bed.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_7_0 "Version 0.7.0" extends Modelica.Icons.ReleaseNotes; end Version_0_7_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_6_0

Version 0.6.0

### Information

- Added the package Buildings.Utilities.IO.BCVTB which contains an interface to the Building Controls Virtual Test Bed.
- Updated license to Modelica License 2.
- Replaced Buildings.Utilities.Psychrometrics.HumidityRatioPressure.mo by Buildings.Utilities.Psychrometrics.HumidityRatio_pWat.mo and Buildings.Utilities.Psychrometrics.VaporPressure_X.mo because the old model used `RealInput` ports, which are obsolete in Modelica 3.0.
- Changed the base class Buildings.Fluid.Interfaces.StaticTwoPortHeatMassExchanger to enable computation of pressure drop of mechanical equipment.
- Introduced package Buildings.Fluid.BaseClasses.FlowModels to model pressure drop, and rewrote Buildings.Fluid.BaseClasses.PartialResistance.
- Redesigned package Buildings.Utilities.Math to allow having blocks and functions with the same name. Functions are now in Buildings.Utilities.Math.Functions.
- Fixed sign error in Buildings.Fluid.Storage.BaseClasses.Stratifier which caused a wrong energy balance in Buildings.Fluid.Storage.StratifiedEnhanced.
- Renamed `Buildings.Fluid.HeatExchangers.HeaterCoolerIdeal` to Buildings.Fluid.HeatExchangers.HeaterCoolerPrescribed to have the same nomenclatures as is used for Buildings.Fluid.MassExchangers.HumidifierPrescribed
- In Buildings.Fluid/Actuators/BaseClasses/PartialDamperExponential, added option to compute linearization near zero based on the fraction of nominal flow instead of the Reynolds number. This was set as the default, as it leads most reliably to a model parametrization that leads to a derivative `d m_flow/d p` near the origin that is not too steep for a Newton-based solver.
- In damper and VAV box models, added optional parameters to allow specifying the nominal face velocity instead of the area.
- Set nominal attribute for pressure drop `dp` in Buildings.Fluid.BaseClasses.PartialResistance and in its child classes.
- Added models for chiller ( Buildings.Fluid.Chillers.Carnot), for occupancy ( Buildings.Controls.SetPoints.OccupancySchedule) and for blocks that take a vector as an argument ( Buildings.Utilities.Math.Min, Buildings.Utilities.Math.Max, and Buildings.Utilities.Math.Average).
- Changed various variable names to be consistent with naming convention used in Modelica.Fluid 1.0.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_6_0 "Version 0.6.0" extends Modelica.Icons.ReleaseNotes; end Version_0_6_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_5_0

Version 0.5.0

### Information

- Updated library to Modelica.Fluid 1.0.
- Moved most examples from package Buildings.Fluid.Examples to the example directory in the package of the individual model.
- Renamed package Buildings.Utilites.Controls to Buildings.Utilites.Diagnostics.
- Introduced packages Buildings.Controls, Buildings.HeatTransfer (which contains models for heat transfer that generally does not involve modeling of the fluid flow), Buildings.Fluid.Boilers and Buildings.Fluid.HeatExchangers.Radiators.
- Changed valve models in Buildings.Fluid.Actuators.Valves so that `Kv` or `Cv` can be used as the flow coefficient (in [m3/h] or [USG/min]).

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_5_0 "Version 0.5.0" extends Modelica.Icons.ReleaseNotes; end Version_0_5_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_4_0

Version 0.4.0

### Information

- Added package Buildings.Fluid.Storage with models for thermal energy storage.
- Added a steady-state model for a heat and moisture exchanger with constant effectiveness. See Buildings.Fluid.MassExchangers.ConstantEffectiveness
- Added package Buildings.Utilities.Reports. The package contains models that facilitate reporting.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_4_0 "Version 0.4.0" extends Modelica.Icons.ReleaseNotes; end Version_0_4_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_3_0

Version 0.3.0

### Information

- Added package Buildings.Fluid.Sources. The package contains models for modeling species that do not affect the medium balance of volumes. This can be used to track for example carbon dioxide or other species that have a small concentration.
- The package Buildings.Fluid.Actuators.Motors has been added. The package contains a motor model for valves and dampers.
- The package Buildings.Media has been reorganized and the new medium model Buildings.Media.GasesPTDecoupled.MoistAir has been added.
  In addition, this package now contains a bug fix that is needed for Modelica 2.2.1 and 2.2.2. The bugs are fixed by using a new base class Buildings.Media.Interfaces.PartialSimpleIdealGasMedium (that fixes the bugs) instead of Modelica.Media.Interfaces.PartialSimpleIdealGasMedium. In the original implementation, initial states of fluid volumes can be far away from the steady-state value because of an inconsistent implementation of the enthalpy and internal energy. When the `Buildings` library is upgraded to to Modelica 3.0.0, it should be safe to remove this bug fix.
- The package Buildings.Fluid.HeatExchangers has been revised and several models have been renamed. The heat exchanger models have been revised to allow computing the fluid volumes either dynamically, or in steady-state.
- The damper with exponential opening characteristic has been revised to allow control signals over the whole range between `0` and `1`. This was in earlier versions restricted. In the same model, a bug was fixed that caused the flow to be largest for `y=0`, i.e., when the damper is closed.
- Additional models for psychrometric equations have been added. The new models contain equations that convert dew point temperature and water vapor pressure, as well as water vapor concentration and water vapor pressure.
- A new mixing volume has been added that allows latent heat exchange with the volume. This model can be used to model a volume of moist air with water vapor condensation inside the volume. The condensate is removed from the volume in its liquid phase.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_3_0 "Version 0.3.0" extends Modelica.Icons.ReleaseNotes; end Version_0_3_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_2_0

Version 0.2.0

### Information

New in this version are models for two and three way valves. In addition, the `Fluids` package has been slightly revised. The package `Fluid.BaseClasses` has been added because in the previous version, partial models for fixed resistances where part of the `Actuator` package.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_2_0 "Version 0.2.0" extends Modelica.Icons.ReleaseNotes; end Version_0_2_0;

## Buildings.UsersGuide.ReleaseNotes.Version_0_1_0

Version 0.1.0

### Information

First release of the library.

This version contains basic models for modeling building HVAC systems. It also contains new medium models in the package Buildings.Media. These medium models have simpler property functions than the ones from Modelica.Media. For example, there is medium model with constant heat capacity which is often sufficiently accurate for building HVAC simulation, in contrast to the more detailed models from Modelica.Media that are valid in a larger temperature range, at the expense of introducing non-linearities due to the medium properties.

Extends from Modelica.Icons.ReleaseNotes (Icon for release notes in documentation).

### Modelica definition

class Version_0_1_0 "Version 0.1.0" extends Modelica.Icons.ReleaseNotes; end Version_0_1_0;