Performance Curves

Location = Libraries/Controls and Performance Data/Perf Curves

 

The Perf Curves (Performance Curves) Library is where the user can specify and/or review polynomial curves characterizing the performance of different types of HVAC equipment.  In addition other non-polynomial curves for pumps and fans are included.   Curve input always contain a range of validity (min. and max. permitted values) for each independent variable and can optionally have limits on the curve output.

 

Each Type in the Type and Sub Type table contains a section that displays a screenshot of the Property Values Table showing the properties associated with the Type and Sub Type.  In the case where the Sub Types have the same properties only one example of the Property Values table is shown.  See Property Values Table to learn about how to interact with the table.

Note: Although not yet fully implemented the intent is that for each section there will be links directly to the EnergyPlus Input Output Reference.  In addition the links will also be included in the Type and Sub Type Mapping Table.

Type and Sub Type Mapping

The table displays the Type and Sub Type options that can be selected from the drop down lists in that area of the workspace, which filter the Source Library to display the variables that the user can specify values for to edit or create a Library Entry.  The last column identifies the EnergyPlus Property Category (object) associated with the Simergy combination of types and sub types.  

Note: The links within the table are to the EnergyPlus Input Output Reference and the explanations of the objects.

 

Select Type Options Select Sub Type Options EnergyPlus Property Category

Mathematical

 Linear
QuadLinear
Quadratic
Cubic
Quartic
Exponent
BiQuadratic
BiCubic
QuadraticLinear
TriQuadratic
FanPressureRise
ExponentialSkewNormal
Sigmoid
RectangularHyperbola1
RectangularHyperbola2
ExponentialDecay
DoubleExponentialDecay
ChillerPartLoadwithLift
CubicLinear		 Curve:Linear
Curve:QuadLinear
Curve:Quadratic
Curve:Cubic
Curve:Quartic
Curve:Exponent
Curve:BiQuadratic
Curve:BiCubic
Curve:QuadraticLinear
Curve:TriQuadratic
Curve:FanPressureRise
Curve:ExponentialSkewNormal
Curve:Sigmoid
Curve:RectangularHyperbola1
Curve:RectangularHyperbola2
Curve:ExponentialDecay
Curve:DoubleExponentialDecay
 
 
Relational

Pressure Drop

 Curve:Functional:PressureDrop
Variable MultiLookUp
OneIndependent
TwoIndependent		  

 

Sub Type Properties

Each Sub Type has a set of properties associated with it that allow the user to either enter text, numeric values, select from a drop down list that is tied to other libraries or a combination of text/numeric value entry and selection from drop down list.  In a majority of cases the properties displayed in the Property Values Table are the same as in EnergyPlus, so links are provided to the descriptions within the EnergyPlus documentation as well.

 

Mathematical: Linear

The equation for the linear curve is:

  y = C1 + C2 * x

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2x (Required)

[numeric value entry] The linear coefficient (C2) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Quadratic

The equation for the quadratic curve is:

  y = C1 + C2 * x +  C3 * x2  

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 (Required)

[numeric value entry] The linear coefficient (C2) in the equation above

Coefficient 3 (Required)

[numeric value entry] The quadratic coefficient (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Cubic

The equation for the cubic curve is:

  y = C1 + C2 * x +  C3 * x2  +  C4 * x3  

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 (Required)

[numeric value entry] The linear coefficient (C2) in the equation above

Coefficient 3 (Required)

[numeric value entry] The quadratic coefficient (C3) in the equation above

Coefficient 4 (Required)

[numeric value entry] The cubic coefficient (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Quartic

The equation for the quartic curve is:

  y = C1 + C2x +  C3x2 + C4x3 +  C5x4  

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 (Required)

[numeric value entry] The linear coefficient (C2) in the equation above

Coefficient 3 (Required)

[numeric value entry] The quadratic coefficient (C3) in the equation above

Coefficient 4 (Required)

[numeric value entry] The cubic coefficient (C3) in the equation above

Coefficient 5 (Required)

[numeric value entry] The fourth-order coefficient (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Exponent

The equation for the exponent curve is:

  y = C1 + C2 * xC3  

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 (Required)

[numeric value entry] The linear coefficient (C2) in the equation above

Coefficient 3 (Required)

[numeric value entry] The exponent coefficient (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Biquadratic

The curve type is a function of two independent variables.  The equation for the biquadratic curve is:

   z = C1 + C2 * x + C3 * x2 + C4 * y + C5 * y2 + C6 * xy 

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 to Coefficient 6 (Required)

[numeric value entry] The linear coefficients (C2) to (C6) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Value of y (Required)

[numeric value entry]   The minimum allowable value of y. Values of y less than the minimum will be replaced by the minimum.

Maximum Value of y (Required)

[numeric value entry]   The maximum allowable value of y. Values of y less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X and Y

[drop down list selection]   Indicates the kind of units that may be associated with the x and y values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Y and Maximum Value of X and Y. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Bicubic

The curve type is a function of two independent variables.  The equation for the bicubic curve is:

   z = C1 + C2 * x + C3 * x2 + C4 * y + C5 * y2 + C6 * xy + C7 * x3 + C8 * y3 + C9 * x2y + C10 * xy2 

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 to Coefficient 10 (Required)

[numeric value entry] The linear coefficients (C2) to (C10) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Value of y (Required)

[numeric value entry]   The minimum allowable value of y. Values of y less than the minimum will be replaced by the minimum.

Maximum Value of y (Required)

[numeric value entry]   The maximum allowable value of y. Values of y less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X and Y

[drop down list selection]   Indicates the kind of units that may be associated with the x and y values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Y and Maximum Value of X and Y. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Quadratic Linear

The curve type is a function of two independent variables.  The equation for the quadratic linear curve is:

   Curve Value = (C1 + C2 * x + C3 * x2 + C4 * x3) + (C4 + C5 * x + C6 * x2 ) * y 

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 to Coefficient 6 (Required)

[numeric value entry] The linear coefficients (C2) to (C6) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Value of y (Required)

[numeric value entry]   The minimum allowable value of y. Values of y less than the minimum will be replaced by the minimum.

Maximum Value of y (Required)

[numeric value entry]   The maximum allowable value of y. Values of y less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X and Y

[drop down list selection]   Indicates the kind of units that may be associated with the x and y values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Y and Maximum Value of X and Y. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Triquadratic

A second order polynomial function of three variable polynomial independent variables, which consists of twenty-seven coefficients.  The equation for the triquadratic curve is:

   Curve Value = A0 + A1 * x2 + A2 * x + A3 * y2 + A4 * y + A5 * z2 + A6 * z + A7 * x2y2 + A8 * xy + A9 * xy2 + A10 * x2y  + A11 * x2z2 + A12 * xz + A13 * xz2  + A14 * x2z  + A15 * y2z2  + A16 * yz  + A17 * yz2  + A18 * y2z  + A19 * x2y2z2 + A20 * x2y2z + A21 * x2yz2 + A22 * xy2z2 + A23 * x2yz + A24 * xy2z + A25 * xyz2 + A26 * xyz

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (A0) in the equation above

Coefficient 2 to Coefficient 27 (Required)

[numeric value entry] The linear coefficients (A1) to (A27) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Value of y (Required)

[numeric value entry]   The minimum allowable value of y. Values of y less than the minimum will be replaced by the minimum.

Maximum Value of y (Required)

[numeric value entry]   The maximum allowable value of y. Values of y less than the maximum will be replaced by the minimum.

Minimum Value of z (Required)

[numeric value entry]   The minimum allowable value of z. Values of z less than the minimum will be replaced by the minimum.

Maximum Value of z (Required)

[numeric value entry]   The maximum allowable value of z. Values of z less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X and Y and Z

[drop down list selection]   Indicates the kind of units that may be associated with the x,y and z values. It is used to display the appropriate SI and IP units for the Minimum Value of X,Y and Z and Maximum Value of X,Y and Z. The unit conversion is not applied to the coefficients. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The available options include:

Note:  If none of these options are appropriate, select Dimensionless which will have no unit conversion.

 

Mathematical: Fan Pressure Rise

The equation for the pressure rise curve is:

∆Pfan,tot = C1 * Q2fan + C2 * Qfan + C3 * Qfan * √Psm- P0 + C4 * (Psm- P0)

 

∆Pfan,tot = fan total pressure rise (Pa) as a function of the volumetric flow through the fan (Qfan ), duct static pressure set point (Psm), and static pressure surrounding the ducts (P0)

Fan Pressure Rise Coefficient C1 (Required)

[numeric value entry]  The required numeric constant coefficient C1 (Pa s2/m6) that must be greater than zero.

Fan Pressure Rise Coefficient C2 (Required)

[numeric value entry]  The required numeric constant coefficient C2 (Pa s/m3) in the curve.

Fan Pressure Rise Coefficient C3 (Required)

[numeric value entry]  The required numeric constant coefficient C3 (Pa0.5 s/m3) in the curve.

Fan Pressure Rise Coefficient C4 (Required)

[numeric value entry]  The required numeric constant coefficient C4 (dimensionless) in the curve.

Minimum Value of Qfan (Required)

[numeric value entry]   The minimum allowable value of Qfan (m3/s).  If values are less than the minimum, they will be replaced by the minimum.

Maximum Value of Qfan (Required)

[numeric value entry]   The maximum allowable value of Qfan (m3/s).  If values are more than the maximum, they will be replaced by the maximum.

Minimum Value of Psm (Required)

[numeric value entry]   The minimum allowable value of Psm (Pa).  If values are less than the minimum, they will be replaced by the minimum.

Maximum Value of Psm (Required)

[numeric value entry]   The maximum allowable value of Psm (Pa).  If values are more than the maximum, they will be replaced by the maximum.

Minimum Value of Curve Output

[numeric value entry]   The minimum allowable value of the elevated curve (Pa).  If values are less than the minimum, they will be replaced by the minimum.

Maximum Value of Curve Output  

[numeric value entry]   The maximum allowable value of the elevated curve (Pa).  If values are more than the maximum, they will be replaced by the maximum.

 

Mathematical: Exponential Skew Normal

See EnergyPlus Input Output Reference for detailed explanation.

 

Mathematical: Sigmoid

See EnergyPlus Input Output Reference for detailed explanation.

 

Mathematical: Rectangular Hyperbola 1

The equation for the rectangular hyperbola type 1 curve is:

  y = (C1 * x) / (C2 + x)  + C3

Coefficient 1 Constant (Required)

[numeric value entry]  The required constant coefficients (C1) (C2) (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The only available option is dimensionless

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The only available option is dimensionless

 

Mathematical: Rectangular Hyperbola 2

The equation for the rectangular hyperbola type 2 curve is:

  y = (C1 * x) / (C2 + x)  + C3 * x

Coefficient 1 Constant (Required)

[numeric value entry]  The required constant coefficients (C1) (C2) (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The only available option is dimensionless

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The only available option is dimensionless

Mathematical: Exponential Decay

The equation for the exponential decay curve is:

  y = C1 + C2 * exp(C3 * x)  

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 (Required)

[numeric value entry] The constant coefficient (C2) in the equation above

Coefficient 3 (Required)

[numeric value entry] The constant coefficient (C3) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The only available option is dimensionless

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The only available option is dimensionless

 

Mathematical: Double Exponential Decay

The equation for the exponential decay curve is:

  y = C1 + C2 exp(C3 x)   + C4 exp(C5 x)  

Coefficient 1 Constant (Required)

[numeric value entry]  The constant coefficient (C1) in the equation above

Coefficient 2 to 5 (Required)

[numeric value entry] The constant coefficient (C2) (C3) (C4) (C5) in the equation above

Minimum Value of x (Required)

[numeric value entry]   The minimum allowable value of x. Values of x less than the minimum will be replaced by the minimum.

Maximum Value of x (Required)

[numeric value entry]   The maximum allowable value of x. Values of x less than the maximum will be replaced by the minimum.

Minimum Curve Input

[numeric value entry]   The minimum allowable value of the evaluated curve. Values less than the minimum will be replaced by the minimum.

Maximum Curve Input

[numeric value entry]   The maximum allowable value of the evaluated curve. Values greater than the maximum will be replaced by the maximum.

Input Unit Type for X

[drop down list selection]   Indicates the kind of units that may be associated with the x values. It is used to display the appropriate SI and IP units for the Minimum Value of X and Maximum Value of x. The unit conversion is not applied to the coefficients. The only available option is dimensionless

Output Unit Type

[drop down list selection] This field is used to indicate the kind of units that may be associated with the output values. The only available option is dimensionless

 

Relatoinal: Pressure Drop

The equation for the pressure drop curve is:

∆P = (K + f L/D) pV2/2

 

∆Pfan,tot = fan total pressure rise (Pa) as a function of the volumetric flow through the fan (Qfan ), duct static pressure set point (Psm), and static pressure surrounding the ducts (P0)

Diameter (Required)

[numeric value entry]  This diameter (D) represents an equivalent diameter for the given branch {m(ft)}. Since varying components may be found on the same branch, this value must be selected along with the other inputs in order to provide a proper value of pressure drop. This is used to calculate the velocity in addition to being used directly in the frictional pressure drop calculation.

Minor Loss Coefficient

[numeric value entry]  This is the pressure drop coefficient (K) typically applied to components such as fittings and occasionally heat pumps and is dimensionless.  This coefficient is used to describe the amount of dynamic pressure lost during the process. This value may be left blank if the user only wants to account for frictional losses in this branch.

Length

[numeric value entry]  This is the length (L) {m(ft)} of a pressure drop process in which friction is applied.  In a pipe, this would be the length of the pipe, however in many cases, pressure drop in other components are applied as an “equivalent length.”  This is only required if the user is wanting to perform frictional pressure drop calculations.

Fixed Friction Factor

[numeric value entry]  The parameter (f) is included to simulate frictional losses and is dimensionless.  If the user has a known friction factor for a given component, this is where it should be entered.

 

 

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