Location = Libraries/Controls and Performance Data/SizingParams
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.
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 the user can select to include, along with a value, in a Library Entry.
| Type Options | Sub Type Options | EnergyPlus Objects (IO Reference links) |
HVAC Design |
Outdoor Air Design Spec
Zone Air Distribution Sizing Zone Sizing Air Loop Sizing Water Loop Sizing Zone HVAC Sizing |
DesignSpecification:OutdoorAir
DesignSpecification:ZoneAirDistribution Sizing:Parameters Sizing:Zone Sizing:System Sizing:Plant |
The input must be either Flow/Person, Flow/Area, Flow/Zone, AirChanges/Hour, Sum, or Maximum. Flow/Person means the program will use the input from the field Outdoor Air Flow per Person and the actual zone occupancy to calculate a zone outdoor air flow rate. Flow/Area means that the program will use the input from the field Outdoor Air Flow per Zone Floor Area and the actual zone floor area as the zone outdoor air flow rate. Flow/Zone means that the program will use the input of the field Outdoor Air Flow per Zone as the zone outdoor air flow rate. AirChanges/Hour means that the program will use the input from the field Air Changes per Hour and the actual zone volume (divided by 3600 seconds per hour) as the zone outdoor air flow rate. Sum means that the flows calculated from the fields Outdoor Air Flow per Person, Outdoor Air Flow per Area, Outdoor Air Flow per Zone, and Air Changes per Hour (using the associated conversions to m3/s for each field) will be added to obtain the zone outdoor air flow rate. Maximum means that the maximum flow derived from Outdoor Air Flow per Person, Outdoor Air Flow per Area, Outdoor Air Flow per Zone, and Air Changes per Hour (using the associated conversions to m3/s for each field) will be used as the zone outdoor air flow rate. The default is Flow/Person.
The design outdoor air volume flow rate per person for this zone in cubic meters per second per person. The default is 0.00944 (20 cfm per person). An outdoor air flow rate is calculated based on the total number of people for all People statements assigned to the zone. Occupancy schedule values are not applied during sizing calculations and are applied during the remainder of the simulation. This input is used if Outdoor Air Method is one of Outdoor Air Flow per Person, Sum, or Maximum.
The positive numeric input for this field is the zone air distribution effectiveness when the zone is in cooling mode. ASHRAE Standard 62.1-2010 provides typical values.
The positive numeric input for this field is the zone air distribution effectiveness when the zone is in heating mode. ASHRAE Standard 62.1-2010 provides typical values
[drop down list] Schedule selection.
Fraction of secondary recirculation incorporated into zone air distribution. Default = 0
Allows the user to specify global heating and cooling sizing ratios. These ratios will be applied at the zone level to all of the zone heating and cooling loads and air flow rates. These new loads and air flow rates are then used to calculate the system level flow rates and capacities and are used in all component sizing calculations.
The user can also specify the width (in load timesteps) of a moving average window which can be used to smooth the calculated zone design flow sequences. The use of this parameter is described below.
The global heating sizing ratio applied to all of the zone design heating loads and air flow rates.
The global cooling sizing ratio applied to all of the zone design cooling loads and air flow rates
The number of load timesteps in the zone design flow sequence averaging window. The default is 1, in which case the calculated zone design flow rates are averaged over the load timestep.
The zone design air flow rate calculation is performed assuming a potentially infinite supply of heating or cooling air at a fixed temperature. Thus the calculated design air flow rate will always be able to meet any load or change in load no matter how large or abrupt. In reality air flow rates are limited by duct sizes and fan capacities. The idealized zone design flow calculation may result in unrealistically large flow rates, especially if the user is performing the sizing calculations using thermostat schedules with night setup or setback. The calculated zone design flow rates are always averaged over the load timestep. The user may want to perform a broader average to mitigate the effect of thermostat setup and setback and prevent the warm up or cool down flow rates from dominating the design flow rate calculation.. Specifying the width of the averaging window allows the user to do this.
Zone Sizing represents the EnergyPlus object Sizing:Zone, which provides the data needed to perform a zone design air flow calculation for a single zone. This calculation assumes a variable amount of supply air at a fixed temperature and humidity. The information needed consists of the zone inlet supply air conditions: temperature and humidity ratio for heating and cooling. The calculation is done for every design day included in the input. The maximum cooling load and air flow and the maximum heating load and air flow are then saved for the system level design calculations and for the component automatic sizing calculations.
The Sizing:Zone object is also the place where the user can input the design outdoor air flow rate. This can be specified in a number of ways as is described below under outside air flow method. This data is saved for use in the system sizing calculation of for sizing zone components that use outside air.
The user can also place limits on the heating and design cooling air flow rates. See Heating Design Air Flow Method and cooling design air flow method below and the explanations of the various heating and cooling flow input fields.
[Required Input] User can select from drop down list either Supply Air Temperature or Temperature difference, which influences which input values will influence the sizing.
The supply air temperature for the zone cooling design air flow rate calculation. Air is supplied to the zone at this temperature during the cooling design day simulation, The zone load is met by varying the zone air flow rate. The maximum zone flow rate is saved as the zone cooling design air flow rate.
[active when temperature difference selected as Input Method] The supply air temperature difference for the zone cooling design air flow rate calculation.
[Required Input] User can select from drop down list either Supply Air Temperature or Temperature difference, which influences which input values will influence the sizing.
The supply air temperature for the zone heating design air flow rate calculation. Air is supplied to the zone at this temperature during the heating design day simulation, The zone load is met by varying the zone air flow rate. The maximum zone flow rate is saved as the zone heating design air flow rate.
[active when temperature difference selected as Input Method] The supply air temperature difference for the zone cooling design air flow rate calculation.
The supply air temperature difference for the zone cooling design air flow rate calculation.
[Required Input] The humidity ratio in kilograms of water per kilogram of dry air of the supply air in the zone cooling design air flow rate calculation.
[Required Input] The humidity ratio in kilograms of water per kilogram of dry air of the supply air in the zone heating design air flow rate calculation.
This alpha field specifies the name of a DesignSpecification:OutdoorAir object which specifies the design outdoor air flow rate for the zone.
This input is a zone level heating sizing ratio. The zone design heating air flow rates and loads will be multiplied by the number input in this field. This input overrides the building level sizing factor input in the Sizing:Parameters object.
This input is a zone level cooling sizing ratio. The zone design cooling air flow rates and loads will be multiplied by the number input in this field. This input overrides the building level sizing factor input in the Sizing:Parameters object.
The input must be either Flow/Zone, DesignDay, or DesignDayWithLimit. Flow/Zone means that the program will use the input of the field Cooling Design Air Flow Rate as the zone design cooling air flow rate. DesignDay means the program will calculate the zone design cooling air flow rate using the Sizing:Zone input data and a design day simulation without imposing any limits other than those set by the minimum outside air requirements. DesignDayWithLimit means that the maximum from Cooling Minimum Air Flow per Zone Floor Area and Cooling Minimum Air Flow will set a lower limit on thedesign maximum cooling air flow rate. The default method is DesignDay: i.e., the program uses the calculated design values subject to ventilation requirements.
The design zone cooling air flow rate in cubic meters per second. This input is used if Cooling Design Air Flow Method is specified as Flow/Zone. This value will be multiplied by the global or zone sizing factor and by zone multipliers.
The minimum zone cooling volumetric flow rate per square meter (units are m3/s-m2). This field is used when Cooling Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets a lower bound on the zone design cooling air flow rate. In all cases the maximum flow derived from Cooling Minimum Air Flow per Zone Floor Area, Cooling Minimum Air Flow, and Cooling Minimum Air Flow Fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is .000762, corresponding to .15 cfm/ft2. The applicable sizing factor is not applied to this value.
The minimum zone cooling volumetric flow rate in m3/s. This field is used when Cooling Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets a lower bound on the zone design cooling air flow rate. In all cases the maximum flow derived from Cooling Minimum Air Flow per Zone Floor Area, Cooling Minimum Air Flow, and Cooling Minimum Air Flow Fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is zero. The applicable sizing factor is not applied to this value.
The minimum zone design cooling volumetric flow rate expressed as a fraction of the zone design cooling volumetric flow rate. . In all cases the maximum flow derived from Cooling Minimum Air Flow per Zone Floor Area, Cooling Minimum Air Flow, and Cooling Minimum Air Flow Fraction is used to set a minimum supply air flow rate for the zone for VAV systems. The default is zero. This input is currently used in sizing the fan minimum flow rate. It does not currently affect other component autosizing.
The input must be either Flow/Zone, DesignDay, or DesignDayWithLimit. Flow/Zone means that the program will use the input of the field Heating Design Air Flow Rate as the zone design heating air flow rate. DesignDay means the program will calculate the zone design heating air flow rate using the Sizing:Zone input data and a design day simulation without imposing any limits other than those set by the minimum outside air requirements. DesignDayWithLimit means that the maximum from Heating Minimum Air Flow per Zone Floor Area and Heating Minimum Air Flow will set a lower limit on thedesign maximum cooling air flow rate. The default method is DesignDay: i.e., the program uses the calculated design values subject to ventilation requirements.
The design zone heating air flow rate in cubic meters per second. This input is used if Heating Design Air Flow Method is specified as Flow/Zone. This value will be multiplied by the global or zone sizing factor and by zone multipliers.
The maximum zone heating volumetric flow rate per square meter (units are m3/s-m2). This field is used when Heating Design Air Flow Method is specified as DesignDayWithLimit. In this case it sets an upper bound on the zone design heating air flow rate. In all cases the maximum flow derived from Heating Maximum Air Flow per Zone Floor Area, Heating Maximum Air Flow, and Heating Maximum Air Flow Fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is .002032, corresponding to .40 cfm/ft2. This input is not currently used for autosizing any of the components.
The maximum zone design heating volumetric flow rate expressed as a fraction of the zone design cooling volumetric flow rate. . In all cases the maximum flow derived from Heating Maximum Air Flow per Zone Floor Area, Heating Maximum Air Flow, and Heating Maximum Air Flow Fraction is used to set a maximum heating supply air flow rate for the zone for VAV systems. The default is 0.3. This input is not currently used for autosizing any of the components.
Air Loop Sizing represents the EnergyPlus Sizing:System object, which contains the input needed to perform a central forced air system design air flow, heating capacity, and cooling capacity calculation for a system serving one or more zones. The information needed consists of the outside environmental conditions and the design supply air temperatures, outdoor air flow rate, and minimum system air flow ratio.
The outside conditions come from the design days in the input. A system sizing calculation is performed for every design day in the input file and the resulting maximum heating and cooling air flow rates and capacities are saved for use in the component sizing calculations.
Supply air conditions are specified by inputting a supply air temperature for cooling, a supply air temperature for heating, and a preheat temperature.
The system sizing calculation sums the zone design air flow rates to obtain a system supply air flow rate. The design conditions and the outdoor air flow rate are used to calculate a design mixed air temperature. The temperature plus the design supply air temperatures allows the calculation of system design heating and cooling capacities.
[Required Input] The user specified type of load on which to size the central system. The choices are Sensible, Latent, Total and VentilationRequirement. Only Sensible and VentilationRequirement are operational. Sensible means that the central system supply air flow rate will be determined by combining the zone design air flow rates, which have been calculated to meet the zone sensible loads from the design days. VentilationRequirement means that the central system supply air flow rate will be determined by the system ventilation requirement.
The design outdoor air flow rate in cubic meters per second. Generally this should be the minimum outdoor air flow. It is used for both heating and cooling design calculations. The assumption for cooling is that any outdoor air economizer will be closed. If Autosize is input the outdoor air flow rate will be taken from the sum of the zone outdoor air flow rates or calculated based on the System Outdoor Air Method selection (field below).
The design minimum central air flow ratio. This ratio is the minimum system air flow rate divided by the maximum system air flow rate. The value must be between 0 and 1. For constant volume systems the ratio should be set to 1. Note that this ratio should be set to reflect what the user expects the system flow rate to be when maximum heating demand occurs. This ratio is used in calculating the central system heating capacity. Thus if the system is VAV with the zone VAV dampers held at minimum flow when there is a zone heating demand, this ratio should be set to the minimum flow ratio. If the zone VAV dampers are reverse action and can open to full flow to meet heating demand, this ratio should be set to 1.
[Required Input] The design air temperature exiting the preheat coil (if any) in degrees Celsius.
[Required Input] The design humidity ratio exiting the preheat coil (if any) in kilograms of water per kilogram of dry air.
[Required Input] The design air temperature exiting the precooling coil (if any) in degrees Celsius.
[Required Input] The design humidity ratio exiting the precooling coil (if any) in kilograms of water per kilogram of dry air.
[Required Input] The design supply air temperature for cooling in degrees Celsius. This should be the temperature of the air exiting the central cooling coil.
[Required Input] The design supply air temperature for heating in degrees Celsius. This can be either the reset temperature for a single duct system or the actual hot duct supply air temperature for dual duct systems. It should be the temperature at the exit of the main heating coil.
If the input is coincident the central system air flow rate will be sized on the sum of the coincident zone air flow rates. If the input is noncoincident the central system air flow rate will be sized on the sum of the noncoincident zone air flow rates. The default is noncoincident.
Entering Yes means the system will be sized for cooling using 100% outdoor air. Entering No means the system will be sized for cooling using minimum outside air (the default).
Entering Yes means the system will be sized for heating using 100% outdoor air. Entering No means the system will be sized for heating using minimum outside air (the default).
[Required Input] The design humidity ratio in kilograms of water per kilogram of dry air at the exit of the central cooling coil. The default is .008.
[Required Input] The design humidity ratio in kilograms of water per kilogram of dry air at the exit of the central heating coil. The default is .008.
The design system cooling air flow rate . This input is an alternative to using the program calculated value. This input is used if Cooling Design Air Flow Method is Flow/System. This value will not be multiplied by any sizing factor or by zone multipliers. If using zone multipliers, this value must be large enough to serve the multiplied zones.
The design system heating air flow rate in cubic meters per second. This input is an alternative to using the program calculated value. This input is used if Heating Design Air Flow Method is Flow/System. This value will not be multiplied by any sizing factor or by zone multipliers. If using zone multipliers, this value must be large enough to serve the multiplied zones.
The method used to calculate the system minimum outdoor air flow. The two choices are ZoneSum and VentilationRateProcedure (VRP). ZoneSum sums the outdoor air flows across all zones served by the system. VRP uses the multi-zone equations defined in 62.1-2007 to calculate the system outdoor air flow. VRP considers zone air distribution effectiveness and zone diversification of outdoor air fractions.
Specifies the maximum outdoor air fraction incorporated in the air loop design. Default = 0. Range = 0 to 1.
Water Loop Sizing represents the EnergyPlus Sizing:Plant object, which contains the input needed for the program to calculate plant loop flow rates and equipment capacities when autosizing. This information is initially used by components that use water for heating or cooling such as hot or chilled water coils to calculate their maximum water flow rates. These flow rates are then summed for use in calculating the Plant Loop flow rates.
The program will size any number of chilled water, hot water, condenser water and other plant loops. There should be one Sizing:Plant object for each plant loop that is to be autosized.
[Required Input] The possible inputs are Heating, Steam, Cooling, orCondenser.
[Required Input] The water temperature in degrees Celsius at the exit of the supply side of the plant loop, Thus this is the temperature of the water supplied to the inlet of chilled or hot water coils and other equipment that places loads on a plant loop.
[Required Input] The design temperature rise (for cooling or condenser loops) or fall (for heating loops) in degrees Celsius across the demand side of a plant loop. This temperature difference is used by component models to determine flow rates required to meet design capacities. Larger values lead to smaller design flow rates.
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