Frequently Asked Questions
User Interface / Application Frame / Views
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Data Model Tree
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Simergy Options
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Model Creator Defaults
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Project
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What weather data is available in Simergy?
Using Custom Weather Files in Simergy
In Simergy, the weather data to be used in the energy simulation is specified on in any of the following ways:
- Project workspace
The ‘Weather Source’ field is a dropdown list allowing you to select:
- Standard (default)
This option allows you to select one of 1,042 locations in the USA. After selecting ‘Standard’ in the ‘Weather Source’ column > select the US state in the ‘Region’ dropdown list > then select a location in that state – in the ‘Location’ field. The screenshot above shows the selection of WA(shington) state and then Spokan-Fairchild AFB. Once selected, the weather data will be downloaded from a US Dept. of Energy server and copied into the Project for simulation.
- Custom
This option allows you to select a custom weather file, typically in other parts of the world. To use this option, first find and download the custom weather data file(s) as described below. Then, after selecting ‘Custom’ in the ‘Weather Source’ column > browse to ‘C:\Users\Public\Simergy\WeatherFiles’ > select the .epw file. Once selected, the weather data will be downloaded from a US Dept. of Energy server and copied into the Project for simulation.
- Simulation workspace
Once you have defined a simulation configuration in the Simulate workspace, if you click on ‘Run Simulation’ and Simergy finds that you have not yet specified a location, you will be prompted to specify the location with the following dialog:
As described above, for the Project workspace, you can select either ‘Standard’ or ‘Custom’ weather sources. After making your selection, you will see more detailed information in the ‘Location metadata’ table below.
- Import workspace
When you are in the Import workspace > if you import a model that does not include a location that is recognized by Simergy, you will be prompted to specify the location with the same dialog as in the Simulation workspace:
As described above (for the Simulation workspace), you can select either ‘Standard’ or ‘Custom’ weather sources. After making your selection, you will see more detailed information in the ‘Location metadata’ table below.
- Using Custom Weather Data
If Simergy’s Standard weather data does not include a location for which you would like to run a simulation, you can download weather data from any of the following sources:
- EnergyPlus weather website (free): https://energyplus.net/weather
Contains over 2,100 locations. About half are locations in the USA and are available in Simergy’s ‘Standard’ weather source.
- Climate One Building website (free): http://climate.onebuilding.org/
- Commercial Weather website: http://weather.whiteboxtechnologies.com/
From any of these, you need to locate EnergyPlus weather files (.epw). Once downloaded, place the file on your disk drive at: ‘C:\Users\Public\Simergy\WeatherFiles’ – which is the weather file folder used by Simergy.
Once the .epw file has been downloaded to this location, you can select it for use in your simulations using the ‘Custom’ weather source option as described above.
What does the formating in the Location field mean?
In the project workspace
When you use the Standard Weather Source and select a US region the location dropdown contains a list of all locations of that region, which are formatted in the following way:
- [normal] rows are normal
- [italic] rows indicate that this location does not have design days
- [bold] indicates that this weather file was already downloaded and it available on the current PC (in C:\Users\Public\Simergy\WeatherFiles)
- [UPPER CASE] rows indicate the older TMY2 format
- (TMY-2-3) In brackets we show the TMY version, TMY, TMY2 and TMY3 (TMY3 being the newest weather file version)
The CZ column contains the ASHRAE climate zone that is automatically determined based on the weather location if possible.
Project Dashboard
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Project Workflow Guide
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How do I assign and create Utility Costs in Simergy?
This document will explain how to define utility cost in a Simergy model: by illustrating the assigned of a utility cost object to a project, by creation of a utility cost object in the library and via an example.
1. Assigning utility cost objects to a project
- Go to the Site workspace
- Click on Site in the project tree
- Click on the Edit button right next to “Select Location”
- In the Locations template check the checkbox for Utilities.
- Select all utility tariffs you want to assign to this project.
Figure 1: Steps to assign a utility tariff to a Simergy project
2. Create utility tariff object(s) in the library
For each energy source (e.g. Electricity, Gas, …), you need to define a Utility Tarif object (Type: UtilityCost Subtype: Tariff) in the library workspace under Location Data and Costs. Each of those Utility Tariff objects is assigned to a Meter that links the cost to the related energy consumption of that meter. You can use any meter from the meter dropdown, but usually one would use a meter at the facility level. Each Utility Tarif object then is referenced by a number of other cost objects that define the cost structure of the tariff. For example, with a cost variable object one can assign a monthly cost value and with a Charge Simple object a simple cost per unit (e.g., 0.5 $ per kWh). Figure 2 illustrates the relationships between these cost objects.
Figure 2: Utility cost objects
3. Example tariff
In the below table is an example tariff defined that has a constant monthly charge as well as a constant demand charge. Furthermore, this tariff is different for summer and winter for the energy consumption and uses on, mid and off peak rates.
Effective Rate – Demand |
Demand |
|||
|
[$/month] |
[$/kW] |
||
|
All hours |
206.02 |
7.79 |
|
Effective Rate – Consumption |
Consumption |
|||
|
[$/kWh] |
|||
|
Summer |
|||
|
|
On Peak (2p – 8p M..F) |
0.07602 |
|
|
|
Mid Peak (6a-2p * 8p-10p M…F) |
0.06032 |
|
|
|
Off Peak (all other hours) |
0.03722 |
|
|
Winter |
|||
|
|
All hours |
0.05 |
For the demand side, we define a Tariff (Type: UtilityCost Subtype: Tariff) object (called Effective Rate – Demand 206.02 monthly – 7.79 per kW) that contains the monthly charge of 206.02.
This demand tariff object is defined by the SimpleCharge object (Type: UtilityCost Subtype: ChargeSimple), which specifies the Category Variable Name as demand charge, provides a constant cost value and sets the season to annual to make this demand applicable for the full year. |
![]() |
For the consumption part we define another tariff object (Type: UtilityCost Subtype: Tariff), see below:
This tariff object references two schedules, a schedule that defined the different peak categories and a schedule that differentiates between summer and winter. See the related peak schedule to the right.
|
![]() |
In addition, three Simple Charge objects (Type: UtilityCost Subtype: ChargeSimple), are linked to the Electricity Rate – Consumption tariff object. They define the cost value, are bound to the season (here summer) and to the peak category.
Finally, one SimpleCharge object (Type: UtilityCost Subtype: ChargeSimple), for the winter season would complete this example.
How do I model Photovoltaics in Simergy?
Photovoltaics in Simergy
First, we need to create a surface array in the Site workspace:
Then we create a Generator:Photovoltaic and select the just created solar surface in Surface Name.
Create/Edit Site Elements
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Building
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Create/Edit Buildings / Sections / Stories
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Create/Edit Zones
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How to use Room Air Models in Simergy?
By default, the Room Air Model in EnergyPlus and Simergy is well mixed. This assumes the temperature (and other parameters) are constant within each zone. However, there are several options to vary room air:
- OneNodeDisplacementVentilation
- ThreeNodeDisplacementVentilation
- CrossVentilation
- UnderFloorAirDistributionInterior
- UnderFloorAirDistributionExterior
All those models can be defined within the Occupancy Template, specifically on the “Air Flow” tab. The user can select one of the five detailed room air models and then select a related library entry that is applied to each zone that is part of the zone group of this template.
OneNodeDisplacementVentilation
The Mundt one node displacement ventilation air model for displacement ventilation defines two fractions and five nodes that are automatically generated by Simergy (see left figure below).
ThreeNodeDisplacementVentilation
“This model is applicable to spaces that are served by a low velocity floor-level displacement ventilation air distribution system. Furthermore, the dominant sources of heat gain should be from people and other localized sources located in the occupied part of the room. The model should be used with caution in zones which have large heat gains or losses through exterior walls or windows or which have considerable direct solar gain. The model predicts three temperatures in the room (see right figure below):
- A foot level temperature (TFLOOR). The floor region is 0.2 meters deep and TFLOOR represents the temperature at the mid-point of the region.
- An occupied subzone temperature (TOC), representing the temperature in the region between the floor layer and the upper, mixed layer.
- An upper node representing the mixed-layer/outflow temperature (TMX) essential for overall energy budget calculations and for modeling comfort effects of the upper layer temperature.” (From the InputOutputReference.pdf)
CrossVentilation
“The UCSD Cross Ventilation Room Air Model provides a simple model for heat transfer and temperature prediction in cross ventilated rooms. Cross Ventilation (CV) is common in many naturally ventilated buildings, with air flowing through windows, open doorways and large internal apertures across rooms and corridors in the building.” (From the InputOutputReference.pdf)
This option will only work in combination with natural ventilation. Please ensure that the zones you define cross ventilation for are also part of the natural ventilation network.
UnderFloorAirDistributionInterior
“This model is applicable to interior spaces that are served by an underfloor air distribution system. The dominant sources of heat gain should be from people, equipment, and other localized sources located in the occupied part of the room. The model should be used with caution in zones which have large heat gains or losses through exterior walls or windows or which have considerable direct solar gain. The model predicts two temperatures in the room:
- An occupied subzone temperature (TOC), representing the temperature in the region between the floor and the boundary of the upper subzone.
- An upper subzone temperature (TMX) essential for overall energy budget calculations and for modeling comfort effects of the upper layer temperature.” (From the InputOutputReference.pdf)
UnderFloorAirDistributionExterior
“This model is applicable to exterior spaces that are served by an underfloor air distribution system. The dominant sources of heat gain should be from people, equipment, and other localized sources located in the occupied part of the room, as well as convective gain coming from a warm window. The model predicts two temperatures in the room:
- An occupied subzone temperature (TOC), representing the temperature in the region between the floor and the boundary of the upper subzone.
- An upper subzone temperature (TMX) essential for overall energy budget calculations and for modeling comfort effects of the upper layer temperature.” (From the InputOutputReference.pdf)
Interiors
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Custom Openings
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Tools
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What do the acronyms in templates mean?
In the systems workspace
We use several acronyms in our HVAC templates, see below for descriptions:
1Sp |
One Speed |
2SP |
Two Speed |
AirCond |
Air Cooled Condenser |
AS |
Autosize |
AT |
Air Terminal |
Blr |
Boiler |
Boil |
Boiler |
BT |
Blow through (fan configuration) |
CAV |
Constant air volume |
Chlr |
Chiller |
ChW-Crl |
Chilled water controlled |
Clng |
Cooling |
CoolTwr |
Cooling Tower |
COP |
Coefficient of Performance |
CSD |
Constant Speed Drive (Pump) |
DD |
Dual Duct |
Dist |
District |
DOAS |
Direct outside air system |
DSP |
Dedicated Supply Plenum |
DT |
Draw through (fan configuration) |
DVAV |
Dual VAV |
dxC |
DX cooled (direct expansion) |
EIR |
Energy Input Ratio |
Elec |
Electric |
elecH |
electric heated |
Flr |
Floor |
Furn |
Furnace |
gasH |
gas heated |
GHE |
Ground Heat Exchanger |
Gly |
Glycol |
HeatEx |
Heat Exchanger |
HP Wtr to Air |
Heat Pump Water to Air |
HPAta |
Heat Pump Air to Air |
HR |
Heat recovery |
HR |
Humidity Ratio |
HW |
Hot Water |
MedTemp |
Medium Temperature |
MxW |
Mixed Water |
No_ReH |
No Reheat |
OA |
Outside air |
Pc |
constant-flow primary-only loop |
PFPB |
Parallel Fan Powered Box |
Pri |
Primary |
PSZ |
Packaged Single Zone |
PTAC |
Packaged Terminal Air Conditioner |
PTHP |
Packaged Terminal Heat Pump |
Pv |
variable-flow primary-only loop |
R-134A |
Refrigerant 134a |
R-22 |
Refrigerant 22 |
R-404a |
Refrigerant 404a |
R744 |
Refrigerant 744 |
Radiant |
Radiant cooling or heating (mostly with lower temperatures) |
RadSlab |
Radiant Slab |
ReH |
Reheat |
RfgCond |
Refrigeration Cooled Condenser |
SD |
Single duct |
Sec |
Secondary |
SHW |
Service hot water |
SSD |
Single Speed drive (pump) |
SSP |
Shared Supply Plenum |
STM |
Steam |
TC |
Temperature Controller |
Temp |
Temperature |
Trans |
Transcritical |
Unctrl |
Uncontrolled |
UnitH |
Unit Heater |
VarPumps |
Variable Pumps |
VAV |
Variable air volume |
VC-Elec |
Vapor Compression Electric |
VRF |
Variable Refrigerant Flow |
VRF |
Variable refrigerant Flow |
VS |
Variable Speed |
VSD |
Variable speed drive (pump) |
WaterCond |
Water Cooled Condenser |
WindAC |
Window Air Conditioner |
WSHP |
Water source heat pump |
wtrC |
water cooled |
wtrH |
water heated |
wtrSTM |
steam heated |
Systems Creator
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Zone HVAC Groups
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Air Loops
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Water Loops
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VRF Loops
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Refrigeration Loops
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How to run parametric analysis with Simergy?
Parametric analysis
Simple parametric analysis can be done in Simergy by developing a base model as Design Alternative 1 and developing various design alternations. Those can be done by
- creating additional design alternatives in the Project workspace
- using measures in the simulation workspace
- using parameterized measures in the simulation workspace and choose various values for those parameters in different simulation configurations.
- any combination thereof
Simergy’s support for OpenStudio measures enables the user to do simple parametric analysis. Each measure can be run and adjust the Simergy model just before the EnergyPlus simulation is performed. These measures are Ruby scripts that use the OpenStudio API to modify the model. These modifications can be small, e.g. just changing one or to parameters of a couple of objects like efficiencies or can make major changes to the model, such as replacing HVAC systems with a totally different HVAC system. These measures can also be parameterized, e.g., to adjust the boiler efficiency by providing the efficiency as a parameter. This way, the same measure can be used to run various scenarios with different measures and measure parameters.
Measure types
Generally, there are three different measure types: Model, EnergyPlus and Report Measures.
The model measures use the high level OpenStudio API to read and write an OSM file. This simplifies access to the OpenStudio Model but does not cover the full spectrum of all EnergyPlus objects. It also includes an additional conversion process from IDF to OSM and back.
EnergyPlus measures (which we recommend), adjust the model at the EnergyPlus object level (IDF file) and is thus a more direct way of adjusting the model. This direct access to EnergyPlus objects requires version specific code or measures to work with more than one EnergyPlus version.
Report measures are run after the simulation and could be based on either the high level OpenStudio API or the EnergPlus object level API. A report measure collects input and results data and generates a specific report.
Measures in Simergy
Simergy bundles several measures within the installation. In addition, more measures can be downloaded via the Online Measure functionality in Simergy V4.0.
The Simergy Local Measure UI lists all locally available measures in a predefined taxonomy and the user can with drag and drop measures onto a simulation configuration or use the “Add selected measures” button. Once a measure is attached to a simulation configuration, its parameters can be adjusted.
Each configuration can have its own set of measures and related parameters. Through adjusting the measures and their parameters across various simulation configurations and/or design alternatives, a parametric analysis can be performed.
Online Measures
With Simergy Version 4.0, Simergy supported downloading of measures from BCL (Building Component Library). The measures are organized on the mentioned topology and can be downloaded and used with a button click.
Measure validation
When entering the Simulation Workspace, Simergy performs a validation check if all objects used in the model are also supported by the OpenStudio API. If issues are found, they can be reviewed in the following dialog and only EnergyPlus and some Report Measures area available for selection.
Feedback from Measures
Details about each measure run can be found by clicking on the successful/error button on each measures row.
Reports and Results Visualization
All results generated in either form, with design alternatives, measures, or combinations thereof, can be viewed within Simergy in reports and in results visualization the same way any simulation results can be viewed.
Writing your own Measures
Besides using existing measures, users can also write their own measures. A reference guides is available here:
https://nrel.github.io/OpenStudio-user-documentation/reference/measure_writing_guide/
Once the general measure structure is setup it is as easy as writing ruby code and using the OpenStudio Model API.
https://openstudio-sdk-documentation.s3.amazonaws.com/cpp/OpenStudio-2.9.0-doc/model/html/index.html
How does autosizing work in Simergy?
Simergy – autosizing of component parameters
Capacity and flow rate parameters can usually be autosized (indicated by the A/S postfix to the parameter name). Note that most of the default templates and library entries have the properties set to autosize.
If you set one or more properties to autosize you also need to provide design days, which are used for the sizing calculations in EnergyPlus. In addition, sizing objects at the Zone Group Occupancy template, air loops and water loops define more specifics about the sizing calculation. Autosizing related objects:
- Design days (typically two summer and one winter design day)
Note: If you select a standard weather source, those three design days are automatically attached to your project. - Zone Sizing
- Air Loop Sizing
- Plant Loop Sizing
- Global Sizing
See an example of each below:
Design days in the location template in the Site workspace
Design days properties in the Object Properties dialog
Zone sizing dialog in occupancy template
Air loop sizing dialog
Water loop sizing dialog
Global Sizing Parameters in the Simulation Parameter template in the Simulation workspace
Sizing parameters in the Object Properties dialog
In the simulation workspace you can automatically set all parameters with autosize capabilities to autosize by clicking the button.
When you click the button, you can apply the sizing results to your model. A new window will pop up that shows the full list of properties with calculated values. You can specify a overwrite value and by clicking the “Save values to model” those values are written into the properties.
Sizing results dialog
Under some circumstances, EnergyPlus fails to properly size components and creates error messages that stop the simulation. Is may be possible to adjust the sizing object values to resolve this issue or by setting these autosize properties to specific values so the sizing and simulation can run through. After the simulation completes you can reapply the sizing values to get better estimates.
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Measures
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How can I inject IDF snippets into the generated IDF file?
Inject IDF snippets
Sometimes it is useful to quickly inject IDF snippets in the IDF file that is generated by Simergy. Adding report variables or meters for example is a use case for this.
When you place an IDF file named “InjectIDF.idf” into the same folder as your simp file, Simergy will automatically add the content of that IDF file into the generated IDF file. Anything can be added that corresponds to correct IDF Syntax.
Radiance Simulations
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Image-based Simulations
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Grid-based Simulations
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Reports
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Simergy Reports
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EnergyPlus Reports
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Custom Reports using Measures
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Radiance Reports
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Results Visualization
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Components
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Where can I find output requests related to comfort models?
In the libraries workspace
You can find comfort models related output variables like PMV and PPT assigned to the People Type in the Interna loads object:
Results Viz Templates
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California Title 24
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Standards
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How can I create a Green Roof in Simergy?
How to create a Green Roof in Simergy
A green roof can be simply created in Simergy by using a special material called Material:RoofVegetation (SimMaterial/OpaqueMaterial/RoofVegatation) as the outside layer of the roof construction (material layer set). Typically, a green roof has a number of additional layers compared to a normal roof for drainage. Depending on your LOD of the model these can be added to the construction.
The following figure shows all properties of the roof vegetation layer
An example of a simplified green roof material layer set:
EnergyPlus documentation suggests that green roofs may require "more timesteps" than normal simulations.
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Propties dialog
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Right-Click Context Menus
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Import BIM
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IDF Import
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IFC Import
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gbXML Import
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Open SimXML
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IDF Export
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IFC Export
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SaveAs SimXML
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Samples
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ASHRAE Standard System examples
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DOE Reference Building examples
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Installer
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Website
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