DesignBuilder is built around the EnergyPlus data requirements

EnergyPlus is the U.S. DOE building energy simulation program for modelling building heating, cooling, lighting, ventilating, and other energy flows.

It builds on the most popular features and capabilities of BLAST and DOE-2 but also includes many innovative simulation capabilities such as time steps of less than an hour, modular systems and plant integrated with heat balance-based zone simulation, multizone air flow, thermal comfort, and photovoltaic systems.

EnergyPlus is a stand-alone simulation program without a ‘user friendly’ graphical interface – which is where DesignBuilder comes in. We have integrated EnergyPlus tightly within the DesignBuilder environment to allow you to carry out simulations without any fuss – just define your building model, request data and let the EnergyPlus simulation engine take care of the details.

DesignBuilder has been specifically developed around EnergyPlus allowing most of the EnergyPlus fabric and glazing data to be input. Databases of building materials, constructions, window panes, window gas, glazing units and blinds are provided.

HVAC is modelled using either the “ideal loads” option or the Compact HVAC (now called “HVAC Template”) descriptions provided by EnergyPlus.  These allow a number of predefined HVAC system types to be defined parametrically without the need for complex system layouts.  These compact descriptions are automatically expanded behind-the-scenes into full HVAC simulation data sets prior to simulation.

No experience with EnergyPlus is necessary, but more advanced users have the flexibility to export IDF input files and edit these to model a very wide range of HVAC system types.

There is a range of EnergyPlus simulation engines to choose from including the current DOE executable release, the current DLL release and any interim releases made available by DOE. If you have built your own version of EnergyPlus you can even run this from within DesignBuilder. You can also carry out DesignBuilder simulations via EP-Launch.

DOE EnergyPlus website

DesignBuilder CFD

What is CFD?

Computational Fluid Dynamics (CFD) analysis is used by building environmental designers to calculate the temperature, velocity and other fluid properties through a 3-D domain. CFD is used to answer design questions such as:

• What sort of temperature distribution could I expect in an atrium under clear sky summer conditions?
• Will the arrangement of supply diffusers provide adequate air movement?
• Is the location of the radiators going to provide good comfort conditions?
• Will natural ventilation provide occupants with adequate comfort in the summer?
• What effect will the shape of the building have on local wind velocity?
• Are there any regions of stale air inside the building?
• Which layout in a hot/cold isle server centre design give most effective cooling of equipment?

DesignBuilder 3-D CFD

DesignBuilder CFD has been especially designed to provide data on airflow and temperature distribution in and around buildings using the same methods as the general purpose pure CFD packages, but at a fraction of the cost and without the need for specialist knowledge.

Using conventional CFD packages for building airflow analysis can be a time consuming task requiring very careful attention to setting up the correct geometry and boundary conditions. Using CFD in DesignBuilder simplifies this process hugely by automatically providing the geometry and boundary conditions. Temperatures, heat flows and flow rates previously calculated by EnergyPlus can be seamlessly used to provide boundary conditions simply by specifying the time/date of the CFD analysis.

The CFD interface has been designed to enable virtual ‘push-button’ CFD analysis from automatically generated rule-based default data, with options to allow more experienced or interested users to modify this data as required. Adopting this approach enables users to obtain realistic 3-D results without having any specialist CFD knowledge.

Some of the key DesignBuilder CFD features:

• 3-D CFD grids are generated automatically from model geometry and boundary conditions to promote optimal solution convergence.
• The CFD engine has been developed around the SIMPLER algorithm, which belongs to one of the most widely used families of CFD solution methods. Turbulence can be modelled using the widely researched and documented k-e model and there are plans to introduce additional models for specific applications.
• The interface incorporates tools to enable a wide range of boundary conditions such as supply diffusers, extracts, temperature patches, etc. to be assigned to room surfaces. A component library is also provided to enable radiators, fan-coil units, furniture, occupants, etc. to be located anywhere within the model and automatically incorporated within the analysis.
• Boundary conditions can be automatically assigned from a previous EnergyPlus simulation.
• 3-D CFD results are displayed using the DesignBuilder OpenGL graphics engine providing impressive, easy-to-interpret images of velocity vectors, temperature contours, iso-surfaces etc.
• The CFD simulation is based on the full 3-D DesignBuilder model taking into account the zone wall and floor thickness, so the domain is correctly generated without additional modification being required.

The high quality output provided by DesignBuilder CFD will help you to communicate your results to clients in a clear visual way that they can really understand.

Validation

DesignBuilder CFD has been independently tested against Pheonics, one of the most powerful and widely respected general purpose CFD packages available. The validation work, carried out by Northumbria University, shows that DesignBuilder is able to reproduce the same results as Pheonics given the same input data. This adds to confidence in the results produced by DesignBuilder CFD.

Download the validation report

CFD Demonstrations

You can view recorded demonstrations of the DesignBuilder CFD software on the Webinars page. These show how DesignBuilder EnergyPlus surface temperature and airflows results can be fed into CFD as boundary conditions and also how DesignBuilder CFD for can be used as part of the HVAC design process.

Availability

DesignBuilder CFD can be purchased either as a standalone module or as part of the Advanced Simulation package.The CFD module can be purchased from the bottom of the products page .

3-D CAD Model Import (gbXML)

DesignBuilder provides interoperability with BIM models through its gbXML import capability. This allows you to import 3-D architectural models created in Revit, ArchiCAD or Microstation (and other 3-D drawing systems that support gbXML data exchange) to provide heating and cooling system sizes and environmental performance data in the most efficient way possible.

Revit users can access DesignBuilder while working on their BIM models through the DesignBuilder Revit Plugin. This allows the model to be checked and analysed without leaving Revit.

An important feature of DesignBuilder gbXML import is the removal and repair of gaps between zone inner volumes, which means that models lose very little geometric information in the transfer from CAD to DesignBuilder. In fact, the imported and rendered DesignBuilder model may look more realistic than it did in the CAD software! An example of a rendered image imported from ArchiCAD is shown below.

• BIM > DesignBuilder > EnergyPlus is a convenient and accurate way to run EnergyPlus simulations from BIM models. In many cases this may be preferable to using black box IFC > IDF translation utilities.
• Because the DesignBuilder modeller is true 3-D, architectural CAD data loses little of its 3-D detail in the transfer. So unlike competing systems, accurate daylighting and CFD simulations can be carried out without the need to reconfigure the model to include partition wall thickness.
• The DesignBuilder gbXML import process includes sophisticated healing algorithms allowing missing, misformed and misaligned CAD surfaces to be corrected.
• Shading surfaces can be imported as well as standard construction surfaces like walls, windows, roofs, floors, doors etc.

Import from SketchUp

Greenspace Reseach offer the gModeller plugin for SketchUp that allows 3-D models created in SketchUp to exported as gbXML and imported into DesignBuilder.

Visualisation

DesignBuilder visualisation generates stunning realistically rendered images with the absolute minimum of effort on your part.  Rendered images can be obtained at any stage of the model creation process simply by clicking on the Visualisation tab.

The underlying DesignBuilder model contains all the necessary information on building geometry, construction and materials and each material has a photorealistic texture associated with it.

Feature highlights are:

• Realistically rendered images in a fast OpenGL screen with shading.
• Explore the model using simple orbit, zoom, pan or window view controls and seamlessly switch to walk-through function which provides full control.
• Solar shading analysis for any time of day and any day of the year.
• Colour-coded layout images show zone activites (usage).
• Cut-away sections.
• Glazing is transparent at multiple levels.
• Software antialiasing provides pin sharp lines.
• AVI movies of solar shading and scene orbit automatically generated.
• Still images can be exported in bmp, jpg, tiff, png, gif formats.
• Export to standard output reports for graphic description of model.
• Export the model in 3-D DXF format for further visualisation.

Example rendered images

Above right Dallas Power & Light West Tower by Jason Gentry, Oklahoma State University

Exaltis Tower by Valentin Grimaud a new DesignBuilder user from France

5 School Lane, House by Rowan Tindale, DesignBuilder, UK

Torre de Ingenieria, DesignBuilder model by David Barrera, Mexico

Villa Pifferi, Italy by Roberto Salimbeni, Evolvente

 New Hospice, Bucks, UK By Colin Lillicrap, CLA, UK

Uffici Sat by Roberto Salimbeni, Evolvente, Italy

Sunpath

You can display a Sunpath diagram for the building at its current location by checking the Show Sunpath diagram Display option and pressing the Apply button. This will display a Sunpath diagram similar to that shown below.

The Sunpath diagram provided in DesignBuilder can be a very useful way to view the paths taken by the sun as it moves through the sky at all times of the year.

Sunpath diagram scale factor

There is an option to override the default scale factor applied to the Sunpath diagram. With a scale factor of 1 the Sunpath diagram fits snugly round the building. The default scale factor is 1.5.

Sunpath day of month

By default DesignBuilder uses the first day of the month when generating the sunpath lines for each month of the year. This option allows you to use any other day of the month from 1 to 28.

Change solar position tool

When both the Show Sunpath diagram and Show shadows Display options are set, the Change solar position tool becomes available. This allows you to move the sun around the diagram. To do this first click on the Change solar position toolbar icon (above). When this tool is active the cursor become a cross and you can use it to click on a junction of time/month sunpath lines to set the new solar position. You can continue to move the sun around the sky by clicking on the diagram in the same way. An alternative way to use this tool is to drag the sun around the sky. You will notice that the Time of day and Month data in the Display options panel are updated along with shadows as the sun moves through the sky.

When you have finished press the <Escape> key to return to Select mode.

3-D Model Export

You can export your 3-D DesignBuilder models for further daylighting, visualisation and other analysis using the free version of Google SketchUp as an intermediate step.

All of the models on this page were created in DesignBuilder, exported in 3-D DXF format using the ‘Whole model with details’ option and imported into Google SketchUp where details such as textures, trees, people and shading were added.

 
 

 Image above created from a DesignBuilder model courtesy of Mario Butera (architect Mario Occhiuto)

The 4 models below are located in Ahmedabad, India and were created by Jigisha Adhwaryu, CEPT University, India

DesignBuilder Daylighting

DesignBuilder provides 3 types of daylighting calculations:

1. Daylight contour plots and average daylight factor and uniformity outputs for each zone calculated using the Radiance daylighting simulation engine. Standard reports detailing eligibility for LEED EQ8.1, BREEAM HW1 and Green Star IEQ4 daylighting credits are provided.
2. Reduced electric lighting and consequent energy and carbon savings due to daylighting through EnergyPlus simulations.
3. Photo-realistic rendered images generated using Radiance.

Contour plot showing daylight availability across a floorplan	Daylight distribution within a zone

Daylight Contour Plots and Daylight Factor Calculations

The daylighting simulations available in DesignBuilder v3 allow you to calculate daylight factors and illuminance data using the Radiance daylight simulation engine. The main DesignBuilder daylighting features are:

• High quality illuminance contour plots can be generated to illustrate daylight availability within each zone, each block or for a slice through the whole building.
• Standard reports are provided detailing eligibility for LEED EQ8.1, BREEAM HW1 and Green Star IEQ4 daylighting credits (an example LEED NC2.2 report is shown below).
• Summary tabular output of average daylight factors and uniformity data can be output.
• Calculations are made using the accurate physics-based Radiance simulation engine which is one of the most widely respected daylighting tools in use today. Radiance generates much more accurate results than the “Split flux” method built into some competing daylighting software.
• DesignBuilder daylighting is fully integrated with the thermal simulation model, so in most cases no extra data needs to be added following previous energy simulation or certification project work. In particular building geometry, zone layouts, surface reflection and glazing visible transmission properties from the thermal model are used in the daylighting calculations.
• The DesignBuilder 3-D model includes the thickness of floors and walls, unlike other competing daylight simulation products which only use 2-D surfaces. Using 2-D surfaces has been noted by experts as a significant cause of errors in daylighting calculations.
• Calculations can be made for various sky types including the CIE overcast sky required for most daylight factor calculations.
• Any zone size or shape can be handled reliably.
• Internal and external shading obstructions and daylighting features such as light shelves can easily be included in the model using component blocks or assemblies at building or block level.
• Window frames and dividers are taken into account if they are included in the model.
• You can include a margin around the edge of each zone to follow CIBSE guidance.
• The grid of calculation points can be edited through a maximum and minimum grid size allowing full coverage of zones having complex shape.
• Default calculation options provide reliable and accurate results but advanced users can access more detailed Radiance parameters to gain full control of the daylighting simulation process.

DesignBuilder v3 HVAC Simulation

For the first time, the advanced HVAC features in EnergyPlus are accessible to the building simulation community in a user-friendly graphical environment.

DesignBuilder v3 now provides a powerful and flexible interface to most EnergyPlus HVAC system types. It is possible to model both air and water sides together in full detail with a good range of components including all ASHRAE 90.1 baseline HVAC systems.
Watch a demo of the DesignBuilder v3 HVAC functionality.

HVAC features include:

• Graphical definition of plant, condenser and air loops through placement of components, mixers and splitters.
• Definition of connecting nodes using ‘universal’ connection tool with drawing guide and snap tools.
• Extensible library of E+ components including boilers, chillers, heating coils, heat pumps, cooling coils, pumps, fans, humidifiers, set-point managers, etc.
• Templates for component data, e.g. boilers, chillers and performance curves etc.
• All ASHRAE 90.1 baseline HVAC system types are included,
• Graphical representation of zones featuring drag and drop facilities for ADUs (air distribution units), radiant heating/cooling devices, fan coil units, etc.
• Zone groups allow multiple zones having similar system types to be grouped together simplifying the HVAC diagram layout and speeding data entry.
• Comprehensive set of ADUs including cooled beams, direct air, dual duct CAV, dual duct VAV, single duct CAV reheat, single duct VAV. with/without reheat, single duct VAV reheat with variable speed fan, series PIU (VAV terminal type), parallel PIU, four pipe induction.
• Chilled ceilings and heated floors can be combined with other system types. They are modelled in detail using water pipes buried in surface layers.
• Multiple air handling units with drag and drop facilities for including fans, heating and cooling coils, humidifiers, etc.
• Multiple boilers and chillers in plant loops with plant operation scheme management options based on load and schedules.
• Zone forced air units including fan coil units, packaged heat pumps and packaged air conditioner. These can be used in zones together with air from AHUs.
• Automatic network integrity and connection compatibility checks.
• Fully automatic generation of EnergyPlus IDF data.
• The HVAC edit screen is integrated with the building modeller.