Simulation Tools
Commercial Windows Website
Façade design begins in the early concepts phase, making it difficult to conduct detailed engineering analysis to derive optimum solutions. Designers must be able to quickly assess trade-offs and quantify impacts on energy use, electric demand and comfort throughout the entire design process.
The Commercial Windows Website lets designers quickly assess energy and non-energy impacts of typical options with its on-line tool.
LBNL has developed, in collaboration with the University of Minnesota, the beginnings of this on-line tool for A/Es or owners to optimize designs and estimate savings quickly from glazing, shading and daylighting strategies. The goal here is to have a well developed site for each city that will use local utility rates and incentive programs. A redesigned version of the site has been launched at Greenbuild 2008.
A companion extensive site for Residential Windows is at Efficient Windows Collaborative in collaboration with University of Minnesota and Alliance to Save Energy.
Commercial Fenestration (COMFEN) Early Schematic Design Tool
The Commercial Fenestration (COMFEN) early schematic design tool enables the architect to do quick what-if scenarios on specific façade, lighting, and shading designs with the powerful EnergyPlus simulation engine under the hood.
COMFEN is intended to promote design and deployment of high performance fenestration systems by making complex simulation comparisons of alternative fenestration design choices accessible to a wide audience of users. COMFEN version 1.0 provides a simple user interface that focuses attention on key variables in fenestration design. EnergyPlus simulates the effects of these variables on energy consumption, peak energy demand, and thermal and visual comfort. Results are presented in graphical and tabular format to help users move toward optimal fenestration design choices for their project.
COMFEN 1 has been released for approximately one year. COMFEN 2 contains enhancements to COMFEN 1 within the same program framework with an anticipated release date of mid-November.
COMFEN 2 additions include:
- Location Library
- Glazing System Library
- Shading Control Scheme Library
Location Library
The Location Library allows the user to add a new city for a simulation, as long as EnergyPlus weather data are available for that location.
Glazing System Library
The Glazing System Library allows the user to read glazing system data from a WINDOW 6 database, or create new glazing systems, using layers and gases from the WINDOW 6 Glass and Gas Libraries.
Shading Control Scheme Library
The Shading Control Scheme Library allows the user to specify different types of interior and exterior shading systems, including venetian blinds, drapes, and insect screens. It also allows control of those shading systems in accordance with the control algorithms available in EnergyPlus.
Modeling Complex Fenestration Systems
At LBNL, surface properties of shading and daylighting systems are first measured using a scanning radiometer (top), then modeled as a system (middle) to produce full bi-directional solar-optical data (bottom).
LBNL provides the industry with a suite of tools to assess the properties of glazing and windows, and new tools to assess energy impacts. Future developments in EnergyPlus and Radiance include the ability to more accurately model complex fenestration systems (e.g., Venetian blinds, frits, daylight-redirecting devices) which scatter light in unpredictable ways.
Glass frits, Venetian blinds, roller shades, and prismatic glazings for example are all classified as complex fenestration systems (CFS), which scatter light and radiation in an unpredictable manner. Nearly all transparent glass on the planet can now be modeled using manufacturer-specific data from the International Glazing Database. All remaining façade treatments can be modeled using CFS-enabled tools. These tools are currently under development at LBNL and involve a number of steps:
