Development History of Learn Green Buildings

Learn Green Buildings is built upon earlier generations of the Learn HVAC:

First Generation HVAC CBE Tool (1994-1999 and 2001)

The first generation HVAC CBE tool was HVAC Energy Primer (aka Energy Trainer). This was first developed during 1994-1999 as a CD-based product. It was funded by US Department of Defense, US Department of Energy, and US Evironmental Protection Agency. It was developed in Adobe Authorware as an interactive multimedia CBE tool by a team that included the Deringer Group, CTG Energetics, and others. The software intelectual property is shared by the Deringer Group and CTG.

HVAC EP was intended to provide an interactive version of the HVAC portion of the US FEMP Energy Manager's training manual. HVAC EP contained four hours of energy efficiency technical content, spanning a number of topics, as well as a Problem-Based Case Study exercise allowing users to improve the performance of an existing HVAC system with eight faults.

In 2001, the Deringer Group modified to software and turned it into a web-based product. This has been available at no charge at since 2001.

Second Generation HVAC CBE Tool (2004-2008)

HVAC ePrimer was the second generation of this set of HVAC CBE tools. This version was developed during 2004-2008 in two parts, and was intended primarily to be utilized in community-college HVAC technician training programs and curriculum development. One part of HVAC ePrimer was a downloadable package that ran locally on a MS Windows operating system, intended for use by students and student teams. Employing 3D simulation animations, HVAC ePrimer taught HVAC technician students how to better operate, maintain, and troubleshoot increasingly complex, digitized HVAC systems and controls in buildings.

HVAC ePrimer software utilized the latest technical education approaches being promoted by the National Science Foundation's Advanced Technological Education (ATE) program, and major funding was provided by a 3-year NSF grant. The Peralta College District (Laney College) in Oakland also provided $25,000 in funding and The Deringer Group provided in-kind funding of close to $75,000.

Several key developments resulted from our initial 3-year NSF grant to develop this second-generation HVAC CBE tool:

  • A set of accurate component simulation models for air-handling components
  • A series of 3D models and related animations
  • A graphic user interface
  • A password-protected instructor website

Third Generation HVAC CBE Tool (2007-present)

Learn HVAC is the third generation of this set of HVAC CBE tools. During a two-year CEC-funded project, which began in late July 2007, an array of new features were incorporated into Learn HVAC in order to improve on the original NSF-funded products, adding new energy-related features and expanding the potential audiences to include more building industry participants.

  • A new, much more robust software development platform (Adobe Flex), new interactive multimedia software (Flash 9), and new charting software (Flex Charts).
  • A much more flexible Graphic User interface, with multiple movable popup windows that can adapt to user screens of varying resolution.
  • Storage and retrieval of input and results files, which permits performance and energy comparisons between initial and revised conditions.
  • Energy and peak demand models were added to existing SPARK HVAC component models for a typical air-handling unit (AHU).
  • An education-focused implementation of the EnergyPlus simulation tool was added, integrating annual, monthly, and diurnal energy impacts to the existing short term (second-by-second) dynamic system operations focus of the existing SPARK component models.
  • New models were added to the existing set of AHU components models, including a boiler, chiller, and cooling tower.
  • New CBE scenarios were developed that integrated the new and existing CBE features.
  • Use cases, and user options and interactions were expanded.
  • Data structures were expanded to permit examination of five zones on a floor.

These additions enhanced the capabilities of the existing CBE tool and brought the tool more in line with CEC's core energy mission.

Always striving to make use of the best-available technology, this version of the HVAC CBE tool initially utilized Lawrence Berkeley National Lab's (LBL) HVAC component models, which ran on LBL's SPARK equation solver. Behind the user interface, SPARK crunched the numbers, updating the simulation every few seconds with realistic data. The current version of Learn HVAC has once again been improved through collaboration with LBL and use of Modelica —a non-proprietary, object-oriented, equation based language to conveniently model complex physical systems.

Alpha and Beta Releases of Learn HVAC

In mid-2008, software downloads were made available for the "client" portion of the Learn HVAC software intended for student use. The web-based instructor site is now public, but as-yet available with limited access.

Current Status and Open Source Developments

Today, thanks to an expansive CEC-funded project, Learn Green Buildings, additional functions and accessibility options are being developed for Learn HVAC. This new endeavor will improve Learn HVAC as an existing technology, as well as build upon its software and problem-based-learning models in order to create similar tools for other building-industry fields, such as lighting, daylighting, and building envelopes. Additionally, we anticipate that an open-source version of Learn Green Buildigns will be available soon after this current phase of development.