Energyplus: New, capable, and linked

A new building energy simulation program, known as EnergyPlus, was first released in April 2001. EnergyPlus builds on the capabilities and features of BLAST and DOE-2 and includes many simulation features, such as variable time steps, configurable modular systems that are integrated with a heat balance-based zone simulation, and input and output data structures tailored to facilitate third party module and interface development - features that have not been available together in a mainstream building energy simulation program. Other simulation capabilities include three thermal comfort models, extensive daylighting and advanced fenestration capabilities, multi-zone airflow modeling, more robust HVAC equipment models, more flexible system modeling, and photovoltaic simulation. Currently, more than 10 private sector companies have stated their intentions to create user interfaces for EnergyPlus. Since EnergyPlus was released in April 2001, more than 20,000 copies have been downloaded, with users in more than 90 countries.