Energyplus: new capabilities in a whole-building energy simulation program

A new building energy simulation program developed under support from the US government was released in April 2001. EnergyPlus is based on the most popular features and capabilities of BLAST and DOE-2 but is a completely new program written in Fortran 90. New features include variable time steps, user-configurable modular systems, an integrated heat and mass balance- based zone simulation, multizone airflow, air pollutant transport, moisture transfer in building components, solar photovoltaic simulation—and input and output data structures tailored to facilitate third party module and interface development. EnergyPlus is primarily a simulation engine without an user interface—although user interfaces are under development by the private sector This paper focuses on the general simulation methods and capabilities of EnergyPlus, contrasting it with those  of  DOE-2  and  BLAST. Plans  for  future releases of EnergyPlus are also described.