Linking the comis multi-zone airflow model with the energyplus building energy simulation program

This paper describes an effort to link the COMIS 3.0 multi-zone airflow model with the EnergyPlus building energy simulation program. COMIS 3.0 is a network-based multi-zone airflow model developed by a multinational team in the framework of International Energy Agency’s Annex 23 for simulating airflows through the building fabric due to infiltration or natural ventilation, and from zone to zone, as well as the interactions of the HVAC system, ducts, and exhaust hoods and fans. EnergyPlus is a new whole-building energy simulation program being developed for the United States Department of Energy that combines the best features of the DOE-2 and IBLAST programs. The EnergyPlus program is modular in structure, and uses the heat balance technique to simulate building thermal loads. The EnergyPlus program calls COMIS from the Air Heat Balance Manager module and passes to COMIS the ambient weather conditions and zone  air temperatures from the previous time step. COMIS uses these as boundary conditions to calculate the airflows, which are used by EnergyPlus in the subsequent heat balance simulation. The paper will describe how this linkage was implemented and discuss  issues  such  as  convergence,  time  steps, program run time, and alternate solution methods.