Development

The recently developed EnergyPlus Displacement (DV) and Cross-Ventilation (CV) models were implemented by NaturalWorks.

The fully-mixed room air approximation currently used in most whole-building analysis tools was extended to a two (CV) and three (DV) node approach, with the purpose of obtaining a first-order precision model for unmixed ventilation systems. The use of additional nodes allows for improved prediction of thermal comfort and overall building energy performance in low energy cooling strategies that make use of unmixed ventilation flows.

The simplified airflow models were developed using a combination of scaled model experiments, computational fluid dynamics and scaling analysis. This combined approach gives insights into the mechanisms and system parameters that control the airflow pattern and the vertical temperature variations.

The new models resulted from research funded by the California Energy Commission (CEC), done at the University of California at San Diego. The project was part of a large research effort in Low Energy Cooling systems, coordinated by Lawrence Berkeley National Laboratory (Dr. Philip Haves).

The results of a recently completed CEC funded project can be found here.