Natural or Hybrid Ventilation: Which is Better for Office Buildings?

The Arlington, VA-based Air Conditioning and Refrigeration Technology Institute (ARTI) released its final report on the research project titled “Simulating Performance of Natural Ventilation and Hybrid Ventilation Systems in an Office Building.”

Findings from the research reveal that while natural ventilation systems performed adequately in certain climate zones, in all climates the performance of these systems was improved with a hybrid ventilation system. Additionally, some climates experienced dramatic improvement. According to ARTI, “... when compared to the mechanical system, a hybrid system saved significant amounts of fan energy and cooling loads in all climates but often resulted in higher heating loads.” The report noted that in many cases, the hybrid ventilation system provided better IAQ control. Despite its ability to provide acceptable thermal control, the mechanical system provided control that was more consistent.

The purpose of the ARTI research was to investigate energy and indoor environmental performance of natural and hybrid ventilation alternatives in low- and mid-rise U.S. commercial buildings in a variety of U.S. climates. The research was funded by ARTI and conducted by the National Institute of Standards and Technology (NIST). To review the executive summary and final report, visit (www.arti-research.org).