What does ASHRAE recommend for ventilation rates and why? How is recommended airflow determined for a space and for a mechanical ventilation system? The answers to these questions have evolved over the years.

The performance of four types of heat-pipe heat recovery unit for naturally ventilated buildings was determined in terms of effectiveness and pressure drop. The effectiveness of the heat recovery units was tested in a two-zone chamber. The pressure loss characteristics of the heat recovery units were determined using computational fluid dynamics (CFD) and experimental measurement. CFD was also used to evaluate the performance of a solar chimney for heat recovery in naturally ventilated buildings.

Solving IAQ problems requires strategies and tools for making observations and measurements. This article covers the tools a future article will impart strategies for using them.