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Presenter Bio: Bill Huang

Bill Huang is the Service and Technical Manager for BROAD U.S.A., responsible for customer service and training. Mr. Huang has worked in the BROAD Group for 18 years. His career has spanned product design and production, HVAC system design and control, product installation and advanced troubleshooting, and project management and implementation. Mr. Huang is a specialist in building retrofit and strategies to optimize energy use.

Presentation Description:

For decades, the indoor air distribution convention in the U.S. has been a hybrid outdoor air and return air, most typically a “30/70” formula:  30% fresh air and 70% return or recycled air.   This is how the majority of Air Handler Units (AHU) in service today operate. However, the Covid-19 pandemic along with the “sick building syndrome” observed for many years has necessitated a re-think on the best way to achieve healthy building ventilation.  How do we make buildings safe and healthy, and reduce risk to owners and occupants?   

100% outdoor fresh air ventilation is the best way to reduce the spread of pathogens, and to best protect the health of the building occupants.  Indoor air quality as measured in PM2.5 and CO₂ levels is an indicator of overall indoor air quality, and the higher the CO₂ level, the more hospitable the indoor environment is for pathogen proliferation.  In addition, a recent study on the associations between exposure to PM2.5 and carbon dioxide indoors and cognitive function in office workers found that lower PM2 levels from higher ventilation not only reduced disease transmission, but also resulted in improved cognitive function among the workers and students in the study. The study concluded that enhanced filtration and higher ventilation rates are important health strategies that can improve employee performance.

In 2008 the BROAD Group invented a “Fresh Air Machine” which was the forerunner of the Energy Recovery Ventilation (ERV) system.  An ERV can either work in tandem with a Central Air Conditioning system and use the same ductwork, or it can be a smaller stand-alone system for a more limited space.  The ERV works by bringing in 100% fresh air from the outside, and filtering the air before delivering it to the indoor space.  The BROAD Group ERV applies a three-step filtration process: the incoming air is first channeled through a coarse filter to remove large particles. The air will then flow through an electrostatic precipitator to remove pathogens and neutralize allergens.   The final step is the HEPA H13 filter, equivalent to above MERV 16, to remove PM2.5 (particulate matter from 2.5 microns to 0.3 microns).   This multi-layer solution delivers healthy, 100% outdoor into the indoor space.  

A polymer energy exchange plate (or wheel in larger units) either warms (or cools depending on the season) the temperature of the incoming air through an air-to-air energy exchange with the exhaust air being vented to the outside.   This overcomes the limitation of solely opening air dampers for ventilation, which can cause heating/cooling loads to spike, as well as introduce dust and allergens into the indoor space. The ERV overcomes this problem.  In one project underway in New York City, BROAD ERV units varying from 59 to 293 CFM will be deployed in individual classrooms in an aging building retrofit project which will not increase cooling or heating loads.

The ERV can contribute to improved health of a building’s occupants, and improve the indoor air quality in the spaces we live, work and study in.