room exhaust, which allows the use of enthalpy wheel heat recovery
without the concern for cross-contamination from the exhaust to the
The filtered fume hoods will continuously filter the room air. Combined with central air quality monitoring, this provides a “belt and
suspenders” approach to safely reduce minimum air change rates in the
laboratories from the typical 6 ACH to 4 ACH occupied, and 2 ACH
unoccupied. For reference, the filter manufacturer, Erlab, maintains essentially zero air changes in their laboratory in France, relying solely on
the fume hoods to contain contaminants and filter the air in the room.
Finally, to decouple the space conditioning from the ventilation, the
design called for fan-coil units, so the exhaust and ventilation air change
rate is never driven by the loads in the space.
The combination of the filtered fume hoods, enthalpy wheel heat
recovery, reduced minimum air change rates with central air quality
monitoring and fan-coil units resulted in dramatic energy savings. By reducing the air-handler capacity from 70,000 cfm to 24,000 cfm, reducing
the stainless steel fume hood exhaust ductwork and cutting the venturi
air valve count by half, significant cost savings were achieved.
Simultaneously, BCC entered into a power purchase agreement (PPA)
to install a 3.2-MW PV array over an existing parking lot. This system
is designed for near zero-net electricity for the entire campus. With the
PPA, the array will be installed at no cost to BCC, and power will be
provided at a lower cost than they currently pay, with no rate escalation.
Overall, the ZNE design eliminated fossil fuel consumption and reduced energy consumption by a predicted 70% compared to the original
high-performance design, saving over $100,000 in energy cost per year.
But the true test came when the detailed cost estimate was completed.
The result: The ZNE solution was $200,000 lower than the high-performance design.
Beyond achieving ZNE at zero-net cost, the project was able to take
advantage of nearly $1.15 million in grants and incentives. Combined
with the capital, energy and maintenance cost savings, the result is a
net-present savings of nearly $2.65 million over the first 20 years of the
—Jacob Knowles, LEED AP
Director of Sustainable Design
BR+A Consulting Engineers
James Moses, AIA, LEED AP
Is your idea going to grow?
Harper helps companies custom engineer thermal
processes for the production of advanced materials.
Nurture your seed of an idea with
Harper as your scale-up partner.
Let us help take your seed of an idea from the lab to full commercialization.