ASHRAE Journal - September 2022 - 63

FIRST PLACE | 2022 ASHRAE TECHNOLOGY AWARD CASE STUDIES
an energy recovery wheel, LED
lighting with vacancy sensors and
variable speed pumping strategies.
However, these strategies alone did
not accomplish the dramatic energy
savings achieved. To go beyond traditional
energy savings, an innovative
approach to HVAC design was
also adopted.
The primary heating and cooling
are provided by the Louisville
Medical Center steam and chilled
water plant. The chilled water plant
and central steam plant currently
operate at 0.8 kW/ton (0.2 kW/kW)
and 75% effi ciency, respectively.
The HVAC system uses four-pipe
active chilled beams with two dedicated
outdoor air units (DOAS) with
energy recovery wheels that subcool
the ventilation to 48°F (8.9°C) to
handle the ventilation and latent
loads in the zones.
To reduce the heating EUI, the
chilled beam zones incorporated
fi ltered recirculation fans to provide
all primary air for beam induction.
The DOAS VAV terminal unit manages
the code ventilation and latent
loads while still providing MERV 8/
MERV 13 fi nal fi ltered air. The recirculation
allows the chilled beams to
maintain an unoccupied setpoint
without primary air from the DOAS.
Finally, the recirculation fans provide
a natural reheat or blended air
to the zone, and the beam chilled
water coil provides any additional
sensible cooling or heating.
Indoor Air Quality
Indoor air quality is an international
focus that the recent
pandemic has highlighted, but we
have known for many years that
IAQ impacts life expectancy, health
metrics and cognitive function.
The typical offi ce building is served
by a variable air volume air-handling
unit with plenum returns
and MERV 8 fi ltration. The Novak
Center is a medical offi ce building
created for sick children and many
steps beyond the typical design
were taken to improve indoor air
quality, including fi nal MERV 8/
MERV 13 fi ltration to ensure elimination
of PM2.5 and PM10 particles
in an urban environment, zone
dehumidifi cation to prevent mold
spores from thriving and ducted
returns to allow a cleanable path
for recirculated air.
What Does This Data Mean?
Typical Offi ce Building TVOC.
Total volatile organic compounds
(TVOC) are organic chemical compounds
that consumer products
and building materials emit. These
pollutants and impact the health of
occupants exposed. LEED-NC guidance
specifi es that the maximum
concentration of TVOC in a building
is 500 µg/m3.
Novak Center TVOC: After one
year of occupancy, the Novak
Center's TVOC level was much lower
than a typical offi ce building and
surpassed the LEED goal.
Typical Offi ce Building PM2.5.
Fine particulate matter (PM2.5) is an
air pollutant that can harm people's
health by traveling deep into the
respiratory tract. WELL Building
Institute specifi es a threshold of
15 µg/m3. Factors such as age and
preexisting health conditions can
increase the risk associated with
exposure to PM2.5.
Novak Center PM2.5. The measured
PM2.5 in the Novak Center
measured signifi cantly lower
than a typical offi ce building and
FIGURE 1 Novak Center energy use vs. baseline.
performed better than the WELL
goal.
Innovation
The use of recirculation fans was
a major innovation in the design
of a chilled beam system. Each
recirculation fan zone is capable of
operating independently from the
DOAS for sensible heating and cooling
requirements. The DOAS is only
required to meet minimum code
ventilation and dehumidifi cation.
The active chilled beam system,
ducted returns and fi nal fi ltration
allow for signifi cant fl exibility
of use for a medical offi ce building.
The majority of the building
is designed to meet International
Mechanical Code; however, sections
of the building are designed to meet
Facilities Guideline Institute (FGI)
guidelines for health care. The system
only requires minor modifi cations
to transition zones to meet FGI
guidelines.
Operations and Maintenance
The building operations and maintenance
were a signifi cant point of
consideration in system selection.
The overall system is kept simple,
S E P T E M B E R 2 0 2 2
ashrae.o rg
a s h r a e . o r g
ASHRAE JOURNAL
A S H
A E J O U R N A L
6 3
https://ashrae.org/
ASHRAE Journal - September 2022

Table of Contents for the Digital Edition of ASHRAE Journal - September 2022
