ASHRAE Journal - May 2023 - 31

SECOND PLACE
2023 ASHRAE TECHNOLOGY AWARDS CASE STUDY
The firm designed the two-story, 25,000 ft2 (2323 m2)
corporate office building with environmental and
occupant health and wellness at the forefront. This
project completed construction in 2018 and is the
first zero energy, WELL Gold Certified Building in
Kentucky. As an early adopter of International WELL
Building Institute Standards, numerous WELL features
positively impact employees' health and productivity.
Specialized characteristics include glare reduction,
daylight management to reduce solar gain and support
employees' circadian rhythm, optimized envelope and
orientation and improved indoor air quality/thermal
comfort as features related to ASHRAE goals.
Energy Efficiency
The building leveraged 20+ years of data and
fundamental design strategies, including concepts
like a geothermal wellfield, water source heat pumps,
DOAS with energy recovery, variable flow water
distribution and high-performance lighting design.
The HVAC system incorporated geothermal variable
speed water source heat pumps with 14.8+ EER (fullload
cooling efficiency) and 5.32+ COP (full-load
heating efficiency). Using variable speed water source
heat pumps instead of staging, the building effectively
maintains the space setpoints while reducing energy
demand and consumption requirements. The building
was designed to perform at an energy use intensity
(EUI) of 23, but is currently at 50% occupancy and
performing at 9.8 EUI. The 108 kW net-metered
roof-mounted photovoltaic system was installed to
offset the energy use and further helps in making
this building zero-energy. Figure 1 shows the building
consumption compared to solar production.
In addition to focusing on system design, CMTA worked
with the architect to develop envelope energy efficiency.
High importance was placed on energy efficient construction
by using high performing windows and ensuring
an airtight structure.
Air infiltration is a primary culprit of unnecessary
energy use and increases the likelihood of discomfort
within an occupied space. During construction, a building
pressure test was performed with drone thermography
to identify and repair areas of the building envelope
that allowed infiltration and exfiltration.
Indoor Air Quality (IAQ) and Thermal Comfort
The ventilation was designed to meet ASHRAE
Standard 62.1-2010. But, to ensure meeting the
International Well Building Institute (IWBI) prescriptive
indoor air quality preconditions, the minimum
required airflow was increased by 30%, and the design
was reviewed through the lens of field-testing specific
contaminants. This included a study determining
potential sources of volatile organic compounds (VOCs),
formaldehyde, carbon monoxide, PM2.5 and PM10 particles,
ozone and radon. VOCs and formaldehyde were
addressed with low-emitting construction materials
and furnishing.
Since testing was performed in an occupied building,
occupants were educated on reducing the use of fragrances
and perfumes to eliminate VOCs from entering
the building. The ventilation unit is on the roof and far
away from potential carbon monoxide sources. MERV
13 filters for the outdoor air systems and 2 in. (51 in.)
pleated MERV 8 filters for the building heat pumps
were used to eliminate the PM2.5 and PM10 particles. A
low exhaust inlet was placed at the copier/printer locaFIGURE
1 Energy consumption vs. production of the building.
160,000
140,000
120,000
100,000
80,000
60,000
40,000
20,000
Sept
21
Oct
21
Nov
21
Dec
21
Jan
22
Feb
22
Consumed
Mar
22
Apr
22
Generated
tions to eliminate ozone potential, and occupied spaces
were above grade and ventilated to address radon risks.
Finally, a building flush to eliminate construction odors
and pollutants was completed. Despite the measures
taken, the formaldehyde levels were ~46-52 ppb,
exceeding the goal of 27 ppb. The CMTA WELL project
administrator purchased a formaldehyde meter and
placed it on surfaces in multiple spaces to determine if
products with unknown formaldehyde were used.
Tracy Steward is partner/mechanical engineer, Tom Nicolas, P.E., is project manager/mechanical engineer, and Jonathan Rogers is mechanical engineer at CMTA in Louisville, Ky.
M AY 2023 ashrae.o rg ASHRAE JOURNAL
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Energy (kWh)
COURTESY OF SMITH + ANDERSEN

ASHRAE Journal - May 2023

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