ASHRAE Journal Supplement - AMCA InMotion - November 2022 - 26

change and prompted us to think about the potential impact
of cooling effects from air-circulating fans for various applications.
While much of the discussion of climate change
and buildings has been focused on the use and conservation
of energy in conditioned spaces, it is imperative to
also focus on the effects of heat strain on occupants, which
the Occupational Safety and Health Administration has
made a point of national emphasis.8 With that in mind,
two questions were identifi ed for exploration:
1) Can cooling effects provided by air-circulating fans
mitigate climate-change-induced increases in occupant
heat strain in heated-and-ventilated-only warehouses?
2) Can cooling effects provided by air-circulating fans
improve the resilience of existing mechanical systems
while maintaining occupant thermal comfort amid
changing climatic conditions?
Modeling Methods
The modeling methods used for our condensed study were
not designed to be as rigorous as those for some existing
works examining specifi c building uses. To address the two
questions above while leveraging existing works as much
as possible, our approach included using DOE reference
building energy models, existing TMY3 (typical meteorological
year) data indexed to future and current climate
states, and tools such as CBE Thermal Comfort Tool, the
National Weather Service's (NWS) Heat Index Calculator,
and a brand of commercial design and analysis software.
Two DOE commercial reference buildings9 were
selected and minimally changed for the study:
■
To study heat-strain effects in an unconditioned environment
(fi rst question), the warehouse reference building
was selected. This building type is representative of
spaces that often are unconditioned and typically have
low occupant density, low internal loads, and a high
envelope load, such as hangars, light-manufacturing
facilities, and fl eet-maintenance operations. This is the
building model used in a study of thermal comfort in
heated-and-ventilated-only warehouses under current
climatic conditions.10
■
To study the second question, the medium-offi ce reference
building was simplifi ed to be single-story but
with the same fl oor area and other characteristics. This
building type has a medium occupant density and a
medium internal equipment load typical of education
environments, retail environments, and other public
spaces that usually are conditioned.
Energy modeling was conducted for each city shown
High-speed-small-diameter (HSSD) air-circulating fans installed in
a conditioned offi ce. Photograph courtesy of Big Ass Fans
26
2022 AMCA inmot ion
in Table 1 using the radiant-time-series heat-balancing
method in the commercial design and analysis software
and TMY3/EnergyPlus Weather (EPW) data. Each facility
was simulated across all 8,760 hours of a year with and
without air-circulating fans under current
and future climatic conditions. The results
of each simulation yielded hourly indoorair
conditions, HVAC design capacity, and
yearly HVAC electrical consumption. These
results were used to address the questions
above. With the hourly indoor-air conditions,
indoor-air dry-bulb temperature
and relative humidity were used to calculate
heat index for each hour as prescribed
by the NWS,11 and the heat indices were
grouped into heat-strain health-risk categories.
Cooling effect provided by airfl ow
from air-circulating fans was calculated
using CBE Thermal Comfort Tool's pythermalcomfort
package.12 The cooling effect
for each hour was subtracted from the drybulb
temperature in a subsequent heat-index
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ASHRAE Journal Supplement - AMCA InMotion - November 2022

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