ASHRAE Journal - August 2024 - 62

2024 ASHRAE TECHNOLOGY AWARDS CASE STUDY
2
ND
Compared to the baseline clinic and its
actual operation in 2022, the new clinic saved
$103,136 its fi rst year of operation. This results in a
12.6 year simple payback without accounting for energy
escalation compared to the baseline clinic and 7 years
compared to the former facility. We saw a 23% escalation
in energy costs for 2022 over 2018 at the baseline clinic.
actual operation in 2022, the new clinic saved
ENVIRONMENTAL IMPACT
Built on the site of an abandoned grocery store,
the clinic spurred community redevelopment and
improvement. The 100% electric facility operates with
a peak demand half the smaller natural gas/electric
baseline clinic (165 kW for the 47,000 ft2 [4366 m2]
baseline facility in August versus 86 kW for the 64,000
ft2 [5946 m2] East side clinic in December). Eliminating
on-site combustion in accordance with Pueblo
renewable energy goals combined with use of on-site
renewable energy in the form of PV and the ground
source heat exchanger reduce environmental impact
as measured in energy consumption, cost and local
emissions. Reducing energy and operation costs results
in more resources available for serving the community.
TABLE 1 Component description.
COMPONENT
DESCRIPTION
ASHRAE STANDARD 90.1-2013 BASELINE PERFORMANCE
REQUIREMENTS (CLIMATE ZONE 5B)
21% window to wall ratio
Wall Construction
Mass: overall U-value = 0.09, overall R-value = 11.4
Wood framed: Overall U-value = 0.051,
Overall R-value = 20
Steel framed: Overall U-value = 0.055,
Overall R-value = 18.2
Insulation entirely above deck:
Roof Assembly
Overall U-value = 0.032, Overall R-value = 30
Attic and other: Overall U-value = 0.021,
Overall R-value = 49
Mass: U-value = 0.057, R-14.6
Steel joist: U-value = 0.038, R-30
Floors
Wood framed and other: U-value = 0.033, R-30
Slab-on-grade fl oors: unheated = F-0.520, R-15 for 24 in.
Heated: F-0.688, R-20 for 48 in.
Windows
Skylights
Shading
62
SHGC=0.40 to 1.10 for all frame types
Nonmetal framing, all: U-value = 0.32
Metal Framing, fi xed: U-value = 0.42
Metal Framing, operable: Assembly U-value = 0.55
0%-3% of roof, U-value = 0.5, SHGS = 0.4
None
Insulation entirely above deck:
R-60 (In our experience 50 - 60 is good target)
Unheated slab-on-grade fl oors:
Unheated F-0.520
Metal framing, fi xed: U-value = 0.21, SHGC = 0.2
(South and West facing) to 0.55 (North facing).
Consider smaller windows shaded with light
louvers on South face, larger windows
on North face.
No skylights anticipated in favor of center atrium.
For South-facing glazing, long East to West axis
preferred, multiple components stacked North to
South provide some self shading, improve
natural light.
ASHRAE JOURNAL ashrae.org A U G U ST 2 0 2 4
Steel framed: R-23 (note that in our climate
going above and beyond with wall insulation sees
diminishing returns in the R-22 to R-23 range for
buildings with AC)
Brick over stud wall, 3 in. polyiso insulation,
Fluid applied air and moisture barrier, 6 in.
Metal stud with 2 in. SPF = R-25 total
Fully adered TPO with 10 in. polyiso
insulation, 1.5 in. metal roof deck - R-60
total
Unheated 4 in. slab-on-grade, R-10 rigid
under slab, R-16.2 at perimeter
Fiberglass windows -
U-value: 0.19
SHGC: 0.21, 0.42 North
Tubular skylights incorporated for natural
light in center atrium, not technically
a skylight
30 in. horizontal overhangs between all
fl oors, circumventing building except
North face
CONCLUSION
After a full year of measurement and verifi cation
the facility operated at 22.55 kBtu/ft2·yr
(256.09 MJ/m2·yr) and $0.415/ft2 per year ($.039/m2 per
year), $0.324/ft2 per year ($.030/m2 per year) after
the additional credit in December. Total energy
consumption of the facility was completely offset by the
on-site 280 kW PV array, which produced 436 MWh/year
for a net EUI of (-0.68) kBtu/ft2·yr (-7.72 MJ/m2·yr).
The East Side Clinic demonstrates that energyeffi
cient facilities do not have to be expensive or
overly complicated. When decisions are made early,
the cost impact was minimal (6%) and the results
were multiplied (from a designed $73,000 to an actual
$103,000 savings compared to the baseline clinic).
Successful zero energy can be defi ned by sustainable
design plus the selection of energy-effi cient systems
and equipment plus incorporation of on-site
renewable energy. The order of operations is critical,
starting with sustainable design, systems selection
and equipment to maximize energy effi ciency, and
selecting and sizing on-site renewable energy systems
and equipment.
INITIAL DESIGN GOALS
BUILDING ENVELOPE
AS DESIGNED PERFORMANCE CHARACTERISTICS
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ASHRAE Journal - August 2024

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