ASHRAE Journal - June 2021 - 64

ASHRAE TECHNOLOGY AWARD CASE STUDIES
Condensation is often a problem for a Wisconsin
humidifi ed building with a curtainwall system. Yet, no
condensation has been observed on the Spark curtainwall
systems since its occupancy, including in January
2019 when the outdoor dry-bulb temperature fell to
below -25°F (-32°C).
Cost Effectiveness
Reducing operational cost was a key consideration. The
local electric rate is one of the continental U.S.'s most
expensive. It includes daily demand charges, monthly
demand charges and energy rates based on a base and
three on peak service periods. The high electric rate was
one reason so many on-peak energy conservation measures
were specifi ed in the design.
Rather than strictly looking at paybacks of individual
measures, the design team used a process of goodbetter-best
to evaluate performance goals, including
fi rst cost, operating cost and decision maker preferences.
This evaluated both fi rst-cost and operational
cost across a wide spectrum of benefi ts. The decisionmaking
committee was then able to make informed
choices.
Even though the analysis showed a 20-year payback
on the geoexchange wells, they were selected as part of
the stewardship of this facility. Prefabricated assemblies
were used whenever possible to reduce construction
time and cost. The project participated in Wisconsin's
utility incentive program, Focus on Energy (FOE). FOE
energy modeling showed design features beyond code
saved $91,000 in energy cost annually and resulted in
a simple payback of 9.8 years after the almost $90,000
incentive.
Extensive modeling, cost benefi t analysis and end user
experience benefi t analysis were studied in schematic
design. Table 1 highlights the performance predictions of
each scenario.
The fi nal project achieved 39% energy cost savings
versus LEED v4's ASHRAE Standard 90.1-2010 Appendix
G baseline. Modeled annual energy costs for the LEEDaccepted
proposed and baseline models were $167,545
and $274,008, respectively. The fi rst full calendar year of
metered data (2019) showed an annual cost of $164,680.
Modeled and 2019 metered energy costs are within 2%.
The 2012 CBECS average for offi ces within the Midwest
census region is $1.59/ft2·yr ($17.11/m2·yr) . The Spark
is 33% and 34% lower than the CBECS Midwest census
64
ASHRAE JOURNAL ashrae.o rg J U N E 2 0 2 1
TABLE 1 Performance predictions for four scenarios.
TOTAL
EUI
Code
Good
Better
Best
(MMBTU)
7,897
6,920
3,673
3,142
(KBTU/FT2)
73
64
34
29
% ENERGY
SAVINGS
TOTAL ($)
- 130,065
12 110,286
53 93,371
60 77,083
$/FT2 % COST
SAVINGS
1.19
1.01
0.86
0.72
region compared to the modeled and measured costs,
respectively .
Operations and Maintenance
The chosen HVAC system was favored by the O&M staff.
The Spark is operated from the corporate headquarters
about 10 miles (16 km) away. So, enabling facilities staff
to maintain many systems remotely was a requirement.
All major equipment is easily accessible for maintenance,
with most equipment collected in a single penthouse with
elevator access. Plumbing equipment is accessible by
being adjacent to the loading dock. Fan coils were strategically
placed in serviceable locations.
The extensive electric, heating hot water, chilled water
and potable water metering met LEED requirements
and allows the company to allocate actual energy and
water use and help troubleshoot, isolate and verify key
components in a successful maintenance strategy. The
project included enhanced commissioning.
Environmental Impact
This project was constructed on a brownfi eld site. The
company choose the site to support the city's goals for
revitalizing and increasing density. The facility has bike
lockers and showers to encourage users to bike, walk or
take public transportation. Low-fl ow plumbing fi xtures,
no permanent irrigation and a water reuse system for the
cooling tower reduce potable water use. Construction followed
LEED building product disclosure and optimization
environmental product declarations and material ingredients
categories and diverted almost 95% of construction
waste. Refrigerants were selected for zero ozone depletion
potential and low global warming potential.
The model shows a reduction of 1,396 metric tons CO2
equivalent emissions based on carbon dioxide, methane
and nitrous oxide emissions from both natural gas and
electric within the MRO East eGrid Subregion, which
has the highest electric carbon dioxide, third-highest
methane and third-highest nitrous oxide factors in the
United States.
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2021
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ASHRAE Journal - June 2021

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