ASHRAE Journal - August 2020 - 46

requirements. ANSI/
ASHRAE Standard 55-2004
does not specify minimum
humidity levels. The output
from the ASHRAE comfort
model indicates that the
indoor design conditions
meet the ANSI/ASHRAE
Standard 55-2004 requirements, with a rating of -0.31
in the summer and a -0.10
in the winter.

FIGURE 2 Total building annual utility consumption.

Misc. +
Unallocated + I.T
DHW - Gas

700,000
600,000

Heat Rejection
Energy Consumption (kBtu)

2020

ASHRAE TECHNOLOGY AWARD CASE STUDIES

500,000
Pumps
400,000

Heating - Gas

300,000

Fans

200,000

Chillers

100,000

Lighting

0
Nov

Dec

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

The most innovative part
of the project is the use of the geoexchange system with
the earth. At depths below 12 ft (3.7 m), the earth is typically at a relatively constant temperature compared with
the surrounding air (approximately 55°F [12.8°C] in the
Puget Sound region). When feasible, this makes it an
ideal medium to either reject heat from the building in
the cooling cycle or draw energy from the earth for heating the building. Rather than sizing the system for peak
loads, the geoexchange system was optimized to provide 75% of the heating. This "right-sizing" resulted in
a system with the best bang for the buck; the additional
money that would be required for a peak load system
was better spent on the solar power system. The system
saves the equivalent greenhouse gas emissions of a vehicle traveling 318,082 miles (511 903 km) per year.
Additionally, over 10% of the building's energy comes
from renewable solar power. This is equivalent to
166,477 kWh per year, which is the same as reducing carbon dioxide (CO2) emissions from 5064 propane cylinders used for home outdoor gas grills, or enough energy
to power 13 homes for one year.
Another innovative component of the project is
the building's smart water systems that will save
828,310 gallons (3,135,495 L) of water per year, a 45.5%
reduction over the baseline, or enough to provide the
water needs for 6.5 four-person households for one year.
Lastly, the exterior ofﬁce zones take advantage of a
mixed-mode operation. When the outdoor air temperature is at its most advantageous for natural ventilation
(or between 50°F [10°C] and 70°F [21°C]), the cooling
system for those zones are shut down, and the occupants are encouraged to open the windows for space
ASHRAE JOURNAL

Oct

Plugs
Modeled Total

Innovation

Sept

ashrae.org

AU G UST 2020

conditioning. If the occupants do not want to open the
windows, an override button has been provided to turn
back on the exterior zones.

Operation and Maintenance
As part of the ﬁve-year performance guarantee, the
design and construction team was, and will continue
to be, an integral part of the building's success. For the
ﬁrst year of operation, the general, mechanical, and
controls contractors all worked hand in hand with the
building operators. This allowed the building operators
to gain ﬁrst-hand knowledge and experience from the
construction team as to how the highly efﬁcient building
equipment and systems should operate rather than relying on operation and maintenance manuals combined
with "old school" thinking. In addition to the construction team's presence, the design team extracted both
energy data and user feedback quarterly to analyze how
the systems were performing and made suggestions on
how to improve that performance.
For years two through ﬁve of the performance agreement, the construction team will leave the site to allow the
building operators to take full system control, but will still
be available for any troubleshooting or questions as they
arise. The design team will still be analyzing the energyuse data, but on a yearly basis instead of a quarterly basis,
to ensure the performance goals are still being met.
Thus far, the building management team appreciates
the numerous sustainable features for this project.

Cost-Effectiveness
With any government facility, cost for mechanical

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ASHRAE Journal - August 2020

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