ASHRAE Journal - June 2020 - 20

TECHNICAL FEATURE

energy recovery coils are unique in that they operate
passively, have no moving parts and require no energy
inputs. The coil is split with supply air ﬂowing through
one side, exhaust through the other. Sealed piping carrying a working ﬂuid (refrigerant R-134a) connects the
two sides. The ﬂuid vaporizes through the absorption of
heat from the warmer airstream, then the low-density
vapor migrates to the cooler side of the coil where it
condenses through the rejection of heat to the cooler
airstream, and the cycle repeats. This type of energy
recovery device is ideal for laboratories because it is
self-contained, highly efﬁcient, prevents any cross-contamination between exhaust and supply, operates well
in both winter and summer, and, except for occasional
cleaning, requires no maintenance.
The climate in Richland, Wash., is dry, with hot summers and cool winters. Summer and winter design
temperatures are 101°F and 5°F (37°C and -15°C). In
this climate, evaporative cooling is very effective, so the
heat pipe energy recovery coil includes an assembly
of water sump, pump and spray heads on the exhaust
side of the coil. This arrangement evaporatively cools
the exhaust air, which increases the temperature differential between exhaust and outdoor air. The result is
an increase in system efﬁciency so that on a design day,
outdoor air is cooled from 101°F to 72°F (37°C to 22°C)
without using the mechanical chilled water system.
The HVAC systems are controlled using a robust building management system (BMS). Each lab has a separate,
dedicated enclosure located on the mezzanine to house
the programmable control devices for equipment serving that particular lab, all connected to an operator's
workstation (and PNNL campus-wide BMS system),
with graphical user interface located in the mechanical
room. This allows changes and updates to be carried out
independently without disruptions or outages in the
other labs. Energy use is monitored including natural
gas, electricity, chilled water and heating water. Potable
water use is also monitored.
The BMS operates on the BACnet protocol. However,
control points for devices such as variable frequency
drives and boilers are hardwired to controllers in addition to the BACnet connection. This ensures maintenance of communication for control in the event of disruptions to the network.
The building was designed to comply with ASHRAE/IES
Standard 90.1-2010 and the U.S. Department of Energy's
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ASHRAE JOURNAL

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J U N E 2020

FIGURE 4 Energy consumption compared to the design and Standard 90.1 baseline.

Energy Consumption
(In Million Btu)
3,284

Baseline

2,840

2,661

Design

Actual (2018)

"Guiding Principles for Sustainable Federal Buildings."5
Compliance with the "Guiding Principles"'s design
checklist results in a building comparable to one
designed to a LEED Silver rating. An energy model
was developed during design that projected the
facility's annual energy use at 2,840 million Btu/yr
(3 million MJ/yr), representing an energy savings of
nearly 14% compared to the Standard 90.1-2010 baseline. In the ﬁrst full year of operation, actual energy
consumption was 2,661 million Btu (2.8 million MJ), a
realized savings of 19% compared to the Standard 90.12010 baseline (Figure 4).

Conclusion
The design of GPCL has proven to be very successful
in meeting the original goals of ﬂexibility, adaptability,
energy efﬁciency, and maintainability while improving
overall usability for research. It has become a showcase
on the PNNL campus, which has more than 2.3 million
ft2 (213 677 m2) of laboratory and support facilities. Due
to the demonstrated success of these strategies and methods, they are currently being incorporated into PNNL's
newest project, a signiﬁcantly larger (138,000 ft2 [12 821
m2]), $65 million Energy Sciences facility. The design for
this building is currently in progress and construction is
scheduled to start in the spring of 2020.

References

1. ANSI/AIHA/ASSP Z9.5-2012 Laboratory Ventilation, Page 26.
2. ASHRAE Handbook-HVAC Applications, Chapter 16.
3. Phoenix Controls. 1999. Laboratory Sourcebook, 5th Edition, Page 30.
4. Mankameyer, Beth. 2013. "Reducing
Laboratory fume hood energy consumption, even
at 100fpm face velocity!" https://tinyurl.com/
y6vabjro.
5. DOE. 2016. "Guiding Principles for
Sustainable Federal Buildings." U.S. Department https://bit.ly/2YUre1l
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ASHRAE Journal - June 2020

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