ASHRAE Journal - August 2020 - 9

LETTERS

TECHNICAL FEATURE

Raising the Bar in
High Performance
Laboratory Design
BY JEFFERY M. SCOTT, P.E. MEMBER ASHRAE

Laboratory facilities are expensive to build (as much as $1,100/ft2 [$11,840/m2]), operate and maintain, and they consume energy at high rates compared to other types of
buildings. In addition, modiﬁcations are frequently required because of ever-changing research needs and activities. The in-house design team at the Paciﬁc Northwest
National Laboratory (PNNL) sought ways to address these issues in the design and
construction of a 14,700 ft2 (1366 m2) wet chemistry research facility on its Richland,
Wash., campus. Speciﬁc goals were reducing energy consumption, improving maintenance and operations to reduce life-cycle costs and incorporating inherently ﬂexible
features to accommodate future modiﬁcations at a lower cost and reduced impact on
an operating facility.
Architectural Design
Architectural challenges that repeatedly arise in
laboratories include ceilings that are too low to accommodate special equipment, narrow corridors, inability
to easily remodel or reconﬁgure spaces, insufﬁcient
space in a single lab module and disruption to research
activity by maintenance personnel accessing equipment above ceilings. The General Purpose Chemistry
Lab (GPCL)'s design team sought to address all of these
issues.
Ceiling height is often a research-limiting factor
since a standard 9 ft to 10 ft (2.7 m to 3 m) ceiling

height may not accommodate specialty equipment.
To address this, the roof height was set at 19 ft (5.8
m). Then, horizontal ductwork, piping, and electrical
conduits were installed at a minimum height of 15 ft
(4.6 m). Piping drops to ﬁre sprinklers were installed
using ﬂexible connectors, and lighting was installed
with ﬂexible conduit. These features allow the acoustical tile ceilings to be raised from a standard height
of 10 ft (3 m) to as much as 14 ft (4.3 m) with minimal
changes to infrastructure. Since the lab spaces are
ventilated on a volumetric basis, energy consumption increases with ceiling height, so the standard

Jeffery M. Scott, P.E., is a senior mechanical design engineer at the U.S. Department of Energy's Paciﬁc Northwest National Laboratory, Richland, Wash.

in this facility the water pump and
spray head assembly discharge
water directly onto the exhaustside heat pipe coil ﬁns. Adding
evaporative cooling to the heat

pipe heat exchanger signiﬁcantly
improves the overall thermal effectiveness and, thus, increases the
energy savings of the system in the
summer.
As shown in Figure 3 of the article,
the summer design condition of
the exhaust air, i.e., the air leaving
the laboratory spaces, is 75°F dry
bulb, 62°F wet bulb (about 47% RH).
Since that is well below saturation,
the exhaust air has the capacity to
absorb a large amount of moisture.
Evaporation of water lowers the
exhaust air temperature due to the
heat of vaporization, increasing the
temperature differential relative to
the warmer outside air. This larger
∆T increases heat transfer through
the phase change process occurring
within the heat pipes.

ENGINEERED, TESTED
U

At the particular design conditions in this facility, the heat pipe
alone would cool the outside air
from 100°F to 86°F, a ∆T of 14°F.
However, with evaporative cooling
the ∆T improves to 28°F to provide a
leaving air temperature of 72°F.
Jeff Scott, P.E., Member ASHRAE
Richland, Wash.

ASHRAE Journal welcomes
letters to the editor. The letters should be no more than
250 words and must relate
to an article published in
ASHRAE Journal.
Please send your letters to
sfoster@ashrae.org.

Originator and manufacturer of The Metraloop, the
energy-eﬃcient LPD Y-Strainer and many other
innovations, Metraﬂex has a solution to ensure your pipes
move freely in any application.
Metraﬂex products are manufactured in Chicago, IL and
distributed through a world-wide rep network, all backed
by our engineering and support teams.

www

738-3800
AU G UST 2020

ashrae.org

ASHRAE JOURNAL

https://www.metraflex.com/ https://www.ashrae.org/

ASHRAE Journal - August 2020

Table of Contents for the Digital Edition of ASHRAE Journal - August 2020