ASHRAE Journal - July 2022 - 48

ASHRAE TECHNOLOGY AWARD CASE STUDIES
able to review and approve for use ASHRAE Standard
62.1-2013 Addendum k, which allows Class 4 air to be
reclassifi ed to a lower air class. This process included
review of the building's HVAC system, the lab's safety
protocols, equipment specifi cations and commissioning
requirements, as well as an analysis of expected
research and chemical use (including spill scenarios).
The wheel manufacturer was sole-sourced based on
testing of desiccants' cross-contamination approved by
the safety offi cer that limited the maximum carry over
to 0.045% per wheel (0.09% for two wheels in series).
Prior to occupancy, the system was commissioned and
verifi ed via a tracer SF6 gas test, in accordance with
ASHRAE Standard 84-2013, Method of Testing Air-to-Air
Heat/Energy Exchangers. In evaluating wheels, design
teams must also consider International Mechanical
Code (IMC) hazardous exhaust and ASHRAE Standard
62.1-2007 requirements. For this project, the owner's
safety offi cer confi rmed that fume hood exhaust was not
hazardous. ASHRAE Standard 62.1-2007 classifi es fume
hood exhaust as Class 4 air and restricts recirculation
of this air. With the DOAS neutral air approach, lab and
teaching classroom ventilation air distribution systems
are manifolded together. As a manifolded system, the
chemical concentration of fume hoods is heavily diluted
via diversity and general exhausts.
The 6,000 ft2 (557 m2) vivarium was provided with a
100% outdoor air dedicated air-handling system with
N + 1 redundancy. The AHU includes a 50% effective glycol
run-around heat recovery system, which captures
heat from the vivarium exhaust system.
The ILSB uses the available high-effi ciency campus
chilled water and high-temperature hot water
plants. The central plant serves chilled water and high
temperature hot water (HTHW) to approximately
1,975,000 gross ft2 (183 484 m2) of the facility space (64%
of the campus). Centrifugal chillers, as well as a chilled
water storage tank, generate chilled water and distribute
it to the building via variable primary pumping distribution.
Pumps, in series with the campus system, boost the
campus chilled water pressure if adequate pressure is
not available from the campus system. This setup allows
for pump energy to be reduced at the building, as well as
optimization of return water temperatures to reduce the
risk of " low delta T syndrome " at the central plant. An
overall plant effi ciency of 0.57 kW/ton (0.16 kW/kW) was
calculated for the central plant, which puts the plant in
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ASHRAE JOURNAL ashrae.o rg J U LY 2 0 2 2
line with high-effi ciency optimized chilled water plants.
This includes the energy used for the chillers, cooling
towers, pumps and distribution losses in the system.
The high temperature hot water plant operates with
a supply temperature of 350°F (177°C) and 200 psig
(1.4 MPa). Boilers produce HTHW at approximately 80%
effi ciency. The main benefi t of HTHW systems is that
they are closed-circuit systems, which eliminate the
need for boiler blowdown and reduce makeup water
requirements as well as distribution losses compared
with steam systems.
Overall, energy use is reduced by over 40% compared
to an ASHRAE Standard 90.1-2007 baseline building.
Space heating and space cooling is reduced by 55% and
67%, respectively.
Indoor Air Quality
The design team met regularly with UMBC's
Environmental Safety and Health team to review the
design, set standards and investigate new technologies.
This process ensured that the laboratories exceeded all
safety requirements. High performance fume hoods
were used to reduce airfl ow rates. Hood velocities were
designed to maintain 65 fpm (0.3 m/s) at 18 in. (457 mm)
sash height versus a standard hood at 100 fpm (0.5 m/s).
Each hood passed the " As Manufactured " (AM) fume
hood testing in the manufacturing facility-certifying
that each type and size achieved a performance rating
equal or better than 0.05 ppm with 4.0 L/m (0.1 cfm)
tracer gas release rate when tested in accordance with
ANSI/ASHRAE Standard 110 .
Teaching labs were designed with adjacent prep spaces
so chemicals could be removed from the teaching environment
daily. This enhanced safety and allowed the
design team to reduce the minimum air change rate to
4 air changes per hour (ACH) when unoccupied (from
6 ACH occupied). The design team manifolded the
teaching classrooms and the laboratories onto the same
100% outdoor air-handling unit distribution system.
The entire building is served via once-through outdoor
air (no recirculation). Laboratory makeup air rates
greatly exceed ASHRAE Standard 62.1-2007 requirements.
Supply VAV boxes serving ventilation diffusers
(decoupled from the chilled beams) vary the outdoor
air required for the teaching classrooms based on CO2
sensor readings. Overall, the total outdoor airfl ow to
the building doubles the required outdoor air quantity
2022
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ASHRAE Journal - July 2022

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