ASHRAE Journal - September 2014 - 76

2014 ASHRAE TECHNOLOGY AWARD CASE STUDIES

heating/cooling distributes fresh air and highly effective
heating and cooling throughout.
The base building system is designed to service classrooms, offices and laboratories from a common infrastructure, allowing the migration of building spaces over
time to different uses without significant renovation
costs.
All spaces except a large lecture theater are served
by three 40,000 cfm (18 900 L/s) dedicated outdoor air
systems (DOAS) in the basement; each have an array
of variable speed direct drive fans in integral acoustic
enclosures and provide energy savings, redundancy,
and increased space efficiency. Coils with low leakage
bypasses open to reduce fan energy when the coils are
inactive, and there is space for an additional 20,000 cfm
(9 450 L/s) "piggyback" unit on top of each unit for the
flexibility to convert more spaces to labs. Shortly after
occupancy and development of a fifth floor shell space
into intensive research labs, one piggyback unit was
added. All air is delivered to the building at 65°F (18.3°C)
through displacement ventilation techniques.
The main duct network is shared and looped on each
floor enhancing reliability, expandability and energy
savings. The supply and exhaust duct mains are sized
for eventual build out to 180,000 cfm (85 050 L/s), so the
existing peak of 140,000 cfm (66 150 L/s) results in significant system pressure drop savings.
The main outdoor air intake at grade feeds a 14 ft (4
m) deep ground coupled intake plenum system that
acts as a preconditioner for the main units. Building
exhaust is routed through filters, a glycol runaround
heat recovery coil and 4 × 40,000 cfm ( 2 × 18 900 L/s)
high plume, dilution exhaust units on the roof. Toilet
and wet exhaust is routed up separate risers and join the
main exhaust on the roof upstream of the heat recovery
module. The high plume exhaust units throttle down in
non-bypass mode during nighttime hours to save energy
and reduce ambient noise to nearby residential areas.
A fourth air handler serving a 180 seat lecture theater
is supplied outdoor air from a ground coupled earth
tube system. Buried 14 ft (4 m) below grade, two-150
ft (46 m) long, 48 in. (1.2 m) diameter concrete tubes
precool ventilation air in summer, and preheat the
air in winter. Heat recovery and heating/cooling coils
supplement the earth tube system. Air is distributed to
a pressurized plenum below the raked seating with low
velocity air outlets in the seat risers, overhead radiant
76

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Heat Recovery
to DOAS Units
High Plume
Roof Exhaust
5th Floor
4th Floor
3rd Floor
2nd Floor
Above Grade
Air Intakes

Main Floor
Ground Coupled
Intake Plenum

Earth Tube
Geothermal
Preconditioner

DOAS Unit 65°F
(Typical of 3)

Basement

Theater AHU 65°F

Main Floor
Theater

Heat Pipe

80°F
Electrical
Room

Exhaust

FIGURE 2: Ventilation systems concept.

panels provide auxiliary heating/cooling. Outdoor
air quantity is demand controlled with CO2 sensors.
Exhaust is passed through a heat pipe energy recovery
unit and then used to cool the main electrical room
(Figure 2).
A central solar chimney at the top of the atrium provides passive smoke venting and natural venting of
non-lab exhaust during mild weather. When the outdoor air temperature is mild, the vents open, exhaust
air bypasses the central exhaust and relieves out of the
atrium by stack effect. This allows the central exhaust
to throttle down, saving energy. The stack pressure also
improves positive airflow through operable windows in
classrooms and offices. Lab windows are fixed closed to
preserve lab pressure relationships.
The owner's district energy system (recovered heat
from cogeneration) provides high-pressure hot water
for generating hot water and 70 psi (483 kPa) steam for
lab use. Distribution and utility piping has been sized for
future build-out to a full lab building and currently sees
reduced velocities and pressure drops. Heating consists
of radiant slabs, unit heaters, and overhead radiant
panel/light shelves in perimeter rooms. The higher heating temperatures for radiant panels and heaters versus
the lower temperature for heating coil glycol and radiant
slabs are served by a cascaded heating system; return
water for each load is used as the supply water feed for
the next load (Figure 3).

ASHRAE Journal - September 2014

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