ASHRAE Journal - November 2014 - 71

PHOTO CREDIT PAGEAU MOREL

PHOTO CREDIT WILKINSON STUDIOS LTD., MCGILL UNIVERSITY ARCHIVES

2014 ASHRAE TECHNOLOGY AWARD CASE STUDIES

ABOVE Lab prior to renovation.
LEFT 1965 photo of Otto Maass Building.

Renovation
The 2009 renovation included 37,500 ft2 (3500 m2) of
laboratories and all mechanical rooms and distribution
shafts serving laboratory areas. The objectives of the project
were to improve safety and comfort for the users, increase
energy efficiency and flexibility, and maintain operations
while retrofitting labs. The building had to be highly energy
efficient while providing improved air quality to occupants
and minimizing impact on the environment. Design conditions in Montreal are -20°F (-28.9°C) in winter and 88°F
dry bulb/75°F wet bulb (31.1°C/23.9°C) in summer.
The biggest concern was maintaining a safe, secure,
and healthy environment for users while replacing all
HVAC equipment. One solution was to install temporary
HVAC systems in the courtyard to supply the spaces that
were left occupied.
To provide adequate air quality to researchers and students, it was necessary to carry out the work in phases.
Four temporary 100% fresh air ventilation systems with a
total capacity of 120,000 cfm (56 600 L/s) were installed
outside the building to ensure a high level of air quality
to the users. Temporary supply and exhaust ducts were
installed on the exterior walls all around the building
and served each occupied room.
During the year-long project laboratory work had to
be carefully planned and scheduled so researchers had
enough lab space to continue their experiments. At the
end of the project, a total of 150,000 cfm (70 800 L/s) of
capacity were installed (six supply systems of 25,000 cfm
[11 800 L/s] each at 100% fresh air and six exhaust systems of similar capacity).
The energy efficient installations included:
* VAV terminal devices and fume hood;
* Motion sensors for light and fumes hoods;
* Ventilation and fume hood face velocity;
* Runaround glycol heat recovery loop;

* Low temperature terminal reheat;
* Low velocity system;
* Reuse of office air for minimum ach required in lab
space;
* Precooling of exhaust air; and
* Heat recovery from major server room located in
the adjacent building (±1,025 kBtu/h [300 kW]) 24/7.

Energy Efficiency
Otto Maass's laboratory areas require large supplies
of fresh air, which must be directly exhausted outside.
Therefore, energy efficiency measures are mainly
focused on heat recovery and on airflow control based
on actual user needs. Systems have typically been optimized with respect to the requirements of ASHRAE
Standard 90.1-2007.
First, a runaround glycol heat recovery loop (to prevent
cross contamination) with a total capacity of 150,000
cfm (70 800 L/s) is used to recover heat rejected from
fume hoods and preheat supply air at 100% outdoor air
(Figure 1). To maximize recovery efficiency during the
summer, the exhaust air is humidified by spraying condensate water collected on the cooling coils. Exhaust air
is precooled with this humidification process, resulting
in a higher temperature difference between supply and
exhaust (and a higher efficiency).
Furthermore, terminal reheat is carried out using a low
temperature heating loop. Energy used to heat this loop
is partially obtained by recovering rejected heat from the
equipment room (laboratory process equipment) located
in the Otto Maass building and from the computer room
located in the neighboring Burnside building (Figure 2).
Energy recovered from Burnside is about 1,025 kBtu/h
(300 kW) and is available year-round.
There were no meters to monitor the building's consumption prior to renovation. So, to evaluate the energy
N OVEM BER 2014

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