The University Academic Building was designed by Shore + Moffat Architects and built in 1963. The ten-storey library has a GFA of 13,935 m2 (150,000 ft2) plus a rooftop mechanical penthouse. Being one of the earlier buildings on campus and its central location are contributing factors to the building becoming an iconic and memorable place to many students, faculty, and alumni. The existing structural frame is primarily a cast-in-place waffle-slab concrete floor and column system. The enclosure system is primarily precast concrete panels. At almost 60 years of age, the building is at a point in its life cycle where the existing conditions need to be carefully assessed, particularly the precast panel anchorage, as well as the general condition of the enclosure and most other building sub-systems. Notwithstanding the existing condition assessment, with ever-evolving energy performance requirements and the emergent availability of more sophisticated cladding and mechanical systems, a robust case can be made to upgrade the University Academic Building and position it as a highly durable and highly energy efficient exemplar.

 

The University Academic Building was constructed in three phases. The first phase began in 1963 and consisted of the basement and levels 1 through 3. The second phase began in 1965 and included levels 4 through 7. The third and final phase began in 1969 and added levels 8 through 10 (plus the penthouse), to ultimately realize the full and complete Shore + Moffat’s masterplan.

Feasibility Study for the University Academic Building

Project Team

Principal-in-Charge: Kevin Stelzer; Project Architect: Krystyna Ng

Location

Waterloo, ON

13,935 m2

Area of Work

Study Completion

May 2021

For the feasibility study, ENFORM proposed a combined approach to enclosure improvement: exterior over-cladding where appropriate and cost effective as well as substantial areas of thermal upgrades achieved via interior work.

  • Exterior over-cladding at building elements that serve as both the structure and cladding (namely the arches at level 2 and the precast panels at level 3).

  • New roofs and soffits (which can be considered as an exterior treatment) at the level 4 sloped roof, level 4 soffit, as well as the level 10 roof and penthouse.

  • Interior approach to improve the perimeter wall by adding an interior stud wall with spray foam insulation. This occurs at level 1 and levels 5 through 10 (the cube) to improve performance but also maintain the existing aesthetic.

This approach bolsters two essential mandates:

  1. the University’s desire to preserve the iconic aesthetic of the building

  2. the enclosure performance to meet Passive House EnerPHit targets

Soffit and roof condition at Level 4

Arches and breezeway at Level 2

Existing penthouse and skylight

EXISTING BUILDING ANALYSIS

The existing enclosure system is a unique but significantly outmoded combination of exterior assemblies. With consideration to the modest window-to-wall ratio, but lacking thermal performance, the design team observed many areas of existing cladding degradation.

EXISTING MECHANICAL

The existing HVAC needs to be addressed holistically to meet EnerPHit requirements.

mechanical equipment

building’s connection to the district energy steam loop

air distribution system

EXISTING ELECTRICAL

Reduced lighting loads by replacing existing light fixtures with LED will be required to satisfy Passive House EnerPHit standards.

Meeting Passive house EnerPHit Standard

THE PHILOSOPHY

The philosophy of the Passive House standard is to make integral and holistically interdependent the performance of the enclosure design with the systems design of mechanical services, with such synergy and alignment that the heating and cooling of the building is achieved by the ventilation system alone.

Passive House achieves this high performance through mandating five fundamental methods: superior insulated exterior assemblies, superb window performance, superior airtightness, limiting thermal bridging across the enclosure, and very high-efficiency energy recovery ventilation. By following these methods, the Passive House designer can achieve significant performance goals, which include

  1. extremely low thermal energy demand of 25kWh/m^2 (EnerPHit)

  2. total source energy intensity limitation of 120kWh/m^2

  3. ERV efficiency of 75%

  4. airtightness of 1.0 ACH (EnerPHit) — which must be verified with as-built testing

refer to EnerPHit for building component method (page 8)

OUR APPROACH

To approach such targets, we use a conceptual tool fundamental to the Passive House Philosophy which is the PH heat balance. Once we can establish the equalization of heat flows through the enclosure systems with the internal heat gains, then a latent and essential passive balance has been established, upon which very slight “trimming” of comfort can be mechanically applied to satisfy the PH energy intensity limitations.

Our team started with the component method. Once assumptions and test assemblies were carried forward, energy simulation runs would test the passive heat balance. Exterior assembly designs were analyzed and modified, then re-run iteratively through the energy simulation model.

WHAT WE FOUND

Concurrently, existing thermal continuities were discovered as well as zones of overheating. These energy simulations were parametric. This allowance meant that the allowable thermal energy intensity was carried as a performance range such that the tested assemblies could be optimized for maintaining the heat balance and attaining minimum compliance.

DESIGN AND DETAILING TENETS
The design team assessed the existing building envelope through field observations and existing drawings. The approach to the envelope upgrade considered EnerPHit requirements. And the University’s desire to preserve the exterior look of the building.

The axonometric detail is of the envelope renewal that occurs repeatedly throughout the building. This detail is important due to its high repetition, and so because it encompasses all three of the design and detailing tenets.

1. ICONIC PRESERVATION

In order to preserve the iconic appearance where possible, we propose an interior approach to upgrading the existing building envelope. The precast detail at the cube (right) demonstrates an interior stud wall filled with spray foam insulation that is constructed on the inner face of the exterior wall, thus preserving the outward appearance of the existing precast panels and maintaining the opaque and glazed proportions.

2. THERMAL & AIR CONTROL LAYERS
Continuous and high-performance thermal and air control layers are essential to the success of Passive House EnerPHit certification. These two parameters significantly contribute to the building’s overall thermal performance, heat gains, and losses through the envelope, and building comfort. The precast detail at the cube (right) demonstrates the moving of thermal boundary , as well as the plane of the glazing and the carefully integrated air control layer.

3. MINIMAL REMEDIATION
The design team paid close attention to designing the improved envelope in such a way as to minimize the area of intensity of abatement.

axonometric detail of window sill and wall at the cube

Building Envelope Renewal

1. typical parapet detail

2. typical precast detail throughout the cube

3. typical soffit to wall transition detail at level 3

Building Modelling Framework

As part of the consulting services required for the feasibility study, the consultant team examined the feasibility of the proposed building enclosure and HVAC retrofits in meeting the performance requirements of the Passive House EnerPHit standard. To assess the EnerPHit energy requirements, the team relied upon three (3) archetypal, parametric energy simulation models that were similar to the University Academic Building in typology, occupancy, climatology, and scale.


1. A library in Mississauga,
2. An admin/office in Mississauga, and
3. A Passive House Certified Admin/Office in Toronto.


The exercise of benchmarking and calibrating projected performance is bolstered by interlacing various applicable models which were well tested and reliable.

Below are the building energy performance maps for one of the 3 archetypal energy models listed above used to replicate the performance of the University Academic Building.

EXAMPLE: LIBRARY ARCHETYPE

Archetype model 1 - with IGU SHGC ~ 0.32 — CEDI approaches Passive House threshold

Archetype model 1 - with IGU SHGC ~ 0.23 (Humber NX IGU’s) — reduces CEDI

ENERGY PERFORMANCE CHANGES: PRE- AND POST-RETROFIT
The graph illustrates the estimated relative energy consumption by end-use between the pre- and post-retrofit University Academic Building. The “before” values are estimated ranges based on similar existing buildings and the “after” values are estimated ranges based on the archetype models noted above. It is worth drawing attention to the fact that the very significant reduction in heating energy shown here will also result in a reduction in overall greenhouse gas emissions.

ENERGY SUMMARY
The archetype energy analysis confirms the feasibility of achieving Passive House EnerPHit compliance with the proposed renovations to the University Academic Building.

MECHANICAL
HVAC system to be replaced by a Variable Refrigerant Volume with Heat Recovery for heating and cooling and Dedicated Outdoor Air Systems for the Building Ventilation, effectively decoupling the latent and sensible loads.

ELECTRICAL
As for electrical and lighting, we propose existing fixtures to be replaced with LEDs, existing switches to be replaced with occupancy sensors/dimmers and deploy daylighting controls throughout the building.