3.4 The case studies
University - Mathematics, Statistics and Computer Science Building
Summary
| Client |
University of Canterbury |
|---|---|
| Site address |
University of Canterbury, Ilam, Christchurch |
| Total floor area |
11,500m2 |
| Cost/m2 |
$2000 (adjusted to 2005) |
| Conventional cost/m2 |
$2300 (15% above project cost) |
| Contract value |
$22 million (adjusted to 2005) |
Economics
The indicative economics for this case study building are in the table below. The building primarily focuses on low energy design as there is no payback for water saving measures due to the method of charging for water use in Christchurch.
The capital cost for the building was significantly below the campus benchmark even though the pre-tender estimate indicated it would be more expensive. This was due mainly to the reduction in scope and size of the mechanical systems required. Rather than re-investing the savings into additional sustainable design features the University chose to incorporate additional student computer labs.
View indicative economics for this case study building (large table).
Environmental summary
- Energy used - 135 kWh/m2.
- Stormwater design - connected to campus stormwater system.
- Site - uses artesian borehole for cooling and sit boilers for the heating; site orientated north/south.
- Waste - no specific strategy.
- Material - limited finishes, high use of local materials; high-performance sine wave slab serving multiple functions.
Client brief
The building was the subject of an architectural design competition won by Architectus CHS Royal Associates. In developing the brief, the University of Canterbury required the building to have low energy consumption. This was supported by both the architects' and engineers' desire for a passive low energy building, maximising both natural ventilation and large amounts of daylight.
Facilities
Housing two academic departments, Mathematics and Statistics, and Computer Science the 11,500 m2 project is split into two main accommodation blocks separated by a five-storey high glass atrium.
The first block comprises three seven-storey blocks containing staff and postgraduate offices (orientated towards north), while the second four-storey block houses the undergraduate teaching facilities. A basement under the atrium contains further teaching and service spaces, with circulation towers enclosing the glass roofed atrium at each end.
Site
The building has its long axis lying north-west to south-east and follows the university grid pattern.
Concept
The designers insisted on the inclusion of effective natural climate control and innovative ventilation strategies from the start. For the offices this included a northerly orientation and fixed overhangs, exposed thermally massive interior walls and ceilings, fixed and adjustable exterior and adjustable interior solar shading devices, and a large number of window or louvre opening options. The 90 individual cellular offices have a wide range of ways to control the environment without using external energy.The four-storey, 15.7 m deep by 55 m long south-west-facing teaching wing is designed to accommodate large open computing laboratories and tutorial spaces. The 6.8 m-wide atrium links the two wings. Its sloping glazed roof is oriented to the south-west, while its glazed internal walls have openable windows to the adjoining wings. Bridges link the two main wings at each level. Building began in 1996, when waste and water minimisation was not a high priority. The main driver for this building was minimising energy use.
Teaching block design
Energy
The passive (non-mechanical) low-energy concept design focuses on the following:
- atrium-assisted natural and smoke ventilation
- passive solar temperature control using thermal mass
- extensive use of daylight via a central atrium and adjoining double-height spaces
- supply air passing through horizontal ducting built in to the sinusoidal concrete structural floor slab. This makes use of the slab's thermal mass to maintain an even temperature.
These passive strategies were overlaid with the following active (mechanical) strategies to further minimise energy costs:
- a highly efficient artificial lighting system with an electricity consumption of 9 W/m2 (half the current New Zealand standard)
- a sine wave structural floor system integrated with an underfloor air conditioning system. This arrangement combines five functions (column free structure, air supply, cable reticulation, ceiling surface and thermal heat sink) and also reflects the mathematical function of the building
- ground water cooling
- a high level of individual control in the academic offices with a wide range of ways to control the environment without using external energy
- plant and motorised window openers controlled via a building management system.
Academic block design
Post-occupancy evaluation
In 2001, a post-occupancy evaluation was carried out on the building to give occupants feedback on its performance and to compare the ratings with national (UK) benchmarks.
Students and staff rated the building highly. It reached a level of satisfaction (measured by noise, lighting, overall comfort, summer and winter temperatures) in the top five percentile of the 2001 benchmark data set. Summer and winter temperatures were rated as comfortable by both staff and students. Noise levels were found to be generally acceptable, with overall air quality and lighting being rated highly. All staff have access to a user manual for the building, and it was pleasing to find that all user control ratings were in the top 15% of the benchmark data set, significantly higher than the benchmark. The UK benchmark for perceived productivity for 2001 was minus 1.87%. The productivity score at MSCS was plus 9.80% (percentile 97%). This should be read to mean 'occupants think that the building boosts their productivity at work by about 10%, compared with their experience of other working environments'.
Materials
A restricted palette of materials was used for the building - including concrete, glass, plywood and cedar sunscreens - making the structure resource efficient. The philosophy of the building was 'what you see is what you get' using materials in their raw state with minimal applied finishes.
High-performance building elements were also used, such as the air floor that serves five functions - structure, air distribution, cable distribution, ceiling finish and exposed thermal mass.
Site
Thermal mass was used specifically to provide stable and natural temperature control for Canterbury's wide range of temperatures, thanks to the northwest/southerly wind shifts.The building is in the new Science West Precinct that will also include the Future Sciences Library building. The MSCS building and the Future Sciences Library building share a new, centrally located artesian borehole for cooling. The borehole water is discharged back to and supplements the flow back in the nearby Oakover stream. Offices have been placed to maximise views of the Southern Alps. The more densely occupied teaching facility with computers is orientated to the south. The sun is controlled to the east and west by massive shear walls with restricted openings.
Transport
The building is an integral part of the out-of-town campus. Buildings are mainly accessed by students on foot and by public transport.
Bicycle parks are provided throughout the university campus, while a small car park is available for staff and visitors.
Water
There are no specific water saving features, as this was not an issue at the time of construction. Water conservation would be addressed more fully if the building were to be designed and built today.
Process
Key to the success of the building's environmental design lies in the initial architectural concept, the collaborative approach taken by the designers, and the exploitation of its potential for environmental control and low energy use.
The main components of the design process are:
- a design brief outlining low energy consumption as a priority
- parallel development of traditional and innovative design solutions for review and comparison with the client
- an increased pre-tender design time of three months
- post-occupancy evaluation to improve and explain the performance of the building from the occupants' perspective
- stakeholder involvement in the project brief and design development from the outset.
Lessons learnt
The MSCS building is a good example of hybrid design (with both active and passive thermal environmental control systems) showing how successful a collaborative design approach is when used from the outset of the project. Including effective natural climate control and innovative ventilation strategies in the building's design added up to money in the bank, with the building significantly under budget, and costing less to run than a typical university building of its size.
Credits
Client University of Canterbury
Project manager University of Canterbury
Architects Architectus CHS Royal Associates
Quantity surveyors Shipston Davies
Contractor Naylor Love
Mechanical, electrical and fire engineers Ove Arup and Partners New Zealand Ltd
