Sustainability was a core driver, with the Department of Engineering setting ambitious targets for the design and construction of all building's at their new campus. Our brief required the design to minimise whole-life energy/carbon, while simultaneously providing a pleasant environment for occupants — promoting natural ventilation where possible, avoiding 'green bling', ensuring future flexibility and making sure the building's performance met predicted design performance targets.

The building's form, massing and location were informed by the local planning requirements, the wider engineering campus masterplan and the technical requirements of the end users.

The building's location was chosen to enhance the existing urban realm, achieved through alignment with the existing buildings and lawn to the west, creating a new courtyard at the approach to the building main entrance. The building's massing and height provide continuity with the existing building to its west, whilst minimise the visual impact to its residential neighbours to the east. Its form and internal layout were driven by the needs of the research to be undertaken in the laboratories, with heavy labs located on the ground floor, lighter labs located on the middle floor and offices arranged around a central courtyard on the upper floor to promote cross ventilation to the open plan offices and provide daylight to the labs below. The building also provides visual connectivity between the labs and public realm to give campus visitors an insight into the research being undertaken.

The Grimshaw led design team were privileged to collaborate the late Sir David MacKay, a world-leading authority in sustainable energy at the University. MacKay wanted to address the proliferation of 'green bling' in architecture and the emerging gap between predicted and actual performance of modern buildings. Using the building as a test-bed, Grimshaw's team worked with MacKay, and other leading academics at the University, to develop the Energy Cost Metric (ECM). By combining whole-life energy and costing assessments into a single analytical tool, the ECM provided a new way to objectively evaluate and whole-life energy savings and associated cost for different design strategies in a single equation to establish which provided the best value to the University. Its use during the design phase directly influenced the decision to specify a ground source heat pump with heat recovery over gas boilers: The University's Estates Department has subsequently incorporated the ECM into their guidance for new buildings. The Department of Engineering has recently published a paper, outlining the ECM's development and application during the projects design phase, to support the construction industry's efforts to minimise whole-life energy and carbon within a cost-conscious framework.

The masterplan for the new engineering campus is conceived as 'loose-fit' framework to maximise the possible growth scenarios available. This approach was essential to accommodate the intermittent nature of funding streams available to finance the Department's move to West Cambridge and to maximise the potential to re-use as much of the existing building stock on site as possible. The building itself adopted a flexible spatial framework employing a regular planning module, zoning of heavy and light engineering activities to avoid operational disruption. The building adopted the principles of circularity by ensuring as many of the primary structural and facade components were designed for quality and longevity and with deconstruction and re-use in mind. An estimated 80% of the structural steel and façade components are recoverable. As a consequence of this approach the buildings whole-life embodied carbon profile was further reduced.

Key

1. Thermal mass – Exposed concrete floor slabs reduce internal annual temperature swings by storing heat in the summer months, preventing overheating, and releasing heat during the winter months to provide passive heating.

2. Natural ventilation & cooling – High level actuated louvres provide background ventilation year-round. In the summer they are supplemented by manual windows to maximise air flow and provide secure night-time cooling/purge ventilation.

3. Active ventilation & cooling – All laboratories are temperature controlled with fan coil units [FCU] with fresh air supplied and exhausted locally from the external façade with heat recovery.

4. Zoned underfloor heating – Office and light laboratory accommodation is heated via a low temperature underfloor heating system which can be zoned to maximise flexibility to subdivide and combine rooms at a later date.

5. Ground source heat pump [GSHP] – Fan coil units and underfloor heating systems are connected to a GSHP which stores excess heat from the laboratories to provide cooling and heating to the building throughout the year. Combined with the on-site PV array, the system provides an all electric, low energy/carbon solution.

6. Daylighting – A central courtyard, 40:60 window to wall ratio, external solar shading and glazing with a high visible light transmission above 55%, all help to maximise daylight within the buildings, while keeping excess glare and solar heat gains to a minimum.

7. Well-measured – Sensors integrated throughout the building measure environmental performance, including energy consumption.

8. Green roof – The entire roof is covered with sedum to provide amenity for wildlife. This provides a net gain in soft planting on site.

9. Woodland belt – The existing woodland belt to the east of the site has been cut back and replanted. These interventions, along with a commissioning of a detailed woodland management plan, will promote a net increase in quality vegetation, which over time should lead to a net gain in biodiversity.

10. Self-healing concrete – In collaboration with the Department of Engineering, self-healing concrete was installed in a section of the ground floor slab. This technology uses a graphene additive that acts as a binder when cracks form, to maintain the concrete's integrity.

11. Dynamic solar shading – A thermochromic film, incorporated into glass shading fins on the western facade, change opacity in response to increases in ambient temperature and direct solar heat gain. On hot sunny days the film becomes opaque helping to omit excess heat gains from the building, while maintaining unobstructed views out. On colder days the fins become fully transparent, maximising access to daylight and passive solar heat gains.