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Low carbon research project, Circular Twin is launched

14 October 2021

Leading businesses from different disciplines within the built environment have worked together on a major project that sets out to radically change existing design, procurement and construction practices to deliver low carbon buildings.

Circular Twin, an exemplar study involved digitally building a school that has already been completed and reworking the scheme from start to finish so that each decision and design choice favoured a lower carbon outcome.

Designed by Cundall, Morgan Sindall Construction, Scape, HLM and Lungfish Architects, the project radically experimented with new working methods, notably adapting who was involved in design work and when, to form an early alliance of experts, with a shared goal to reduce the building’s whole life carbon.

In comparison to the original school - built in 2017 - Circular Twin achieved:

  • 67% reduction in whole life carbon
  • 72% reduction in upfront embodied carbon (48% reduction in lifecycle embodied carbon - this achieves the RIBA 2030 and LETI 2030 embodied carbon targets)
  • 52% reduction in annual energy consumption
  • 39% reduction in forest consumption (for products and 30-year UK offset)
  • CAPEX delivered within standard budgetary parameters with multiple paybacks over asset lifetime

Alex Carter, partner at Cundall commented: “The education sector is leading the way when it comes to low carbon design and Circular Twin addresses many of the key challenges we see when designing sustainable schools.

We’re working together as an industry to create low carbon design solutions and therefore greener, more sustainable learning environments for our children. Working with the supply chain on material selection and collaborating with the wider design team to develop low carbon design options will allow us to make more informed decisions in the future. This not only increases the skills of all involved, but also helps the whole of the building industry to raise its game."

Cundall’s final design embraced various Passivhaus fabric first principles, full mechanical ventilation with heat recovery and integral air-source heat pumps as the principal heating and ventilation strategy, as well as other various low energy measures to provide an overall annual energy target of just 45 kW/m2. Offsetting this annual energy load with a roof mounted PV array will allow the design to achieve net zero carbon at day one operation.

Embodying the philosophy of less net, more zero Circular Twin meets or exceeds industry-leading standards and methodologies such as the Construction Playbook, the UKGBC Net Zero Buildings Framework Definitions, and the RIBA and LETI Guides, as well as SCAPE’s own Recommended Project Environmental Standards.

Circular Twin drew on contributions and guidance from over 250 supply chain partners, enabling the generation of a comprehensive future forecast for the 60+ years life expectancy of the asset in the form of a lifecycle cost model. This helps to create a compelling business case for public sector clients to offset even modest capital cost uplifts.

If you’d like to find out more about the project, please click here.

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