Taking a Passivhaus certified retrofit system onto scaled-up zero carbon trajectory

The paper describes collaboration a between industryand academia in enhancing a Passivhaus certifiedsystem for retrofit and putting it onto a zero carbontrajectory. The system was initially developed for onsite stick construction, using fixed insulationthickness and under the current UK climate. Thecollaboration with the university has contributed to aproduct development that is adaptable to differentbuildings and future climates, achieved by multiobjective optimisation. This process considers carbonemissions and comfort as functions to be optimised,and applies a number of design variables, takingdiscrete values within specified ranges of thesevariables, and producing numerous combinations fora single design. Dynamic simulations are conductedover these combinations, producing a solution spacethat is subsequently searched by a genetic algorithmfor optimum solutions. A resultant chart gives arange of trade-off solutions that enable the designteam to enhance retrofit system and make it zerocarbon ready. In addition to the design optimisation,the scaling up of this system is facilitated by onsite3D laser scanning, which enables a transition to anoffsite solution developed in flying factories. Thepaper reports on a practical application of this workto designing a retrofit for two semi-detached houses