One Portwall Square is a new category A commercial office development by Nord Bristol Ltd, located less than five hundred metres from Temple Meads railway station. The scheme comprises a six-storey freestanding office building and a pocket square/park at ground level. Construction works (by Skanska) are programmed for completion in 2021. The scheme is connected to the city-wide heat network which is currently being developed by Bristol City Council (BCC) as part of it’s heat decarbonisation works. Therma Mech were appointed by BCC to carry out the technical design (RIBA Stage 4) and installation/connection of the building heat interface substation. The prefabricated 261kW heat interface substation was manufactured by Danfoss. Installation works were successfully completed in November 2021 in readiness for the building heat-on date. Therma Mech look forward to supporting Bristol City Council in the future development and extension of their heat network and in their goal of becoming a carbon neutral city by 2030.