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Major Development, London
Cityzen provided specialist input, demonstrating the feasibility and opportunity for carbon reduction when developing this high-profile site.

Energy consultancy

We were approached by RTKA to provide specialist consultancy services for the development of Admiralty Arch, a Grade I Listed structure. Planning permission was being sought for i) change use from offices to a hotel with associated bars, restaurants and catering facilities; ii) construction of a series of basements for spa, fitness and leisure facilities, ballroom and private dining; iii) construction of further basement levels providing plant space.

The turnaround time for our input was incredibly tight. We were engaged with just weeks to spare to complete the sustainability aspect of the application. The proposed development was classed ‘Major’ by the London Plan, and the project as whole aimed to achieve a BREEAM rating of ‘Very Good’.

Energy consumption was already high in relation to the existing use of Admiralty Arch, due to the poor thermal performance of the Listed building fabric. A change of use, combined with increasing the internal floor area, would increase the level of consumption. Yet we needed to demonstrate energy reductions in order to secure a ‘Very Good’ rating, and achieve an acceptable compromise between conserving energy and preserving the historic building fabric and appearance for future generations.

Cityzen spent a number of weeks modelling the existing building, taking the architect’s Revit model and using iSBEM software to review all feasible options.

These options included making use of the local district heating network (considered a low and zero carbon technology) and a site CHP plant, operating both seasonally.

We also factored in a highly efficient heating and cooling system, along with heat recovery from the proposed mechanical ventilation. LED lighting was specified to all front-of-house guest areas, with occupancy sensors throughout. There was an opportunity for additional insulation (in appropriate parts of the building) as well as upgrading the existing fabric and installing secondary glazing.

And a roof-mounted PV array would provide a proportion of the annual energy requirement.

Part of our remit involved working with Westminster Council, to ensure that the scheme met with their approval. And also liaising with Whitehall District Heating Network, to future proof the design (to accept supplies from a potential future heat network).

In collaboration with the architects and overarching M&E designers, we provided multiple iterations to reach the desired result. And an illustrative EPC achieved an ‘A’ rating for the new build aspect of the development.

The final iteration was incorporated into the London Plan report and submitted to Westminster Council with supporting evidence to gain a positive outcome.

Due to the high-profile nature, size and scope of this project, design and construction works are still ongoing.

More about the project can be found here: