May 24th 2023

2 Aldermanbury Square: SWECO on track for NABERS UK 5 Stars rating using IESVE

2 Aldermanbury Square: SWECO on track for NABERS UK 5 Stars rating using IESVE

Sweco, appointed by GPE as building service and sustainability consultants, used IESVE to carry out the detailed modelling required for NABERS UK Design for Performance, for one of their largest developments to date: 2 Aldermanbury Square.

This new London 12-storey building development will be located in the heart of the City, and will comprise of 29,565m2 office area, 144m2 of retail space, and 778m2 of reception area located on the ground floor.

Base case modelling in accordance with the NABERS UK process, is a move away from the traditional building service design process which tends to focus on design for compliance rather than performance. Using physics-based performance modelling tools such as IESVE turns the focus to energy-efficient design to ensure high-performance building operation.

Sweco UK’s Building Sustainability team used IESVE to carry out the base case modelling to create a digital twin of the building. The resultant model accurately replicates the architecture of the building and the HVAC systems and BMS controls as per design specifications. This physics-based modelling allows the prediction of building service loads and a detailed breakdown by end uses of building operational energy based on a set of building operation conditions. The performance and resilience of building design, to changes in operational conditions and parameters, is the tested part of NABERS UK off-axis analysis.

The NABERS UK Design for Performance process is underway, currently at RIBA Stage 5 and the results indicate a comfortable margin of over 25% to achieve NABERS UK 5 Stars Rating.

A NABERS UK 5 Stars Rating equates to energy savings of over 50% compared to “typical practice” building in the UK, as defined by the Real Estate Environmental Benchmark. The current UK Typical practice is 234 kWh/m2/annum (NLA), Whole Building Energy and the NABERS UK 5 Stars Rating metrics: 115 kWh/m2/annum (NLA), Whole Building Energy.

The energy performance of the building is attributed to Sweco’s façade first approach coupled with high-performance; all-electric heat-pump-based building services design. All aspect of the building services is designed around energy efficiency resulting in high performance due to cumulative effect.

The use of IESVE Software allows the passive solutions to be evaluated in the early stages of design and the model is populated with the developing design information as part of the NABERS UK process, to formulate the base case model, which in turn provides a breakdown of energy use data resulting in the projected NABERS UK rating specific to the project. As a lesson learnt, all aspects of building design require to be scrutinised for performance with priority on passive solutions. 

This NABERS UK Design for Performance pilot project is currently entering RIBA Stage 5 and the main contractor Lendlease has been appointed to take the project forward to construction. 

“IESVE allowed Sweco’s Building Performance team to produce an accurate digital twin of the development and to optimize the HVAC systems design and operation.”
Matteo Policella, Senior Energy Consultant