KJ Tait have produced Scotland’s first Design for Performance accredited scheme at 30 Semple Street in Edinburgh.  After completion of the Independent Design Reviewer process, the BRE have confirmed a NABERS Target Rating of 5 stars.  During RIBA stages 3 and 4, the KJ Tait Energy Modeller and Mechanical Engineer worked together to understand the optimum design and control strategy to reduce the building’s energy demand.

Using the advanced modelling engine of IES, Apache HVAC, we modelled the building with and without the ability for the windows to be openable and found that there would be a 24% saving in the building’s energy demand just from this initiative.  The building occupants will be given a signal as to when conditions allow to open the windows, this will be via a traffic light system.  Once open, the local  fan coil units will switch off via the window contact sensors to save energy.   Further energy savings were realised using demand control ventilation (15%) and an economy cycle (no heating or cooling the outside air between 15 and 18 degrees during the summer) for the AHU (11%).

We developed a metering strategy that conforms to the NABERS UK metering rules with 3No distribution boards installed per half floor.  The inclusion of a mechanical distribution board alongside the traditional lighting and power boards allows for the fan coil units energy consumption to be included in the rating but for the Tenants’ lighting and small power usage to be excluded.

Working with the Client, we created the Rating Achievement Plan as to how we intend the building to actually achieve the NABERS Target Rating once in use.  At the completion of RIBA Stage 5, a Soft Landings handover will be conducted to ensure the building’s occupants and management team are fully aware of how to use their spaces.  During the first year of occupation, monthly energy reporting will be carried out that assesses the utility and sub-meter readings against the metering information from the Apache HVAC model.  Any discrepancies will be communicated to the on-site team with a view to correction as soon as possible.

After 12 months of at least 75% occupation, KJ Tait will complete the In-use NABERS assessment using the actual utility and sub- meter readings to establish the Actual Rating of the building.  The expectation is that due to the robustness of the modelling, the Soft Landings handover and the In-use energy reporting, the building will achieve at least 5 stars once in occupation.