2 Kingdom Street Demand Driven Strategy
As 2 Kingdom Street achieved a BREEAM Excellent rating on completion in 2010, it would have been easy to believe little more could be done to improve its energy credentials. But this was not the case.
The 12-storey office block – owned by British Land and home to a variety of businesses, including Microsoft – is situated on the Paddington Central campus in London.
Cavendish Engineers identified energy-reduction opportunities through the modernisation of the three core systems on site: system architecture bundling; air handling unit (AHU) optimisation; and chilled water (CHW) and low temperature hot water (LTHW) optimisation.
It used a demand-driven strategy (DDS) to optimise minimum HVAC input power, while still achieving the best possible indoor air quality (IAQ).
A higher-level controls system (CTech) was integrated into the existing network and BMS. The CTech system uses data imported from the BMS to implement the demand driven strategy and control the HVAC assets.
Remote sensors were strategically located through the tenancies to measure carbon dioxide levels, temperature and humidity, and the DDS controls the AHUs to provide fresh air at optimal efficiency. CO2 levels are controlled to never exceed 800ppm, as defined by the Well Building Standard If CO2 levels fall below 800ppm AHU supply/extract fan speeds are reduced to save energy. As a result AHU consumption has fallen by 35%.
The chilled water (CHW) and low temperature hot water (LTHW) control strategy was also optimised using the DDS. It focuses on ensuring only genuine CHW/LTHW demands are met using large temperature differentials supplied at hydraulically efficient pump speeds.
The project challenged the existing notion that new buildings are automatically designed to be efficient. Through its design driven strategy Cavendish Engineers has achieved a 15% gas reduction and a 10% electricity reduction, since practical completion in August 2017, and this was after normalising for the warmer summer in 2018.
The entry demonstrated both the importance and potential benefits of active, ongoing building management.
Cavendish Engineers is challenging the notion that modern buildings are always efficient and that’s helping to close the performance gap.
It shows how much can be done with a bit of willpower to tackle the existing stock.
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