One Island East showed an outstanding outcome in energy saving through carrying out retro-commissioning (RCx) works driven by the company Sustainable Development (SD) 2030 strategy. Facilitated by the monitoring-based commissioning (MBCx) platforms, that have adopted rule-based diagnosis and cloud computing for KPIs visualisations, RCx opportunities can be spotted efficiently. Identifying the oversupply in pump head of secondary condensing water pumps (SCWP) which causes low pump efficiency of the condensing water circuit, the Team has worked out and applied a new operation strategy by increasing the number of condensing water pumps operating at lower frequencies based on various cooling load demand. On average, the energy consumption is reduced by around 6%.
Energy saving opportunity was also identified in the Air Handling Unit (AHU) system. By resetting the static pressure setpoint, while maintaining a good level of indoor air temperature and CO2 level, the airside energy consumption has yielded an approx. 10% reduction.
In addition to HVAC control modification, another Energy Saving Opportunity ESO is carpark ventilation optimisation. The mechanical ventilation in the basement carpark was managed by operating the exhaust air fans (EAFs) 17 hours per day. An EAF control strategy was adapted to minimise the operating hour of EAFs based on CO concentration feedback from CO sensors that are already installed. The strategy includes fine-tuning the on/off condition and the fan speed of EAFs, while maintaining a strict CO level in carpark; which saves up to half of the carpark ventilation consumption compared to that of 2017. In consideration of energy saving measures, One Island East demonstrates a good balance between maintaining the wellbeing and energy saving.