Replacement of existing air-cooled chillers for the Bank of Ireland at No.1 Temple Quay, Bristol.
No. 1 Temple Quay, Bristol is a seven-storey office building. Chiller water is used for space conditioning via core air handling plant (AHUs), some fan coil units (FCUs) and chilled beams (ceilings) throughout the office floors.
Chilled water is provided to AHUs and FCUs at flow / return temperature of 6°C-12°C. Chilled water to the chilled beams is 14°C -17°C temperature.
The existing air-cooled chillers, installed during the construction of the original building at Temple Quay were located within plant compounds at roof level, with adjacent plant rooms housing pumps, AHUs and boiler plant. The plant compounds have louvred roofs and sides such that from external view the building appears to have a single, shallow pitched slate clad roof.
Various options were considered for the replacement of the existing air-cooled chillers. Replacement works needed to reflect that the building was occupied and minimal disruption can be tolerated to the space conditioning.
The options considered were:
a) Strip down and rebuild the existing chiller in sections.
b) Sequential replacement using multiple small air-cooled chiller modules
c) Sequential replacement using maximum size chillers to match existing loads.
The agreed solution was to strip out the existing chillers in sections and replace with new to minimise downtime of the space service. Only one service was affected at a time and hence by adjustment of the South Side or West Side BMS and control respectively, the impact to the office spaces was minimised. Each chiller was off line for a limited period of approximately one week.
Key design issues resolved:
- Selection of replacement air cooled chillers that could be craned through the maximum opening in the louvred roof, without removal of main structural elements
- Consequently, one existing chiller was replaced by a pair of new chillers
- Modification of pumps and pipework to accommodate the hydraulic requirement of a pair of chillers, of equivalent duty to the previously provided single chiller
- Primary pump pressure and speed control
- BMS chiller and pump control modifications
- Structural steelwork design, including new chiller support, final positioning of new chillers and design of access gantry to facilitate ongoing maintenance
- 5-year maintenance and extended warranty period
Key Challenges:
- Logistics of roof removal and replacement
- Positioning of fabricated steel work
- On site splicing of purlins
- Multiple crane lifts over six weekends
