08 September 2021
Carrier centrifugal chillers delivering 16MW of cooling have been installed at a new technologically advanced 62-storey building in London.
22 Bishopsgate, described as a "vertical village" comprises 1.275 million square feet of residential, office and indoor amenity space designed to achieve the highest standards of sustainability and occupant comfort, with a Building Research Environmental Assessment Method (BREEAM) rating of Excellent. Built by principal contractor Multiplex, 22 Bishopsgate is also pursuing certification under the WELL Building Standard.
Tenants include Nasdaq Stock Exchange Group, Hiscox, Beazley, THB Group, RGA, Covington & Burley and Europe’s largest renewable energy generator, Statkraft, along with 12,000 residents and visitors. Together with umerous shops, restaurants, an auditorium, a fitness centre, and dedicated leisure and learning facilities, they are all air conditioned by four Carrier AquaEdge 19XRV high-efficiency centrifugal liquid chillers.
The recently-completed 22 Bishopsgate in London
Installed by Michael J Lonsdale, each chiller delivers 4MW of cooling with efficiency levels as high as 6.8 European Efficiency Rating (EER). Equipped with Greenspeed Intelligence variable speed drives, the chillers constantly match cooling output to the building’s heat load, optimising comfort, reducing energy consumption and minimising impact on the environment.
The chillers use a new high-efficiency dual-stage, aerodynamic impeller design, with tunnel diffusers based on aircraft engine technology. The compressor motor is cooled by refrigerant gas injection, further improving efficiency, while a patented float-valve system optimises sub-cooling and refrigerant level in the evaporator.
The chillers are controlled by the Carrier ChillerVu plant system manager (PSM), a sophisticated and scalable BACnet control solution that has an onboard library of factory-engineered control programmes designed to provide automatic control and monitoring of the most common chiller plant configurations.
At 22 Bishopsgate, the Carrier PSM connects with the overarching building management system (BMS), providing high level oversight of cooling for the entire building, management and control of the chilled water system pumps, water quality control, and demand limiting and load shedding when the building is running on generator power. The PSM also provides the BMS with real-time operating conditions, including chilled and condenser water temperatures, chiller capacities and their status.
“Space was a key issue,” said James Snowball, project manager with Michael J Lonsdale, who led the air conditioning installation. “The building’s foundations and basement plant rooms were originally designed for a different project with a smaller overall floor space. This initial design was abandoned when the project was acquired by its current owners in favour of a new, larger building with a greater focus on occupant well-being. As a result, the building’s foundations were adapted, resulting in challenges to accommodate the building services plant required to support the larger building.
“A solution from another manufacturer turned out to be too bulky to fit in the available space. Carrier’s 19XRV centrifugal chillers were proposed instead. They are highly energy efficient and able to provide the high-capacity cooling needed in the available plant room space.”
The chillers, located in basement plant rooms, are connected to evaporative cooling towers on level 58. A pressure break at level 25 effectively creates a lower and upper system, requiring careful balancing at the commissioning stage to optimise flow rates and ensure excellent performance while minimising energy use.
The four units were manufactured at Carrier’s global centre of excellence for chillers in Montluel, France. Due to their high capacity and size, one of the units was shipped to the US to carry out the customer witness tests at Carrier's Charlotte, North Carolina, facility.
Carrier's AquaEdge 19XRV centrifugal chiller
Following successful completion of the tests, Carrier managed the supply logistics to ensure the chillers were ready for installation at the key points in the project build. The chillers were shipped to the UK and stored securely before delivery to the site for installation and commissioning.
“Carrier provided outstanding support throughout all stages of the project, ensuring we had the technical information needed as well as timely back-up and logistical support to ensure we delivered for the client,” James Snowball said.
Carrier also provided the equipment for cooling the building’s 54 lifts and associated motor-winding rooms.
The project developers were AXA IM – Real Assets and Lipton Rogers, with WSP as building services consultant.