Two Carrier AquaSnap 30RBP air-cooled chillers with Greenspeed Intelligence inverter-driven speed control are providing high-performance, low noise cooling for wards and operating theatres at Royal United Hospitals Bath. The high-efficiency chillers are running on lower global warming potential (GWP) refrigerant R-32 as part of a major upgrade of the hospital's air conditioning system. Refrigerant R-32 is up to 10% more efficient than R-410A, the refrigerant it replaces, and its global warming potential is 68% lower.
The chillers, mounted on a new roof-top platform, replace two older split-system chillers by other manufacturers, significantly reducing servicing requirements and related costs due to their compact, fully packaged design. The selection also aligns with Carrier’s 2030 Environmental, Social and Governance goals to reduce its customers' carbon footprint by more than 1 gigaton.
Due to the combination of variable-speed electronically commutated condenser fans, high-performance Novation heat exchangers and compressors optimised for operation with R-32, the chillers have a very high seasonal energy efficiency rating (SEER) of 5.18. The N+N system design ensures a second unit is available to take over full cooling duties in the unlikely event of a failure, providing the resilience required in this critical hospital application.
"Key requirements for the project were excellent efficiency, reliability, resilience, low sound levels and reduced environmental impact, and the Carrier chillers and system design deliver this," said James Allard, Director of Brunel Integrated Services, consultant on the project.
"Carrier provided excellent support throughout the project. There was an issue with the hospital's electrical supply, which was limited and couldn't be upgraded in time for the start-up of the new chillers. Carrier responded quickly and programmed a load limit into the chiller control system to ensure they would not draw more than the maximum allowed, protecting the hospital's electrical system while ensuring cooling needs were fully met.”
The chillers went into service while work continued to upgrade the electrical supply. The chillers were also equipped with soft-start electronics, which provided a further safeguard to peak electrical load.
Additional options specified included enhanced acoustic attenuation to further reduce noise given the sensitive hospital application, and Enviroshield condenser coil protection, with a three-year warranty.
"Although the National Health Service was Carrier's direct customer on the project, Carrier provided excellent support to the installer, Intoheat Ltd, and worked closely with them to support the project to completion,” noted James Allard.
Based on the positive experience on the project, Brunel Integrated Services recommended a similar Carrier solution for a replacement project at another hospital located in the West of England.
