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 the Royal United Hospital 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, which it replaces, and its global warming potential is 68% lower. Carrier is part of Carrier Global Corporation, ‘a global provider of healthy, safe and sustainable, and intelligent, building and cold chain solutions’.
The chillers, mounted on a new rooftop platform, replace two older split-system chillers from other manufacturers, and, Carrier says, will significantly reduce 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 over 1 gigaton.
Carrier said: “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 that a second unit is available to take over full cooling duties in the unlikely event of a failure.”
“Key requirements for the project were excellent efficiency, reliability, and resilience, low sound levels, and reduced environmental impact, and the Carrier chillers and system design deliver all this,” explained James Allard, director of Brunel Integrated Services, consultant on the project. “Carrier provided excellent support throughout. Carrier responded quickly to an issue with the hospital's limited electrical supply – which couldn't be upgraded in time for the start-up of the new chillers – by programming a load limit into the chiller control system to ensure they would not draw more than the maximum allowed. This protected the hospital's electrical system, while ensuring that its cooling needs were fully met.”
The chillers, which went into service while work continued to upgrade the electrical supply, were also equipped with soft-start electronics, providing a further safeguard to peak electrical load. Additional options specified included enhanced acoustic attenuation to further reduce noise, and Enviroshield condenser coil protection, with a three-year warranty.
"Although the NHS was Carrier’s direct customer on the project, Carrier provided excellent support to the installer, Intoheat, and worked closely with it 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 in the West of England.