What is a chiller – and how is it different from a heat pump?

As energy efficiency, connected systems and environmental considerations reshape HVAC priorities, York chillers, distributed by Airotech through Johnson Controls, are raising the standard for smart, adaptable and efficient cooling.

At a glance, chillers and heat pumps share a lot of DNA. In fact, a heat pump is essentially a reversible chiller. “A chiller produces cold water to cool a building, while a heat pump can reverse the cycle to produce hot water,” says Gert Deale, sales manager: Airotech. “In some systems, one unit can do both.”

York chillers operate by circulating chilled water, often around 6°C, through a building’s air handling units, which then cools the air inside. In contrast, during winter months or in systems with heat recovery, a reversible model can supply hot water to provide space heating.

York chillers come in a wide range of capacities, from small installations of around 10kW to industrial-grade systems exceeding 20MW. The latter are ideally suited for commercial properties, hotels, industrial facilities and data centres.

In larger buildings, it’s common to install multiple chillers for redundancy. “You’ll usually find at least two units in big systems so that if one fails, the other can still keep the building operational.” York offers both air-cooled and water-cooled chiller configurations, each with its own advantages:

• Air-cooled chillers are simpler to install and more common in green building certifications, thanks to reduced water usage
• Water-cooled chillers are more energy-efficient, but involve more complex infrastructure, including cooling towers and water treatment systems

Despite their superior performance, water-cooled chillers are less favoured in modern green building initiatives due to concerns about water consumption. “That might be a bit short- sighted. If you look at the full picture – energy use, emissions and water usage – water-cooled chillers are perhaps the better long-term choice.”

York chillers now come with connected capabilities, enabling remote monitoring, predictive maintenance and performance optimisation. “You can log in from anywhere in the world to check system status, detect faults early and even adjust operations,” says Deale. This not only minimises downtime but also helps reduce energy consumption by ensuring the system is running at optimal efficiency.

“One of our most recent launches was theYORK model YVAM. It is an air-cooled magnetic bearing centrifugal chiller that is specifically designed for hyperscale and colocation data centre applications.”

York chillers also support low-GWP refrigerants, helping customers comply with tightening international regulations. Deale explains that refrigerants like R513B, R1234ze, R1233zd and R515B are already available across York’s product lines. Natural refrigerants like R290 and ammonia are also available in our chillers, which is perhaps going to be a growing requirement in future.

Extract from a longer article that can be found in the RACA journal here.

Smart, green and essential – the rise of chillers – RACA Journal Publication