Modular Air-Cooled Chillers: When Are They the Right Choice?

A modular chiller is built from several independent modules, each with its own compressor and heat exchanger, connected to one water loop through shared headers. The total capacity is the sum of the modules. For projects where load varies during the day or where space and access are limited, it is a serious alternative to a single large chiller.

Advantage one: stepped capacity and part-load efficiency

When building load is low, only some modules run while the rest stay off. The system spends less time at poor load and uses less electricity for most hours of the year. For buildings with variable load, such as hotels, offices and malls, this is a real advantage.

Advantage two: reliability and service

If one module fails, the others keep running and the building is not left without cooling. This matters for places that cannot go for hours without cooling, such as hospitals and public halls.

Advantage three: transport and space

Modules are smaller and lighter and reach a roof or terrace without a very large crane. In existing buildings with no room to manoeuvre this difference matters. Modules can be placed side by side or in several rows.

Points and limits

• There is more header piping and more valves; it must be done carefully with an isolation valve on each module.
• For very large capacities, a larger chiller with screw or centrifugal compressors may need less cost and space.
• Noise from many fans and distance from neighbours must be checked.
• Keep the air clearance between modules as per the data sheet; air-cooled units depend on fresh air.

When modular, when a single chiller?

For small to medium loads with large variation and a need for high reliability, modular is a good choice. For large steady loads, or when very high efficiency matters, compare a single or water-cooled chiller too. The articles on air-cooled vs water-cooled chillers and the VRF or chiller decision framework help with this choice.

What to state in a quote request

Required cooling load, preferred number of steps, location and space dimensions, ambient temperature, heating need and BMS protocol. See installation examples in the installation gallery and use the chiller page to request a quote.