I had this come up recently… what is a CRAC (pronounced ‘crack’)? What is different from it than a CRAH (pronounced ‘craw’ or ‘cray’)?
CRAC = Computer Room Air Conditioner
A CRAC is often thought of as having an internal compressor, thus not needing the support of a centralized chilled water system. But this also means it has to reject heat somewhere – like to a coupled rooftop drycooler. A CRAC is also thought of as having refrigerant internal to the system, and with those extra motors and parts they need more maintenance care and have higher failure rates.
CRAH = Computer Room Air Handler
A CRAH is essentially a specialized air handling unit for computer room environments. Most are a simple fan arrangement with an internal coil supported by a centralized chilled water system.
Clients may decide to go with one nomenclature or another, but knowing the difference can be important when working with design engineers, operations personnel and clients.