CRAC Units & Computer Room Air Conditioning

A CRAC unit is a Computer Room Air Conditioner, a floor standing precision air conditioner built to hold a room inside a tight temperature and humidity band continuously. It differs from a comfort air conditioner in three ways: it runs 24 hours a day at a steady duty rather than cycling, it is built for sensible heat because IT equipment produces almost no moisture, and it controls humidity in both directions. The CRX4 range starts at 5.5 kW a unit across thirty sizes, and a room is built from as many units as its load needs.

A CRAC unit has its own refrigeration circuit, so it rejects heat through a condenser or a condenser water loop. A CRAH unit has no compressor, it is a coil and fan fed with chilled water from a central plant. CRAC suits rooms up to roughly 120 kW a unit and sites with no chiller. CRAH is the better platform above that, and it is 100 percent sensible with no dehumidification penalty.

Downflow if you have a raised floor to discharge into, because the air then rises through perforated tiles directly in front of the racks. Upflow if you do not, because it discharges into the room or a ceiling void. Upflow is the usual answer for comms rooms, switch rooms and retrofits into buildings that were never designed as data halls. Both are available across the range.

Three reasons. A comfort unit is designed for people, so a large share of its capacity goes to removing moisture that IT equipment never produced, which wastes capacity you paid for. It is built to cycle rather than run continuously, so a 24 hour duty shortens its life considerably. And it cannot add humidity, so in a dry room you have no defence against static.

It comes from the IT load in kW, plus the room fabric, lighting, people and any fresh air, then a redundancy allowance on top. Floor area on its own is close to meaningless, because two rooms of identical size can differ by a factor of ten in heat load. Send us the IT draw and the room details and we will size it properly.

N+1 means one more unit than the load requires, so any single unit can fail or be taken out for service without the room losing cooling. Whether you need it is a question of what an over temperature event costs you. Group control across up to 8 units handles capacity sharing and standby rotation automatically, so the spare unit is not sitting idle and ageing differently to the rest.

Usually, and it is a common piece of work. The sequencing depends on whether you have redundancy to lean on, where the pipework runs and how the unit gets in and out of the building. Temporary cooling is sometimes needed to carry the load during the swap. It is set at design stage against your maintenance windows.

The range runs R410A, with R32, R134a and R513A available. Australia's HFC import quota steps down over the next decade, so the practical questions on an existing unit are charge size, leak detection and whether the platform can take an alternative refrigerant later. All three are worth asking before you commit to a replacement.

Yes, and we would rather you did not buy it separately. Every CRX4 indoor unit has a matched CRX4 condenser from 8 to 99 kW, single or dual circuit, specified and commissioned together. On a coastal site, specify the coil coating, because an uncoated coil will not last.

Yes. Preventive maintenance, filter changes, refrigerant checks, control faults and emergency response, across Australia, New Zealand and the Pacific Islands, on most brands as well as our own.