General Features and Uses

Construction Details

Free Cooling

Free cooling CRAC control systems analyze the outdoor air conditions and will use outdoor air when outside temp and humidity conditions permit. When free cooling is engaged all other cooling is turned off; only unit fans are active.

Most geographic locations’ climate conditions permit the use of free cooling during most off-peak temperature and humidity conditions to maximize energy efficiency.

Chilled Water

In using a chilled water option, air is cooled by passing through a chilled water coil within the CRAC unit that utilizes the Data Center owners central chilled water plant. This allows for full recirculation of data center air during peak outdoor humidity and temperature air conditions where evaporative air cooling is not possible. This usually occurs during peak temperature hours during the summer. Water pressure drop through Silent-Aire CRAC units is typically/roughly is half that of an equivalent off the shelf CRAC unit.

Direct Expansion (DX) Cooling

(DX) cooling is a traditional mechanical refrigerant based cooling system that is available in air cooled and water cooled systems. The water cooled systems tie into owners chilled water system.

Air cooled systems utilize outdoor condensing units and are ideal when central chilled water system is unavailable. Available in a wide range of environmentally friendly HFC based refrigerants

Direct / Indirect Evaporative Cooling

Silent-Aire is the only manufacturer to incorporate direct / indirect evaporative cooling in CRAC units. In using Direct evaporative cooling, air is cooled by evaporation of water in the airstream without the need for compressorized refrigerant-based systems. Evaporative cooling requires up to 95% less energy than what is associated with traditional cooling systems. It is most effective when high temperature and low-medium humidity outdoor conditions exist. In dry climate conditions are such that entire peak design cooling load can be handled entirely by direct evaporative cooling without the need for additional mechanical cooling.

Non-Tradtional Cooling Methods

As a custom manufacturer of CRAC units Silent-Aire has the engineering and manufacturing capability to work with clients to implement non-traditional and novel cooling methods.

In-house research/development allows for prototype testing and performance tuning.

Performance Data

Our CRAC / CRAH units are capable of cooling performance measures up to 260 tons for each mode of cooling. As a standard we achieve between 20,000 and 104,000 CFM. The CRAC / CRAH units are downflow as a standard, however, upflow and horizontal configurations are available. As a custom manufacturer we can accommodate other configurations and sizes.

Our control solution is based on pCO Sistema: the CAREL range of programmable logic controllers. This consists of programmable controllers, user interfaces, communication and remote management interfaces to offer HVAC/R market flexibility and easy integration with commonly-used building management systems. Supervisory communication protocols supported are: Modbus®, LonWorks®, BACnet™, and SNMP. Units can operate independently on their own control strategy or can be remotely operated by a supervisory system or master PLC. An optional Field-Bus communication port for control of RS485, CANbus, tLAN industrial devices can be added.

Our control solutions can also be customized to flexibly adapt to a client’s control scheme. Further, we can implement a variety of interface terminals from alphanumerical monochrome to color HMI touchscreen.

• Inspect fans/motors for signs of wear or damage,
  dirt and corrosion every 3-4 months
• Inspect foundation bolts, set screws and fasteners for tightness annually.
• Clean coils every 2-3 months.

• Clean evaporative cooler media and flush system every 4-6 weeks
  during operating season, inspect for signs of damage or wear.
• Clean water filters weekly
• Inspect filters regularly, replace when visibly dirty.