CLOSE CONTROL UNIT
Close Control Unit Or Precision Air conditioner.
CCU also commonly know as Close control air conditioner or Computer room air conditioner (CRAC) or Server room air conditioner. Close control unit not only maintains temperature but also humidity together to precise set level. Data center Cooling is most important factor for its operations. Selecting right type of cooling system is most critical decision in data center designing. Reliability of close control unit will directly related uptime of datacenter. To make cooling system more reliable, addition standby units can be install. As we discussed in our cooling Solution section it is very important to transport heat generated by IT equipment in datacenter to outside to avoid failure of IT equipment and to increase their life. Depending on medium used to transport heat generated inside datacenter to outside, Datacenter cooling is broadly divided into three major categories. These are Air Cooled System (DX Unit), Chilled water cooled System, Dual Fluid cooling System. In addition to these categories there are many more methods like water cooled system, Glycol cooled system which are rarely used. Each type of system has its own advantages and disadvantage.
In coming segment we will explore on major type of close control units in detail.
Difference Between Comfort Cooling & Precision air Cooling.
Precision air conditioner is totally different than comfort air conditioner in many sense. Some of the major difference as follow:
- Temperature and humidity control: Close control unit controls temperature and humidity with precision. While comfort air conditioner are designed to control temperature but not humidity.
- Cleanness: Precision air conditioning system in addition to cooling it does efficient filtration of air to remove airborne particles with help of high quality filters equipped in it. Comfort air has insufficient filtration which needed for datacenter and server room.
- Reliability: Server room air conditioner are designed to operate for 365 days a year continuously unlike comfort air conditioner.
- Energy saving: Precision air conditioners are more energy efficient then comfort air conditioners.
Chilled Water Type Precision Air Conditioning Unit
In this system medium to transport heat generated inside datacenter to outside environment is chilled water. Chilled water having temperature of 5 to 7 deg C supplied to indoor AC unit from Chiller. AC unit inside datacenter transfers heat generated by IT equipment to this chilled water due to which temperature of returning chilled water increases. This this hot returning chilled water forced back to chiller and hence it removes heat from Datacenter. Chiller rejects heat from this returning chilled water and again generates chilled water to force back to indoor AC unit to remove more heat from datacenter. This cycle gets repeated. Chiller can be of different types like water-cooled or Glycol-cooled chiller. Advantages of this system is that it is economical, it has high heat removal capacity, chilled water can run for long distances and it has small footprint.
DX Type Data center cooling systems
DX Unit (Direct Expansion) close control unit also called as Air cooled System. It uses refrigerant as medium to transport heat generated in datacenter to outside. It is made up of Indoor unit, outdoor air-cooled condenser and refrigerant piping between indoor and outdoor unit. Refrigerant circulates between indoor and outdoor condenser and take heat out generated in datacenter. Hot refrigerant then get cooled at outdoor condenser. Indoor units consisting of compression, expansion valve, evaporator coil, heater, blower fan and filter. Alternatively compressor can be install in outdoor condensing unit. Advantage of DX system that it is fully independent system, overall cost is less and easy to maintain. however there is limitation for length of refrigerant piping. For long piping, we need to installed Glycol-cooled System.
Dual Fluid Type Server Room Cooling Systems
As name suggests, this close control unit system use two medium to reject heat generated in datacenter. It is combination of Direct Expansion (DX) unit and Chilled Water type precision air conditioner. System consisting of single indoor unit which in houses cooling coil, filter, humidifier, heater and blower fan. Indoor units consist of to two cooling circuits DX and chilled water circuit. Chilled water circuit connected to chilled water supply, which uses chilled water to transfer heat. While DX circuit connected to outdoor air-cooled condenser through copper refrigerant piping. Heat transferred outside with help of refrigerant. Any one cooling circuit can be use as default while other is use as standby cooling circuit. Or We can program schedule working of both cooling circuit of dual fluid server room air conditioner.
Control Technologies FZE
PO Box 122271, SAIF Zone,
Sharjah, United Arab Emirates.
T: +971 6 5489626
F: +971 6 5489626
Sunday to Thursday
08:30 AM to 06:00 PM