A data center (American English) or data centre (British English) is a building, dedicated space within a building, or a group of buildings used to house computer systems and associated components, such as telecommunications and storage systems. Since IT operations are crucial for business continuity, it generally includes redundant or backup components and infrastructure for power supply, data communications connections, environmental controls (e.g. air conditioning, fire suppression) and various security devices. A large data center is an industrial-scale operation using as much electricity as a small town.

1. COOLING SYSTEM IN
DATACENTER
PRECISION AIR CONDITIONER

2. Type of Cooling system
Free Cooling:
Rotating wheel heat exchanger can be used for indirect free cooling, since indoor
and outdoor air flow in different paths for heat exchange. While its power usage
effectiveness (PUE) increases inevitably under the same climatic conditions.
Air Cooled System:
The cold air is fed to the rack and hot air leaving rack is sucked into CRAC.
Hot Aisle Containment: The Hot air is contained in closed area which is
called hot aisle.
Cold Aisle Containment: The Cold air is contained in closed area which is
called cold aisle.

3. Indirect Air Evaporative System:
An air-duct that is connected to an indirect air evaporation cooler is
utilized. Cool air from outside is used to add cooler air to the
airflow within the data center.
Pumped Refrigerant:
Chilled water is pumped into heat exchanger where refrigerant
takes out the heat.
Chilled Water System:
In this system chilled water is managed to pass in closed pipe
alongside of devices which are to be cooled.

4. Cold Aisle Containment

5. Cold Aisle Containment
The Perforated floor is placed between two row of racks which is
called cold aisle. The cool air is confined in cold aisle. This makes the
cooling efficient. The mixing of cold air and hot air is eliminated.
Blanking plates are used to block the cold air to mix with hot air
through the vacant space in the rack. All the 42 units of racks are not
filled at once. Some units may remain empty. The passage is covered
with plastic and the top space is covered with automated window
which can be opened during emergency. Hot aisle and Cold aisle are
separated to improve the efficiency.

6. CRAC Vs Comfort AC
In our CRAC units R407 and R410 are used as refrigerant. It is totally
different from the comfort AC because of following facts:
 Year Round Operation: CRAC is a special cooling device which
is capable of operating 24/7.
 Electronic Load : CRAC is specially designed for IT environment.
 Temperature Control : CRAC has greater range of temperature
control.
 Humidity Control : CRAC maintains perfect humidity level.
 Air Volume : Required air flow rate can be maintained in CRAC.
 Air Filtration : The air filtration is best in CRAC for IT
environment.

7. Parts of CRAC Units:

8. Operating Principle of CRAC
The CRAC operates in 4 phases:
1. Suction Line
2. Discharge Line
3. Liquid line
4. Refrigeration

9. Hot Aisle Containment in row cooling

10. Hot Aisle Containment
It consists of a physical barrier that guides hot exhaust airflow back to
the AC return as a benefit of in row cooling. The refrigerant used in
this system is R410. It takes advantage of the natural properties of
warm air rising. The mixing of cold air and hot air is eliminated.
Blanking plates are used to block the cold air to mix with hot air
through the vacant space in the rack. All the 42 units of racks are not
filled at once. Some units may remain empty. The passage is covered
with plastic and the top space is covered with automated window
which can be opened during emergency. Hot aisle and Cold aisle are
separated to improve the efficiency.

12. Advantages of CACS
 Cold and Hot air does not mix.
 It is cheaper to implement as it mainly requires doors at aisle ends
and a cap above the space you are looking to contain.
 Raised flooring can be more easily used to deliver cooling and to
store cabling.
 Cold supply air is delivered directly to each cold aisle and can be
matched to the server airflow requirements with proper controls.

13. Disadvantages of CACS
 Allowing the discharge air from the hot aisle to fill the room results
in temperatures anywhere from 80 to 100 degrees F throughout the
majority of the data center. This can create perception issues for
company executives or for tenants of a co-location data center. It
also may create operational issues if any non-contained equipment
such as low-density storage or communication racks, is installed in
the general data center space.
 Cold aisles have intermediate ceilings over the aisle. This may affect
the overall fire protection and lighting design, especially when
added to an existing data center.

14. Advantages of HACS
 HACS is more efficient than Cold Aisle containment system.
 HACS makes more comfortable working environment as working
area is cooler.
 As long as the cool air is introduced into the general space and hot
air is properly returned, expensive raised floor supply distribution
systems and extensive supply ductwork can be avoided.
 Accurate distribution of supply air throughout the space is less
critical.

15. Disadvantage of HACS
 When data center technicians need to access the equipment and its
infrastructure, a contained hot aisle can be a very uncomfortable
place to work. While this problem can be mitigated using temporary
local cooling, the high hot-aisle temperatures need to be considered,
especially for a facility that needs frequent access to its equipment.

16. How to improve efficiency?
 Implement Hot-Aisle/Cold-Aisle both.
 Arrangement of heavy and light load in the rack units properly.
 Avoiding direct mixing of Hot and Cold air.
 Use Close-Coupled Cooling.
 Regular maintenance of mechanically moving parts of CRAC and
replace if not maintainable.
 Using efficient Backup system.

17. THANK YOU!!!!