Training & Discussion Session for Critical Environment Management Part I HVAC Systems in datacenter.pdf
1. Public
Training & Discussion
Session for Critical
Environment Management
| Part I - HVAC
Chillers play a critical role in maintaining optimal temperatures in various
industries and buildings. Let's dive into the world of chillers and explore
their importance.
by Sumit Dharmarao
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Introduction to Chillers
Chillers are essential cooling systems used in a wide range of applications, from
industrial processes to commercial buildings.
Chillers are mechanical devices used to cool water or other fluids for various
purposes. They work on the principle of transferring heat from the fluid being chilled
to a separate medium, such as air or water. Chillers are commonly used in HVAC
systems for controlling building temperatures, as well as in industrial processes,
medical facilities, datacenters, and other applications that require precise cooling.
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Chiller Operating Principles
A.VCRC B.VARC
1.Compression: The cycle begins with the chiller's compressor, which
pressurizes the refrigerant gas, causing its temperature to rise.
2.Heat Exchange: The high-pressure, high-temperature refrigerant gas
flows to the condenser, where it releases heat and condenses into a high-
pressure liquid.
3.Expansion: The high-pressure liquid refrigerant then moves through an
expansion valve or device where it undergoes a significant pressure drop,
leading to a decrease in temperature.
4.Evaporation: The low-pressure, low-temperature liquid refrigerant enters
the evaporator, absorbing heat from the water or process fluid being
chilled, causing it to evaporate into a gas once again.
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Types of Chillers
1.Air-Cooled Chillers: These chillers use air to remove heat from the
refrigerant. They are self-contained units with condensers that use ambient
air to cool the refrigerant.
2.Water-Cooled Chillers: Water-cooled chillers use water to remove heat
from the refrigerant. They typically involve a cooling tower to reject heat
from the condenser water loop.
3.Absorption Chillers: This type of chiller uses heat energy to generate the
cooling effect. Absorption chillers are often used in industrial and
commercial applications and can be powered by waste heat or low-cost heat
sources.
4.Centrifugal Chillers: Centrifugal chillers utilize centrifugal compressors to
provide cooling. They are known for their high cooling capacity and energy
efficiency.
5.Reciprocating Chillers: These chillers use reciprocating compressors to
provide cooling. They are commonly used in smaller-scale applications.
6.Screw-Driven Chillers: They use screw compressors to provide cooling and
are known for their efficiency and reliability.
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Components of a Chiller System
Get acquainted with the key components that make up a chiller system, such as the compressor, evaporator, condenser, and expansion valve, and
understand their roles in the cooling process.
The basic parts of a chiller typically include:
Compressor: The compressor is responsible for circulating refrigerant through the chiller system. It compresses the low-pressure refrigerant vapor and
raises its temperature and pressure before releasing it to the condenser. 1.Centrifugal 2. Screw 3.Reciprocating Type
Condenser: The condenser receives the high-pressure, high-temperature refrigerant vapor from the compressor and removes heat from the
refrigerant, causing it to condense into a liquid.
Evaporator: The evaporator facilitates heat exchange between the chilled water or other cooling medium and the refrigerant. As the refrigerant
absorbs heat from the water, it turns from a liquid into a vapor.
Expansion Valve: The expansion valve regulates the flow of the refrigerant into the evaporator, maintaining the pressure difference between the high-
pressure side and the low-pressure side of the chiller system.
Control Panel: The control panel houses the controls and electronics that manage the operation and monitoring of the chiller, including temperature
settings, safety features, and system diagnostics.
Water Pump: In water-cooled chillers, a pump is used to circulate the chilled water through the chiller and the system it is serving.
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Chiller Efficiency
IKW (Kilowatts per Ton of Refrigeration):
IKW stands for Kilowatts per Ton of Refrigeration. It is a measure used in the field of HVAC (Heating, Ventilation, and Air Conditioning).
Specifically, it represents the energy consumption in kilowatts required to produce one ton of refrigeration (TR).
The formula to calculate IKW/TR is: [ IKW/TR] where:
KW represents the actual power consumption (in kilowatts).
TR represents the refrigeration capacity (in tons).
The EER is a metric used to assess the energy efficiency of air conditioners, including chillers.
It focuses on the instantaneous efficiency at a specific operating point (usually a fixed outdoor temperature).
1. The calculation involves dividing the cooling capacity by the power input
EER Calculation Example:
1. Cooling capacity: 253.1 RT (refrigeration tonnage)
2. Power consumption: 164.9 kW
3. Now calculate the EER: [ text{EER} = frac{890 text{ kW}}{164.9 text{ kW}} = 5.86 ]
lower EER value indicates better efficiency because it means the chiller delivers more cooling capacity for the same power input.
IPLV is calculated as a weighted average of 4 loading points. The calculation presumes that a chiller or air conditioner operates (you will find the
equation below):
•12% of the time at 25% load (D in the equation).
•45% of the time at 50% load (C in the equation).
•42% of the time at 75% load (B in the equation).
•1% of the time at 100% load (A in the equation).
Here is the full IPLV formula:
IPLV = 0.01A + 0.42B + 0.45C + 0.12D
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Applications of Chillers
➢ Food & Beverages
➢ Commercial Buildings
➢ Processes Industries
➢ Metallurgy
➢ Space Industry
➢ Medical Facilities
➢ Data Centers
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Comfort Cooling &
Precision Cooling
PAC/CRAC & PAHU/CRAH
Comfort Cooling
➢ Precision Air Conditioning or Computer Room Air Conditioning
➢ Precision Air Handling Unit or Computer Air Handling
Basic Difference
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Trouble Shooting of
PAHU/PAC
➢ Mother Board
➢ PID Valve Issues
➢ Loss of Air
➢ Cooling Coil Choke up/leakage
➢ WLD Alarm
➢ Vibrations
➢ Valve Failure