When designing and selecting air conditioning (AC) equipment, several factors need to be

considered to ensure optimal performance, energy efficiency, and comfort. Here’s a breakdown
of the process:

1. Types of Air Conditioning Systems

Different AC systems cater to various needs based on the application, scale, and efficiency.
Common types include:

• Window AC – Suitable for small rooms.

• Split AC – Ideal for medium-sized spaces; consists of an indoor and outdoor unit.

• Packaged AC – Used in commercial applications where space constraints exist.

• Central AC (Chiller Systems, VRF/VRV, AHU Systems) – Suitable for large buildings,
airports, and industries.

2. Key Design Considerations

a. Cooling Load Calculation

The cooling capacity required for the space is calculated using:

• Room size and orientation.

• Number of occupants.

• Heat gain from lights, equipment, and appliances.

• Ventilation and infiltration rates.

• Climate conditions.

b. Energy Efficiency

• Use high-efficiency systems with Inverter Technology.

• Look for Energy Star ratings or IEER (Integrated Energy Efficiency Ratio).

c. Air Distribution & Duct Design

• Proper duct sizing reduces friction losses and improves efficiency.

• Use VAV (Variable Air Volume) systems for better control.

d. Refrigerant Selection

• Choose environmentally friendly refrigerants like R-410A or R-32, avoiding R-22

(phased out due to ozone depletion).

e. Humidity Control

• Proper dehumidification ensures comfort in humid climates.

• Desiccant systems or reheat coils may be needed.

f. Noise Levels

• Install vibration isolation mounts and acoustic insulation for quiet operation.

g. Maintenance and Serviceability

• Ensure easy access to filters, coils, and compressors.

• Use BMS (Building Management Systems) for remote monitoring.

3. Equipment Selection

Based on the load calculations and design requirements, the following are selected:

• Compressor Type: Scroll, Reciprocating, Screw, or Centrifugal.

• Cooling Method: Air-cooled or Water-cooled.

• Coil Type: Copper coils are preferred for better heat transfer.

• Filters: HEPA filters for improved air quality.

4. Additional Features for Enhanced Performance

• Heat Recovery Systems – Utilize waste heat for preheating air or water.

• Smart Thermostats & IoT – Enhance automation and energy savings.

• Zoning Systems – Control temperatures in different areas separately.

Would you like a detailed recommendation based on a specific application, such as an office,
industrial facility, or aviation hangar?

3. Equipment Selection in Air Conditioning Systems

Selecting the right air conditioning equipment is crucial for achieving energy efficiency, optimal
cooling performance, and long-term reliability. The selection process involves evaluating key
components based on the cooling load, application type, budget, and environmental factors.

3.1. Key Components in Equipment Selection

1. Compressor Type

The compressor is the heart of an air conditioning system, responsible for circulating the
refrigerant. Different compressors are suitable for different applications:

• Reciprocating Compressors

o Works like a car engine with pistons and cylinders.

o Best for small to medium applications (e.g., window AC, small split units).

o Pros: Affordable, simple design.

o Cons: High vibration and noise, lower efficiency.

• Scroll Compressors

o Uses two spiral-shaped scrolls to compress refrigerant.

o Ideal for residential and commercial split ACs and packaged systems.

o Pros: High efficiency, quiet operation, fewer moving parts (less maintenance).

o Cons: Limited capacity range.

• Screw Compressors

o Uses two helical screws to compress refrigerant.

o Suitable for large commercial buildings, data centers, and industrial cooling.

o Pros: High efficiency at large capacities, continuous operation.

o Cons: More expensive, requires skilled maintenance.

• Centrifugal Compressors

o Uses high-speed impellers to compress refrigerant.

o Best for chillers and large HVAC systems (airports, hospitals, industrial plants).

o Pros: Very high capacity, low maintenance, highly efficient.

 o Cons: Expensive, requires large installation space.

2. Cooling Method: Air-Cooled vs. Water-Cooled

Cooling systems can be categorized based on how they reject heat from the refrigerant.

• Air-Cooled Systems

o Uses ambient air to cool the refrigerant.

o Common in residential split ACs, rooftop units, and small commercial buildings.

o Pros: Lower installation cost, easy maintenance.

o Cons: Lower efficiency than water-cooled systems, affected by high ambient

temperatures.

• Water-Cooled Systems

o Uses a cooling tower to reject heat via water circulation.

o Found in large commercial buildings, hotels, data centers.

o Pros: Higher efficiency, works well in hot climates.

o Cons: Needs a continuous water supply and more maintenance.

3. Evaporator and Condenser Coil Selection

Coils are responsible for heat exchange, and their material affects efficiency and durability.

• Copper Coils (Recommended)

o Better heat transfer, corrosion-resistant, long-lasting.

o Easier to clean and repair.

• Aluminum Coils

o Cheaper but prone to corrosion and difficult to repair.

o Used in budget AC models.

4. Refrigerant Selection
The type of refrigerant impacts efficiency, environmental sustainability, and regulatory
compliance.

Refrigerant Environmental Impact Efficiency Applications

R-22 (Phased Out) High ozone depletion Moderate Old AC systems

R-410A No ozone depletion, high GWP High Split ACs, VRF/VRV

R-32 Lower GWP, no ozone depletion Very high Residential & commercial AC

R-134a Low toxicity, medium GWP Medium Chillers & refrigeration

R-290 (Propane) Ultra-low GWP, highly efficient Very high Small air conditioners

• GWP (Global Warming Potential): Lower is better for sustainability.

• Future-Proofing: Opt for low-GWP refrigerants like R-32 or R-290 to comply with
evolving environmental regulations.

5. Air Filtration & Indoor Air Quality (IAQ)

Filtration is crucial for air quality and system longevity.

• Standard Filters (MERV 8-13) – Used in homes and offices for dust and pollen control.

• HEPA Filters (MERV 17-20) – Essential for hospitals and clean rooms.

• Carbon Filters – Absorb odors and gases (used in commercial buildings).

• UV Germicidal Lamps – Kill bacteria and viruses in high-purity applications.

6. Smart Features & Controls

Modern AC systems offer automation and energy-saving features:

• Variable Speed Compressors (Inverter Technology) – Adjust cooling capacity based on

demand, reducing energy waste.

• Smart Thermostats – Control temperature remotely via mobile apps.

• Building Management Systems (BMS) – Integrates HVAC with lighting and security for
energy optimization.
7. Additional Selection Criteria

Factor Considerations

Capacity Match with cooling load calculation. Oversizing = energy waste, undersizing
(Tonnage) = inadequate cooling.

Noise Level (dB) Lower noise preferred for homes, offices. Centrifugal systems are quietest.

Installation Space Consider footprint, ductwork, and outdoor unit clearance.

Climate & Hot climates → Water-cooled or VRF systems. Cold climates → Heat pump
Weather integration.

Maintenance Easy access to filters, coils, and compressors. Water-cooled systems require
Needs frequent maintenance.

Conclusion

Choosing the right AC system depends on capacity, efficiency, refrigerant type, cooling method,
air filtration, and advanced features.

Would you like recommendations for a specific application (e.g., an aviation hangar, office
building, industrial plant)?

Air Conditioning Equipment: Components & Types

Air conditioning equipment consists of various components that work together to regulate
temperature, humidity, and air quality in an indoor space. The choice of equipment depends on
the application (residential, commercial, or industrial) and cooling requirements.

1. Main Components of Air Conditioning Equipment

Each air conditioning system consists of the following key components:

1.1. Compressor (The Heart of the System)

• Increases the pressure and temperature of the refrigerant gas before sending it to the
condenser.
 • Common types: Reciprocating, Scroll, Screw, and Centrifugal.

• Used in all air conditioning systems, from split ACs to large chillers.

1.2. Condenser (Heat Rejection Unit)

• Transfers heat from the refrigerant to the environment.

• Can be air-cooled (uses fans) or water-cooled (uses cooling towers).

• Found in outdoor units of split ACs, central ACs, and chillers.

1.3. Expansion Valve (Pressure Regulator)

• Controls the flow of refrigerant into the evaporator.

• Reduces pressure and temperature of the refrigerant before it absorbs heat.

1.4. Evaporator (Cooling Coil/Heat Absorber)

• Extracts heat from indoor air, cooling it before returning it to the room.

• Located in the indoor unit of split ACs and air handling units (AHUs) in central systems.

1.5. Refrigerant (Cooling Medium)

• The working fluid that circulates through the system to transfer heat.

• Common refrigerants: R-410A, R-32, R-134a, R-290 (Eco-friendly options).

1.6. Air Handling Unit (AHU) / Fan Coil Unit (FCU) (Air Distribution System)

• AHU: Used in central AC systems to circulate and filter air in large spaces.

• FCU: A smaller version for individual rooms in hotels, offices, etc.

1.7. Ductwork and Vents (Air Distribution & Return System)

• Channels air from the air handler to different parts of the building.

• Essential for central AC, VRF, and HVAC systems.

2. Types of Air Conditioning Equipment

Air conditioning equipment can be categorized based on application, capacity, and cooling
method.

2.1. Residential & Small Commercial AC Systems

These are used in homes, offices, and small retail spaces.

a) Window AC

• Compact unit installed in windows or wall openings.

• Suitable for single rooms or small offices.

• Easy to install but noisy and less efficient than split ACs.

b) Split AC

• Consists of indoor (evaporator) and outdoor (condenser) units.

• Available in standard split (single indoor unit) or multi-split (multiple indoor units).

• Energy-efficient, quiet operation, and good for homes, offices, shops.

c) Inverter AC (Energy-efficient version of Split AC)

• Uses variable-speed compressors to adjust cooling based on room temperature.

• Saves up to 30-50% electricity compared to non-inverter models.

• Ideal for residential and commercial use.

2.2. Large Commercial & Industrial AC Systems

Used in offices, malls, hospitals, airports, factories, and data centers.

a) Packaged AC System

• All-in-one unit containing compressor, evaporator, and condenser.

• Installed on rooftops of commercial buildings and halls.

• Cools large areas without ductwork but requires good ventilation.

b) Ducted AC System

• Similar to split AC but with hidden ducts for air distribution.

• Used in hotels, banquet halls, hospitals, and corporate offices.

• Aesthetic, quiet operation but expensive installation.

c) VRF/VRV (Variable Refrigerant Flow / Volume) System

• Advanced system using multiple indoor units connected to one outdoor unit.
 • Offers individual temperature control for different rooms/zones.

• Used in office buildings, hotels, and malls due to high efficiency.

d) Central Chilled Water System (Chillers + AHUs + Cooling Towers)

• Used in airports, large industries, power plants, and commercial skyscrapers.

• Two main types:

o Air-Cooled Chillers – Suitable for places with limited water supply.

o Water-Cooled Chillers – More efficient, used in large buildings.

• Expensive initial setup but best for large-scale cooling.

2.3. Specialized Industrial AC Systems

• Precision Air Conditioning (PAC) Units – Used in server rooms & data centers for
precise cooling.

• Explosion-proof ACs – Designed for oil refineries, chemical plants.

• Evaporative Coolers – Used in factories, warehouses where high airflow is needed.

3. Selection Criteria for Air Conditioning Equipment

Choosing the right AC equipment depends on:

Factor Consideration

Application Home, office, factory, airport, data center, etc.

Cooling Load Measured in tons or BTUs based on room size & heat gain.

Efficiency (EER/SEER/IEER Higher efficiency = lower energy cost. Look for inverter, VRF, or
Ratings) chillers.

Humid areas → Need dehumidification. Hot climates → Water-

Climate Conditions
cooled systems.

Budget & Installation Costs Split ACs are cheaper, VRF & chillers require higher investment.

Rooftop, ducted, or concealed systems based on building

Space & Ventilation
design.

Noise Levels Residential areas need quiet operation (Split AC, VRF).

Environmental Impact Prefer R-32, R-290 refrigerants for eco-friendliness.

4. Latest Trends in Air Conditioning Equipment

• Smart ACs – Wi-Fi-enabled systems controlled via mobile apps.

• Energy Recovery Systems – Use exhaust air to pre-cool fresh air.

• Solar-Powered ACs – Hybrid systems that reduce grid electricity use.

• AI-based HVAC Optimization – AI adjusts cooling based on occupancy & weather.

Conclusion

Air conditioning equipment selection depends on application, cooling load, efficiency,

refrigerant type, and installation requirements.

Would you like recommendations for a specific project, such as an aviation hangar or an office
space?
Cooling Load & Heating Load Calculation

Cooling and heating load calculations determine the capacity of an HVAC system required to
maintain indoor comfort. These calculations are essential for selecting the right air conditioning
and heating equipment.

1. Cooling Load Calculation (Heat Gain Calculation)

The cooling load is the amount of heat that must be removed from a space to maintain a
comfortable temperature. It includes heat gains from external and internal sources.

1.1. Components of Cooling Load

Heat Source Description

Solar Heat Gain Heat entering through windows, walls, and roofs due to sunlight.

Internal Heat Gains Heat from occupants, lights, computers, and appliances.

Ventilation &
Heat brought in by fresh air and leakage.
Infiltration

Moisture from people and external humidity (affects

Latent Heat
dehumidification).
2. Heating Load Calculation (Heat Loss Calculation)

The heating load is the amount of heat that must be added to a space to maintain comfort in
cold weather.

2.1. Components of Heating Load

Heat Loss Source Description

Transmission Loss Heat loss through walls, roofs, and windows.

Infiltration & Ventilation Heat loss from cold air entering the building.

Internal Heat Gains Heat from people, lighting, and appliances.

3. Software for Load Calculation

For detailed load calculations, use:

✔ ASHRAE Load Explorer
✔ Carrier HAP (Hourly Analysis Program)
✔ Trane Trace 700
✔ EnergyPlus

Conclusion

• Cooling Load is based on heat gain from external and internal sources.

• Heating Load is based on heat loss due to cold air infiltration and transmission.

• Proper load calculation optimizes AC & heating system size, reducing energy waste.

Would you like a custom cooling/heating load calculation for your aviation hangar or another
project?

Refrigerant: Types, Properties, Environmental Impact & Selection Criteria

A refrigerant is a working fluid used in air conditioning and refrigeration systems to absorb and
release heat during the cooling cycle. The selection of an appropriate refrigerant is crucial for
efficiency, safety, and environmental sustainability.

1. Types of Refrigerants

Refrigerants are classified based on their chemical composition and environmental impact.

1.1. Classification of Refrigerants

Type Examples Characteristics Application

High ozone depletion Banned globally

potential (ODP), high due to
CFCs (Chlorofluorocarbons) R-11, R-12
global warming environmental
potential (GWP) harm

Phasing out under

HCFCs Lower ODP than CFCs,
R-22, R-123 the Montreal
(Hydrochlorofluorocarbons) still harmful
Protocol

Residential &
R-134a, R-410A, R-
HFCs (Hydrofluorocarbons) Zero ODP, high GWP commercial AC,
407C
refrigeration
Type Examples Characteristics Application

Automotive AC,
HFOs (Hydrofluoroolefins) R-1234yf, R-1234ze Zero ODP, low GWP
chillers

R-290 (Propane), R-
Eco-friendly, Industrial
600a (Isobutane),
Natural Refrigerants flammable/toxic in some refrigeration, heat
R-744 (CO₂),
cases pumps
Ammonia (R-717)

2. Properties of Refrigerants

The selection of a refrigerant depends on key thermodynamic, physical, and safety properties.

2.1. Thermodynamic Properties

Property Definition Ideal Requirement

Temperature at which refrigerant Low for better cooling

Boiling Point
evaporates performance

Temperature above which gas cannot

Critical Temperature High for stable operation
liquefy

Latent Heat of
Heat absorbed during phase change High for better efficiency
Vaporization

Specific Heat Capacity Heat required to raise temperature Low for faster cooling

Thermal Conductivity Heat transfer ability High for better performance

2.2. Physical & Safety Properties

Property Definition Ideal Requirement

Toxicity Harmful effects on humans Non-toxic preferred

Flammability Risk of ignition Low for safety

Chemical Stability Resistance to decomposition High for long lifespan

Lubrication Compatibility Ability to mix with compressor oil Good compatibility

Property Definition Ideal Requirement

Material Compatibility Reactivity with system components Low to prevent corrosion

3. Environmental Impact of Refrigerants

3.1. Key Environmental Factors

Factor Definition Effect

Ozone Depletion Potential Measures damage to the High ODP = harmful (e.g., CFCs,
(ODP) ozone layer HCFCs)

Global Warming Potential Measures greenhouse gas High GWP = contributes to climate
(GWP) effect change

Duration refrigerant stays in

Lifetime in Atmosphere Shorter lifespan preferred
air

3.2. Environmental Impact of Common Refrigerants

Refrigerant Type ODP GWP Status

R-11 CFC 1.0 4,750 Banned

R-22 HCFC 0.05 1,810 Phasing out

R-134a HFC 0 1,430 Phasing out

R-410A HFC 0 2,088 Phasing out

R-32 HFC 0 675 Preferred replacement

R-1234yf HFO 0 4 Eco-friendly

R-290 (Propane) Natural 0 <10 Eco-friendly

R-744 (CO₂) Natural 0 1 Best for sustainability

4. Refrigerant Selection Criteria

Selecting the right refrigerant depends on the following factors:

4.1. Efficiency & Performance

✔ Low boiling point for effective heat absorption

✔ High latent heat of vaporization for better cooling capacity
✔ Low energy consumption for efficiency

4.2. Environmental Impact

✔ Zero ODP and low GWP

✔ Compliance with global regulations (Montreal Protocol, Kigali Amendment)

4.3. Safety & Regulations

✔ Non-toxic, non-flammable for residential & commercial applications

✔ Compliance with ASHRAE and ISO safety standards

4.4. System Compatibility

✔ Compatible with compressors, lubricants, and materials

✔ Available replacement options for older refrigerants

5. Best Refrigerants for Different Applications

Application Recommended Refrigerants Reason

Residential & Commercial AC R-32, R-410A, R-290 High efficiency, low GWP

Automotive AC R-1234yf, R-134a Low GWP, safe for vehicles

Industrial Refrigeration Ammonia (R-717), CO₂ (R-744) Natural, energy-efficient

Supermarket Refrigeration CO₂ (R-744), R-290 Eco-friendly, high performance

Chillers & Large Buildings R-1234ze, R-134a, CO₂ Low GWP, high efficiency

6. Conclusion

• Traditional refrigerants like R-22 & R-410A are being phased out due to environmental
concerns.

• New alternatives like R-32, R-290, and R-1234yf offer high efficiency with lower GWP.
 • Natural refrigerants like CO₂ (R-744) and Ammonia (R-717) are sustainable choices for
industrial applications.

• Future HVAC systems are moving towards low-GWP, non-toxic, and high-efficiency
refrigerants.

Would you like refrigerant recommendations for aviation hangar cooling, data center HVAC, or
another specific application?

Refrigeration Systems: Cycles & Refrigerants

Refrigeration is the process of removing heat from a space or substance to maintain a lower
temperature. It is widely used in air conditioning, food storage, and industrial applications. The
main refrigeration cycles include the Reversed Carnot Cycle, Vapor Compression Cycle, and
Vapor Absorption Cycle.

1. Reversed Carnot Cycle (Ideal Refrigeration Cycle)

The Reversed Carnot Cycle is an idealized refrigeration cycle that represents the maximum
possible efficiency for a refrigeration system. It is the reverse of the Carnot Heat Engine and
consists of four processes:

1.1. Processes in the Reversed Carnot Cycle

1. Isentropic Compression (1 → 2):

o Refrigerant is compressed adiabatically in a compressor.

o Temperature and pressure increase.

2. Isothermal Heat Rejection (2 → 3):

o Heat is rejected to the surroundings at constant temperature in the condenser.

o The refrigerant changes phase from vapor to liquid.

3. Isentropic Expansion (3 → 4):

o The refrigerant expands in an expansion valve or turbine.

o Pressure and temperature drop.

4. Isothermal Heat Absorption (4 → 1):

o The refrigerant absorbs heat at constant temperature in the evaporator.

 o The refrigerant changes phase from liquid to vapor.

1.2. Limitations of the Carnot Cycle in Refrigeration

• Not practical due to the need for an isentropic and reversible compression/expansion
process.

• Real refrigeration systems use throttling valves instead of turbines, leading to

inefficiencies.

• The cycle assumes perfect heat exchangers and an ideal working fluid, which is
unrealistic.

2. Vapor Compression Refrigeration Cycle (VCRC)

The Vapor Compression Cycle (VCC) is the most commonly used refrigeration cycle in air
conditioning and refrigeration systems. It is more practical than the Carnot cycle and is used in
domestic refrigerators, AC units, and industrial refrigeration.

2.1. Working of the Vapor Compression Cycle

The cycle consists of four main components:

1. Compressor: Increases the pressure and temperature of the refrigerant.

2. Condenser: Rejects heat and condenses the refrigerant from vapor to liquid.

3. Expansion Valve: Reduces the pressure and temperature of the refrigerant.

4. Evaporator: Absorbs heat from the surroundings and evaporates the refrigerant.
2.2. T-S and P-h Diagrams

The cycle follows these four processes:

1. Compression (1 → 2): Adiabatic compression (increase in pressure & temperature).

2. Condensation (2 → 3): Isobaric heat rejection (gas → liquid phase change).

3. Expansion (3 → 4): Throttling process (pressure and temperature drop).

4. Evaporation (4 → 1): Isobaric heat absorption (liquid → vapor phase change).

2.3. Advantages of the Vapor Compression Cycle

✔ High efficiency compared to other cycles.

✔ Widely used in domestic and commercial applications.
✔ Compatible with various refrigerants.

3. Vapor Absorption Refrigeration Cycle (VARC)

The Vapor Absorption Cycle is an alternative to the Vapor Compression Cycle, using a heat
source instead of a mechanical compressor. It is used in applications where waste heat, solar
energy, or geothermal energy is available.

3.1. Working of the Vapor Absorption Cycle

The cycle consists of:

1. Generator: Heat source boils the refrigerant out of the absorbent.

2. Condenser: Cools and liquefies the refrigerant.

 3. Expansion Valve: Reduces pressure and temperature.

4. Evaporator: Absorbs heat to provide cooling.

5. Absorber: Refrigerant vapor is absorbed into a liquid solution.

3.2. Common Working Fluids in VARC

• Water-Ammonia System:

o Water (absorbent), Ammonia (refrigerant)

o Used in industrial refrigeration and gas-powered refrigerators.

• Lithium Bromide-Water System:

o Lithium Bromide (absorbent), Water (refrigerant)

o Used in large-scale air conditioning (chillers).

3.3. Advantages of the Vapor Absorption Cycle

✔ Uses waste heat or renewable energy instead of electricity.

✔ Ideal for remote locations without electricity.
✔ Low operating cost.

3.4. Disadvantages of the Vapor Absorption Cycle

✖ Lower efficiency compared to the Vapor Compression Cycle.

✖ Requires large equipment (bulky and expensive).
✖ Slower response to load changes.
4. Refrigerants and Their Properties

A refrigerant is a working fluid that absorbs and rejects heat during the refrigeration cycle. The
selection of refrigerants depends on thermodynamic, physical, and environmental properties.

4.1. Classification of Refrigerants

Type Examples Application

Banned due to Ozone

CFCs (Chlorofluorocarbons) R-11, R-12
Depletion Potential (ODP)

HCFCs Being phased out under

R-22
(Hydrochlorofluorocarbons) the Montreal Protocol

HFCs (Hydrofluorocarbons) R-134a, R-410A No ODP, but high GWP

HFOs (Hydrofluoroolefins) R-1234yf, R-1234ze Low GWP, eco-friendly

R-290 (Propane), R-600a

Eco-friendly, used in
Natural Refrigerants (Isobutane), CO₂ (R-744), Ammonia
industrial applications
(R-717)

4.2. Key Refrigerant Properties

Property Definition Ideal Requirement

Temperature at which refrigerant Low for efficient heat

Boiling Point
evaporates absorption

Critical Temperature Max temp where gas can liquefy High for better performance

High for better cooling

Latent Heat of Vaporization Heat absorbed during phase change
capacity

GWP (Global Warming

Contribution to climate change Low for sustainability
Potential)

ODP (Ozone Depletion Zero for environmental

Impact on the ozone layer
Potential) safety

Toxicity & Flammability Safety concerns Low for residential use

4.3. Best Refrigerants for Different Applications

Application Recommended Refrigerants

Home & Commercial AC R-32, R-410A, R-290

Automotive AC R-1234yf, R-134a

Industrial Refrigeration Ammonia (R-717), CO₂ (R-744)

Supermarkets & Cold Storage CO₂ (R-744), R-290

Large Buildings (Chillers) R-1234ze, R-134a, CO₂

5. Conclusion

• Reversed Carnot Cycle is the ideal case but not practical.

• Vapor Compression Cycle is the most widely used system in refrigeration.

• Vapor Absorption Cycle is useful when waste heat or renewable energy is available.

• Refrigerant selection is based on efficiency, environmental impact, and safety.

Would you like a detailed calculation or selection guide for a specific refrigeration application?

Air Conditioning Systems & Psychrometrics

Air conditioning involves controlling temperature, humidity, and air quality to provide comfort
and maintain indoor air quality. The study of air properties and conditioning processes is known
as psychrometrics.

1. Psychrometric Properties & Psychrometric Chart

1.1. Key Psychrometric Properties

Psychrometrics deals with the thermodynamic properties of moist air. The important properties
are:

Property Definition

Dry Bulb Temperature (DBT) Temperature of air measured by a thermometer (°C or °F).
Property Definition

Wet Bulb Temperature (WBT) Temperature considering evaporative cooling effect.

Temperature at which air becomes saturated and

Dew Point Temperature (DPT)
condensation starts.

Ratio of actual moisture in air to maximum moisture air can

Relative Humidity (RH)
hold.

Specific Humidity / Humidity

Mass of water vapor per unit mass of dry air (g/kg).
Ratio

Enthalpy (h) Total heat content of air (kJ/kg).

Specific Volume (v) Volume occupied by unit mass of air (m³/kg).

1.2. Psychrometric Chart

A psychrometric chart graphically represents these properties. It helps in air conditioning design
and process analysis. The major lines in the chart include:

• Dry bulb temperature (X-axis)

• Humidity ratio (Y-axis)

• Relative humidity curves

• Wet bulb temperature lines

• Enthalpy lines

The chart is used to analyze air conditioning processes like heating, cooling, humidification, and
dehumidification.

2. Air Conditioning Processes

2.1. Sensible Heating

• Definition: Increasing air temperature without changing humidity.

• Process: Air passes over a heating coil or heat exchanger.

• Graphical Representation: Moves right on the psychrometric chart.

• Example: Room heaters, electric coils, radiators.

2.2. Sensible Cooling

• Definition: Decreasing air temperature without changing humidity.

• Process: Air passes over a cooling coil.

• Graphical Representation: Moves left on the psychrometric chart.

• Example: Air conditioning cooling coils, refrigeration systems.

2.3. Humidification

• Definition: Increasing moisture content in air.

• Process: Adding water vapor using steam or water spray.

• Graphical Representation: Moves upward on the psychrometric chart.

• Example: Humidifiers in HVAC systems, evaporative cooling.

2.4. Dehumidification

• Definition: Removing moisture from air.

• Process: Air passes over a cooling coil where moisture condenses.

• Graphical Representation: Moves downward on the psychrometric chart.

• Example: Air conditioners, dehumidifiers.

2.5. Cooling and Dehumidification

• Definition: Cooling air below dew point to remove moisture.

• Process: Used in air conditioning to provide comfort.

• Example: AC units in humid climates.

2.6. Heating and Humidification

• Definition: Increasing temperature and moisture simultaneously.

• Process: Used in cold and dry climates.

• Example: Steam humidifiers in winter.

3. Air Conditioning Systems

3.1. Classification of AC Systems

System Type Application

Comfort Air Conditioning Homes, offices, hotels.

Industrial Air Conditioning Factories, pharmaceutical industries.

Precision Air Conditioning Data centers, laboratories.

3.2. Types of Air Conditioning Systems

1. Window Air Conditioner

• One unit with compressor, evaporator, and condenser.

• Used in small rooms.

2. Split Air Conditioner

• Indoor & outdoor units (compressor outside, evaporator inside).

• Used in homes, offices.

3. Central Air Conditioning System

• Large-scale cooling for buildings & commercial areas.

• Uses chillers, ducts, and AHUs.

4. Packaged Air Conditioning System

• Pre-assembled unit for medium-sized spaces.

• Includes air handling unit (AHU) & refrigerant system.

5. Variable Refrigerant Flow (VRF) / Variable Refrigerant Volume (VRV) System

• Used in large buildings.

• Highly efficient with multiple indoor units.

4. Conclusion

• Psychrometrics helps in understanding air conditioning processes.

• Heating, cooling, humidification, and dehumidification are key AC processes.

• Different AC systems are used based on the application.

Would you like calculations or system recommendations for your aviation hangar design? ✈

Troubleshooting & Maintenance of Air Conditioning Systems

Proper maintenance and troubleshooting of air conditioning (AC) systems are crucial for
efficiency, longevity, and performance. This guide covers common issues, troubleshooting
steps, and preventive maintenance practices.

1. Common AC Problems & Troubleshooting

1.1. AC Not Cooling Properly

Possible Cause Troubleshooting Solution

Dirty air filter Clean or replace the filter.

Low refrigerant level Check for leaks & recharge refrigerant.

Dirty condenser coil Clean condenser coils with water/brush.

Faulty compressor Check for overheating or electrical failure.

Blocked vents or ducts Inspect and remove any obstructions.

1.2. AC Not Turning On

Possible Cause Troubleshooting Solution

Tripped circuit breaker Reset the breaker and check wiring.

Faulty thermostat Replace or recalibrate thermostat.

Blown fuse Replace the fuse.

Loose wiring Inspect and tighten electrical connections.

1.3. AC Making Unusual Noises

Noise Type Possible Cause Solution

Banging Loose or broken compressor part Inspect & repair compressor.

Hissing Refrigerant leak Identify and seal the leak, then recharge.
Noise Type Possible Cause Solution

Clicking Faulty electrical component Check relay switches and capacitor.

Screeching Worn-out fan belt or motor bearings Replace belt or lubricate bearings.

1.4. Water Leaking from AC

Possible Cause Troubleshooting Solution

Clogged condensate drain Clean the drain pipe.

Dirty evaporator coil Clean coils to prevent ice formation.

Improper installation Ensure the unit is level for proper drainage.

1.5. AC Freezing Up

Possible Cause Troubleshooting Solution

Dirty air filter Clean or replace the filter.

Low refrigerant Check and refill refrigerant if needed.

Faulty blower motor Inspect and replace the motor.

2. Preventive Maintenance of AC Systems

Regular maintenance ensures higher efficiency, lower energy consumption, and fewer
breakdowns.

2.1. Monthly Maintenance

✔ Clean air filters – Prevents clogging and improves airflow.

✔ Check thermostat settings – Ensures correct temperature control.
✔ Inspect air vents & ducts – Avoids blockages that reduce efficiency.

2.2. Seasonal Maintenance (Before Summer & Winter)

✔ Clean evaporator and condenser coils – Prevents overheating.

✔ Check refrigerant levels – Low levels indicate possible leaks.
✔ Inspect electrical components – Avoids short circuits and failures.
✔ Lubricate moving parts – Ensures smooth operation and reduces noise.
✔ Test drainage system – Prevents water accumulation and mold growth.

2.3. Annual Maintenance

✔ Deep clean coils and drain lines – Prevents dust buildup.

✔ Check compressor health – Monitors pressure and performance.
✔ Calibrate the thermostat – Ensures accurate temperature control.
✔ Inspect insulation of ducts – Prevents energy loss.

3. AC Maintenance Checklist

Inspect and replace air filters every 1-3 months.

Clean condenser and evaporator coils every 6 months.
Check refrigerant levels annually.
Test thermostat accuracy.
Inspect electrical connections and tighten if needed.
Clean drain pans and pipes.

4. Conclusion

• Troubleshooting AC issues early prevents costly repairs.

• Routine maintenance improves efficiency & extends system life.

• Hiring a professional HVAC technician for annual servicing is recommended.

Would you like a maintenance schedule for your aviation hangar’s air conditioning system? ✈

Detailed Classification of Air Conditioning Systems

Air conditioning (AC) systems are classified based on purpose, cooling method, and
applications. Below is a detailed classification of different types of AC systems.

1. Classification Based on Application

Type Description Example Use

Maintains comfortable indoor conditions by

Comfort Air Homes, offices, hotels,
controlling temperature, humidity, and air
Conditioning hospitals.
quality.

Industrial Air Designed for manufacturing processes where Factories, textile mills,
Conditioning temperature and humidity control is critical. pharmaceutical labs.

Maintains highly stable environmental

Precision Air Data centers, research
conditions with tight temperature & humidity
Conditioning labs, server rooms.
control.

2. Classification Based on Cooling Method

2.1. Direct Expansion (DX) Systems

• Uses refrigerant as a working fluid for cooling.

• Common in smaller spaces like homes and offices.

DX System
Description Example
Type

Single compact unit with all components in one

Window AC Small rooms, apartments.
box.

Split AC Has indoor and outdoor units. Homes, offices, hotels.

Medium-sized unit with all components in one

Packaged AC Small commercial spaces.
outdoor box.

VRF/VRV Uses a single outdoor unit with multiple indoor Large commercial buildings,
System units for flexibility. offices.

2.2. Chilled Water Systems

• Uses chilled water instead of refrigerant to cool air.

• Used in large buildings and industrial applications.

Chilled Water System
Description Example
Type

Air-Cooled Chillers Uses outdoor air to cool water. Small buildings, data centers.

Uses cooling towers for heat Large offices, malls,

Water-Cooled Chillers
rejection. hospitals.

3. Classification Based on Air Distribution

3.1. Centralized Air Conditioning Systems

• Large-scale systems for multi-room or multi-floor buildings.

Type Description Example

All-Air System Uses air ducts to distribute cooled air. HVAC systems in malls, offices.

All-Water Chilled water systems in

Uses water pipes for cooling.
System hospitals.

Air-Water Uses both air and water for temperature

Laboratories, industries.
System control.

3.2. Decentralized Air Conditioning Systems

• Independent units for small spaces.

Type Description Example

Split AC Separate indoor and outdoor units. Homes, hotels.

Window AC Self-contained unit mounted on windows. Small rooms.

Packaged AC Pre-assembled cooling units. Small offices, commercial spaces.

4. Classification Based on Functionality

4.1. Cooling-Only AC Systems

• Provides only cooling without heating.

• Used in hot climates.

4.2. Heating & Cooling (HVAC) Systems

• Provides both cooling and heating.

• Includes heat pumps, ducted ACs, and VRF/VRV systems.

• Used in cold and moderate climates.

5. Classification Based on Refrigeration Cycle

Type Description Example

Vapor Compression Uses a compressor, condenser, expansion valve, Window AC, Split AC,
System and evaporator. Chillers.

Uses a heat source instead of a compressor

Vapor Absorption Industrial cooling,
(ammonia-water or lithium bromide-water
System solar-powered ACs.
systems).

6. Special Air Conditioning Systems

Type Description Example

Uses variable-speed compressor for energy

Inverter AC Residential split ACs.
efficiency.

Evaporative Uses water evaporation for cooling, ideal for

Desert coolers.
Cooling dry climates.

Ductless Mini- No ductwork required, individual

Homes, small offices.
Split AC temperature control for rooms.

Geothermal Uses underground heat exchange for Sustainable cooling for homes
HVAC cooling & heating. & industries.

7. Conclusion

• Split & Window ACs → Best for homes & small spaces.

• Packaged ACs & VRF Systems → Best for offices & commercial use.
 • Chilled Water Systems → Best for large buildings & industries.

• Geothermal & Absorption Systems → Best for energy-efficient solutions.

Would you like recommendations for your aviation hangar AC system? ✈

Detailed Layout and Components of an Air Handling Unit (AHU) in Central Air Conditioning

An Air Handling Unit (AHU) is a crucial component in the central air conditioning system. It is
responsible for conditioning and circulating the air throughout the building. AHUs are typically
used in large buildings, like office complexes, hospitals, shopping malls, and airports, to handle
large volumes of air, maintain air quality, and control temperature and humidity. Below is a
detailed explanation of the AHU layout and its associated components:

1. General Layout of an AHU

An AHU generally consists of a large metal box (or enclosure) that houses various components
needed for heating, cooling, ventilation, and air distribution. The layout of an AHU typically
includes the following sections:

1.1. Sections in an AHU:

1. Inlet Section (Fresh Air Intake)

o This section is where fresh outdoor air enters the AHU from the outside. It often
includes filters to remove larger particles and contaminants before the air enters
the system.

2. Filter Section

o The filter section is one of the most crucial components. It is where airborne
particles, dust, and contaminants are filtered out to improve air quality before
the air is conditioned.

o There are typically two types of filters:

▪ Pre-filters: To capture larger particles.

▪ Fine filters (HEPA or Carbon filters): To capture finer particles, allergens,

and even odors.

3. Cooling Coil Section

 o This is where the chilled water from the central chiller plant flows through
cooling coils. The air passing over the coils is cooled and dehumidified as it
absorbs heat from the air.

o The temperature and humidity of the air are controlled in this section.

4. Heating Coil Section

o Heating coils are used to raise the temperature of the air when the outdoor
temperature is too low or when additional heating is required. The heating coils
are generally connected to a boiler or heat pump system.

5. Humidifier Section

o This section is used to add moisture to the air in dry conditions. It often includes
steam humidifiers or evaporative cooling systems. This is particularly important
in environments where humidity control is essential, like in offices, hospitals, or
museums.

6. Fan Section

o The fan section consists of large fans that circulate the conditioned air through
the entire ductwork system.

o The fan type can vary based on the application but typically includes centrifugal
fans (for high pressure) or axial fans (for low-pressure systems).

7. Duct Connection Section

o After air is conditioned, it exits the AHU through this section and is distributed
through the ductwork to various zones or rooms in the building.

8. Drainage Section

o As air is cooled and dehumidified, condensation occurs. The AHU will have a
drainage section that collects the condensed water and channels it safely away
to prevent water accumulation and potential damage.

9. Return Air Section

o This section is for recirculating air from the building back to the AHU. It may
include mixing dampers to control the amount of return air mixed with fresh
outdoor air.
2. Associated Components of an AHU

2.1. Filters

• Pre-filters: These are used to filter out larger particles, such as dust and debris, before
the air reaches the finer filters.

• Fine Filters: Such as HEPA (High-Efficiency Particulate Air) filters, which are capable of
capturing very small particles, including allergens, bacteria, and fine dust.

• Carbon Filters: Used to remove odors and gases from the air.

2.2. Coils

• Cooling Coils:

o These are typically chilled water coils connected to a central cooling system
(chillers). The air passes over the coils, and heat is exchanged between the air
and the coolant, cooling the air.

o These coils can also be part of a DX system (direct expansion system), where
refrigerant runs directly through the coils instead of chilled water.

• Heating Coils:

o These coils are often powered by hot water from a boiler or an electric system.
They heat the air before it is circulated throughout the building.

2.3. Fans

• Centrifugal Fans:

o High-pressure fans that are ideal for large ducted systems. They provide
sufficient air pressure to circulate air through long ducts and multiple zones.

• Axial Fans:

o Used when low-pressure air circulation is needed, such as in systems with

shorter duct runs. They are generally quieter and more energy-efficient at lower
pressure.

2.4. Humidifiers

• Steam Humidifiers:
 o These use steam to add moisture to the air, often in areas with low humidity.
They ensure that the air has the ideal moisture level for comfort or specific
applications.

• Evaporative Humidifiers:

o These work by passing water through a wick, and as air passes over it, the water
evaporates into the air, increasing humidity.

2.5. Dampers

• Volume Dampers:

o These are used to regulate airflow in specific areas of the system, allowing for
the distribution of air at the required rate.

• Mixing Dampers:

o Used in the return air section to control the ratio of outdoor fresh air and return
air from the building, optimizing both energy use and indoor air quality.

2.6. Drainage System

• Condensate Drainage:

o Since cooling air can lead to condensation, AHUs are equipped with drainage
pipes to remove excess moisture.

o Condensate pumps may also be used in case the unit is installed below the
building’s drainage line.
3. Control and Monitoring Systems
3.1. Sensors and Controllers

• Temperature Sensors:

o Measure the air temperature at various points to control the cooling and heating
coils, maintaining the desired room temperature.

• Humidity Sensors:

o Measure the moisture content in the air to control humidifiers and

dehumidifiers.

• Pressure Sensors:

o Used to monitor and control the fan speed and ensure consistent airflow through
the AHU.

3.2. Building Management System (BMS)

• AHUs are typically integrated with a BMS that allows the monitoring and control of the
system remotely. It helps optimize energy usage, set schedules, and maintain air quality
parameters. The BMS also helps with fault detection and can send alerts if there is an
issue with any of the components.

4. AHU Operation and Functioning

1. Air Intake:

o The fresh air intake section draws air into the AHU. It passes through the filter
section, where dust and particles are removed.

2. Air Conditioning:

o The filtered air moves to the cooling coils (or heating coils if required), where it is
either cooled or heated, depending on the system's requirements.

3. Dehumidification:

o If humidity control is needed, the air passes over the dehumidification coils or
through a humidifier to adjust the moisture level.
 4. Fan Circulation:

o After conditioning, the fans blow the air into the ducts, where it is distributed to
the various parts of the building through the air ducts.

5. Return Air:

o The air returns from the building through the return air section, where it is
mixed with the fresh air for recycling or sent for further conditioning.

6. Drainage:

o Condensation from the cooling process is collected in the drainage system and
removed safely.

5. Conclusion

The Air Handling Unit (AHU) is a central component in an HVAC system for large buildings,
ensuring efficient air circulation, temperature control, and air quality. By combining
cooling/heating coils, fans, humidifiers, and filters, the AHU helps to provide a comfortable,
healthy, and energy-efficient environment for occupants.

Would you like to explore further on the types of AHUs or specific components that are best
suited for your terminal or hangar design?

Designing an air conditioning (AC) system for a 15000 sq. ft. airport terminal building involves
careful consideration of temperature control, air quality, and passenger comfort. Here is a
detailed HVAC solution tailored to your terminal building:

1. Design Considerations for Terminal Building AC

1.1. Key Factors

• High Passenger Load: Thousands of passengers at peak times contribute to heat gain.
This requires zoned cooling for efficiency.

• Large Open Spaces: Airports typically have wide halls, check-in counters, lounges, and
baggage claim areas, all of which need specialized cooling systems.

• Humidity Control: Passengers and luggage areas require stable humidity levels to avoid
discomfort and damage to goods.
 • Air Quality: High air filtration and fresh air circulation are required due to the volume of
people in confined spaces.

2. HVAC System Components for Terminal Building

2.1. Cooling and Heating Systems

• Chilled Water System:

o Central Chilled Water Plant: A large-scale chilled water system can provide
cooling for the entire terminal building, with cooling coils installed at different
zones, including check-in areas, departure gates, and lounges.

o Air Handling Units (AHUs): AHUs with cooling coils circulate chilled air
throughout the building. AHUs should be located at strategic points like
concourses and hallways to efficiently distribute cooled air.

• Variable Refrigerant Flow (VRF) System:

o The VRF system is a great option for a terminal, as it provides independent

cooling and heating to different zones based on occupancy. For instance, the VIP
lounge or administrative offices can be cooled while other areas, like check-in
zones, are not.

o Energy-efficient and can be zoned for flexibility.

• Packaged Terminal Air Conditioners (PTACs):

o For smaller areas like ticket counters or restrooms, PTAC units can be used to
provide individual cooling. These are small, compact units that provide cooling,
heating, and dehumidification as needed.

• Underfloor Air Distribution (UFAD):

o UFAD is a unique system that supplies cool air at floor level, which is then drawn
upward to create comfortable conditions while avoiding the discomfort of direct
cold air blowing onto passengers. This system is particularly effective in large
open spaces like terminals.

2.2. Ventilation & Fresh Air

• Dedicated Outdoor Air Systems (DOAS):

 o A DOAS system provides fresh air to the terminal while also removing stale air.
The system filters the incoming air, ensuring high indoor air quality and reducing
the risk of airborne diseases.

o Heat recovery can be integrated into DOAS to improve energy efficiency by pre-
conditioning incoming fresh air with exhaust air.

• Demand-Controlled Ventilation (DCV):

o DCV uses CO2 sensors to detect the number of passengers and adjusts the
airflow accordingly. This reduces energy consumption during off-peak hours
when the terminal is less crowded.

2.3. Dehumidification

• Dehumidifiers:

o Humidity control is essential for passenger comfort and the preservation of

luggage and merchandise. Humidifiers or integrated dehumidification coils in
the air handling units (AHUs) will control the moisture levels in critical areas, such
as the baggage claim area and waiting lounges.

3. Energy Efficiency Measures

3.1. Energy Recovery Systems

• Energy Recovery Ventilators (ERV):

o ERVs recover heat from exhaust air and use it to preheat incoming air, which
helps reduce energy costs by reducing the load on heating and cooling systems.

3.2. Smart Building Management System (BMS)

• The BMS controls the HVAC system, adjusting air distribution, temperature, and
humidity in real-time based on occupancy and ambient conditions. It can help in:

o Managing HVAC efficiency: The system can schedule air conditioning based on
terminal operating hours and passenger volume.

o Zone-based control: Allows cooling and heating to be adjusted per zone,

reducing energy waste.

4. Zoning and Zonal Cooling

 • Check-in Area: Requires cooling for passenger comfort as this area experiences high
traffic and heat gain from lighting and people.

• Departure Gates and Waiting Lounges: These zones will benefit from VRF systems or
underfloor air distribution (UFAD) for better airflow and more uniform cooling.

• Security Checkpoints: Needs moderate cooling to maintain comfort for passengers.

• VIP Lounges & Offices: These areas should have individual cooling units (e.g., VRF
systems) to maintain a comfortable, constant temperature for fewer people.

• Baggage Claim Areas: Since these areas have a lot of luggage being processed, humidity
control is essential to prevent moisture damage to the baggage.

5. Example HVAC Solution for a 15,000 sq. ft. Airport Terminal

For a 15,000 sq. ft. terminal, you might want to implement the following:

1. Centralized Chilled Water System:

o A central chiller plant with air handling units (AHUs) will cover the large open
spaces, including corridors, check-in areas, and lounges.

2. VRF System for Zones:

o Use VRF systems for more specific cooling needs in areas like the VIP lounge or
offices that may require heating during cooler months.

3. DOAS for Ventilation:

o Integrate a DOAS to bring in fresh air, filter it, and then distribute it throughout
the building using ducts and AHUs.

4. Dehumidification Coils in AHUs:

o To ensure proper humidity control in areas like baggage claim or merchandise

zones.

5. BMS Integration:

o Set up a Building Management System (BMS) to manage energy consumption,

detect areas requiring cooling, and optimize HVAC operations based on real-time
conditions.
6. Conclusion

An efficient AC system for a 15000 sq. ft. airport terminal needs to be flexible, energy-efficient,
and comfortable, taking into account factors such as high foot traffic, humidity control, and
continuous fresh air.

The combination of central chilled water systems, VRF systems, underfloor air distribution,
and energy recovery ensures a well-optimized, cost-effective, and comfortable environment for
passengers and staff.

Would you like to explore cost estimations, HVAC layout designs, or any other aspects related
to your terminal building's AC system?

For your mid-size aircraft hangar (such as the ATR-72), the design of the air conditioning (AC)
system should prioritize energy efficiency, cooling large volumes, and maintaining comfortable
conditions in specific areas like maintenance zones, spare parts warehouses, and office spaces.
Here's a customized HVAC solution tailored to your requirements:

1. HVAC System Components for Aircraft Hangar AC Design

1.1. Cooling System

• Air Handling Units (AHUs):

o Used for ventilation and cooling in offices, briefing rooms, and administrative
areas.

o Ensure proper filtration to maintain air quality by removing dust, smoke, and
pollutants from the hangar environment.

o Variable Air Volume (VAV) system for adjusting airflow based on the load in
different zones.

• HVLS (High-Volume Low-Speed) Fans:

o Large industrial fans that help in air circulation, distributing cooler air to the
entire hangar area.

o Improves air movement in areas where traditional cooling systems may not be
as effective (like large open areas).

1.2. Spot Cooling Systems

• Portable Cooling Units or Ducted Spot Coolers:

 o Focused on maintenance zones or where work on aircraft is conducted. These
units can provide localized cooling, especially around workstations, preventing
the need for a complete hangar-wide cooling setup.

1.3. Evaporative Cooling

• Direct Evaporative Coolers:

o A highly energy-efficient solution for cooling the larger, open spaces in the
hangar. It is particularly effective in dry climates. Evaporative cooling helps
reduce temperature while keeping humidity within an acceptable range for both
personnel comfort and the integrity of spare parts and tools.

1.4. Exhaust and Air Filtration

• Exhaust Ventilation Systems:

o These systems will remove fumes, smoke, and exhaust gases from aircraft
engines or other maintenance activities.

o Ensure that toxic fumes from fuel, solvents, and paints are safely vented out of
the hangar.

• HEPA Filters:

o Installed in the ventilation units to maintain a high standard of air quality within
the hangar. They will help capture small particles that can affect both the quality
of the aircraft and the health of personnel.

2. Heating and Humidity Control

2.1. Heating System

• Infrared Radiant Heaters:

o Used for localized heating in maintenance areas or cold storage zones.

o They directly heat objects and areas where personnel are working without
needing to heat the entire hangar volume, which can be costly and inefficient.

2.2. Humidity Control

• Dehumidifiers:
 o Necessary for controlling the humidity in the hangar to prevent corrosion of
aircraft components and spare parts.

o These can be integrated into the centralized HVAC or be used in specific areas
like spare parts storage.

3. Energy Efficiency Measures

3.1. Smart Controls & Zoning

• Building Management System (BMS):

o Integrates all HVAC components into a centralized control system, allowing for
better monitoring and adjustment of temperature, airflow, and humidity across
different zones in the hangar.

o The system can automatically adjust based on occupancy, weather, or other

factors, ensuring efficient energy use.

3.2. Insulation and Heat Recovery

• Thermal Insulation:

o Ensure that the building is properly insulated to minimize heat loss or gain,
helping reduce the load on the HVAC system.

o Proper insulation is particularly crucial for high ceilings and large doors where air
loss can be significant.

• Heat Recovery Ventilation (HRV) Systems:

o Allows for the recovery of heat from exhaust air to precondition incoming fresh
air, reducing the load on the heating system and improving overall energy
efficiency.

4. Example HVAC Solution for Your Hangar

For a mid-sized hangar like the one you are designing for the ATR-72, the system design might
include:

• Chilled Water System:

 o A central chiller plant for cooling the large areas like the hangar floor, using
water-cooled chillers.

• Air Rotation Units:

o Large fans that push air down from high ceilings, ensuring consistent
temperature and ventilation across the hangar space.

• Zone-based AC:

o Different zones like the maintenance area, office spaces, and warehouse can
have their own cooling units to allow for better control and comfort.

• Exhaust System:

o Install a dedicated exhaust system in maintenance areas for engine testing and
cleaning, removing potentially harmful fumes and contaminants.

5. Conclusion

The key to designing an effective and efficient AC system for your aviation hangar is to focus on
energy-efficient cooling, zoning, and ensuring that the system meets the specific needs of
different areas. Your system should be tailored to handle both large open spaces and more
confined areas, with systems in place to handle ventilation, humidity control, and air quality.

Would you like further cost estimations or layout recommendations for your hangar HVAC
design? ✈