Types of Chillers for HVAC System

❄️ Types of Chillers: Working Principles, Applications, Specifications & Brands

Chillers are essential components in HVAC systems, responsible for removing heat from water or process fluids to provide cooling. Whether you're designing for a hospital, data center, or industrial plant, selecting the right chiller type requires understanding how each one works, its capacity range, refrigerants, and operational efficiency.

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🧪 How Chillers Work: The Core Cycle

Most chillers operate on the vapor-compression refrigeration cycle, which includes:

1. Evaporator: Heat from the building’s chilled water is absorbed by the refrigerant, causing it to evaporate.
2. Compressor: The low-pressure vapor is compressed into a high-pressure, high-temperature vapor.
3. Condenser: The vapor releases heat to air or water and condenses into a liquid.
4. Expansion Valve: The liquid refrigerant is throttled to reduce pressure and temperature before re-entering the evaporator.

Some chillers use absorption cycles, driven by heat instead of electricity.

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🌀 1. Scroll Chillers

🔧 Working Principle

Scroll chillers use two spiral-shaped scrolls—one stationary and one orbiting—to compress refrigerant. As the scrolls rotate, pockets of refrigerant are trapped and compressed toward the center.

📊 Specifications

• Capacity: 5–150 tons
• Cooling Method: Air-cooled (mostly)
• Refrigerants: R-410A, R-407C
• Efficiency: COP ~2.8–4.0

✅ Applications

• Small offices
• Residential complexes
• Modular cooling systems

❌ Drawbacks

• Limited capacity
• Not suitable for large-scale cooling

🏢 Top Brands

• Mitsubishi Electric
• Daikin
• Voltas
• LG

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🔄 2. Screw Chillers

🔧 Working Principle

Screw chillers use two interlocking helical rotors to compress refrigerant. The rotors trap refrigerant between them and reduce its volume as it moves along the screw path, resulting in continuous compression.

📊 Specifications

• Capacity: 20–1,000 tons
• Cooling Method: Water-cooled or air-cooled
• Refrigerants: R-134a, R-407C, R-410A
• Efficiency: COP ~3.5–5.5

✅ Applications

• Hospitals
• Hotels
• Industrial plants
• Data centers

❌ Drawbacks

• Higher initial cost
• Less efficient at very low loads

🏢 Top Brands

• Johnson Controls
• Daikin
• LG
• Tempcon 

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🌪️ 3. Centrifugal Chillers

🔧 Working Principle

Centrifugal chillers use high-speed impellers to impart velocity to the refrigerant vapor. This kinetic energy is converted into pressure energy via a diffuser, compressing the refrigerant without physical contact.

📊 Specifications

• Capacity: 300–2,000+ tons
• Cooling Method: Water-cooled
• Refrigerants: R-134a, R-1233zd, R-513A
• Efficiency: COP ~5.5–7.0

✅ Applications

• Airports
• Malls
• District cooling
• Large commercial buildings

❌ Drawbacks

• Surge risk at low loads
• Requires stable operating conditions
• High upfront cost

🏢 Top Brands

• Carrier AquaEdge
• Trane CenTraVac
• York YK Series
• Hitachi

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🔧 4. Reciprocating Chillers

🔧 Working Principle

These chillers use pistons in cylinders to compress refrigerant. As the piston moves down, it draws in refrigerant vapor; as it moves up, it compresses and pushes it into the condenser.

📊 Specifications

• Capacity: 30–150 tons
• Cooling Method: Air-cooled or water-cooled
• Refrigerants: R-22, R-134a, R-407C
• Efficiency: COP ~2.5–3.5

✅ Applications

• Small commercial buildings
• Modular systems
• Backup cooling

❌ Drawbacks

• High maintenance
• Noisy operation
• Lower efficiency

🏢 Top Brands

• Carrier
• Trane
• York
• Blue Star

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🔥 5. Absorption Chillers

🔧 Working Principle

Absorption chillers use a heat source (steam, hot water, or gas) to drive the refrigeration cycle. The refrigerant (usually water) is absorbed by a solution (typically lithium bromide), then separated via heat and condensed.

📊 Specifications

• Capacity: 100–1,500 tons
• Cooling Method: Water-cooled
• Refrigerants: Water + Lithium Bromide
• Efficiency: COP ~0.6–1.2

✅ Applications

• Cogeneration plants
• Hospitals with steam availability
• Industrial waste heat recovery

❌ Drawbacks

• Low efficiency
• Complex maintenance
• Sensitive to crystallization

🏢 Top Brands

• Thermax
• Broad
• Yazaki
• Robur

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📊 Comparison Table

Chiller Type	Working Principle	Capacity Range	Cooling Method	Refrigerants	Efficiency (COP)	Best For
Scroll	Spiral scroll compression	5–150 tons	Air-cooled	R-410A, R-407C	2.8–4.0	Small offices
Screw	Helical rotor compression	20–1,000 tons	Air/Water	R-134a, R-410A	3.5–5.5	Hospitals, hotels
Centrifugal	Impeller velocity compression	300–2,000+ tons	Water-cooled	R-134a, R-513A	5.5–7.0	Malls, airports
Reciprocating	Piston-cylinder compression	30–150 tons	Air/Water	R-22, R-134a	2.5–3.5	Small buildings
Absorption	Heat-driven absorption	100–1,500 tons	Water-cooled	LiBr + Water	0.6–1.2	Steam-rich environments

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