Chiller Capacity Calculator

Chiller Configuration

Chiller Type Water-cooled: COP 5.0-6.5 | Air-cooled: COP 2.5-3.5

Compressor Type

Rated COP (-) Water-cooled: 5.0-6.5 | Air-cooled: 2.5-3.5 | Magnetic: 6.0-8.0

Load and Capacity Parameters

Peak Cooling Load (kW)

Oversizing Safety Margin (%) Recommended standard: 10% safety margin

Design Part Load Ratio (%) Expected operating load. Most chillers operate at 60-80% load.

Evaporator (Chilled Water Side)

Chilled Supply Temp (°C) Standard HVAC: 6.0°C - 7.0°C

Chilled Return Temp (°C) Standard Delta T is 5.0K or 6.0K

Condenser (Heat Rejection Side)

Condenser Water Supply (°C) Water-cooled only: leaving cooling tower, typically 29-30°C

Condenser Water Return (°C) Water-cooled only: entering cooling tower from chiller

Ambient Dry-Bulb (°C) Air-cooled only: outdoor design dry-bulb temperature

Fluid and Refrigerant Selection

Refrigerant Fluid Reference only - does not currently affect the calculation

Fouling Factor Allowance (m²·K/W) Reference only - does not currently affect the calculation

Estimation & Operation Parameters

Annual Runtime (hours)

Electricity Tariff (per kWh)

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Chiller Capacity Selection

Chillers are the heart of HVAC cooling systems. This calculator helps engineers select the right chiller by analyzing cooling load, efficiency (COP/EER), and operating costs. Water-cooled chillers offer higher efficiency but require cooling towers and more maintenance. Air-cooled chillers are simpler but less efficient, especially at high ambient temperatures. Magnetic bearing chillers provide the highest efficiency with oil-free operation and reduced maintenance.

Key Points:

Water-cooled chillers: COP 5.0-6.5, require cooling tower, lower operating cost
Air-cooled chillers: COP 2.5-3.5, no cooling tower, higher operating cost
Magnetic bearing: COP 6.0-8.0, oil-free, lowest maintenance, premium price
Absorption chillers: Use heat instead of electricity, COP 0.7-1.2
IPLV (Integrated Part Load Value) better represents real-world efficiency than full-load COP
Most chillers operate at 60-80% load - select for part-load efficiency
5°C ΔT on chilled water is standard (7°C supply / 12°C return)
Oversizing wastes energy; undersizing causes comfort issues

Calculation Steps:

Enter all required parameters
Click "Update Calculation"
Review results and analysis

Formula Variables:

Q Cooling Capacity (kW)

P Power Input (kW)

COP Coefficient of Performance (-)

EER Energy Efficiency Ratio (Btu/W·h)

IPLV Integrated Part Load Value (-)

ṁ Mass Flow Rate (kg/s)

ΔT Temperature Difference (K)

PLR Part Load Ratio (%)