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    HVAC / Chillers

    Chiller Plant Sizing

    Chiller capacity in tons, the electrical input at a given efficiency, and the annual running cost. The kW/ton figure is the one to compare between machines.

    Capacity341 tonsInput power240 kWkW/ton0.70
    Capacity
    341 tons
    1200 kW
    Input power
    240 kW
    COP 5.0
    kW/ton
    0.70
    Lower is better
    Annual cost
    $63,360
    5.280e+5 kWh
    Efficiency conversions
    1 ton of refrigeration = 3.517 kW of cooling.
    Efficiency conversions
    Efficiency (kW/kW)COPkW/ton
    0.166.30.56
    0.25.00.70
    0.254.00.88
    0.33.31.06
    0.42.51.41
    Inspect the model
    Choose a quick result view, a scaled comparison, or the complete diagnostic set.
    Annual cost against efficiency
    A 20% better machine saves 20% of the bill, every year.
    Annual cost against efficiency0.0002.839e+45.677e+48.516e+41.135e+51.419e+50.160.160.200.200.250.250.300.300.400.40Chiller Plant Sizing
    Canonical equations
    The exact relationships implemented by this engine.

    tons = kW / 3.517 · US refrigeration tons.

    1 / (kW per kW) · Higher is better.

    engineering methodology

    A clear path from inputs to results.

    Chiller capacity in tons, the electrical input at a given efficiency, and the annual running cost. The kW/ton figure is the one to compare between machines.

    Step-by-step methodWorked exampleAssumptions explained

    How to use

    1. Set cooling load (kw).
    2. Set input (kw per kw cooling).
    3. Set equivalent full-load hours.
    4. Set electricity ($/kwh).
    5. Read the headline metrics, then check the table for the detail.

    The formula

    tons=kW/3.517tons = kW / 3.517

    Reference: Tons, COP and kW/ton conversions.

    Worked example

    At the default inputs

    Inputs
    • Cooling load (kW): 1200; Input (kW per kW cooling): 0.2; Equivalent full-load hours: 2200; Electricity ($/kWh): 0.12
    Calculation path
    1. 1

      Capacity: 341 tons · Input power: 240 kW · kW/ton: 0.70 · Annual cost: $63,360

    Result

    Capacity: 341 tons · Input power: 240 kW · kW/ton: 0.70

    Interpreting the result

    A 1200 kW load needs 341 tons and draws 240 kW.

    Assumptions & limitations

    • Full-load efficiency only.
    • No chilled or condenser water pump power.

    Frequently asked questions

    What is a good kW/ton?

    Around 0.55–0.65 for a water-cooled centrifugal machine at full load.

    Why does part load matter more?

    Chillers run most hours at part load, where the unloading curve decides the annual energy.

    Methodology last reviewed 2026-10-22. Results are informational and not financial or engineering advice — see our disclaimer.