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Calcimator

Hydraulic Cooling Calculator

Calculate heat generation and size a heat exchanger for a hydraulic system based on pressure, flow, and efficiency.

Inputs

%
%

Results

Required cooler capacity (BTU/hr)

5,210

Required cooler capacity (kW)1.53
Heat generated (BTU/hr)7,424
Hydraulic input power (HP)11.67
Natural dissipation (BTU/hr)3,082
Water flow needed (GPM)0.52
Heat generated (kW)2.18
Oil temp rise per pass (°F)4.3
Fan Hp0.05
How to Use This Calculator
  1. Enter System pressure (PSI), System flow rate (GPM), and Overall system efficiency.
  2. Set Ambient temperature (°F), Max fluid temperature (°F), and Reservoir capacity (gal).
  3. Adjust Cooler safety factor as needed.
  4. Review the Required cooler capacity (BTU/hr) result.
  5. Use Required cooler capacity (kW) and Heat generated (BTU/hr) to inform your decision.

How the result changes with Overall system efficiency

Overall system efficiencyRequired cooler capacity (BTU/hr)
1925,167
4017,683
658,774
87934

What each input means

System pressure (PSI)
Operating pressure of the hydraulic circuit.
System flow rate (GPM)
Total hydraulic flow rate in gallons per minute.
Overall system efficiency
Combined pump, valve, and actuator efficiency (70-85% typical).
Ambient temperature (°F)
Maximum ambient air temperature.
Max fluid temperature (°F)
Maximum allowable hydraulic fluid temperature (140°F typical for petroleum oil).
Reservoir capacity (gal)
Hydraulic reservoir volume in gallons.
Cooler safety factor
Additional cooler capacity margin (20% typical).

What each result means

Required cooler capacity (BTU/hr)
Heat exchanger capacity needed including safety factor.
Required cooler capacity (kW)
Cooler capacity in kilowatts.
Heat generated (BTU/hr)
Total heat produced by system inefficiency.
Hydraulic input power (HP)
HP = PSI × GPM / 1714.
Natural dissipation (BTU/hr)
Heat naturally radiated from the reservoir surface.
Water flow needed (GPM)
Cooling water flow for a water-oil heat exchanger (20°F water ΔT).
Heat generated (kW)
Waste heat in kilowatts.
Oil temp rise per pass (°F)
Temperature increase of fluid in one pass through the system.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    System pressure (PSI) = 2000, System flow rate (GPM) = 10, Overall system efficiency = 75, Ambient temperature (°F) = 90 = 7 input(s) provided
  2. Calculate Required cooler capacity
    Required cooler capacity = netHeatLoad * safetyFactor
    5210 = 5210
  3. Calculate Required cooler capacity
    Required cooler capacity = requiredCoolerBtuHr / 3412.14
    1.53 = 1.53
  4. Calculate Heat generated
    Heat generated = wasteHp * 2545
    7424 = 7424

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