How It Works

Heat Generation in Hydraulic Systems

Every hydraulic system converts some input power to heat. The heat generated equals the wasted power:

Heat (BTU/hr) = HP × 2545 × (1 - efficiency)

  • HP = Input horsepower to pump
  • 2545 = BTU per HP-hour
  • efficiency = Overall system efficiency (decimal)

Cooler Sizing

The oil cooler must reject at least the heat generated. Cooler capacity depends on the temperature differential between oil and ambient:

Cooler Flow = Heat / (500 × delta-T) GPM through cooler

where 500 = specific heat factor for petroleum oil (BTU/hr per GPM per deg F).

Cooling Capacity Calculator

Size hydraulic oil coolers based on system horsepower, efficiency, and temperature limits.

Typical: 60-85% overall

Power Distribution

Useful Work
Heat
Useful: -- HPWaste Heat: -- HP

Cooling Results

Heat Generated--
Recommended Cooler--
Oil Flow Through Cooler--
Heat in kW--
Temperature Rise Allowance--
Wasted HP--
Cooler Safety Margin (1.25x)--

Cooler Sizing Guide

Heat LoadCooler TypeNotes
<10,000 BTU/hrAir-oil, smallFan cooled
10-50k BTU/hrAir-oil, mediumIndustrial
50-200k BTU/hrWater-oilShell & tube
>200k BTU/hrLarge water-oilPlate type