Full definition
Equipment removing heat generated in the hydraulic system (losses in valves, pump, and lines) to keep oil temperature below 60°C. Ideal temperature: 40-50°C. Types: air-to-oil (electric fan or engine-driven, most common, ΔT ~30°C), water-to-oil (higher heat capacity, requires cooling water). Heat calculation: Q_heat = pressure loss × flow rate. Standard ISO 4413. Brands: Hydac (HEX), Parker (Aero-Quip), Bosch Rexroth, API Heat Transfer.