The total power lost by a hydraulic system is converted into heat, which is largely absorbed by the pressure fluid. It is comprised of the
- pressure losses caused by pipe friction and flow deflections,
- leakage losses,
- losses caused by throttle processes of local resistances in the system.
The dissipated heat can be estimated for finished systems by measuring the change in temperature over several hours. The start temperature, end temperature and the oil volume are used to calculate the hourly heat flow.
A rough estimate of the dissipated heat can be achieved by taking an average of the overall efficiency if there is no appreciable throttle:
and in the case of throttle losses:
