Petro-Canada recently participated in a hydraulic fluid energy efficiency evaluation on a Denison T6CM mobile vane pump at 2,900 psi. This pump is typically found on a wide variety of mobile equipment in the construction, forestry, mining, and transportation industries. A range of commonly used monograde hydraulic fluids, including ISO 22, 32, 46, and 68 grades, were compared to Hydrex XV All Season multigrade hydraulic fluid.

For this article, we discuss the performance of an ISO 22 monograde (commonly used in winter season conditions) and an ISO 46 monograde (commonly used for summer season conditions). It was necessary to estimate typical average oil temperatures at the pump cartridge under continuous operating conditions for typical mid-size, mid-flow-rate hydraulic pumps during both seasons. This was accomplished by averaging the results of field measurements and incorporating an adjustment for internal heating at the pump itself.

The evaluation showed that 23.8 kW were required to power a hydraulic pump using a winter season ISO 22 hydraulic fluid with a flow rate of 12 gpm. This compares to Hydrex XV, which required 24.2 kW of power with an actual flow rate of 14.6 gpm. The data was calculated at an operating oil temperature of 158° F, a pressure of 2,900 psi, and a speed of 2,000 rpm.

The power needed to drive a hydraulic pump using a summer season ISO 46 hydraulic fluid measured 23.9 kW with a flow rate of 12.2 gpm. This compares to Hydrex XV, which required 23.9 kW of power but with an actual flow rate of 12.8 gpm. This data was calculated at an operating oil temperature of 194° F, a pressure of 2,900 psi, and a speed of 2,000 rpm.

The energy required to deliver the same volume of fluid under a given pressure and pump speed (energy efficiency savings) is calculated using the following formula:

EnergyMonograde / EnergyHydrex XV = PMonograde * Qa(Hydrex XV) / [PHydrex XV * Qa(Monograde)]

where P = Power (kW) needed to drive the pump and Qa = actual flow rate (lpm).