Fluid cooling

Many systems are currently designed with oversized reservoirs as they are believed to act as oil cooler. Conventional reservoirs do cool oil but minimally. Today's high performance coolers can perform all the cooling requirements by themselves while being light and compact. A properly sized coolers will keep the system temperature within the desired range whatever the environment. Traditional reservoir requires appropriate differential temperature ratio between oil and ambient air to perform in that matter and even so, their cooling capacity is modest at best. The following example shows the relative limited cooling capacity of conventional reservoirs vs. coolers.

Thermal capacity

Comparison between reservoirs and a fluid cooler
Cooling capacity
Temperature diffential
Reservoir size Reservoir surface 30 Celsius / 86 Farhenheit 50 Celsius / 122 Farhenheit
Liters Gal. imp Meter2 Foot2 Kw Hp Kw Hp
100 26 1.4 15 1.0 1.3 1.3 1.8
200 52 2.3 25 1.6 2.1 2.2 3.0
300 78 2.9 31 1.9 2.6 2.8 3.7
400 104 3.5 38 2.5 3.3 3.4 4.6
500 130 4.2 46 2.9 3.9 4.1 5.5

Source: Womack Machine

Too often conventional reservoirs are used to cool the fluid.

It shouldn't be their task!

Air/oil cooling type
Air/oil type
Water/oil plate cooling type
Water/oil plate type
Water/oil tube cooling type
Water/oil tube type

The typical 2-3 minutes dwell time found on classic reservoirs to eliminate air bubbles is no longer a necessity when using the VVR since the system is sealed and airless. However a specific procedure must be followed to bleed the system (see Fill procedure).