Tag Archive: cooler

How to select a hydraulic cooler

At this article, I show my vision on how to:

  • determine the value of the heat needs to be rejected from the system;
  • calculate and select the right cooler size.

…and will provide an example of cooler calculation and selection.

What is a cooler and what is a heat exchanger?

The hydraulic cooler is one of the heat exchangers type. But, what is a heat exchanger? The best definition of the heat exchanger is:

Heat exchanger is a device that transfers heat between two fluids.

The simple sentence but a very good description, because fluids can be either oil, air, water, etc., and because transferred heat can be for either cooling or heating target.

There are two most popular types of heat exchangers in hydraulic systems:

Plate heat exchangers

Plate heat exchanger

Plate heat exchanger

This type has the best value of efficiency/reliability and designed for both cooling and heating applications and a very good for low-viscosity fluids. Pairs of plates can be removed individually for maintenance, cleaning, or replacement. Another advantage of the plate is exchangers is their low initial cost, as well as easy and inexpensive operation.

Fan radiators (air-cooled)

Fan radiators (air-cooled)

Fan radiators (air-cooled)

This type is the only option where water is unavailable or expensive for a delivery. From benefits: low maintenance and operating costs and the only option for oil cooling in mobile applications.

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Hydraulic cooler: suction or blowing air flow?

Just got an interesting response from Emmegi technical specialist about a choice between suction and blowing air flow of hydraulic coolers. The response is short but very deployed, so I would share it “as is”:

Here is our take on suction vs. blowing air flow:

  1. Blowing air flow: If you have seen a cooler that has been in the field for a while you will notice a clean doughnut shaped area where the air is blowing thru the cooler. In all four corners and in the center you will notice gunk/debris.

This indicates that the full surface area is not being utilized.

  1. Suction air flow: The fan creates a vacuum between the fan and cooling element. The air is very evenly distributed across the face of the cooler utilizing the full surface area.

On the downside, the fan blade is operating in less dense hot air, reducing the performance of the fan.

SUMMARY: For most hydraulic cooling applications the two effects cancel each other out and end up having nearly identical performance. The exception to this rule is for high temperature applications (oil temps above 175F).

  • For high temp applications the reduction of air density makes the blowing design more efficient.
  • The reason we supply standard coolers with suction air flow is that since the performance is typically the same, the suction air flow traps debris on the outside of the cooler where it is not only visible, but can be cleaned much easier.

if be honest, before this time I thought the suckers are more efficient coolers. Even to order cooler you need to specify symbol to make a blower (because the sucker is a standard).