Barry Schoenborn, of thermal Transfer products, presented the final session at the Fluid Power Conference & Expo in Milwaukee.

Barry explained how inefficiencies of a hydraulic system result in heating of the hydraulic fluid. He said that when heat generation causes fluid to become too hot, heat exchangers are an effective way of controlling fluid temperature. He then covered many important aspects of determining heat generation and how to select the best type and size of heat exchanger to keep heat under control.

No less than 30 people attended this session, and the overwhelming majority of session surveys showed positive responses across the board.

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covered many important aspects of determining heat generation and how to select the best type and size of heat exchanger to keep heat under control.

Alan;
Is there something missing/wrong/lacking in the above scenario??????????????

It would seem a lot more energy efficient to use the information gleaned from determining the Heat Generating Inefficiencies of the circuit and design them out. Then there would be a Double Energy Savings. LESS ENERGY input to make the HEAT and NO ENERGY USED to get rid of the unnecessary HEAT produced.

Always seemed logical to me once I determined where the heat was coming from.

We can all look around and find Hydraulic Circuits that run cool without a Heat Exchanger. It is not Rocket Science to figure the components that make the heat. However, it does take some planning to design around the Heat makers. Often the circuits are more expensive to build but they run better and usually give a fast payback in energy savings.

Needless to say, there are some systems that must operate inefficiently due to the need for precice control of Speed and/or Positioning. Proportional and Servo circuits are two that I believe will always have Wasted Energy so they can meet the requirements of the machine function. So the Heat Exchanger manufacturers will not go Belly-up just have less business.

Designing hydraulic circuits with minimal wasted energy is challenging and will hardly ever be the Low Bid. But, when end users realize the long term savings in ENERGY they will not have to be sold on paying extra up front.

At least that has been my experience over the years.

I agree, Bud. When possible, it's always better to design a system that is energy efficient from the start. But as you pointed out, some systems must run inefficiently as a tradeoff for precise control. Also, there seems to be a big trend toward reducing the size of reservoirs. A smaller reservoir means less surface area to dissipate heat, so a heat exchanger may be necessary to remove heat that the reservoir can't.
Barry's opening remarks implied that if you can design a system that doesn't need a heat exchanger, do it. But for those where a heat exchanger is a "necessary evil," here are some guidelines.
Interestingly, the June issue of H&P has a column by Jack Johnson, PE, titled , Myth #4: High efficiency is always good." Here is a link:

http://www.hydraulicspneumatics.com/200/Issue/Article/False/80810/Issue

As always, Bud, thanks for your valuable comments.

Alan;

Sorry, I should have listened to the presentation.

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Originally posted by Alan L. Hitchcox:
Barry Schoenborn, of thermal Transfer products, presented the final session at the Fluid Power Conference & Expo in Milwaukee.

No less than 30 people attended this session, and the overwhelming majority of session surveys showed positive responses across the board.

I have never been to a Hydraulics Seminar, or Trade show, and as You mentioned Barry's was the last session (so attendance would naturally be thinning out), but is 30 people attending a presentation a lot?

I have read the article You mentioned to Bud, and I am intrigued by the resonance thing discussed in the article, I have seen bouncy action in a cylinder, but I always thought it was from air contamination in the cylinder. Perhaps in My case it always was, because when the cylinder was drained, and then the reservoir properly maintained (fluid level not allowed to go too low) the problem did not reappear.

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I am just recently getting interested in Fluid Power for turning a shaft, and in My first experiment/project I will be using a high volume, low pressure system (mostly because I don't want to be sitting over/near an accumulator storing over 1500PSI), the information I have acquired on this forum as well as a local Hydraulics Guy has been invaluable.

I also wouldn't mind attending a Show/Seminar if there is going to be one within 150 miles of Sarasota, FL, is there a link here somewhere that lists events that I may have missed?

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Secrets of Heat Transfer

Kern's book is simply called 'Process Heat Transfer'. There are, of course, other references - Coulson & Richardson Vol 6 p659 for example. I find Kern's book unreadable, don't know why.

Rocky
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