Basics of Engine Test Cell Water Circuits

Learn from industry expert, Rick Ballo, about the practical and technical aspects of water circuits. Throughout this interactive presentation, Rick will educate and consult about different variants of cooling system installations, weighing the pros and cons of each.

In every dynamometer test, there needs to be some mechanism of heat removal.  In smaller installations, this can be as simple as allowing the unit to air cool after a short duration test. As you scale up to larger dynamometers you move from air-cooled systems to more complex apparatus’ that rely on water to effectively displace the energy from the test. These are commonly called water circuits.

In this webinar, we review the Basics of Engine Test Cell Water Circuits including why they’re needed, how they function in practice, important considerations, and cover a variety of installation options.

Why Do I Need a Water Circuit?

The entire function of an engine is to generate energy to accomplish some sort of task.  Whether it’s to move your car or operate a piece of heavy duty construction equipment, the engines energy output is redirected into mechanical movement.  But when you’re running a test, and artificially creating a load on your test engine with the use of a dynamometer there is no mechanical output involved.  That same amount of energy is created, but it doesn’t work towards a mechanical end, the only output left is heat.

With some tests lasting up to 48 hours, often with a heavy load, the heat output can be extraordinary. The risk of overheating your engine can lead to catastrophic failures, and air-cooled systems don’t have  the capacity to dissipate the heat, the most cost effective and practical solution is a water circuit.

What Does a Water Circuit Do?

At it’s most basic, a water circuit provides a method of removing power in the form of heated water from the dynamometer and the engine. It supplies cool water to the dyno and engine inlet, and carries heated water away for discharge or cooling. The water flows continuously through the system and maintains a reasonable temperature for the duration of the test.

In regions blessed with an abundance of water, you can draw directly from your source and discharge the heated water.  It’s simple and effective, but is only a fit in the best of circumstances.  For everyone else, a standard circuit featuring a cooling tower and reservoir is likely necessary.

Standard Water Circuits

A standard, or typical water circuit is what you’re most likely to find at your average installation. With this set-up, the cooling capacity is directly proportional to the size of the reservoir, and the rate of flow.  Starting at the beginning, cool water stored in a reservoir and is drawn into the engine under test. The engine, along with the dyno, dissipate heat into the water where it is discharged into an adjacent hot reservoir. A pump draws hot water into the cooling tower, where evaporation acts as the main method to return the water to a usable temperature where it is then returned to the cold reservoir.

The idea that cool water is filtered through the engine is actually a misnomer. The water is actually still quite hot, though still sufficiently cool to draw energy from the unit under test.

Diagram of standard Cell Water Circuits with cooling

A series of optional components can be added to the system to lend additional cooling capacity such as an After Cooler Cooling Column, a Charge Air Coole, or and Engine Cooling Column. These can increase the capacity of your system and allow for extended testing.

Design, Construction, and Installation

We understand that building a complex system such as the ones outlined in the webinar can be a daunting task. At Power Test, we have an entire team dedicated to the design, construction, and installation of such systems. We work directly with you to navigate the obstacles that your installation faces and deliver a result that accommodates all of your considerations.  Let us know if you have additional questions about a potential system, and we’ll do everything in our power to Make Your Testing Easy.

AC Regenerative Solutions

From the Custom Engineered Solutions division at Power Test, learn about different braking technology featured in our dynos and see if an AC Regenerative Solution may be right for you.

Rob Kazmier will explore, in depth, a number of topics including AC Regenerative Technology, Applications for AC Regen, and Technological Decision Factors. He will also answer any questions you might have in this conversational and consultative webinar.

AC Regenerative Solutions

Power Test is proud of it’s wide variety of standard products.  From Chassis Dynos to 10,000HP engine dynos, and everything in between, we have the experience and engineering expertise to deliver on your testing challenges. Our standard offerings serve industries including construction, oil and gas, transportation, military, marine, mining, and high performance racing, and have delivered results for over 40 years.

But what happens when you’re challenge needs more than a cookie cutter solution? In instances such as these, Power Test Custom Engineered Solutions is ready to take your call.  This division aims to identify and solve non-standard problems before delivering custom equipment built to address each and every need for the customer. Our catalog of examples should give you a good scope of projects where we’ve delivered exceptional results.

One of the more profound challenges what we face, is the need to effectively manage the energy involved in a test.  We’ve found that AC Regenerative Technology is an exceptional means to accomplish cost-effective, green, and efficient testing for such circumstances.

In this webinar, our Lead Engineer of the Custom Engineered Solutions Division will walk you through the different types of common testing technologies, give you a synopsis of AC Regenerative Technology and identify some of the key applications of AC Regen.

Different Braking Technologies

The most common braking technology used in Power Test dynamometers is a water brake. Water brake systems use water momentum transform, or shearing, to create a load on a rotational component being testing.  The absorbed power heats the water, which then must either be cooled, or dumped into the sewer. One of the key differentiators between technologies is how the excess energy is dispersed, which makes the regenerative solution so enticing. Water brake systems can be used in applications as small as an electric motor and are effective in testing engines up to 10,000HP.

Eddy current systems are another common testing technology. Eddy current place a load on an engine under test by inducing a magnetic field in a rotating disc. These systems require electrical input to induce the magnetic field, and generate a fair amount of heat as the rotor spins within the magnetic flux. With eddy current brakes, the excess energy is typically displaced via Air-Cooling systems, somewhat limiting their capacity.

The final piece of technology we explore, is AC Regenerative. In an AC Regenerative system an electric motor serves as both the primary mover and the load which the unit under test is held against. The biggest benefit of such a set-up is that the energy created by the mover, isn’t dissipated as heat. Instead it’s absorbed by the AC motor where it is cleanly put back onto a utilities grid; hence the term Regenerative.

AC Regenerative Decision Factors

Why Choose a Chassis Dyno

In this webinar, learn all you need to know about the benefits, of which there are many, to owning your own chassis dyno from Power Test.

For the most part, people intuitively understand the benefits of owning a chassis. It makes sense to test your work before releasing it back to your customer.  But in their experience, chassis dynos are an expensive hassle that never seem to justify their costs. 25 years ago, this assessment may have been accurate. But with advancements in breaking technology, particularly with Power Test’s Eddy Current Chassis Dyno, these testing solutions are now more convenient and economical than ever.

Types of Chassis Dynamometers

Chassis dynos are comprised of a number of key components that make up the foundation of the machine. The first and most important is the absorption technology.  Commonly, water brakes are used as the primary absorption method in chassis dynos, but Power Test’s Eddy Current Chassis Dynamometers provide a clean, inexpensive, convenient alternatives. Whereas water brakes rely on a clean water source, are susceptible to flooding, and have long periods of downtime, the air-cooled eddy current brake is relatively hassle free. An inexpensive electrical connection is all you need to have an effective testing method at your fingertips whenever you need it.

The second most obvious components of a chassis dyno are the rollers. At Power Test we offer a lifetime warranty on our precision rolled 22’ concentric rolls, guaranteeing their quality forever.  Accompany this with our structural steel frames (also guaranteed for life) and our chassis dynos are built to provide durable dependable product performance for you and your customers.

How Do I Know if a Chassis Dyno Makes Business Sense?

Even if you’re confident that a Power Test Chassis Dyno is an effective piece of equipment, I imagine it’s still tough to justify the purchase from a business perspective. Based on conversations we’ve had with past customers and individuals in the industry, we’ve identified some key points that may make you reconsider your position.

  • Chassis Dynos eliminate liability and lost time from road testing.
    • NO CDL license required to test on a chassis dynamometer
    • No traffic jams to get stuck in and zero risk of traffic accidents
    • No drive time to get to areas where you can only partially test engine cooling and performances
    • Immediate ability to re-create performance complaint issue
    • Ability to fully replicate any MPH, RPM, or output load level while recreating a reported issue
    • No Time spend hooking up the trailer
  • Eliminates multiple staff deployed for road testing
    • Allows technicians more time to work billable hours in the shop
    • No second technician needed to read the OEM PC software
    • You don’t have to be on the road!
  • Proper and professional verification of repair
    • Proves that performed services have resolved the customer’s reported issues
    • Increased customer satisfaction with your service organization
    • Significant value add in providing professional reports
    • Instantaneous credibility and confidence in your repair
  • Reduction or elimination of come-backs
    • Reduced risk of warranty coverage
    • Simulates loaded conditions under inaccessible terrain
    • Increase of service volume from referrals
  • Incremental Shop Income
    • Additional performance issues can only be identified on the dyno
      1. These issues may not be found on a normal test drive
    • Former drive time is now replaced with additional billable repair time
      1. Increase in parts sales derived from increased repair time
    • The market allows you to charge for dynamometer testing services
  • Additional Business Benefits
    • Proves to your customers your dedication and ability to efficiently identify and resolve their equipment issues
    • Ability to test used trucks prior to accepting them in a trade
    • Dynamometer testing services for outside organizations, including your competition
    • Provides a direct benefit to used truck business
      1. Properly assess trade in values
      2. Tout it as a value add during the sale

These benefits may seem abstract, but at Power Test we’ve seen it in action more times than we can count. Contact us to go through our Cost Calculator, where we work through specific examples of your shop to prove to you that a Chassis Dyno is not a purchase, but an investment.

Why Choose a Chassis Dyno?

For the most part, people intuitively understand the benefits of owning a chassis dyno. It makes sense to test your work before releasing it back to your customer. But in their experience, chassis dynos are an expensive hassle that never seem to justify their costs. 25 years ago, this assessment may have been accurate. But with advancements in breaking technology, particularly with Power Test’s Eddy Current Chassis Dyno, these testing solutions are now more convenient and economical than ever.

This quick video explores the basic technologies common in chassis dynos and dives into how Power Test can provide a system that earns you money in the short- and long-term.



Here are some key considerations that are reviewed during the presentation:

1.) Chassis Dynos eliminate liability and lost time from road testing.
2.) Eliminates multiple staff deployed for road testing
3.) Proper and professional verification of repair
4.) Reduction or elimination of come-backs
5.) Incremental Shop Income

At Power Test we’ve seen it in action more times than we can count. Contact us to go through our Payback Calculator, where we work through specific examples of your shop to prove to you that a Chassis Dyno is not a purchase, but an investment.