Wave pools have progressed just in the short time that we have been tinkering with them. And looking back, you can almost pinpoint the ‘era’ a wave generator was built. Like automobiles being distinguished to a particular decade by a gearhead.
We start with the originals, the Venus grotto pool by King Ludwig II of Bavaria or the 1929 Munich pool. These utilized simple mechanisms to create pools that simply wanted to have moving water. Then came the pump-n-dump wave pools—think Big Surf and Typhoon Lagoon. Enough water and form to ride a surfboard on.
After, came the hydrofoil—KSWCo and WaveGarden 1.0. This technology changed the game and allowed engineers to create the first artificial barrel. Now, pneumatic systems seem to be the craze—Wave Source, Endless Surf, AWM, and Surfloch. This is not to say previous models are obsolete, but rather, this is the evolution of wave machines. Pneumatic technology is the most customizable to date, allowing a controller to create various types of waves on the fly
We are in the age of pneumatic systems
Wavegarden has a concise layout for wave systems on their website. Every system can simply be deduced to 5 main components. Energy → motor → power delivery system (pneumatic/hydraulic/electromechanical) → wave generator (paddle/plunger/caisson) → wave. We will be comparing the ‘power delivery system’ portion of wave generators. Here is where pneumatics play a part.
Pneumatic systems create power with a compressible fluid (commonly air) compared to hydraulic systems that create power with an incompressible fluid (commonly oil). Electromechanical systems transmit power through mechanical linkages—gears, levers, belts, etc. Across industry, pneumatic wave generators can be simplified into four parts. There is a blower, caisson (large box to be filled with air or water), valve, and release vent. These four components essentially create a giant piston that moves water.
The blower will fill the caisson with air at a higher pressure than water. Combined with the valve, this prevents water from entering. Air is then released through a vent, the valve opens and causes water to fill the caisson. This suction forms the trough of a wave. Water then rushes out of the caisson, with help from the blower, and forms the peak of the wave. The cycle repeats. Again, this is a very simplified explanation. System designs and actuation vary widely from company to company.
Because the fluid is compressible, pneumatic systems have inherent energy inefficiencies.
Air leaks more than oil. Or, in the case of electromechanical machines, no energy is lost through fluids. This is usually during compression and heat loss. The compressible fluid limits pneumatic systems from producing more force. In hydraulic systems, because the fluid is incompressible, it can handle larger loads with ease. The same goes for electromechanical machines. By designing pneumatic systems with more caissons, the load burden is distributed.
A lot of the beginning energy is also converted to heat, which is lost to the environment. Blowers get hot, constantly running and maintaining the pressure. These must remain on during wave sets, refilling the caissons for the next firing. Blowers, which are the power delivery backbone for pneumatic systems, have a general efficiency range of 60%-80%. This varies based on the design of the blower and the amount and size of the waves being produced.
When compared to electromechanical systems, pneumatic technologies are generally less efficient and actuate slower. It takes time to fill the caisson and run through an ‘engine’ cycle, as opposed to directly activating the wave generator (paddle, foil, plunger). It doesn’t go without noting that every part of a system is constantly being iterated by engineers to improve efficiency. For example, combining off-grid energy with pneumatic systems is one way to counter the energy problem. This is already being done with The Wave Source LLC and could become standard with pneumatic systems.
On the other hand, there are benefits. Pneumatic systems require the least amount of parts, making them relatively easy to build with lower upfront costs. Because they have fewer parts, there are fewer chances for things to break down. Fewer things to wear out. And when they do, the system will likely still operate. Pneumatic systems are designed to have multiple caissons. So when one is inoperative, the other caissons can pick up the slack, allowing waves to still flow. Parts that need maintenance operate out of the water and are easily accessible. No draining required. This plays into having low preventative and reactive maintenance expenditures for the lifespan of the machine. But because of energy inefficiencies, it may have a higher running cost because of energy consumption.
Older pneumatic technology used to be slow, but when combined with quick-response valves, actuation is fast. Pneumatic systems are generally utilized for fast movements and lighter loads. By adding more caissons, less work must be done by individual caissons. This shortens the time to fire another wave and also aids with the customization of a wave. Like keys on a piano. More notes (or caissons) allow for more complexity. This is probably the most notable feature of pneumatic systems.
Pneumatic systems may not provide as much power as hydraulics or be as fast and energy efficient as electromechanical systems. But their attractive quality lies in their simplicity. Powerhouses being built from few parts that can outlast for a fraction of the cost.
Pneumatic wave machines have established an era within wave generating technology. An era distinguished by showing that we can create nearly any type of wave, instantly, from a single machine. It is proven technology that has served as the catalyst for commercial viability and expansion. Contributing to about 10 out of 30+ commercially operational surf parks. They have attracted more attention from investors and real estate developers than any of their predecessors.
Iowa-born Jamison Dierenfield discovered surfing while attending Hawai’i Pacific University. Fascinated by wave machines, he later earned a Mechanical Engineering degree from Iowa State University. After working at NLand in 2018 and engineering fire sprinkler systems in Arizona, Dierenfield is transitioning into surf parks, aspiring to biomimetically design wave-making technology.
