Composites World Magazine has referred to the liner-less, Type 5 (Type V) fuel storage tank as “the pressure vessel industry’s Holy Grail." While there have been some aerospace companies who have successfully developed a “liner-less” tank, they are often small scale with low operating pressures; most tanks are less than a foot in diameter with an operating pressure of less than a 1,000 pounds per square inch (psi). These tanks are effective in small aerospace applications, such as cube satellites, and other applications where weight savings is key. An example from the link above is Composite Technology Development Inc.’s (CTD) tank design for 1.9L of argon gas storage, with a burst pressure of less than 2,500 psi.
So what are the benefits of going liner-less? Why is this technology perceived as the “Holy Grail” of the pressure vessel industry? Two simple, but important reasons: weight and capacity.
Weight is not a key metric for everybody, but for the companies or users that are weight sensitive, it could translates to millions of dollars saved in the long run. Let’s take the newly emerging space market including Orbital Science Corporation and SpaceX. Their first rocket launches came with a price tag of roughly $40,000 per pound of cargo sent into space. While this number has improved, they are still targeting a price of $10,000 per pound! This means that every pound of weight saved will result in tens of thousand of dollars in savings or the ability increase revenue through additional payloads.
In addition to the aerospace industry, the weight savings in heavy and medium-duty vehicles can result in a large savings and/or an increase in revenue for the CNG industry. For example, a cement mixer or a garbage truck can only legally carry a set amount of weight. When a CNG fuel system is added to a vehicle, it increases the overall tare weight of the truck. This increase in fuel system weight results in a loss of cargo the vehicle can carry. What if a company were able to reduce the Type III system with a liner-less, Type V fuel tank system, and reduce the fuel system weight by up to 40 percent? Such a reduction in weight would not only increase cargo potential but can improve fuel economy, adding further to the fleets or vehicles bottom line. It is important to note that every 100 pounds added to a vehicle can reduce fuel economy by as much as 2 percent.
The other major advantage of a liner-less design is capacity. Traditionally, Type III and Type IV tanks reduce the weight of Type I and II tanks by incorporating a full fiber reinforcement that holds most of the pressure. The liner, plastic or metal, is still necessary for use as a permeation barrier, to prevent the gas from escaping. Unfortunately, the liner adds weight and reduces storage capacity because it takes up internal volume. With range anxiety being a common issue among natural gas vehicle owners, any extra capacity is valuable.
CleanNG has been developing a liner-less pressure vessel even before it was founded in 2010. Prior to the CleanNG’s MagnumCel, there has never been a high-pressure, scalable solution to save weight and increase fuel storage capacity for high pressure applications. CleanNG is the first liner-less design to acquire Department of Transportation approval.
If your company or vehicle is focused on cargo transportation, fuel economy, saving fuel costs, reducing emissions output, or fuel capacity driven; CleanNG’s MagnumCel is the tank for you.