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Sunday, June 15, 2025
Wednesday, June 4, 2025
Why Liquefy Hydrogen?
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| Source: "Liquid Hydrogen Systems Course", Moran, 2025. |
No Free Lunch (But Keeping it Chill Has Some Benefits)
It takes energy to store hydrogen whether it's liquefied, compressed, converted to/from another carrier fluid, or absorbed/adsorbed in a solid state material. So when does liquefaction make sense as the storage method of choice?
The answer lies in a properly executed systems engineering analysis and design trade study for the application being developed. There are a few key features and capabilities of liquid hydrogen (LH2) systems that come into play when comparing options:
- Higher volumetric density
- Lower pressure storage
- Higher storage mass fraction
- Cooling capacity
- Pressurization capability
The first three have been discussed in previous posts, and are the reason why so many mobility applications are using or contemplating LH2. These characteristics also increase in importance for large scale applications such as maritime, rail, long-distance trucking, offtake and fueling infrastructure, delivery and export, etc.
However, the last two capabilities are often underappreciated or ignored by those not experienced with cryogenic systems. The cooling capacity and self-pressurization benefits of LH2 are used in a variety of ways in a properly designed system.
Both of these capabilities can effectively recover some of the energy expended during liquefaction, a fact that many reports and studies tend to ignore. State-of-the-art liquefaction plants require about 10 KWh of input energy per kg of liquefied hydrogen, and conceptual plant designs are expected to bring this down by more than 50% (see below). But part of that energy is still accessible in the stored LH2 for those who know how to use it.
A Cool Thing to Have Around (And Who Needs a Compressor)
The cooling capacity of LH2 can be used in heat exchangers to reject heat from other subsystems; maintain structures below their maximum temperature limits when subjected to high heat loads; or keep superconducting components at the required cryogenic temperature. This can all be done as part of the warming process of a hydrogen stream being fed to a fuel cell or engine.
Cooling is also available through the Joule-Thomson effect which can be produced using a pressure drop device with LH2 or GH2 below 200 K (e.g., orifice, valve, etc.). Another cooling mechanism unique to hydrogen is the endothermic reaction of the para-to-ortho conversion that can be catalyzed in a vaporized hydrogen stream.
And when it's time to pressurize a hydrogen system, the LH2 will do the job with no input power needed. Metering a small amount of LH2 into an isolated volume and allowing it to vaporize and warm results in any pressure required if done properly. This "pressure-building" method has been widely and routinely used for decades in LH2 systems of all sizes and types. No compressor or compressed gas needed.
It all comes down to knowing how to make cryogenics work in your favor. And the first law of thermodynamics is where to start (see below). Applying good systems engineering can uncover a great deal of overall efficiency improvements keeping this fundamental equation in mind.
Author Bio
Matt Moran is the Managing Member at Moran Innovation LLC, and previous Managing Partner at Isotherm Energy. He's been developing power and propulsion systems for more than 40 years; and first-of-a-kind gas, slush, and liquid hydrogen systems since the mid-1980s. Matt was also the Sector Manager for Energy & Materials in his final position at NASA where he worked for 31 years. He's been a cofounder in seven technology-based startups; and provided R&D, engineering, and innovation consulting to several hundred organizations. Matt has three patents and more than 50 publications including his online Cryogenic Fluid Management guide and Decarbonizing Mobility with Liquid Hydrogen SAE report. He has created and taught liquid hydrogen courses, webinars, and workshops to global audiences.
Monday, June 2, 2025
New Tools for LH2
After 40 years of developing cryogenic liquid hydrogen (LH2) technologies and systems for many organizations, it's time for a significant business pivot at Moran Innovation. The global community needs more widely available tools and resources to move faster on decarbonizing our energy usage with hydrogen. And your help is needed to ensure that that these new LH2 tools and resources meet your most critical needs and solve your most pressing problems.
The first building block of this pivot is a new cryogenic liquid hydrogen systems book under development with a leading publisher. The focus is on the knowledge needed to develop operational systems and technologies for emerging applications. A holistic perspective addresses engineering, business, and strategy aspects of successful integration and deployment of innovative cryogenic hydrogen systems. What topics would you like to see addressed in this book?
The second building block is development of an online software as a service (SaaS) portal. It will contain integrated tools and resources to enable faster planning, development, and launch of new LH2 systems. The focus is on learning, innovating, creating, building, operating, leading, and strategizing. All content will be created, curated, verified, and validated based on subject matter expertise to provide the highest quality information and results. What specific tools and resources would be most useful to you in this online portal?
Please let me know your thoughts on the book and portal by whatever communication method is most convenient. Thank you for any feedback you can provide, and let's continue creating a better future together with hydrogen!
Author Bio
Matt Moran is the Managing Member at Moran Innovation LLC, and previous Managing Partner at Isotherm Energy. He's been developing power and propulsion systems for more than 40 years; and first-of-a-kind gas, slush, and liquid hydrogen systems since the mid-1980s. Matt was also the Sector Manager for Energy & Materials in his final position at NASA where he worked for 31 years. He's been a cofounder in seven technology-based startups; and provided R&D, engineering, and innovation consulting to several hundred organizations. Matt has three patents and more than 50 publications including his online Cryogenic Fluid Management guide and Decarbonizing Mobility with Liquid Hydrogen SAE report. He has created and taught liquid hydrogen courses, webinars, and workshops to global audiences.
Friday, May 30, 2025
Transfer of Liquid Hydrogen
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| Effect of LH2 Injection Method on Receiving Tank Pressure and Temperatures [1] |
Distribution costs are driven by the delivery modes chosen. For scenarios where LH2 is produced onsite and transferred to a nearby or onsite storage or fueling facility, vacuum-jacketed transfer piping, valves, fittings, pumps, and other necessary equipment to support draining and filling of storage tanks are required.
For offsite ground transport, a fleet of trucks and LH2 trailers are needed to meet delivery frequency. Interface systems for loading or offloading are also required at all distribution sources and delivery locations. Rail service may be an alternative ground transport option for some locations subject to similar requirements for mobile storage, delivery schedules, and interface systems. Shipping by barge or tanker ship is an option where port infrastructure is in place to support loading and offloading.
The currently dominant LH2 distribution paradigm involves liquefaction plants owned and operated by a few incumbent companies (e.g., Air Liquide, Linde, and Air Products). LH2 produced at these facilities is primarily distributed to large, existing customers in over-the-road trailers. Delivery by barge and train is less common. In some cases, the customers’ LH2 receiving and storage system is leased from the provider.
This distribution approach is growing in popularity as more customers ramp up their LH2 usage. Additional distribution scenarios and providers are also coming online to meet various LH2 customer requirements for new applications, locations, quantities, and delivery frequencies. Smaller and more modular liquefaction systems have become commercially available to provide capabilities as needed. Small scale liquefaction is particularly in demand for mobility applications that are under development. As these applications scale up in the market, reliable but flexible LH2 distribution will be critical to ensure commercialization success.
For very large-scale, intercountry distribution, new import–export trade deals are being implemented in some global markets. Regions with an abundance of renewable energy and feedstock resources can produce, liquefy, and export LH2 to regions with high demand that have more constrained or costly production resources.
Conversely, island nations and other remote or isolated regions can combine the entire production, liquefaction, delivery, and end use in one location. This unique characteristic of hydrogen relative to fossil fuels eliminates the need for long-distance distribution altogether. Other hybrid approaches are also being developed, such as distribution of gaseous hydrogen via pipelines to be liquefied onsite at the point-of-use.
Thermal management of LH2 and mitigation of boil-off throughout the delivery pathways is critical to minimizing hydrogen loss and associated costs. Identifying the appropriate options to mitigate boil-off losses requires systems engineering to identify the best trades for a particular use case.
References
[1] Image source: Liquid Hydrogen Systems Course, 2025.
[2] Text source: Decarbonizing Mobility with Liquid Hydrogen, SAE Research Report, 2024.
Author Bio
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