Hydrogen From A to Z: T for Thermal Insulation
By: GenH2 Staff
Read Time: 3 minutes
Continuing on in our defining the Hydrogen economy from A to Z series, we are focusing on the letter T and discussing Thermal Insulation, a critical part of Cryogenics and the whole of Hydrogen.
In the field of cryogenics, dealing with the effects of heat transfer is a constant challenge. Referencing Cryogenic Society of America, Cold Facts article by Robert S. Bell, thermal insulation is imperative. According to the Cryogenic Heat Management book just published by Fesmire and co-authors, Thermal Insulation Systems are the first line of defense in managing heat leak into cryogenic systems. Until thermal insulation technology was developed, there was no method of significantly slowing the heat flux from the outside world to a liquid cryogen. To minimize heat leaks and product loss, high-performance insulation materials and systems are needed to provide high levels of thermal isolation.
In the beginning, early researchers were able to produce mists of the common cryogens (oxygen and nitrogen), but the massive heat loads from the surrounding environment never allowed for suitable quantities of liquids to be stored and studied. However, in 1892, a spectacular invention by chemist and physicist, Sir James Dewar at the Royal Institution of Great Britain, changed everything. Dewar developed the vacuum flask, a double‐walled container, constructed with reflective surfaces and insulated by an intervening vacuum. Commonly referred to as a “dewar,” the vacuum flask is widely considered one of the most important discoveries in the history of cryogenics. The vacuum plus reflective shield system, or dewar, was, and still remains, the prime enabling insulating technology in the field of cryogenics today. However, it should be understood that vacuum insulation is not always possible in some situations. In other cases, vacuum is not required in a cryogenic system, depending on the type of cryogenic liquid or the storage and transfer requirements. There are several applications where the cost, weight and complexity of a vacuum system are not permissible; in these cases, aerogel-based thermal insulation systems can provide the optimum performance.
Thermal insulation materials and systems can take multiple forms, bulk filled like perlite or glass bubbles to foam and multiple layered insulations (MLI) concepts which are being significantly advanced over the last decade. These multi-layered advances include a variety of aerogels, aerogel blanket composites, hybrid aerogel-multilayer insulation (MLI) composites, layered composite insulation (LCI), layered composite extreme (LCX), prefabricated MLI, discrete spacer MLI, new structural composites, aerogel-foam composites, vacuum panels, and more. The complete thermal characterization of insulation materials is a key part of enabling the development and incorporation, use of efficient, low-maintenance cryogenic systems. The choice of insulation or the combination of insulation systems depend upon performance requirements and the size, types of storage tanks used for the application. Every mechanical part, component, instrument, wire and/or structure must address the heat transfer requirements of low temperature systems in the surrounding area. Understanding heat transfer mechanisms through novel insulation materials has led to GenH2’s development of the Cryostat CS-900, a multipurpose platform for the testing of materials, composites, and tanks with liquid hydrogen. This core testing technology will further advance controlled storage systems for liquid hydrogen with zero product loss and ease of liquid transfer.
GenH2’s controlled storage system takes advantage of innovative approaches to insulating, refrigeration and design. The energy savings are a fundamental underlying benefit for this technology combination by simultaneously saving hydrogen and energy. In effect, the solution is a combination of active and passive forces. Refrigeration and Insulation are both equally important. The refrigeration element of this process can be cooling the liquid and/or liquefaction of the gas. This combination now makes storing liquid hydrogen safe and efficient, offering substantial commercial benefits.
GenH2’s development of specialty equipment for thermal insulation design, simulation, testing and evaluation, allows us to support the management and control of heat in hydrogen liquefaction, storage and transfer which will meet the infrastructure needs required to ensure the hydrogen economy thrives.
Please follow us next week as we discuss Turbo-expanders, another important component of the Hydrogen economy value chain.
