MechChem Africa October 2018

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Ben Stafford: materials science expert for the online material search platform, Matmatch Superconductors for electrical transportation

Industry diary November Health and SafetyManagement: ISO 45001 – Lead Auditor 12-16 November 2018 Midrand, Gauteng, donnavin@crestadvisoryafrica.com nico@crestadvisoryafrica.com As pressure increases to reduce emissions in transport, HTS won’t just offer improve- ments on conventional devices but will be- come a key-enabling technology for electric transportation. q craft are already in full swing, with multiple companies working on prototypes including Airbus, Wright Electric and Zunum Aero. These are mostly hybrid concepts, which will demonstrate electrical machines working in tandemwithturbineenginesforpropulsion.In sucha configuration theHTSmotors are likely to make significant contributions. NASA has laid out plans to develop the N3-X aircraft. This should provide a 70% re- duction in fuel consumptionby using two gas- driven HTS generators to power distributed HTS motor-driven propulsion fans. Despite the advantages, in reality the adoption of HTS in propulsion has been slow. Most probably this is down to the complexi- ties of the technology and the associated de- velopmental costs. Nevertheless, the advancements made in exploitingHTSmaterial properties since their discovery in the80s has been immense. Effort is still required to implementHTSmotors on a large scale, yet, especially in the case of avia- tion, ambitious development goals havenever stood in the way of progress.

B ased on the public concern for green- house gas emissions, global sales of electric vehicles (EVs) are surging. Transport produces 14% of global emissions but this isn’t confined solely to road vehicles; inter- national aviation and shipping each account for more than 2.0% of the emission’s total. The big difference between the electrical motors required for aircraft and shipping compared to those for EVs is that they have much more extreme requirements in terms of weight and power output. So conventional electricmotors composed of copper, iron and permanentmagnets, which suffice for electric cars, just won’t do if wewant to get an airliner off the ground. High-temperature superconductors (HTS) are, however, making high power, lowweight motors possible. HTS materials lose their electrical resistancebelowa superconducting transition temperature. For conventional superconductors, transi- tion temperatures are so low that they usu-

ally need to be cooled using liquid helium at -269 °C. HTS on the other hand operates at comparatively high temperatures and can be cooled at -196 °Cusing liquid nitrogen, which is a cheap and abundant coolant. Multiple manufacturers have developed methods for producingHTS conductors, thepriceofwhich is already approaching that of copper. So how do HTS fit into the world of transport? One of the main constraints in constructing ever-larger cargo ships is the size and complexity of the propulsion system. Electric ship propulsion has been around since the 19 th century but mostly limited to small vessels. HTSwire can conduct the same current as a copper cable through about one tenthof the cross sectional area. Sowhen used to replace copper windings and permanent magnets, HTSwire offers a huge volume reduction and much strongermagneticfields canbe created. This enables much more compact and higher power electric motors to be produced. Another major advantage of replacing copper with HTS in motors is the absence of resistive heating during operation, meaning thatmuch less cooling power is requiredonce the superconductor is below its transition temperature. The cryogenic system required tocool the rotatingHTSwindings is, of course, a major technical challenge, but engineers have largely resolved this problem. Over the past few decades, several manu- facturers have been constructing and testing powerful HTS motors with the high torque required for marine propulsion. Siemens, for example, has demonstrated aHTS-basedmo- tor with a power of 4.0 MW, while American Superconductor Corporation (AMSC) has developed a 36.5 MW system. When it comes to aviation, electric aircraft seem even more far-fetched than electric ships. Theworkput intoHTS shipmotors over theyears,however,hasdemonstratedthatthe advantages HTS bring to motor technology are just as or even more suitable for aviation. Aircraft have stringent weight require- ments, which is evident in the industry’s in- terest in additive manufactured components along with some less well-known solutions such as the Japanese airline that is asking passengers to relieve themselves before boarding. Reducing weight reduces fuel consump- tion, which is not only essential for reducing emissions but it is also a massive financial driver. Add to that the benefits of reduced noise and air pollution, the electrification of aviation becomes very attractive to the industry. Developments for passenger electric air-

Photo: NASA / Lillian

NASA plans to build a series of X-planes fuelled by green energy, among which is the N3-X aircraft.

2018 SAEEC Conference Emperors Palace, 13-14 November. The Southern African Energy Efficiency Confederation (SAEEC) Conference is an energy event of national scope for end-users and energy professionals in all areas of the energy field. It is the one truly comprehensive forumwhere the big picture can be fully assessed: exactly how all the economic and market forces, new technologies, regulatory developments and industry trends merge to shape the critical decisions for our energy and eco- nomic futures. The 2018 SAEECConference features a conventionagendawithseminars andex- hibition on a variety of current topics and will be post-validated for CPD points by the SAIEE in accordancewithECSApolicy. The 13 th SAEEC Conference will take place on 13 and 14 November 2018 at Emperors Palace, Ekurhuleni, Gauteng, South Africa. www.saee.org.za

PumpEfficiencyandReliability:HarryRosen 19-21 November 2018,

Graceland Hotel, Secunda, 2KG Training, Phindi Mbedzi +27 11 325 0686, +27 71 125 6188 phindi@2kg.co.za

Altair Engineering.......................................................................28 AxiomHydraulics........................................................................32 BI........................................................................................................16 Bonfiglioli.................................................................................... IBC Cape Union Mart.......................................................................8, 9 Engen...............................................................................................23 Festo............................................................................................ OFC Grundfos.......................................................................................IFC Hägglunds......................................................................................39 Marthinusen & Coutts..............................................................21 Mixtec.........................................................................................OBC Multotec.........................................................................................37 Omron.............................................................................................45 ROSE Foundation........................................................................20 SEW..................................................................................................12 Solar Mining Services.................................................................. 3 Zest WEG Group.........................................................................43 Index to advertisers

48 ¦ MechChem Africa • October 2018