{"id":9937,"date":"2015-05-19T10:22:39","date_gmt":"2015-05-19T17:22:39","guid":{"rendered":"http:\/\/cafe.foundation\/blog\/?p=9937"},"modified":"2015-05-26T23:24:05","modified_gmt":"2015-05-27T06:24:05","slug":"singapore-firm-boeing-team-hydrogen","status":"publish","type":"post","link":"http:\/\/cafe.foundation\/blog\/singapore-firm-boeing-team-hydrogen\/","title":{"rendered":"Singapore Firm, Boeing Team Up on Hydrogen"},"content":{"rendered":"

EV World<\/em> reports<\/a> that a Singapore-based company, Horizon Energy Systems, has test flown the world\u2019s first hydrogen powered quadracopter, a small UAV that is claimed to fly for hours, instead of the minutes a lithium battery pack would provide.<\/p>\n

The report asks that tantalizing question for all who suffer from range anxiety, especially while in flight.\u00a0 \u201cWhat if you could increase flying time by a factor of ten? Instead of half-an-hour, you could keep the UAV flying for five hours, and then charge it in a couple minutes time? That’s what Singapore-based Horizon Energy Systems is promising. They have developed micro fuel cells that can be fueled by\u00a0three types of hydrogen storage systems<\/a>\u00a0from small compressed gas cylinders to ‘on-demand’ hydrogen generation chemical cartridges rated at 700 Watt-hours per kilogram (Whr\/kg), significantly higher than the best lithium batteries.\u201d<\/p>\n

\"Horizon's<\/a>

Horizon’s Hycopter can fly up to four\u00a0hours on a dollop of hydrogen<\/p><\/div>\n

Horizon\u2019s Hycopter micro UAV quadracopter stores 120 grams (0.26 pounds) of hydrogen in its structure, equivalent to three kilograms (6.6 pounds) of lithium batteries. According to EV World, \u201cSince the Hycopter has less weight to lift, it can fly longer: the company claiming up to four hours of flight time.\u201d<\/p>\n

As noted above, Horizon Energy Systems produces three different approaches to storing H2:<\/p>\n

    \n
  1. Gaseous fuel storage of compressed hydrogen. This option costs $1 per hour for 200 Watts, and offers the least system complexity if there is enough room in the airframe to accommodate the tanks.<\/li>\n
  2. \u201cOn demand\u201d hydrogen generation using liquid chemical cartridges. This option offers the same energy available but in half the volume of the tanks of compressed H2.\u00a0 It\u2019s also slightly lighter and \u201closes\u201d the weight of fuel as it is consumed.\u00a0 This, of course, would be important in a small UAV, which might weigh no more than a few pounds.<\/li>\n
  3. \u201cOn demand\u201d hydrogen generation using solid chemical cartridges. Horizon explains that there are no catalysts required, and the chemicals offer unlimited storage duration.<\/li>\n<\/ol>\n

    From their specification sheet<\/a>, we see that a one kilowatt AeroStak system, complete with controller, would weight 2.25 kilograms, or 4.95 pounds.\u00a0 The system also requires an external 36 Volt power supply. Stack size of the 50-cell unit is 252 x 126 x 190 millimeters (9.92 x 4.96 x 7.48 inches).\u00a0 Advertised as \u201c10 times lighter and smaller than other Horizon fuel cells,\u201d how do Aerostaks stack up against lithium-ion batteries?<\/p>\n

    Your editor chose to make a 10 kW stack as a comparison unit for the Eck-Geiger lithium-ion battery pack used in many ultralight motorgliders, such as the Swift.\u00a0 10 one-kW stacks could be arranged as a block about 10 x 15 x 7.5 inches, or possibly in a string that could be 100 x 5 x 7.5 inches, or in other configurations that would fit into an airframe.\u00a0 We\u2019ll stick with the first arrangement, since that comes close to the Flytec\u2019s battery module size.<\/p>\n

    Using Horizon\u2019s ratio of 0.26 pounds of hydrogen equaling 6.6 pounds of lithium batteries (energy density unspecified), it would take about 2.16 pounds of stored H2 to equal a Flytec 100 Amp-hour battery pack weighing 25 kilograms (55 pounds), according to Flytec\u2019s 2015 listings.<\/p>\n

    This would give over an hour\u2019s flight, based on Gerard Thevenot\u2019s flight across the English Channel in 2009.\u00a0 His La Mouette hang glider used the Eck-Geiger HPD-10 motor and consumed 550 grams, or about 1.3 pounds of hydrogen per hour.\u00a0 2.16 pounds of H2 would have provided 1.66 hours of flight, a comfortable margin for that 22-mile trip.<\/p>\n

    It\u2019s hard to judge whether the Horizon systems would give a 10-fold increase in endurance over batteries \u2013 the numbers don\u2019t seem to indicate quite that, but the system does allow clean running, even though at this point, possibly higher operating costs than lithium batteries.\u00a0 Their quoted $1 per hour for 200 Watts would equal $50 per hour for the full output of a 10 kW motor.<\/p>\n

    Such stacks and their attendant hydrogen-generating systems could be used as the sole means of powering an aircraft, or possibly in conjunction with a conventional battery pack as a range extender.\u00a0 Depending on unit cost and availability, Horizon Energy Systems\u2019 packs may provide an alternative worth exploring, although one may be tempted to find a cheaper fuel source.<\/p>\n