![\"20151026_134233\"](\"https:\/\/wpcdn.web.wsu.edu\/wp-hub\/uploads\/sites\/1121\/2015\/09\/20151026_134233-396x223.jpg\")
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Left to Right:\u00a0Cameron Stone – Greg Wallace – Nathaniel Jones – Riley Howard – Will Wilber<\/p>\n<\/p><\/div>\n<\/section>\n Compressors have been the Achilles heel of hydrogen refueling stations worldwide.\u00a0Our team intends to change that. Instead of a typical 10,000 psi compressor we are going after a reasonable 1400 psi. This is attainable thanks\u00a0to our patent pending vortex tube\u00a0system.<\/strong><\/p>\n <\/p>\n <\/p>\n<\/p><\/div>\n<\/section>\n One of the biggest faults in previous hydrogen refueling stations has been the compressors. To pack enough hydrogen into a small tank, hydrogen powered cars use high pressure gas tanks as storage. Current models of cars use 10,000psi tanks, so refueling stations must produce hydrogen hydrogen at that pressure. Conventional stations use only compressors to achieve this. But at such high pressure, mechanical failures are common, causing excessive down time and costly repairs. Our method of compression through liquefaction is intended to minimize this risk by using low pressure compressors. The compressors drive the liquefaction process, providing enough pressure for the vortex tube and throttle valve to operate. These will liquefy the hydrogen which can be boiled to produce pressures even higher than 10,000psi.<\/p>\n <\/p>\n<\/p><\/div>\n<\/section>\n Most\u00a0hydrogen compressors (especially for refueling stations) operate via piston, scroll, or diaphragm.\u00a0The various types of compressors and their advantages are as followed:<\/p>\n Piston Compressor<\/strong>\u00a0[More Info<\/a><\/span>] \u2013 Uses a piston to compress fluid. A design that has been tried again and again, and that can be made as simple or complex as needed. \u00a0They are efficient and can be made in large sizes, but tend to be costly and have many moving parts.<\/p>\n Diaphragm<\/strong>\u00a0Compressor<\/strong>\u00a0<\/strong>[More Info<\/a><\/span>]<\/span> \u2013 Instead of a piston, this uses a flexing diaphragm to manipulate\u00a0pressure. \u00a0Metal-based diaphragms are low volume but high pressure. \u00a0Rubber\/Silicone diaphragms are high volume, low pressure and need replacement often.\u00a0 The drive fluid can be lubricated without risking contamination of the working fluid.<\/p>\n Scroll Compressor<\/strong>\u00a0[More Info<\/a><\/span>] \u2013 Uses one fixed and one moving spiral. \u00a0The moving spiral orbits the other, but does not rotate, to push fluid against the non-moving spiral to create suction and compression. \u00a0These are quiet, smooth, and reliable, especially at lower volumes. \u00a0They have fewer moving parts but are highly susceptible to debris (which should not be present in our system).<\/p>\n Centrifugal Compressor<\/strong> [More Info<\/a><\/span>] – Use a high speed impeller and a diffuser to increase the pressure of a gas.\u00a0 These are similar to gas blowers, but operate at much higher velocities and pressures.<\/p>\n Ionic Liquid\u00a0Piston Compressor<\/strong>\u00a0[More Info<\/a><\/span>] \u2013 Acts similarly\u00a0to\u00a0\u00a0piston compressor, but uses an ionic liquid rather than a metal piston. \u00a0These have very few parts and are long lasting.\u00a0 These produce very little waste heat.<\/p>\n Electrochemical hydrogen compressor<\/strong>\u00a0[More Info<\/a><\/span>] \u2013 \u00a0Uses electricity to separate hydrogen into protons and electrons and force them across a membrane.\u00a0 They can maintain high pressure, are compact, uses no moving parts, and has good efficiency.<\/p>\n Hydride Compressor<\/strong>\u00a0[More Info<\/a><\/span>] \u2013 Absorbs hydrogen ions at low temperature and pressure and expels them at high pressure when heated. \u00a0High volume flow rate with no moving parts, but are expensive and heavy and high amounts of produce waste heat.<\/p>\n Gas Booster <\/strong>[More Info<\/a><\/span>] – Takes compressed air and creates compressed gas through pneumatics. A large cylinder is actuated with 90psi air. This pushes on a smaller piston for the working gas. Since force = pressure x area, the smaller piston creates a higher pressure than that which was applied on the larger one, at the expense of flow rate. This requires a large volume of compressed air, but is cheaper to buy than an specialized hydrogen compressor.<\/p>\n <\/p>\n Some compressor systems have been studied and tested to great lengths. Others are\u00a0barely\u00a0in research and development. Since we will not have the time or funding to create a compressor from scratch, we are limited to more established methods of compression: piston, scroll, diaphragm, or centrifugal. The most efficient method for us\u00a0is to chose a pre-developed compressor from a company that specializes in their construction.<\/p>\n <\/p>\n<\/p><\/div>\n<\/section>\n The compressor takes in hydrogen from two components: the \u201chot\u201d gas expelled from the vortex tube and excess hydrogen from the storage tank. This injects the hydrogen back into\u00a0the pre-cooling cycle and the vortex tube where it will be liquefied and then stored. To maximize system efficiency,\u00a0the following are our requirements:<\/p>\n <\/p>\n<\/p><\/div>\n<\/section>\n Finding an adequate compressor within our budget has been difficult. Few pre-designed compressors fit our specifications. Instead, would most likely need<\/p>\n an expensive custom-built compressor. Until that problem is solved, we will focus on using gas boosters, which are already available for accomplishing our goals. For our proof of concept, we will use a lower flow rate than our initial plan, but this can be driven with two Haskel<\/a><\/span> gas boosters we already own:<\/p>\n Haskel AGD-15<\/strong> (Single Stage, Double Acting) – 1,400psi stall pressure<\/p>\n Haskel AG-152<\/strong> (Single Stage, Single Acting) – 13,500psi stall pressure<\/p>\n Both were inherited by the HYPER lab after use in previous projects. They are being repaired to ensure safety and efficiency. While gas boosters are not as efficient as direct compression, they are currently available on the market and are cheap to buy. Until a compressor is found which fits all our needs, we will continue using gas boosters. The following are the compressor companies we have been in contact with:<\/p>\n RIX [RIX Industries<\/a><\/span>] – Piston Compressors<\/p>\n Air Squared\u00a0[Air Squared<\/a><\/span>] – Scroll Compressors<\/p>\n Hydro-Pac\u00a0[Hydro-Pac Inc.<\/a><\/span>] – Piston Compressors<\/p>\n Sundyne\u00a0[Sundyne<\/a><\/span>] – Centrifugal and Diaphragm Compressors<\/p>\n<\/p><\/div>\n<\/section>\n With the\u00a0hydrogen sufficiently compressed and the gas flowing as needed, it can finally move on to the next stages. All the output of the compressor will next go through a heat exchanger system<\/a><\/span> to remove excess heat and then move on to the pre-cooling system<\/a><\/span>.<\/p>\n <\/p>\n <\/p>\n<\/p><\/div>\n<\/section>\n","protected":false},"excerpt":{"rendered":"Background<\/h2>\n<\/header>\n
Compression Methods<\/h2>\n<\/header>\n
![\"scroll](\"https:\/\/hydrogen.wsu.edu\/wp-content\/uploads\/sites\/44\/2015\/09\/scroll-compressor-better-396x93.png\")
<\/a>![\"\"](\"https:\/\/upload.wikimedia.org\/wikipedia\/commons\/2\/25\/Electrochemical_Hydrogen_Compressor_Theory.svg\")
<\/a>Design Specifications<\/h2>\n<\/header>\n
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Design Options<\/h2>\n<\/header>\n
![\"AGD-15](\"https:\/\/wpcdn.web.wsu.edu\/wp-hub\/uploads\/sites\/1121\/2015\/09\/haskel-gas-boosters-396x297.jpg\")
What’s next?<\/h2>\n<\/header>\n
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