Hydrogen-fuel Airplanes

Other Unique Engineering Ideas

Aircraft companies are working to make their planes more efficient because airlines are fighting in prices and, therefore, they need cheaper flights. The objective of Boeing and other companies is to get more efficient planes that use cheaper energy resources.''Hydrogen is almost an environmentalist's dream come true,'' wrote Robert H. Williams and Joan M. Ogden, researchers at Princeton University, in a recent study on making hydrogen from solar power. We will look into the discussion of green car congress to emphasize the importance of hydrogen as a fuel.

1. Description

2. Why H2–The FOUR Challenges

3. How Hydrogen Helps

4. Advantage of this System

5. Future Trends

6. Related Links

Useful links: Hydrogen, Hydrogen fuel (1,2), Zero emissions

Description

A very important consideration in using hydrogen as aircraft fuel, is the possibility of a significant reduction in harmful emissions. During the combustion of kerosene in today's engines, carbon dioxide (CO2) and water (H2O) are produced. Additionally lesser amounts of sulphur dioxide (SO2), carbon monoxide (CO), nitrogen oxide (NOX) and unused hydrocarbons (HC) are also emitted. The last three substances are considered to be greenhouse gases.This element, the simplest -- and most abundant -- in the universe, has one proton with a single electron revolving around it. Hydrogen also weighs the least of all the elements atomically.Hydrogen is stored in materials that can hold the element and release it when needed. Some types of metal, like metal hydride, can trap hydrogen molecules within their compositional structure. Here, the hydrogen is stored safely and released when the metal is heated.It can pack quite a punch, creating vast amounts of energy when oxygen and an ignition source are introduced.  Hydrogen emits little or no greenhouse gases (GHGs). Its major byproducts are water vapor and heat.                             

Why H2 -The FOUR Challenges

An abstract from the green car congress [http://www.greencarcongress.com/2007/06/iata_director_g.html ]

The Director General and CEO of the International Air Transport Association (IATA) has issued four challenges to drive the air transport industry towards a vision of zero-emissions aviation. Climate change will limit our future unless we change our approach from technical to strategic. Air transport must aim to become an industry that does not pollute—zero emissions.

(I) Air Traffic Management: Governments and air navigation service providers must eliminate the 12% inefficiency in global   air traffic management. Cut air traffic inefficiency in half by 2012 and we immediately save 35 million tonnes of CO2.

(II) Technology: The aerospace industry must build zero-emissions aircraft in the next 50 years. Clean fuel is also critical. The first target is to replace 10% of fuel with low-carbon alternatives in the next ten years.  And the second is to begin developing a carbon-free fuel from renewable energy sources.

(III) A Global Approach: Climate change is a global issue, requiring a global solution.

(IV) Green businesses: The final challenge is for airlines to implement green strategies across the business. IATA is developing IATA Project Green to help airlines implement global best practice Environmental Management Systems. This will place environment alongside safety and security as a core promise to our 2 billion passengers.

How Hydrogen Helps

(Ref: Is It the Clean Fuel of the Future? - By MATTHEW L. WALD, N Y Times - Published: November 1, 1989)   http://query.nytimes.com/gst/fullpage.html?res=950DE1D91330F932A35752C1A96F948260&sec=&spon=&pagewanted=2

Hydrogen is not so much a fuel as a form of storage, holding energy generated by electricity and then releasing it without producing carbon dioxide, the gas thought to be responsible for half of global warming. To make the hydrogen, electric current, which can be generated by photovoltaic cells that tap the sun's energy, is run through water that has a chemical catalyst, in a device called an electrolyzer. The water molecules are divided into hydrogen and oxygen gases. The hydrogen can then be shipped by pipeline for use in many of the same ways as natural gas. For use as a transportation fuel it must be compressed into a liquid or combined with other chemicals, to decrease the size of the fuel tank necessary to hold it. Burning the hydrogen - or recombining it with oxygen in a reaction that gives off heat - produces nothing but H2O and small amounts of nitrous oxide, from nitrogen picked up from the air. These can be easily controlled. Hydrogen is easier to store than electricity itself, barring major breakthroughs in chemical batteries or superconducting materials that could be used as batteries.

Advantages of this System

  • First, this technology only has one byproduct: water.
  • There's no CO2 contamination of any kind.
  • The energy efficiency of these hydrogen cells is double the efficiency of combustion engines.
  • Although most air pollutant emissions would be reduced, a hydrogen-fueled airplane would produce nitrogen oxides.
  • The liquid hydrogen contains about 2.8 times as much energy as jet kerosene on a pound-for-pound basis.

In spite of these advantages hydrogen is not generally preferred as a fuel because an airplane’s hydrogen fuel tank would be lighter but bigger than a kerosene tank. The hydrogen fuel takes 3 to 4 times as much space.

Future trends

Recently, little progress made in hydrogen-powered airplanes for civilian use. NASA evaluated the concept of a hydrogen fuel cell aircraft and found it to be impractical without dramatic technology advances. The propulsion system would be much heavier, and the plane would probably be noisier than conventional jets.

Related Articles

Related links