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Politics : Formerly About Advanced Micro Devices -- Ignore unavailable to you. Want to Upgrade?

To: Daniel Schuh who wrote (124111)	9/18/2000 12:45:12 PM
From: nixtox	Respond to of 1572369

Dan, BMW just demonstrated such a concept using a 740 a few month ago. Th main inconvenience is the refrigerated tank losing ~1% of liquid hydrogen by evaporation every day. The system however works very well. You probably can contact BMW they have a brochure about the experiment. I saw it in french while in Europe a month ago. Regards, Nick

To: Daniel Schuh who wrote (124111)	9/18/2000 1:07:58 PM
From: pgerassi	Read Replies (2) \| Respond to of 1572369

Dear Daniel: Ever see a rock hit a propane tank? First, it releases a stream of propane gas and then the spark ignites the gas. The heat weakens the steel around the hole and increases the tank pressure thus, causing the hole to expand. This quickly snowballs into a large explosion. Now, think of the thinness of the material in a typical condensor or even worse the evaporator. Having a fire and explosion inside the passenger cabin will make you very dead. 2 pounds of propane has the equivalent blast of a stick of dynamite when mixed with air. Even if it does not blow up, a fire in the passenger compartment will probably produce toxic gases, high heat, asphyixation, death all by itself. My mother had it happen to a VW bus gasoline powered heater (and it was designed to be safe (yeah right!)) so, do not think it lightly to use a flammable mixture for A/C. Refrigeration is not that hard to even 18K, simply compressing the hydrogen to 30 atm, cooling to air temp (300K), and letting it expand though a orafice will generate LiH (just like air conditioning and ordinary refrigeration but with higher pressure). Various companies have been doing this for years (with far harder helium no less) so the technology is proven. The quantities are much smaller for a maintenance function than a LiH generation function. The big saving comes from economies of scale (20M units per year can make it very cheap). The venting system is designed for the storage of LiH, LP (Liquified Propane), and CNG (a more explosive threat). LiH blows a less likely (the Challenger disaster required LOX (Liquid Oxygen)) than LP (its under pressure) or LNG (Liquified Natural (Methane) Gas) (it is also stored under pressure and super cooled as well) does when exposed to air. Yet, they fuel cars with CNG (under high pressure) and LP. 25 liter dewar weighs about 100kg including LiH (25 gallons of gasoline in a tank weighs about 85kg) but it is built to far tougher standards than a gas tank but no less than a LP tank. A CNG tank actually weighs even more than a dewar (the contents are not under high pressure for the dewar) for the same energy. 18K can be increased if the LiH is under pressure (I do not remember to what extent). You could get the same energy density if, you pressurize to 2000 atm (30K PSI) without any needs for cooling (or heating in cold weather like diesel or gas (in even colder weather)). So the problems can be solved and are less dangerous than a flammable A/C coolant. The thing stopping it is hydrogen gas supply, cost of mobile unit, and number being manufactured (a specialty prototype can easily reach $1 million even with an IC gas engine). Pete