Lawrence, We discussed Guy Negre's CAT cars about a month ago, cf the archive look for "compressed air" in the subject lines. IIRC we came to the conclusion that out of the ~12kWh mechanical energy the 300 bar 300L compressed air tanks can give you, about 9kWh must come from the environment (expanding air gets cold, and heat energy is taken from the environment to bring it back to ambient temperature and thus to its full original volume). In effect it' sa heat pump mechanism. Also Robin judiciously noted that when you compress the air at home, if you're clever enough to capture the equal valued (9kWh) compression heat e.g. for domestic hot water, the 12kWh you will get only cost you 3kWh!
The article you quote tells clearly how the auxiliary fuel is used for longer trips: it heats the air even further to make it occupy even more volume... I must admit that I am a bit surprised that this trick can be so efficient that it yields 120 miles per gallon of fuel, if this is for real the guy must have put his finger on the most efficient way to turn combustion energy into mechanical energy! Michel ----- Original Message ----- From: "Lawrence de Bivort" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, February 13, 2008 9:32 PM Subject: [Vo]:Compressed air car Source: http://news.bbc.co.uk/2/hi/science/nature/7241909.stm "An engineer has promised that within a year he will start selling a car that runs on compressed air, producing no emissions at all in town. The OneCAT will be a five-seater with a glass fibre body, weighing just 350kg and could cost just over £2,500. It will be driven by compressed air stored in carbon-fibre tanks built into the chassis. The tanks can be filled with air from a compressor in just three minutes - much quicker than a battery car. Alternatively, it can be plugged into the mains for four hours and an on-board compressor will do the job. For long journeys the compressed air driving the pistons can be boosted by a fuel burner which heats the air so it expands and increases the pressure on the pistons. The burner will use all kinds of liquid fuel. The designers say on long journeys the car will do the equivalent of 120mpg. In town, running on air, it will be cheaper than that." SNIP
