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Was: Moss/Lichen on roof, now we are into pollution.
"The Natural Philosopher" wrote in message
... IMM wrote: Because there have been minor improvements in a flawed highly inefficient piston engine design over the past 30 years, you appear to think this exonerates the internal combustion engine, or it is efficient or clean or something. It is NOT. The engine it at the end of its lifespan, it should have gone 50 years ago. snip As I mentioned in another post, according to MIT the fuel cell is not viable yet for vehicles, which are the world's worst polluters. Far more efficient Rotary and Stirling diesel and petrol units appear the best options to fill the gap. The Stirling is external combustion, which is much a clean on the burn. Even the Rev Tec Aussie engine, a piston engine, improves thermal efficiency from 25% to over 50%. What you have failed to realise, is that even these are only stopgaps too. It is obvious that I know that, as I have already said that. At the very best, a fuel BURNING engine delivers only 60% efficiency - maybe a little more. The rest is waste heat. If you had goine to a snotty uni, where the theory is taught, you would understand that any heat engine - and all the above are heat engines - has its efficiency dictated by the ratio of the temperature of burn to the echaust temperature. Not quite right. The overall mechanical efficiency of the unit has to be up to it. Also in road engine, the power to weight ratio is one of the most important factors. The big picture is about energy conservation, especially in terms of waste heat, and the irreversible (in the short to medium term) problem if taking fossilised carbon out of the ground and pumping it into the air. To solve that you need to - use less. - burn plants you grew last year. - generate power by means that don't generate waste heat OR - use waste heat to replace the use of fuel elsewhere (CHP) ...and use less fuel cleanly. Use of the engines described does not solve any of these apart from, in a minor way, the first. I did say in the short to medium term the diesel and gasoline engines will have to do, but there are far more efficient versions around than the abomination we all currently use. Fuel cells can solve many of the above, but in the end. electricity is bets because it generates very little waste heat when used to generate mechanial motion. It is the loses at generation and transmission losses. This can be reduced by having smaller local power stations, the UK had, using natural, using CHP to heat the local district. Transmission losses then are low and overall energy efficient is very high. Sweden do this. The issues then become how to generate electricity without using fossil fuel and/or heat engines. Feul cells are not heat engines, but usually use fossil fuel. Nuclear power doesn't use fossil fuel, but does use a heat engine. windmills do neither, but are ugly, of variable power, and woefully inefficient in terms of space used. "woefully inefficient in terms of space used"? You see cows grazing under them. They can be in the middle of fields and only occupy a small footprint. There are windmill farms being built off-shore all over the UK right now, Out of sight. Water and wave power does neither, but is localised as to its applicability. solar cells are even ore woefully inneficient, Wet solar panels generally inefficient per squ foot, but have the whole of a south facing roof being a solar panel and the by shear size you have an efficient collector, that will virtually provide all of the houses needs if you can store the heat in a large thermal store Put PV cells on every south facing roof and most of the power generation station will not be needed. The solutions are there. It needs political will to force it through. but there mat be better technology coming.. burning domestc rubbish and biomass is good as it doesn't use (much) fossil fuel - i.,e. it's more or less carbon neutral, but it does tend to need treatement to reduce pollution of toxic flue gasses. There is no easy answer. But simply slightly better heat engines burining fossil fuils are almost the worst of all possible answers. On the domestic and commercial build front, insulation levels to superinsulation, passive solar design of homes, as Germany as doing with Passiv Solar regs, south facing roofs having integrated wet solar/PV cells, boiler with integrated CPH elec/gas Stirling boilers and soon to be introduced. The Stirling CPH boilers cut the peaks of electricity usage. All this is right now, and can and should be implemented. Doing so will drastically cut fuel usage and emissions and prevent fuel poverty. And more efficiency is on the way... What looks promising and appear likely to be introduced is the Zeolithe heat pump, which runs on natural gas for the provision of domestic heating and hot water. Currently these units are floor mounted and resemble a typical boiler in appearance. Zeolithe heating appliance's use less energy and are more environment-friendly than electric heat pumps and gas boilers. It provides considerably higher output levels than the current conventional and condensing boilers. Carbon-dioxide emissions are reduced by approximately 20 to 30%. On the vehicle side, matters are more complex. Of course, local CHP power stations drip charging electric car overnight is very sensible, but we do not have the infrastructure for this, as yet. Also what do you do in a city, when you car is parked on the road? How do you charge it? There are far more efficient diesel and gasoline engines around, and are running. These can be developed fully and integrated into a hybrid setup. Another method suggested is waste heat from an advanced rotary engine (not an inefficient Wankel design) which has well over 50% efficiency, driving a small Stirling engine from its waste heat, which drives a compressor, which charges an air tank. The compressed air assists drive via an air motor in a hybrid setup. This is a fine stop gap, and around town the car can run on non-polluting air, which is generated from what would have been wasted heat. The whole setup can be small in size as rotary engines are small and a compressor/air motors is also small. The compressor can also be the starter motor too. --- -- Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.558 / Virus Database: 350 - Release Date: 02/01/2004 |
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