victorian/edwardian houses or new houses?

[Franz Heymann]

The figure itself is irrelevant, if it is a figure for "efficiency per square foot". Any value, whatever it may be, will, according to you, be able to yield more power out than is put in, if you employ a large enough area.

That is an entirely different can of fish.

No. a square foot is not a ratio of any kind whatsoever. It is an area.

which is much more than the input output ratio of a squ foot of flat

You appear to be trying to say that any given area of Thermomax will yield a larger power output than the same area of what you call "flat panel". If my guess is right, I will have no reason to disagree with you.

Yes.

No. The efficiency is not proportional to the area. If the efficiency per square foot of Thermomax is, let us say, 30% per square foot, then a setup with, say, 20 square feet, would be 600%, which would violate the first law of thermodynamics.

The mootness will immediately disappear into thin air if you would stop talking about "efficiency per square foot" and just stick to the shorter phrase "efficiency", without conjoining the "per square foot".

Franz

[Franz Heymann]

That is the beginning of a circular argument.

Thanks for the homily.

I agree that in general usage, "efficiecy" is bandied around with gay abandon. However, the discussion about solar panels was a scientific/engineering one. To talk about "efficiency per unit area" in such a context is pure nonsense.

In engineering and scientific parlance, efficiency is to do *only* with energy and power. The efficiency of a sytem for converting energy from one form to another is uniquely defined as the ratio between the output and the input power. Since energy is simply the integral of power with respect to time, the same definition for efficiency will then also determine the ratio between the input and the output energies.

Franz

[Franz Heymann]

Fusion power is going to turn out to be a great deal filthier than fission power.

Fission power is the cleanest and least polluting energy source ever produced on earth.

The number of deaths per kilowatt hour which occur in the extraction and processing of fossil fuels is a lot higher than the corresponding number for the extraction of uranium

The pollution of the atmosphere by fossil fuel stations is vastly worse than the pollution caused by nuclear power stations.

The radioactive contamination by a nuclear station is negligible, despite the protestations of the anti-nuclear lobby. And even that contamination is largely caused by irresponsible practices.

Franz

[Franz Heymann]

Quite. And you don't even have to measure the area to deduce the efficiency.

Franz

[Dave Plowman]

Since you love to quote figures, here's some for you. The Mazda RX-8 is a four door coupe, so I'll compare it to the BMW 'standard' 3 Series 4 door saloon - a larger heavier car in every way. Lets take the 323i as being the closest in performance.

Top speed 0-60 0-100 30-70 Test MPG Touring route MPG RX-8 142 7.1 18.1 6.8 12 27

323i 141 7.6 19.8 7.1 23 31

So drive a sports car like the RX-8 in a spirited fashion and it does about half the MPG of a heavier saloon car with an engine near twice its nominal capacity, but broadly similar performance. Drive it gently over a mixed town and suburban main road route where its light weight should really benefit, and it still does badly.

[IMM]

What balls!

I reserve a part of a roof of 20ft x 10ft, 200 squ foot. I put in flat plate collectors, I get n volume of solar heated hot water on a certain isolation at a certain time of year. I put in the same 200 squ foot Thermomax solar collectors. I get n x 2 volume of hot water on the same isolation and certain time of year. For each squ foot of roof the Themomax is 100% more efficient. Is that clear?

I could use 400 squ foot of flat plate collector on the roof, twice the area, and produce the same volume of solar hot water as the Thermomax solar collectors which takes up half as much square footage.

The area is "very" important in this instant. Is that clear?

[IMM]

If every power staionin the world was nuclear we would be in big trouble getting rid of the waste.

The human element. When it breaks down, big, big problems. Best forgot nuclear as cleaner, lower tech alternatives are around right now.

[martin]

[IMM]

Thank you for your solid contribution.

[Rod Hewitt]

"IMM" wrote in news:bu11a2$vvk$ [e-mail]:

Last I heard, it sounded as if 'they' were going to add a small petrol burner to provide heating. Apparently this was the most efficient/sensible option, at least in the early days of such vehicles.

Perhaps we will get SEDBUK ratings on them as well as mpg equivalents?

Rod

[IMM]

A car has no insulation, as they produce so much waste heat the engines can provide enough even in the coldest conditions. Adding insulation, bonded to the cars sheet metal around the cabin, would improve matters. The drive motors and batteries produce heat, so this must be available for use.

[Rod Hewitt]

"IMM" wrote in news:bu1tnl$luj$ [e-mail]:

And also add to the cost and weight...

I doubt that any heat would be available from motors if they are fitted into the wheel hubs.

There may be problems supplying enough electrical power for the demisters, seat heaters (oops, well I have a Saab), and other things (maybe needing a heater for the screen/headlamp wash and other currently unnecessary/rarely fitted devices).

Rod

[IMM]

Insulation should not add that much weight. Cost? Mass production will bring that down.

If they are. Most electric cars have one motor.

Cars are full of unnecessary crap which add cost and weight affecting fuel consumption, such as rev counters. Why does anyone need to know how much the engine is revving in a normal road car? Beats me. I know when it is revving, I hear and feel it. If it is revved too much the management system cuts it out. An electric window on the drivers side is unnecessary too, as are electric sunroofs, which are a British fascination. The French don't want to know them.

Why isn't the a/c an absorption system using waste engine heat, instead of taking power off the crank, reducing mpg?

[The Natural Philosopher]

How can a plain white PDF file do your eyes in?

[The Natural Philosopher]

Oh, I am sure it ouuld be triple insulated to latest building standards and heat by dint of the sun shining on it...

[The Natural Philosopher]

They CAN be. One allegedly is.

Yes, but the alternatives are worse. At least the potential to generate electricty from non fossil sources exists: hydrogen cars still need hydrogen, and have neither the range, nor indeed the possibility to generate the hydrogen cheaply except by electricity. The battery wins over the hydrogen car. Period.

Whatever is dirty in a power statin is dirtier in a car. If you can go froim fuel to power in a car at a certain level ofeffciency, then certainly you can go from fuel to power, and electricity at least as efficiently and at least at same level of pollution in a power station. In fact its possible to do better when the weight limitations of car engines are removed.

Otherwise we would have to look at biofuels - methanol, biodiesl etc. - and hope that the economics of production make more sense.

I don;t think they do.

[The Natural Philosopher]

I don't think so. The fisson products would all be relatively short lived isoptopes, and teh main product is helieum. Non radioactve helieum

Its only the vast amounts of radiation intereacting with the shielding that would cause some radioactive compounds to be generated.

Yes, I tend to agree with you.

I would not be surprised.

That is certainly true.

Yes, the arguments are kind of curious:-

"We mustn't use nuclear power because the waste it generates might after a few hundred years cause a little environmental change in certain deep caves or the bottom of the ocean, so we had better stick to natural gas and oil and coal, which are running out, are absolutely known TO BE causing MAJOR environmental impact, and WILL DEFINITELY affect the WHOLE HUMAN RACE in a few years, extremely adversely".

The real reason is probably to limit the suppies of enriched uranium in case some gets into the wrong hands...

[The Natural Philosopher]

Yes, but efficiency is independent of that IMM.

Thats tantamount to saying a 5oKw boiler is twice as efficient as a 25Jw one.

Because it takes up the same floor space.

[The Natural Philosopher]

Might cost less than trying to get rid of all the CO2 tho.

The biggest single disaters have been caused by other things.

Earthquake in Iran, 30,000 dead. Smilar erahquake in San francisco with modern building regs, 3 dead.

How many died at Bhopal. Non nuclear accident. How many die in coal mines. Non nuclear accidents. How many did Saddam Husseing gas and kil. Non nuclear accident, and, if he had no oil to sell, because we wre all nuclear, how many would he have been ABLE to kill? How many die on oil platforms every year. Non nuclear. How many die when monsoons fail, or bangladesh gets flooded (again) Strong evidnce to link with fossil fuel burning.

In short, the Nuclear power scenario stacks up to one or two accidents - five mile island and chernobyl. Chernobyl was probably no more expensive than an oil tanker sinking in terms of clean up. Fve mile island - I forget, but it hasn't ruined the country.

[The Natural Philosopher]

The total power needed to run our car at - say - 30 mph, is about 5kW. At least 5% of that is likley to be wasted as heat - say 250W. That is potentially available to heat the car without losing anything.

I would not think that more than another 2-300W would be needed to heat the car in any circumstances. So yes, there is enough energy. Maybe the heater and/or aircon would knock the range down 20%, but it does that on a normal car anyway.