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Technology / Re: Are heat pumps viable in areas of high density housing?

« on: 24/06/2020 23:21:55 »

Ground source heating is fraught with problems,... 

Thanks for your comments. My concern with large numbers of air source heat pumps and wind is more to do with the ambient outside temperature. I would think that on occasions when wind speed is very low or zero, large numbers of heat pumps may cause pooling of frigid air in the locality. A breeze would replenish the supply of air, and move pooled cold air away. My garden is on a gentle downward slope towards the house, with high fences on each side. I would think that an air source pump would cause a quite deep layer of very cold air to accumulate against the wall of the house.
I agree entirely that insulation is key to solving many of the problems of heating buildings, but in many cases there are problems with installation.

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Technology / Are heat pumps viable in areas of high density housing?

« on: 22/06/2020 23:34:42 »

It is proposed that in the near future most houses will be built using ground source heating instead of gas heating. I am fully in favour of such schemes, but given that, according to one estimate, an average house requires 300 - 700 square metres of  land to accommodate the heat collecting pipes, in areas of high density housing (surely the largest sector) how can sufficient heat collecting pipes be accommodated. Given that an enormous quantity of heat would be extracted from the soil, what effect would the lowering of temperature have on the flora and forna in and on the soil? If the solution to these problems was to be the use of air source heat pumps,  would the effect on the outside temperature lead to similar problems, ie more severe frost when wind speed is low.

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Technology / Re: How are we going to charge electric cars?

« on: 23/12/2019 23:55:22 »

As a non-scientist (in fact not well educated at all) might I make some comments?
These arguments are becoming tedious. We have known since the 1980's that burning fossil fuels will severely damage the environment. It was Exxon I believe who employed a team of scientists to assess the risks involved. I understand that those scientists' predictions tallied closely with ones made by more recent research. Exxon of course did not make their findings public.
Since those days the arguments have continued with monotonous regularity, with much fossil industry funded propaganda. Since the 1980's we could have been working to solve the problems, leading perhaps to a point where we would now be much more prepared to complete the transition to a non fossil fuel regime.  Instead we now find ourselves in the position where the arguments continue and the time we have left to make the required changes is frighteningly short.  Many people and institutions seem adamant that nothing should be done.
When the time has finally expired (I don't know how that will be defined), I foresee headlines such as "WHY DID THEY NOT TELL US!! WHAT MUST WE DO NOW?? WHOSE FAULT WAS ALL THIS??"
At least a start has been made, we have advances in electric transport and in sustainable energy production. They have not solved the problem YET. But to carry on as normal until we reach the point where it is too late to start trying is surely madness. In other words, can we say that after all of mankind's marvellous achievements in science, technology and engineering in the last couple of centuries, this is where we fail? 
 

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Technology / Re: How are we going to charge electric cars?

« on: 23/12/2019 23:49:24 »

Same applies to electric vehicles: great for the few, wholly impractical for everyone.

Or rather, great for the many, impractical for the few. So we should scrap the whole project just because it doesn't favour the few?

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Technology / Re: How are we going to charge electric cars?

« on: 23/12/2019 23:44:40 »

The National Grid forecast 6 GW will not match the consumption of Luton airport with four turnrounds.

So, drastic reductions in air travel are required then.

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Technology / Re: How are we going to charge electric cars?

« on: 23/12/2019 23:40:57 »

I think electric vehicles were quite common in the 1890,s but as soon as the petrol and Diesel fuel distribution system got going it was seen as the better way to go but we learn nothing from history.

True, in fact EV production in the USA did not stop until I think the early 1930's.

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Technology / Re: How are we going to charge electric cars?

« on: 19/12/2019 23:20:50 »

. Additionally we have vast quantities of organic waste as general rubbish, sewage, inedible bits of agricultural products, and plastics. And the promise of unlimited free electricity  whenever the wind blows or the sun shines, but not when we want it. So the sensible thing to do is to devise means of using this opportunistic energy to convert waste into liquid fuel.

What would be the efficiencies involved in converting waste to liquid fuel? 

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Technology / Re: How are we going to charge electric cars?

« on: 19/12/2019 23:08:24 »

The use of Hydrogen to power electrical vehicles via fuel cells  is often advocated but does this not require high purity Hydrogen and possibly high purity Oxygen can this readily be obtained ?One alternative would be to burn the hydrogen in a IC engine producing nitrous oxide as well as water and power conversion of less than 50%.

I think modern fuel cells take oxygen from the ambient air, but the hydrogen must be high purity.
The Clean Air Transport for Europe project, running fuel cell powered buses proved that the vehicles used overall in excess of 80% more energy than the baseline diesel vehicles.

The BMW "Hydrogen 7" ( an ICE powered car modified to run on hydrogen) required 220% more energy overall than the average European car.

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New Theories / Re: Do we need to alternate polarity, when we transmit RF?

« on: 02/12/2019 20:52:58 »

Excuse me interrupting (as a non-expert) but is this topic related to Single Sideband Transmission? As invented by radio hams decades ago?

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 02/12/2019 20:39:55 »

Thanks for the information, a bit over my head (pun intended), but what then is the ratio of lift power to drag power in level flight at the most economical speed? Given perhaps that conditions are perfect.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 20/11/2019 23:35:32 »

All your statistic shows is that the UN prediction was wrong.

In that it was too optimistic?

Modern airliners are almost as efficient as gliders but clearly carry a lot more deadweight (toilets, galleys, luggage, unspent fuel...) so maybe expend about 5 - 10 kW per passenger fighting gravity and about 600 kW per passenger moving through the air.

It seems that the total drag on an aircraft is the sum of the drag due to it's frontal area and the induced drag, which is the result of deflecting airflow downwards to support the aircraft's weight. The former obviously increases with airspeed, while the latter decreases with airspeed. The optimum speed of the aircraft (in terms of energy required) is that at which the two quantities are approximately  equal. At this speed, the energy required to move forward is nearly equal to that required to maintain altitude. This is explained in:-

Sustainable Energy - without the hot air         David JC MacKay

 In "C  Planes II, page 269, available online.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 15/11/2019 19:55:18 »

... so banning frivolous flying...

When did I say we should BAN holidaymakers etc.? I repeat we have to REDUCE airline traffic.
And of course all other sources of ghg production, but road vehicle manufacturers seem to be more enthusiastic at moving forward (excuse the pun).
As for the 50% of passengers flying for business purposes, you yourself have frequently pointed out that people can conduct much of their work by electronic links.   
A new International Council on Clean Transportation (ICCT) report finds that aviation emissions are increasing 70% faster than UN projections that already point to a tripling of CO2 by 2050. In other words, the climate challenge for aviation is worse than expected.

imagine the fun you can have in a weightless flexible ship moving in 3 dimensions!

I thought that in the 1st half of the last century airships were the height of luxury in travel. I wondered though whether the lack of need for fuel to fight gravity would be offset by the large air drag caused by the size of the structure.

...battery powered trainers (that rely on Russian gas to make the electricity to charge the battery)...

Battery charging need not rely on Russian (or any other) gas, or coal, or nuclear power.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 13/11/2019 23:58:04 »

...but what right do you have to decide whether someone else's journey is legitimate? 

None at all. (Syhprum's friends might say "Judge not, lest ye be judged"). Nor do  I have the right to condemn future generations to floods, drought and starvation, by squandering valuable finite resources for my own recreational purposes.

Sea passengers travelling on freighters still need all the deadweight of a bed, food, water, etc.

But a few passengers travelling on a freighter, which is laden with thousands of tonnes of goods being transported at the most economical cost constitute a small part of the total weight.
And that weight does not have to be supported against gravity by burning fuel.

Walk to your candle-lit hospital when you are ill. Starve and/or freeze in winter, and spend your summer tending your hand-dug organic crops. It will solve the political problem of queues of lorries at Dover, since there won't be any lorries.

I don't think that ANY of my comments have suggested that fossil fuel use should have never been used, or should be banned now or in the future. I have tried to point out (ineffectively it seems) that profligacy in their use is leading to an early exhaustion of the resources at best, and a disastrous effect on the climate at worst.
To put it more simply, I do not suggest that people should not travel long distances, merely that they should do so (in some cases much) less frequently.

Meanwhile, for what it's worth, the prize for the first aeroplane to carry two people 100 miles in 1 hour on 1 gallon of fuel was won about 6 years ago. I'm saving up for one, just in case I really have to be somewhere else sometime.

Impressive, sounds like a genuine attempt to improve. Will it scale up to hundreds of passengers? How much more exciting though are projects such as NASA's X57 Electric Aeroplane.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 09/11/2019 21:13:14 »

Climate is changing (it always has),

But the only relevant changes are those that have occurred since our species came into existence.

Our comfortable lives depend to a great extent on burning fossil fuel. There is insufficient renewable capacity to extend those comforts to everyone, but everyone wants them.

Therefore we should make every effort to not use fossil fuel wastefully. After all it takes something like 300 million years to make a litre of oil.

You seem to have missed the distinction between freight and travel.

I am aware of the distinction between freight and travel. I have been at pain to point out that huge amounts of fossil fuel are being consumed unnecessarily to move people great distances. I agree that travelling by sea is also wasteful of energy (unless passengers hitch a ride on a freighter that's going their way, quite common I think years ago). This has been my main point I think, since this discussion moved from advertising ethics. Maybe a partial solution would be palletised passengers. Come to think of it, that might go a long way to reduce the number of  passenger miles travelled!

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 30/10/2019 23:51:27 »

"Utter drivel. Airliners do not fly for the fun of it..."
But much of their payload does.

"The efficiency of jet engines approaches 60%"
But I understand that roughly half their power output is needed to overcome gravity.

"You could save a bit of fuel by using sea transport,.."
The energy consumption for air freight is 1.6 KWh/net tonne-Km, that for sea freight is 0.1 KWh/net tonne-Km. (published in 2009)

" Sea freight is cheap, sea travel is expensive."

At last, a glimmer of light!!...
Considering that "expense" is directly related to CO2 production. Remember my main point about discouraging long distance travel.

I realise though that air freighted food transport reduces CO2 by displacing the need for heated greenhouses in, the UK for example.

"British people have no right to drink coffee.."
I don't remember my history teachers telling me that Sir Walter Raleigh had to arrange air transport for his newly discovered coffee. (Sorry, I couldn't resist that)

 "Life is not supposed to be enjoyable or even comfortable"
Frequent long distance travel is not necessary for an enjoyable life, I can attest to that.
I think that we are very selfish to risk, by continuing our present lifestyle, condemning future generations to (far) less enjoyable or comfortable lives.

With respect, your comments on the possible future of the Kenyan economy and availability of green vegetables in the UK etc. mimic the protestations of climate change deniers over the last 30 years
Why single out the Kenyan economy? What about all the other poorer countries whose economies will be devastated by climate change? I've just watched a BBC news item about the drought in South Africa, particularly in an area where temperatures are rising by 2degrees more than the global average, and no rain has fallen for 5 years.

I don't think I implied that I wish to ban mechanised travel, or even air freight. Only that we should try much harder to improve the prospects for those who live after us.

Air travel is still rising, and predicted to keep rising for the coming decades. There seem to be no suggestions for achieving significant reductions in emissions, so we should be trying to reduce the number of passenger miles travelled. Perhaps you can understand my concern.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 24/10/2019 21:17:14 »

Rubbish! The whole point of transport is to move people or stuff from A to B, and you measure the efficiency of any modality by the quantity of fuel needed to shift one unit of payload (passenger or ton of freight) one mile. The fuel required to move an empty train or ship is enormous and the efficiency thereof is zero. Nothing NEEDS to be moved, and commuting to an office is surely the greatest waste of time and fuel ever invented. We move stuff (including ourselves) because we want it somewhere else - though I don't know of anyone who would rather be in an office than at home.

So if nothing NEEDS to be moved,...…...
This is my point, who really NEEDS to fly many hundreds of miles on stag or hen parties, weddings, international sports events, music festivals or even holidays? All these passenger miles are unnecessarily contributing hugely to atmospheric pollution. And instead of discouraging people from flying we reward them by giving even cheaper flights under air miles schemes. The aim should be to drastically reduce the number of long distance journeys, and given that there are thought to be on average of 93,000 airline flights daily around the world, a good starting point would be the air travel industries.
Unloaded vehicles have 0% efficiency, so what would (the theoretical) 100% be in terms of passengers or tonnes of freight?  Bearing in mind that what we need is very substantial reductions in the fuel used per flight, regardless of per passenger.

Let's not forget that glaciers are shrinking, and polar ice is melting at rates that were not previously predicted by meteorological scientists.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 20/10/2019 15:14:57 »

Shifting stuff consumes fuel. A 747 drinks about 8 gallons/mile when carrying 400 passengers and their baggage, i.e 50 passenger-miles per gallon. That's about the average for petrol cars, which rarely carry more than two occupants, whereas airliners are usually 80 -  90% loaded. Modern airliners are more efficient- remember the 747 is 50 years old! - although interestingly the Airbus 380 isn't: its attraction is in the reduced administrative overheads of shifting more passengers (up to 850) in a single airway and ground handling slot.

So we should only move stuff by air if that stuff NEEDS to be moved, ie to disaster areas, war zones, medical supplies etc.
But my point is that stating fuel consumption in terms of passenger miles per gal/litr only shifts focus from the large amounts of fuel used per flight. It is I think an accountancy measure rather than a scientific measure. And the equivalent amount of fuel would never be used for travel if air travel weren't so cheaply available. The numbers of  people travelling thousands of miles in cars would never remotely approach the numbers of airline passengers.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 07/10/2019 22:23:27 »

All living things pollute their environment. It's a question of choice.

But other species have not reached sufficient numbers to overwhelm the environment.
And we have the choice, to try and reduce our impact and leave conditions in not to bad a state for those that come after us.

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 07/10/2019 22:14:48 »

You are required to state "purpose of travel" on immigration documents. Are you suggesting that there should be an extra tax for frivolous travel? Would anyone admit to it?  I'd happily charge £10 per mile for any passenger who spoke above 50 decibels or claimed to be a nervous/confident/frequent/novice flyer.

I think you know that by "frivolous" I mean in this context, as I have said, travelling great distances for stag and hen parties, weddings, sporting events, entertainment events, tourist attractions such as Disney World, etc. How many people travel to Olympic Games, football, rugby, cricket, athletics events, and what is the cost in tonnes of CO2? And couldn't they watch them on TV?

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Technology / Re: Is this a stunning breakthrough in petrol engine thermal efficiency?

« on: 07/10/2019 22:12:25 »

Unlikely. Mine only weighs a ton fully loaded, and will fly for about 6 hours (700 miles)  on a full tank (0.1 ton).

So 700 miles on 100 Kg = 7 miles per Kg? So scale up to a 100 tonne aircraft and passengers and that might become 0.07 mile per Kg, and at 500 mph in one hour would be 7100Kg?

It seems that a Boeing 747 (which model I don't know) consumes about one gallon of fuel per second at cruising altitude. I assume US gallons, so 3.8litrs * 3600 seconds = 13680 litres per hour, or if fuel density is 0.8Kg per litre, 0.8 * 13680 = 10944Kgs or almost eleven tonnes. I know that more modern aircraft are more efficient, but I think the 747 is still the most common amongst large aircraft.