Use of coal, oil and fossil fuels

[John HaineParticipant @johnhaine32865]

Posted by Anthony Knights on 07/08/2023 08:17:02:

I seem to remember reading some where that extracting energy from the tides would slow the earth's rotation down?

Well, sine ALL the energy in the tides is already dissipated by hydrodynamic friction with the land we are already doomed!

[Bob WorsleyParticipant @bobworsley31976]

As CS says, is this 300% efficiency real? I asked earlier if anyone had real data they could present, none so far.

My experience of messing with aircon units is that the electricity they use to run the compressor and fans doesn't make for any great efficiency, considering the cost of buying the unit in the first place. Of course, then the grid is overloaded and get blackouts then efficiency drops to 0%.

As for water temperature, if radiators are designed for 70C then obviously going to be colder with 40C, but why not just run the water pump for 12 hours per day rather than 3 hours? Electricity obviously, but heat output per 24 hours will be the same.

[JasonBModerator @jasonb]

heat pump will need to run for longer as OAT drops as it can only extract a certain wattage/hr.

300% is possible on a hot day but drops a lot when you avarage it out over a whole year.

Really best suited to UFH where there is plenty of insulation under the slab and the slab acts as a heat store and doe snot need to be as hot as a radiator

They are now very popular for heating ponds and swimming pools, partly because the pump is running to filter the water anyway so that reduces the cost of running considerably and you also have a big heat store that only need sto be heated to 25-30deg

Edited By JasonB on 07/08/2023 10:40:31

[Graham MeekParticipant @grahammeek88282]

As regards Tidal power Guy Martin showed a system in operation off the coast of Scotland, (I think it was). It had two underwater turbines which were either side of a moored pontoon.

Why aren't there more of them, good question. After all as long as the Moon is there we will have energy. The tides do not stop so it is constant energy. I suspect the answer to the question is the Grid is not there to bring the power ashore. It would also suit the NIMBY's as they are virtually invisible.

As regards the Severn, a Barrage has been proposed on more than one occasion. This would have provided a roadway as well, but like all these suggestions it was kicked into touch. I think the French built one, and of course you get power on the incoming tide and on the out going tide.

As regards politics, I have no inclination to even try banging my head against a brick wall. "There is too much we have always done it that way involved" Although the pay and holidays are very good.

Regards

Gray,

Edited By Graham Meek on 07/08/2023 11:26:18

[blowlampParticipant @blowlamp]

Posted by SillyOldDuffer on 06/08/2023 21:33:26:

Posted by blowlamp on 06/08/2023 13:28:19:

The most efficient ground sourced heat supply we have is oil, coal and wood.

Martin.

Three wrongs in one sentence! I won't explain why because Brandolini's Law applies.

I'm confident Martin can't justify his claims, but I sure we all want him to try. Watch this space!

Dave

They are the most efficient sources because they are readily available and straightforward to process.

If we could extract electricity directly from the ground or wherever, store it indefinitely with little loss and transfer it quickly & easily in dense energy form, then that might be a preferable alternative.

Which more efficient, ground sourced heat supply, alternative fuels are you using to power your existance?

Martin.

[SillyOldDufferModerator @sillyoldduffer]

Posted by derek hall 1 on 07/08/2023 07:19:09:

What happened to Tidal Energy?

In the Severn river the tidal range is the second highest in the world. We are an island surrounded by strong tida water, surely there is a way to harness this without too much stress on the environment?

…

I guess it's due to lack of strategic long term planning or is it a lack of knowledgeable qualified people at the top who are capable of making informed decisions.?

The problem is a combination:

• There aren't many places in the world where a tidal barrage would work well. The Severn Estuary is one, the Thames Estuary isn't.
• The stress on the environment is enormous. A barrier changes the entire nature of the area from a sea-way and river to a lake.
• The sea-way services a major port, and several small ones. How there are affected depends on where the barrier is built. The sea-way is also used to dispose of sewage from 3 large cities and many towns
• The river is a major source of drinking water
• The Estuary provides coolant for a large Nuclear Power Station
• A barrier is a seriously massive engineering project – it has to be strong enough to manage the weight of millions of tons and water, and cope with Atlantic scale storms, including severe storm plus high-tide plus a low pressure depression. In the worst case, failure of the barrier would be off-the-scale expensive : think flooding from Newport Cardiff and Bristol into the Midlands.
• The size of the barrier means it will be expensive to build. This means it has to generate a lot of energy before it's worth building. At the moment it's not competitive with other renewables – maybe later
• Tidal ebb-and-flow means the energy available rises and falls on daily and annual cycles. Inconvenient rather than a showstopper, but another reason for seeking alternatives.

Wave energy is promising, but the engineering is difficult and looks to be high-maintenance. It's easier to build large towers with a wind turbine on top, they're easier to maintain.

Geothermal is also promising with challenging engineering – a couple of wide-bore holes potentially several miles deep, penetrating into the magma to create super-heated steam. The theory is straightforward, but we don't have the technology or need yet.

I don't think the issue is lack of expertise at the top. We're talking big money and significant change versus vested interests and a lot of people who fear losing out and don't understand the science. They think it's a political argument, when the Laws of Physics are in charge. Thermodynamics aren't influenced by human opinion. Add more heat to the environment, and what happens next follows physical laws, not human wishes. It's a nasty situation: those who understand the science know full well bad things are happening and have several ways of reducing the damage. Unfortunately, they haven't been able to persuade those who don't understand the science, and those who don't want to. It's a mess. Regret to say that those who don't understand have so far won the argument, and not enough has been done. In consequence the original target of allowing a 1.5°C increase in average temperature is now unachievable, and the new target will be between 2 and 4°C.

Things will change, because we've gone beyond warning of trouble ahead. Now, man in the street is starting to notice something odd is happening to the weather. Climate is difficult for individuals to comprehend, but rapid sequences of record breaking rainfall, storms, heat-waves, freezes, droughts are harder to ignore. Reality always wins in the end.

The danger is public opinion is swinging far too slowly to avert seriously rough times ahead. Politicians fail because they can't afford to upset their supporters, even if they know their supporters are completely wrong. The Laws of Physics care absolutely nothing for human affairs, left or right.

Dave

[duncan webster 1Participant @duncanwebster1]

Wrong button

Edited By duncan webster on 07/08/2023 12:17:35

[vic neweyParticipant @vicnewey60017]

Members of "just stop oil" have found the solution for everyone

[JAParticipant @ja]

Tidal power – always a nice idea.

One further comment to Dave's list on the Severn Barrage, the Severn Estuary has a very mobile sea bed. If built, expect silting up of the turbines. As usually the French are years ahead of us. The tidal barrage across La Rance was built in the 1960s. Although it produces power I was told, about 30 years ago, that it was usually used as a pump storage system.

Tethered tidal turbines seem to be tested daily. Again they appear to make sense but the loads on them are very high. Water is very much denser than air with the turbine structure subjected to high water speeds. That is before vibration problems are considered.

JA

[John Doe 2Participant @johndoe2]

Posted by Nigel Graham 2 on 04/08/2023 12:30:08:

A heat-pump is fine within its limits: it needs to be connected to a system suitable for it (which may mean replacing all the pipes and radiators), in a home insulated and ventilated suitably for it (which means many existing houses are not.

Cost may reduce and reliability might increase with time; but you can't beat physics and they will not heat water to the same temperature as a combustion-type boiler will; hence needing an auxiliary, electric immersion-heater tank.

In theory at least the heat in the atmosphere is practically inexhaustible

How often do we shower, or wash the dishes in water hotter than 40-45°C? The way domestic hot water works now is that we heat a small tank to about 60-70°C and then dilute that water about 50/50 with cold to fill our bath or sink to obtain a temperature of 35-38°C. If we have a "free" source of heat under our feet or from the air in our garden or our loft – (albeit at 40-45°C instead of 60°C), then surely we can find a way of using it effectively.

Heat pumps and windmills are not new inventions, just a pity we did not develop them 100 years ago, but instead pumped billions of tons of carbon into the atmosphere.

[JasonBModerator @jasonb]

It's the fact you would need to be able to store 3 or 4 times the amount of warm 40deg water as you would 65deg that is the biggest problem, closely followed by how long it would take a HP to get that amount of water back upto 40deg on a day when outside temps are low. Could always switch the emersion on though!

No chance for small properties that only have room for a combi boiler where would they put four hot water cylinders

Edited By JasonB on 07/08/2023 13:32:42

[Nigel Graham 2Participant @nigelgraham2]

There is another problem with stored hot-water systems: Legionella.

The bacterium for this respiratory disease seems to be able to withstand normal water-treatment enough for individual to find their way from Nature to stored water, where they multiply quite happily at about 40ºC.

Heating the water to 55ºC or above will kill it. Instant, or on-demand, systems that raise the incoming mains water to well above that, kills any stray bacteria, even if we then mix the hot water with more cold: the number of bacteria in the cold water is too low to be a problem.

We become infected not by drinking the germs but by breathing them in with the fine spray and low-temperature vapour from, e.g. showers.

In theory it is possible to contract Legionella disease from waterfall spray but I don't know if this is ever known. There may be too few of the little blighters in the water to attack us.

[duncan webster 1Participant @duncanwebster1]

Posted by JA on 07/08/2023 12:55:43:

Tidal power – always a nice idea.

One further comment to Dave's list on the Severn Barrage, the Severn Estuary has a very mobile sea bed. If built, expect silting up of the turbines. As usually the French are years ahead of us. The tidal barrage across La Rance was built in the 1960s. Although it produces power I was told, about 30 years ago, that it was usually used as a pump storage system.

Tethered tidal turbines seem to be tested daily. Again they appear to make sense but the loads on them are very high. Water is very much denser than air with the turbine structure subjected to high water speeds. That is before vibration problems are considered.

JA

Why don't the barrage type silt up over the years? The LaRance barrage is reported to have caused major changes to the ecosystem, can't see us getting away with that in the UK. All change is wrong, even if the overall effect is beneficial. 

Edited By duncan webster on 07/08/2023 16:07:42

[Nigel Graham 2Participant @nigelgraham2]

Having visited it I think I can answer that.

The LaRance turbines are in a row along the bottom of a quite short dam, and consequently almost all of the river flows through them at every low tide. So the reservoir is being flushed at every use.

Also there might not be much sediment in the R. Rance, and the barrage is very close to the sea. So the mud is going into the sea as it would normally, and not washed back and forth by the tides as it is in the Severn Estuary a long way inland.

Regarding the environmental considerations, I don't know when that scheme was built but whether it could be now, for environmental reasons, is another question. You'd have to ask the French Embassy, or EDF!

[JAParticipant @ja]

What mankind really needs is a proper pandemic such as the Black Death. The survivors' descendents will probably have fewer problems than us. However society is likely to be very different.

La Rance barrage is very small compared with some suggested Severn barrages. I think any large Severn barrage would be an environmental catastrophe (I live about 12 miles from the Severn).

JA

[Graham MeekParticipant @grahammeek88282]

I think the ecosystem is a valid point, but I also think we have left things a bit late in the day to worry about local environmental issues. Salmon used to be caught in large numbers on the Severn but they have declined to the extent that only a handful are caught now.

Dumping effluent into the water courses has put paid to many a stream and river. Another issue where Big Money and foreign investment has dictated UK company policies. Shareholders before wildlife.

I also doubt the two bridges across the Severn have not had an impact on the water courses or the habitat since they were built. My late Uncle worked on the first bridge when it was being constructed. Empty tins of Red Lead paint were regularly thrown down into the river. As well as empty milk bottles. Milk which they had to drink to combat the red lead. I doubt that was the only littler from this site.

Besides if we can construct such a barrage I am pretty sure we can dredge the silt build up. I would also like to add that I am not pro, or anti the Barrage, I mentioned it earlier as the Severn was mentioned.

Things started to go wrong for the Earth when man stopped being a hunter-gatherer.

Regards

Gray,

 

Edited By Graham Meek on 07/08/2023 16:53:34

[Robert Atkinson 2Participant @robertatkinson2]

Heat pump efficency of 300% is conservative when heating. Almost all of the electrical power input comes into the house as heat so only needs to pump twice the input power. Outside air temperature has little effect on efficency with typical UK winter temperatures. The only real issue is the water output temperature with the air to water pumps the government are pushing. Air to air heat pumps are much better IMHO. You do however still need a water heater. That can be a instant flow gas or electric.
I've been using air-air heat pumps for over 20 years in two properties and have been very happy. I use a miix of gas and electric instant flow heaters for hot water. One other important detail is the use of "inverter" type units. These use the same technology as VFDs and vary the speed of the compressor (and fans on most designs) according to demand. This is more efficent and you don't get the Bang-on Bang-off noise of old fashioned aircon systems.
One reason for pushng air water heatpumps is you can't use them for cooling. I suggest anyone considering heat pumps to forgo the £5000 garant and go for a full Air-Air system with cooling capability. You don't have to use cooling every day or all the time but it's very nice to hae the option.

Robert.

Edited By Robert Atkinson 2 on 07/08/2023 18:18:15

[File HandleParticipant @filehandle]

Was listening to a piece on fusion today. needs a lot of development, but it was suggested that heat output could be 10x input. just needs investment money to develop further. proof of principle has already been done. Unlike the military use of fission, this can't exist for fusion.

[Michael GilliganParticipant @michaelgilligan61133]

They are building five small-ish houses to the rear of my property, which are coming close to completion …

In case it’s of any interest, I managed to grab a photo of the product label on the Heat-Pump carton.

They are using Mitsubishi Model: PUZ-WM50VHA-BS

… for which we can probably find a Manual.

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

https://library.mitsubishielectric.co.uk/pdf/download_full/4144

gives the basics

and for pricing, plus downloadable manuals:

https://www.swatengineering.co.uk/shop/mitsubishi-electric-ecodan-heat-pump-puz-wm50vha-r32

 

MichaelG.

Edited By Michael Gilligan on 07/08/2023 19:03:41

[Michael GilliganParticipant @michaelgilligan61133]

Very recent story in FT Edit:

US government scientists have achieved net energy gain in a fusion reaction for the second time, a result that is set to fuel optimism that progress is being made towards the dream of limitless, zero-carbon power.

MichaelG.

[JAParticipant @ja]

Ever since ZETA the word DREAM has been used with Fusion, never REALITY. Investing in British vineyards would, at least, give you a return.

I do not consider myself a cynic.

JA

 

 

Edited By JA on 07/08/2023 20:21:01

[Mark RandParticipant @markrand96270]

Posted by Michael Gilligan on 07/08/2023 18:53:30:

**LINK**

gives the basics

and for pricing, plus downloadable manuals:

**LINK**

MichaelG.

Edited By Michael Gilligan on 07/08/2023 19:03:41

The units appear to be pre-gassed and contain 2.0 kg of R32, so I'm a bit puzzled as to why the sellers claim that F-gas certification is required for intallers.

I've got an interest in this, but am conflicted as to whether the option of pay someone to do the install and claiming the (£5,000) grant will save any money compared with doing the install myself and ignoring the grant.

When I installed our CH system in 1988, I anticipated that we'd have children. So I designed it with radiators that would work happily at 45°C and that's been where we've run the boiler in all the years since.

[Ady1Participant @ady1]

Posted by Michael Gilligan on 07/08/2023 19:24:53:

Very recent story in FT Edit:

US government scientists have achieved net energy gain in a fusion reaction for the second time, a result that is set to fuel optimism that progress is being made towards the dream of limitless, zero-carbon power.

MichaelG.

It's a bit of an Oppenheimer moment if it does happen

The only thing stopping us from chewing up and processing this entire planet is the cost of energy

The only thing stopping an unlimited megawar is the availability of surplus energy

Edited By Ady1 on 07/08/2023 23:16:17

[SillyOldDufferModerator @sillyoldduffer]

Posted by Graham Meek on 07/08/2023 16:52:41:

…

Dumping effluent into the water courses has put paid to many a stream and river. Another issue where Big Money and foreign investment has dictated UK company policies. Shareholders before wildlife.

I also doubt the two bridges across the Severn have not had an impact on the water courses or the habitat since they were built. My late Uncle worked on the first bridge when it was being constructed. Empty tins of Red Lead paint were regularly thrown down into the river. As well as empty milk bottles. Milk which they had to drink to combat the red lead. I doubt that was the only littler from this site.

…

Big money and foreign investment have indeed failed to stop unprocessed sewage being dumped, but the problem pre-dates them. The Victorian approach to effluent produced on an island was was simply to dump it into the sea, often via a river or canal. Public health improved enormously when they realised the need to keep it away from sources of drinking water, often achieved by by piping sewage to the seaside rather than pouring into rivers.

At first the Victorian system worked quite well because there was much more sea than sewage and not many people went swimming. However, as towns got bigger, it soon became obvious that more needed to be done. Adding sewage farms to the system was a considerable improvement because they process effluent in various ways to render it less dangerous. Their output of a comprehensive treatment plant is safe to drink provided the system is in good order, and working within it's operating limits.

Most of Britain's sewage system was built by local government, funded by rate payers plus central government grants. The problem with government funding is that no-one likes paying tax! Therefore governments constantly look for ways to 'save' money. Ideally savings are made by improving efficiency, but this is easier said than done. In consequence 'savings' are achieved by 'stretching the assets' – reducing maintenance, delaying replacement of clapped out equipment, and/or overloading existing assets. Gradually, the system degrades. The policy always ends badly – discovering that 70 years of neglect means the entire system is trashed, and that the cost of fixing it is enormous. Sewage systems fail by releasing part-processed and raw effluent.

When the problem reached crisis point in the 1970's government dealt with it by privatising the system. New money was made available, not borrowed by the government which makes the books look good, but still borrowed – by water companies. The public still pay. Improvements were made, but companies are in business to make profits, and they too are struggling to do all that is needed. Private companies believed to be more efficient than public services, but this is rarely true. When underfunding is the root cause, public services are inefficient because they can only operate within a budget, whilst private companies are inefficient because they have to achieve profit margins. In both cases, whoever is in charge is forced to "stretch the assets". Wildlife are a long way down the list of considerations!

Everything humanity does has an impact on the environment. The issue is how bad the damage is. No doubt building the Severn Bridges meant hundreds of tons of nasty rubbish ended up in the river, but the disturbance is tiny compared with building a tidal barrage.

Today the population is larger than a century ago and we have much richer lifestyles. In the past, mankind lived without causing serious damage to the environment, and greedy freedoms were safe enough. Easy to generate wealth when there's no responsibility for depleting natural resources, wildlife, or other people. Not now! Human activity is seriously damaging our eco-system, and, unless the problem is managed, the consequences will be appalling. No good naively pretending it's still 1955 and most of the planet hasn't been exploited. – that innocent carefree world has gone.

Dave

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