Use of coal, oil and fossil fuels

Wrong button

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

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

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

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.

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

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.

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

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!

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

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

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

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.

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.

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

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.

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

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.

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

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

Tidal lagoon energy is very expensive to build and has a significant environmental impact - not from harmful chemicals, (although making concrete is one of the biggest producers of CO2), but from the impact on nature of damming river estuaries.

When I referred to tidal energy, I specified tidal FLOW, not tidal lagoon.

Water is 8 times as dense as air, so water turbines can be 1/8 the size of a wind turbine for the same output. The tide flows four times a day, and is predictable hundreds of years into the future.

We could put a water turbine at the base of every off-shore wind turbine post - horizontally arranged so it would work with any direction of flow without needing azimuth adjustment. Sea water is very corrosive, so only the turbine would be below the water, the generator and electrics etc. would be housed and protected inside the wind turbine post.