SteamyTea

Is the quite correct, there could be an error as they do happen.

Before going down this difficult route, can you actually afford to self build, it is generally more expensive that people ever imagine.

Should have had a GRP flat roof, I can stick just about anything to that.

From here. You can get two half trays at 28.60, so £57.20

All that really happen is that the outside unit, instead of of blowing air though a very cold radiator, it blows air though a warm radiator. To save that energy you would need to collect that warmed air as it exits the ASHP unit, then store it in something well insulated. Not really feasable. GSHP can be set up to warm the ground where the boreholes/slinkies are, but if you have moving ground water, the energy is just taken away. You may find that an EAHP works better, it takes that warm air out the house, with that air replaced with outside air. Would probably work well where I am because the OAT is never that high, 28°C is a very, very, rare event, over 22°C only happens for a few hours a year, like today, but now, at 21:50, it is 14°C, with the house at 21°C. It should be possible to design a system that can provide genuine air conditioning and recover that energy to heat DHW, while also providing UFH when it is needed. I think the real problem is cost and complexity, basically switching from heating a slab in winter to cooling air in summer, two different mediums need to to piped and controlled. Fain Coil Units in a forced air heating system may be one method that is a bit simpler, it works in offices. But no one wants to 'loose space'' to large duct work. But I would question how large that ductwork needs to be be a low energy dwelling, probably not as large as people imagine. I am all for just heating the air in a building if possible, then you can forget about wet pipework, water leaks, over complicated controls, reliance of 'heating engineers' that do not understand heat pumps and it would be easy to fit another FCU or three to a larger heat pump if more heating and cooling were needed, then can run in series, one after the other in an insulated box.

We will have to wait till the current working generation of Architects have all died. I was chatting to a lady in the cafe today, she runs a writing and publishing service. I somehow managed to mention that I have an interest in energy and usage. She said, 'me too, many of my clients write about energy' Me 'Oh yes, that is interesting' Her, ' yes, life energy' Me 'not really real energy is it, science has defined energy very accurately' Her 'yes, I know about quantum energy' Me, well I just looked at her bare legs and tried to take a peek down her blouse. FFS

Where you getting PV modules from for 50 quid? https://midsummerwholesale.co.uk/buy/roof-integrated-solar-pv

Or just totally replace it with something thermally better. I am sure @craig will know of a suitable product.

Well that made me angry, perpetuating the same myths, with very little knowledge, and polarised contributors. The BBC has some fantastic scientific programs, why can't they get a descent physicist to contribute.

BBC Radio 4's You and Yours is about to do a bit about energy saving in houses. https://www.bbc.co.uk/programmes/articles/1YnZrF9w7xR82St8d7Pgc6x/contact-you-yours#programmes-content They love horror stories.

The problem seems to the that the window frames will be sitting on the cold concrete surface. The inside part of the cill has a relatively small surface area, but the outside part is massive, and cold. That means the frame will also be cold. The frame will have a relatively large area when combined with the cold cill. I am not sure how low a window frame can get thermal transmittance, but will have to be good in both the vertical and horizontal planes.

Assuming 80⁰F Then the energy in that air is, if it started at 10⁰C is 41 kJ That is about a third of the energy that the cup of coffee I have just bought, 1,100 kJ. Even if it is 80⁰C, that is 500 kJ. Half the coffee. Now let us assume that the solar collector area is 2 m² and you are getting 1000 W/m² today. 2000W, or 2 kJ/s. To heat 41 kJ will take 20 seconds, 500 kJ, 250 s, or 4 minutes.

We have known that for generations.

They will still speak funny. https://en.wikipedia.org/wiki/Welsh_phonology

@@joe90 Won't be big enough to heat your place in Wales, Zoothorn will be sucking all the power to keep his place warm.

I was chatting to a heat pump guy a few years back and he said there had been a few commercial CO2 installations, mainly cooling. I also seem to remember there were a number of domestic CO2 units available about a decade ago. Maybe @markocosic knows more.

Not sure. One thing that is a problem is that the gas must not be corrosives, and play nicely with lubricants. Water and hydrogen can both be used, but they cause problems. From my limited understanding, hydrogen plays an important part in the phase change of the current generation of gassed, but it is bonded strongly to the carbon atoms.

Basically the refrigerant gasses, and much sturdier engineering. You can get CO2 heat pumps for domestic installation, they just tend to be expensive and there is a real lack of installers. Ammonia is flammable, and poisonous, but cheap to make. It is a good refrigerant and can also be used to power ICE, we make billions of litres of it every year.

The 'exploding' demand for giant heat pumps Published 7 hours ago Share IMAGE SOURCE,MAN ENERGY SOLUTIONS Image caption, This MAN heat pump system in Denmark is one of the biggest in the world By Chris Baraniuk Technology of Business reporter There are 2.5 million litres of water in an Olympic-sized swimming pool. If for some reason you wanted to bring it from a pleasant 20C to boiling point, German firm MAN Energy Solutions has a heat pump that could do it. And it would take less time than Kenneth Branagh's film version of Hamlet. "We can do this in less than four hours," explains Raymond Decorvet, who works in business development at MAN Energy. "Or we could freeze the whole thing in about 11 hours." Theirs is among the largest heat pump units in the world. Heat pumps work by compressing gently warmed refrigerants to raise the temperature of these fluids. That heat can then be passed on to homes or industrial machinery. Heat pumps require electricity to work but can produce around three or four kilowatts of heat for every kilowatt of power they consume, making them highly efficient. Plus, some designs can provide cooling as well. Heat pumps are increasingly popular with some home owners but domestic devices are relatively small and tend to have outputs of several kilowatts or so. MAN Energy's biggest commercial heat pump is thousands of times more powerful - with a total heating capacity of 48 megawatts (MW). It can produce temperatures of up to 150C and heat thousands of homes, not just one. The company recently installed two of these machines in the port city of Esbjerg, in Denmark. In this installation, the heat pumps' CO2 refrigerant will absorb a small amount of heat from seawater. Compressors boost the temperature of the CO2 and the system can then transfer this heat, providing water of up to 90C to a district heating system serving 27,000 households. IMAGE SOURCE,MAN ENERGY SOLUTIONS Image caption, Industrial-sized heat pumps are a thousand times more powerful than domestic versions "The demand for district heating is exploding," says Mr Decorvet. An urgency to move away from fossil fuels is leading to a rush - particularly in Europe - for bigger and beefier heat pump systems that can power entire towns. But who has the biggest, megawatts-wise? It might seem like a relatively straightforward question but it is actually quite tricky to answer definitively. Not least because heat pumps don't tend to work at maximum capacity all the time. In Esbjerg, MAN Energy's heat pumps will run at about half their potential output, for instance. And trying to compare the world's largest heat pump systems is difficult because, often, they are made up of multiple smaller heat pumps chained together. Take the district heating system in Stockholm, Sweden, often referred to as the largest heat pump set-up in the world. This is probably true, it has a maximum capacity of 215MW - but that total is the sum of seven heat pumps, two 40MW and five 27MW devices, a spokesman for energy provider Stockholm Exergi explains. Elsewhere in Sweden, Gothenburg has a 160MW heat pump system that consists of four units. Two of them are actually bigger than those in Stockholm, with capacities of 50MW each. They have been in operation since 1986 and probably hold the title of the most powerful individual heat pumps currently in use, though they are clearly rivalled by newer devices such as those made by MAN Energy. Last year, German chemicals firm BASF and MAN Energy announced their intention to build a 120MW heat pump that would, reports suggested, be the world's largest. It would have provided heat for industrial uses at a site in Ludwigshafen. However, it was not to be. "BASF has decided not to proceed with the project," a spokesman told the BBC. The firm is exploring other potential heat sources instead, which it hopes will be more economically attractive. IMAGE SOURCE,GETTY IMAGES Image caption, In countries like Sweden big heat pumps are used to heat whole districts Size isn't necessarily everything, notes Dave Pearson, group sustainable development director at Star Refrigeration. Efficiency matters and he argues that ammonia - his firm's choice of refrigerant - helps to make heat pumps particularly efficient. Veronika Wilk at the Austrian Institute of Technology and colleagues have studied the use of heat pumps for industrial applications, to provide heat in pharmaceutical, food or paper factories, for example. So long as they don't require very high temperatures beyond 200C, companies are increasingly turning to heat pumps, Dr Wilk argues, because it allows them to move away from natural gas, which has become extremely expensive following Russia's invasion of Ukraine. But industrial heat pumps tend to be merely several MW in capacity or so. You are more likely to spot truly giant heat pumps in a district heating system, such as those mentioned above, says Dr Wilk. "The beauty of district heating is that you can decarbonise a lot of households at once," she adds. IMAGE SOURCE,AIT & KRISCHANZ Image caption, Veronika Wilk points out that district heating can decarbonise a lot of homes in one go There are many other examples of heat pump-powered district heating systems springing up. In Vienna, a 55MW system using three heat pumps is due to go live this autumn. The machines will harvest heat, around 6C, from treated wastewater, explains Linda Kirchberger, division manager asset decarbonisation and new technologies at Wien Energie. The treated water used to go straight into a river. "Now it does a detour and we take it through the heat pump system," she says. The system will lift temperatures from 6C to 90C and the heat will go on to supply 56,000 households. In 2027, Wien Energie plans to double the system's capacity with three more heat pumps, reaching 110MW in total. While still impressive, and weighing more than 200 tonnes each, these individual units have a capacity of less than 20MW. The manufacturer, Johnson Controls, confirmed to the BBC that its largest heat pumps have a maximum output of 28MW.A similar system, also using heat from wastewater, is planned in Hamburg, according to reports. It will have a capacity of 60MW, though this too will rely on multiple heat pumps linked together, a spokeswoman for Hamburg Wasser, the water company involved in the project, says. But keep an eye on the future. In the Finnish capital Helsinki, a plan is afoot to construct a gargantuan heat pump system with a total capacity of 500MW. This will likely be comprised of multiple units, as in Stockholm, Gothenburg and Esbjerg, but Helen, the energy company behind the scheme, has not yet revealed how it will all come together. MAN Energy is one firm bidding for the contract. A spokesman declined to explain exactly what configuration of heat pumps would allow the company to provide 500MW of heat. Mr Decorvet says, simply, "I hope we are going to win."

Can you get rid of it when you get the triple glazing put in?failing that, can you get insulation on the outside, basically box it in.

Avoid anything that is PVC if your Lego blocks are polystyrene.

Careful, could be other things, burst water pipe, blocked gutter, blown render (what happened to my house) badly fitted window. @Pollyanna, your roof has a good angle for winter PV production, which way does it face and how much shading does it get on the sunny side?

Won't the thermostats/blending valves behave a bit odd if they see a cooler temperature entering?

Is that downpipe flooding the area?

Cleanliness is next to godliness. It also caused an explosion in Christianity. https://www.bbc.co.uk/sounds/play/m001mc70