JamesPa

((actual delta t)/(delta t at which the rad is specified (ie 50)) to the power 1.3 So if a radiator emits 1kW at delta T 50, then the power output at delta T 20 will be 20/50^1.3 *1000 = 300W. The inverse ratio (50/20)^1.3 = 3.3 is called the oversize factor. This can conveniently be used to work out the dt50 rating required for a particular output at the design dt. So if my room needs 400W and the oversize factor is 3.3 then I need to look for a radiator rated at 1320W.

Radiators are normally specified for deltaT50. Many heat pump designers will work out the heat loss and from that (and the flow temperature) work out the DT50 rating that this would require, because its then easy to pick the radiator. Or they will produce a table that includes both. For a most radiators output is proportional to deltaT^1.3. Another way installers do the calculation is to work up the 'oversize factor' = (50/(actual deltaT)^1.3. Again an easy way to work when looking through radiator catalogues. Take another look at the quote, they have probably done one of these.

I'm getting an electric car, which I'm sure will mop up any unused electricity. I am asking them to fit a charge point at the same time. One problem with an electric car is that they generally take a fixed (high) load or at best have a high minimum load. So they cant easily 'mop up' excess electricity when the amount available is less than the minimum, without also importing. Various options: Ignore Batteries (best functionally but expensive) Solar diverter to heat DHW (which can mop up variable amounts of electricity to match available excess, but, depending on your panel capacity and DHW use, unlikely to be sufficient load on its own over the day in height of summer Solar diverter plus car, arranged so that the car charges when there is sufficient excess (decide for yourself what 'sufficient' is Im currently experimenting with the last of these as I already had a diverter and just bought an electric car. |An automation in HA switches on the car when the amount being exported exceeds half the load taken by the car, tested every 10 mins. The amounts to be saved, particularly if you are paid for export, aren't great, so 'ignore' is also definitely an option. Certainly there are more cost effective (or enjoyable) ways to spend time!

You are correct. The classic PID (proportional, integral, differential) controller uses the current deviation of the variable (eg temperature) from the desired value, the cumulative difference between the target and actual value, and the current rate of change of the variable into account (in various proportions) to decide the change made in the controlled parameter (eg energy input) PID controllers appear in many control systems, there is a raft of theory on them and tuning them to get the right proportions of p, I and d can be 'interesting', particularly if there is long delay between changing the input and when the output changes (as there is in a heating system) or nonlinearity.

Wow I'm genuinely surprised, I would have thought gas was more dangerous than oil!

Energy is more or less bound to get a lot more expensive over the next decade, as indeed it should given the destructive effects fossil fuels have. So invest in energy generation, insulation and energy efficient heating (aka heat pumps) and transport (aka public transport and electric cars). That's of course unless the nutters (aka 'right' wing) take over in which case energy will temporarily get cheaper as a populist stunt, cynically to take control, but once control is taken and the science asserts it's supremacy (because the science is supreme) your children will need to be in the top 1% of wealth to avoid living in conditions that are close to, but not quite, intolerable, as servants to people locked away in air conditioned boxes in the remaining habitable parts of the planet. It's your choice through the ballot box. Use it wisely

(Question was why a heat pump not a fossil burner?) ...and hopefully because it's the right thing to do to help combat climate change. Roughly same running cost and one third of the carbon emissions. In a new build or extension that requires heating system replacement it's a no brainer for anybody with either a conscience or children that they care about.

Makes sense that you are not required to remove the gas line. The carbon footprint of a gas hob is about the same as that of an electric (induction) hob at present. Some gas retailers appear to charge for disconnection, others not. It would be worth checking before throwing out the gas hob. You might want to switch retailers and then disconnect!

The elected Councillor in charge of planning appears to support them. She told me, when I spoke with her, that she 'wouldn't want her gardening disturbed by my noisy ASHP'. She is Green party BTW, just saying.

I'm pretty chuffed yes, and somewhat relieved after two years of hard slog. As to what my LPA will do more generally - that's anyone's guess, but I think they would struggle to continue down their present path.

Technically I agree. However there would be a difficulty enforcing the use of the ashp on this case and there would be a good few who, for whatever reason, just switch it off and use the gas, resulting in a total waste of public money. I'm not sure there is a golden bullet here. There rarely is I suspect with deliberate market distortions, which are nevertheless necessary to kick start change.

Notably both the Daikin R290 and the Samsung R290 units are larger and quieter than their predecessors. I think its reasonable to conclude, as you suggest, that the extra volume is to accommodate sound insulation. Unfortunately in the case of the Samsung unit for certain (not sure about the others) this pushes the volume over 0.6cu m which is the max allowed under permitted development. Hopefully this figure may be raised soon, as suggested in the consultation carried out by DENZ earlier in the year (before the election).

Correct sadly, its been a two year nightmare, thanks to the industry and more particularly a mad planning authority which, if you need/seek planning permission, requires a heat pump to be 50 times (17dB) quieter than national standards. If I knew two years ago what I know now, I would have gone about this a different way! However today there is light on the horizon in the form of the outcome from my planning appeal, which was to uphold the appeal and thus grant permission. Better still the 'conditions' the planning inspector has imposed are more favourable (in my view) even than I had requested, and totally trash the conditions proposed by my planning authority which would have meant that, when the heat pump fails in say 20 years time, I would have been obliged to replace it with exactly the same model of heat pump, or seek a new planning approval! So with an industry that has matured a bit, and the knowledge accumulated over the the two years of pain (the knowledge, not the pain, mostly due to the members of this forum and the Renewable Heating Hub), I can now start to move forward! Strictly I should wait 6 weeks, because that's the time within which the decision of a planning inspector can (like any planning approval) be challenged by judicial review.

Environmentally probably not in most cases. Heat pump will reduce CO2 emissions to 33% of emissions with fossil fuel, few properties could achieve that by fabric upgrades alone That said there is good financial logic in first upgrading the fabric then doing the heat pump so on balance I dont see a reason to oppose that approach.

@allthatpebbledash Original legislation (as most recently amended), which is definitive, is here https://www.legislation.gov.uk/uksi/2022/565/contents I can't find any requirement to disconnect gas. Nor have I seen this stated elsewhere in any guidance I have read. Suggest you ask whoever advised you to give you the clause number.

Why an ashp? Because your second sentence is utter nonsense.

Yep that also. Either way probably easier than re orientation of the pipework to fit a diverter valve. Which to choose depends on whether you prefer plumbing or wiring. I know which I would choose but others will doubtless choose the plumbing.

Or, much easier (if it has been miswired as s plan) organise for one to be off when the other is on. At most this needs a relay and depending on the contacts available not even that. No plumbing needed. However first check nothing is malfunctioning before concluding a mis-wire

That comment, while quite probably true, is scary. Do we really conclude that your local plumber can't cope with diagnosing a fault in a couple of standard valves? This is very, very simple plumbing, not rocket science and nothing really to do with heat pumps (same principles apply to any boiler with variable flow temperature/weather compensation); plumbers use these valves all the time. Are they really incapable of making the leap? Sadly possibly we do reach that conclusion.

Most older houses have an 'airing cupboard' with a cylinder in in which slightly damp clothes are placed (after 'drying') to finish the drying off process. Towels are also often stored there and they can also be good for proving dough. Basically if the cylinder isnt too large and the plumbing is kept compact the space above and in front/to the side has a useful purpose!

All of the monitoring software will work, the challenge is to work out the cheapest way to get the data to it. @JohnMohas set out the basics, so it's a case of how can you get at it?. The data on your heat pump is sparse so I don't know what it provides natively (eg via some sort of bus), but that's the place to start. If you can't get anything out of the controller you need a flow/ water power meter such as sharky and others sell, an electrical power meter eg shelly, and temperature sensors for inside and outside. These can then hook up to the software. It's a bit of a pity this is needed, the heat pump controller 'knows' most of the figures, it's a case of whether it exposes them.

What ashp do you have. Openenergymonitor and home assistant are both free software, any cost is the interface to the system which depends on the system you have. Several native controllers give basic stats

It might be worth taking a look at Icelandic heating sites where hot spring heating is common, as is pumping the hot spring water straight to the tap. When I went there for a holiday last year I got used to the smell of sulphur when I ran hot water. Actually rather nice once you get over the shock.

Indeed, I had the same thought. Also the min bend radius of the commercial pipe is horrid.

Thanks; that's actually the conclusion Im rapidly coming to, but faced with an unpleasant problem I like to explore alternatives even if unconventional to ensure convention isn't hiding untruths. A few years ago many people would have said (and some still do say) 'just put in a buffer tank like any sensible person would!'. Hopefully, as I say, the issue doesn't arise and my planning appeal is granted for a location close to the house. My (very) back of the envelope calculations using figures from a commercial twin pipe insulated system suggested a loss of order 300W and order 2-6% efficiency penalty if I need to remote it; not disastrous but not desirable either.