SteamyTea

I shall have to come over and see if that logger is still l logging, that had a couple of the better DHT22 on it. Though you do then your MVHR off in the summer.

Any chance you can log some numbers when the tank is in different states i.e. heated but unused, after use, in use and being heated. Be interesting to see how much turbulence is created. It will if the thermal outputs are equivalent, not if the ASHP is smaller. During those times you can heat the tank up to a higher temperature with a normal immersion heater. Just remember to turn runoff when they leave.

It probably only hits 80% sometime after peak temperature. Suppose the trick is to predict this time of 'not very nice to sit in' combination of temperature and humudity, and start to force more dryer and cooler air in before it becomes uncomfortable.

Large bodies of salt water tend to stabilise the RH. Trouble is there is not enough salt in it to reduce the RH to a comfortably low level.

That is tackling the same problem, but with different technologies. First thing to know is your DHW demands. Do you need 50, 100, 1000 litres a day. Without knowing that, it is just speculation based on guesses. And don't get temperature, energy and power mixed up. They are different things.

electricity prices are pretty stable, and now that the government has committed to supply all housing with RE (and nuclear probably), and with the cheapest form of new generation being wind and solar. I can see prices dropping in real terms. We can generate from wind and solar cheaper than gas now.

Isn't this looking at the problem from the wrong perspective. Rather than say 200lt at 50°C, if you calculate it as the effective energy stored, say 17 MJ, then within a tiny bit, a UVC and a TS, or even a traditional WH cylinder of the same size and the same temperatures, store the same amount of energy. If you extract water (energy) at the same rate, I am really (not being difficult) struggling to see the difference. Now you can 'average' the stored temperature out by allowing turbulence within the store i.e. constant pumping, but that is not the same thing.

Yes, and this is why I am claiming that sizing is important. There will be a slight temperature drop due to the heat exchanger efficiency, but that leaves more energy in the store. If space heating load is also being drawn off at the same time as DHW, then sizing is even more important.

Is there some sort of different physics going on then.

Those prices seem rather high, but a factor of 5.

Something like this, maybe. https://www.ebay.co.uk/i/324152361393

That is just sizing correctly isn't it. My cylinder is 200lt, heated to about 40°C. If I did the same with a 50lt cylinder, I would run out of hot water while filling a bath. Just sizing really, not temperature as such.

I genuinely do not under stand why they will not get 'hot enough', because of the type of cylinder/store.

I shall ponder this, but it is probably just a case of putting in a time delay to allow the RH peaks to settle.

Yes, I do remember fitting a pump (still working) and a mixer tap (gives no problems), to my existing system over a decade ago. Oh and when I had to change my 32 year old cylinder, it was £220 (from your helpful mate) and I got quite a few quid back on the old one. KISS, it is the only way.

Wasn't it done on some grant scheme, so we all have paid for it, already.

I think our old mate Jeremy Harris, who is just west of Salisbury had a list of people he would recommend. The lit may be on his website. http://www.mayfly.eu/

I am not sure about SAP, but seem to remember that there is no RHI on A2AHPs. This is because they are cheaper to start with.

They will probably come and arrest you for attempting an RHI fraud. The NIs and Spanish are the world leaders at this.

It is to do with the nature of phase change materials. When a block of ice changes to liquid water, there is a phase transition at 0°C. During this change, the energy that can be released. Water as a liquid has a specific heat a capacity of 4.2 J/g.K, when it is solid (ice) it is 2 J/g.K When it is actually changing state, is it ~325 J/g.K Now the Sunamp does not have water as the phase change material, so the numbers will be different, but it works on the same principle, it draws the majority of the energy while it undergoes transition. This is why it is hard to use Temperature as a state of charge indicator. It is not linear, but stepped i.e it drops at one rate, levels off, then drops at another rate. The same is true for charging it up, but in reverse, obviously.

You can make it even cheaper to self install if you use a vented DHW system, none of that G3 nonsense. And the kit is cheaper as well, which annoys plumbers as they cannot add on such a large mark up. https://www.gledhill.net/master-pressure-get-g3-qualified/

You may find it cheaper overall to not use the MCS/RHI route. Have you done the costings yet?

Because of the thermal losses through the floor and into the ground. Just a case of working out the losses and see what comes out in the wash.

You may find that UFH is not the best option. Have you considered 'skirting radiators'?

Our Jeremy Harris put in solid copper between his ASHP and the distribution manifold. Then found it noisy. He then RTFM and found that the reason it came with a coiled flexible pipe was to dampen the sound.