Vaillant high(er) temperature ASHP?

[ProDave]

3 minutes ago, Nickfromwales said:

 

3. That will not satisfy G3. End of. The pressurised cylinder categorically must have a stat on it that arrests the input of heat.

 

Let me explain more.

 

I do have a cylinder stat and that cylinder stat is connected to the motorised valve that feeds the how water in from the ASHP.

 

But it does NOT use that as it's normal control.

 

The Heat pump has a temperature probe that sits in a thermostat pocket and the heat pump stops heating when that probe senses it has reached the set temperature.  That enables you to adjust the set temperature from the heat pumps control panel.

 

The Tank thermostat and motorised valve are there as the safety device to shut off the heat source should the heat pump malfunction and not stop heating, and must be set to a higher temperature than your normal hot water target temperature.

 

If that does not comply I don't know what you can do about it. I am sure most heat pump setups are like that.  I could lower the tank thermostat temperature to try and match it, but if the tank thermostat turned off 1 degree before the heat pump thought it was hot enough then the heat pump would carry on trying to get it to target (with the water just bypassing)

[Nickfromwales]

24 minutes ago, ProDave said:

Let me explain more.

 

I do have a cylinder stat and that cylinder stat is connected to the motorised valve that feeds the how water in from the ASHP.

 

But it does NOT use that as it's normal control.

 

The Heat pump has a temperature probe that sits in a thermostat pocket and the heat pump stops heating when that probe senses it has reached the set temperature.  That enables you to adjust the set temperature from the heat pumps control panel.

 

The Tank thermostat and motorised valve are there as the safety device to shut off the heat source should the heat pump malfunction and not stop heating, and must be set to a higher temperature than your normal hot water target temperature.

 

If that does not comply I don't know what you can do about it. I am sure most heat pump setups are like that.  I could lower the tank thermostat temperature to try and match it, but if the tank thermostat turned off 1 degree before the heat pump thought it was hot enough then the heat pump would carry on trying to get it to target (with the water just bypassing)

That lot = compliant.

The only non-compliant part of that installation now is........................................................ You!!

[ProDave]

Fear not @Nickfromwales  My friendly plumber is going to test it and sign the installation paperwork at the same time he does my Gas Safe test and certificate.

[Jeremy Harris]

21 hours ago, joth said:

 

Being able to bring sunamp back into the mix as a viable option is of some interest, except I finally got back numbers for the heatloss of a 300L tank with 100mm of insulation and it's really not that much worse than a sunamp Uniq12 -- 1.3 vs 0.9 kWh/day.  If we keep the cylinder at 50°C and don't have it fully charged all the time I think we might actually achieve lower heat loss with the cylinder than with the sunamp (nice thing with the mixergy tank is comprehensive feedback on how much charge it's holding, vs none on the sunamp).

Removing heat loss from the equation, it comes to cost and reliability vs space; as we have enough space for the cylinder I think the decision will be made for me. 

 

 

The real problem here is that the methodology for determining cylinder heat loss uses a tapping cycle that is nothing like real-world use, if the cylinder is kept hot most of the time.  As an example, I bought a 260 litre thermal store that had a stated heat loss of 1.8 kWh/24 hours.  In reality, when run at 65°C, the measured heat loss was over 3.5 kWh/24 hours.  That was with a double thickness sprayed foam insulation layer that I'd asked the manufacturer to add, which should have reduced the spec figure of 1.8 kWh/24 hours a bit.  The heat loss was so great that our services room reached temperatures of around 40°C, and the inside face of the door leading to it cracked quite badly.  I added an extra layer of insulation, by making up an octagonal box of PIR foam, which was foamed to the tank, with all the joints taped, and that reduced the loss to around 2.5 kWh/24 hours, but it still didn't meet the spec.  Reducing the temperature to 55°C reduced the loss to around the spec figure.

 

I can say from experience of having both a very well insulated thermal store and a Sunamp in the same location, doing the same job, that the real world heat losses from the Sunamp are far lower than those from the thermal store.  The 9 - 10 kWh Sunamp UniQ we have has a stated heat loss of 0.738 kWh/24 hours, so less than 1/3rd of the measured heat loss we had from the "super insulated" thermal store, accepting that, at 210 litres equivalent capacity, it's a bit smaller.  I doubt that any 210 litre UVC has a real world heat loss much below 1.5 kWh/24 hours, though, which still makes the Sunamp twice as efficient.

[joe90]

2 hours ago, Nickfromwales said:

In 20 years the SA will have paid for itself

 

Ha, I,ll be dead by then.?  I cannot argue heat loss figures but my DHW tank at 48’ hardly warms the airing cupboard at all.(like @ProDave).

[SteamyTea]

I think @JSHarris had one of those combined cylinders with the F&E tank on top.

Mine is just a bog standard cylinder. The F&E is in the loft.

Have insulated the pipes.

[Nickfromwales]

55 minutes ago, joe90 said:

 

Ha, I,ll be dead by then.?  I cannot argue heat loss figures but my DHW tank at 48’ hardly warms the airing cupboard at all.(like @ProDave).

I did have a chat with an elderly couple at the Kent Build It event and had to politely tell them they'd need to live another 25 years to break even. I think 5 would have been pushing it lol.

They very politely thanked me for my diligence, and explained that they wanted to preserve their kids and grand-kids futures in a property that was to stay in the family for the next few generations. Very lovely couple they were too.

[Dan F]

@Nick1c  The product Vaillant are launching, that Sunamp have mentioned, is an R290 (propane) Monobloc ASHP, not CO2.  Expected lauch date is 1st June 2020.

[BMcN]

Anyone heard any more updates on this product?  

 

I will be in the market for an ASHP in the coming months.

[Dan F]

58 minutes ago, BMcN said:

Anyone heard any more updates on this product?  

 

I will be in the market for an ASHP in the coming months.

 

1st June 2020 (pre-launch in April). Clik on tweet below and expand the replies to see further info on dates..

 

 

Also:

https://www.vaillant.co.uk/downloads/aproducts/r290/r290-leaflet-final-aw-1604751.pdf

Edited December 5, 2019 by Dan Feist

[joth]

25 minutes ago, Dan Feist said:

 

1st June 2020 (pre-launch in April). Clik on tweet below and expand the replies to see further info on dates..

 

 

Also:

https://www.vaillant.co.uk/downloads/aproducts/r290/r290-leaflet-final-aw-1604751.pdf

 

A bit cheeky request, but as you have their attention (and, a twitter account),  do you fancy tweeting them again to ask if the UK [MCS certified] model will support cooling mode too? :-) 

 

EDIT to add: their existing R410A based aroTHERM does support cooling, but only mentioned as an aside in the installation manual, so I'm guessing the R290 will be similar.

 

Edited December 5, 2019 by joth

[Dan F]

19 minutes ago, joth said:

 

A bit cheeky request, but as you have their attention (and, a twitter account),  do you fancy tweeting them again to ask if the UK [MCS certified] model will support cooling mode too? ?

 

EDIT to add: their existing R410A based aroTHERM does support cooling, but only mentioned as an aside in the installation manual, so I'm guessing the R290 will be similar.

 

 

Was told product is currently going through MCS and then PCDB (??).  I will chase for specs in Jan now I have their email etc.

[A_L]

3 hours ago, Dan Feist said:

Was told product is currently going through MCS and then PCDB (??). 

 

PCDB = Product Characteristics DataBase - performance characteristics used in RdSAP (epc's)  and SAP

[joth]

Latest RHI myth or little known fact: heatpumps are limited to max 65°C to be eligible for RHI payments. Limit applies to heating and DHW

Was told this by a certified installer, but I can't find any reference for it. If it's in the MCS rather than RHI guidelines, it would also impact ability to install them under permitted development.

 

If true, it would be a significant impact on take up of these higher temp heat pumps, or using sunamp PCM58 with a heatpump. Interested if anyone else has ever heard of this?

Edited December 7, 2019 by joth

[Nick1c]

I spoke to someone this week about this. Apparently there are 2 models, one with a box of tricks integrated into it (including an electric backup heater) & one as a bare unit. The bare unit is planned to be available in June, the other in April. He expects it to support cooling. The RHI temperature limit needs investigation though.....

[joth]

25 minutes ago, Nick1c said:

I spoke to someone this week about this. Apparently there are 2 models, one with a box of tricks integrated into it (including an electric backup heater) & one as a bare unit. The bare unit is planned to be available in June, the other in April. He expects it to support cooling. The RHI temperature limit needs investigation though.....

Interesting. Was that valliant installer?

 

Not sure how sensible it is having the backup heater in the monobloc, outside the thermal envelope. Would be interesting to find out what other tricks are planned for the box. 

[oranjeboom]

On 07/12/2019 at 08:56, joth said:

Limit applies to heating and DHW

 

Your HP does not need to do both space and DHW for RHI eligibility. Not sure if that's what you were implying here. 

 

https://www.ofgem.gov.uk/environmental-programmes/domestic-rhi/applicants/eligible-heating-systems:

 

 

 

On 07/12/2019 at 08:56, joth said:

heatpumps are limited to max 65°C to be eligible for RHI payments

 

Not seen that in any docs either. Best bet is to refer to the eligibility list and see whether the HT pump is included. I did note that Hitachi appear to have a HT pump on there with temp up to 75c (if i read that correct):

 

 

Link to PEL: https://www.ofgem.gov.uk/publications-and-updates/domestic-renewable-heat-incentive-product-eligibility-list-pel

 

[joth]

8 minutes ago, oranjeboom said:

On 07/12/2019 at 08:56, joth said:

Limit applies to heating and DHW

 

Your HP does not need to do both space and DHW for RHI eligibility. Not sure if that's what you were implying here. 

 

 

no,  not exactly what I meant. (I knew at the time it was ambiguous wording but at the time couldn't think of any clearer way to say it).

 

What I mean is: if you have a ASHP that is say set to 35°C for heating and 70°C  for DHW then the DHW temp would invalidate it for claiming any RHI payments at all. There's no option for saying "please only consider the heating output, and ignore the DHW part".  That is what I was being told by this installer, anyway.

There's so much misinformation and confusion out there already, I don't put a whole lot of weight behind this one specific view point. and I feel a little ashamed I may be perpetuating another myth here -- just wanted to test the water (no pun intended) and see if anyone else had heard of this before writing it off

 

14 minutes ago, oranjeboom said:

I did note that Hitachi appear to have a HT pump on there with temp up to 75c (if i read that correct):

 

Thanks - that's a useful reference.

I guess, like cooling, it could  be that the model is compliant, so long as it is setup a particular way. And.. there's very stopping a technically capable user from re-configuring it after the MCS install was signed off..... [apart from the fear of making an annual declaration].

All in all I'm really inclined to make my choices I'm not getting RHI anyway. Mostly just curious as to the position to try and guess how it might impact of uptake of them.

 

 

 

[DenkiJidousha]

(Several people have already pointed out it was R290 propane, not C02 - but that's almost as good from a green house warming point of view)

Edited December 29, 2019 by DenkiJidousha

[PeterW]

When I looked into this I couldn’t make the maths stack up. 
 

If you take a standard ASHP with a 50c output and you want a 300 litre tank at 70c, then you’ll use a little over 1000kWh in a year. At direct electric prices on E7, that is about £70/yr. At a CoP of 2 - which is reasonably optimistic at 70c, this reduces to £35. 
 

A HT ASHP with a lifetime of 20 years would need to cost less than £700 more than a standard ASHP to make financial sense over using a standard 3Kw immersion to do the top up. Most I’ve seen are north of £12-1500 more so it’s a no brainer. 

[SteamyTea]

16 minutes ago, DenkiJidousha said:

Several people have already pointed out it was R290 propane, not C02 - but that's almost as good from a green house warming point of view

Only 3.3 times worse.

Propane molecule followed by Carbon Dioxide.

 

[oranjeboom]

On 10/10/2019 at 10:45, Nickfromwales said:

I’m chewing through some “inside information” atm, and I’ll update accordingly ?

 Any update on these CO2 units Nick? Suspect they will be too uber niche for the UK and will come with an uber niche price? And was it CO2 or propane (Vaillant or Nibe) ?

Edited January 2, 2020 by oranjeboom

[joth]

50 minutes ago, oranjeboom said:

will be too uber niche for the UK and will come with an uber niche price?

The quotation from sunamp rep in OP said "price will be in the ballpark of their current offerings"..... So all riding on that!

(I guess that means I should go ahead and get a quote for their current offering, as a baseline)

 

[Dan F]

By way of an update, I got some info from Vaillant rep and these R290 "aroTHERM plus" models will apprently:

 

1) Be due out in June.

2) Have models between 3KW and 12KW.

3) Have COP of up to 5.4  (A+7/W35kW)

4) Have flow max temperature of 75C (COP at 65C is 2.3)

 

EDIT: Full specs haven't been released in U.K. yet, but I found these specs from the Netherlands for some of the models: https://www.vaillant.nl/professioneel/producten/arotherm-plus-warmtepomp-65024.html

 

Edited February 4, 2020 by Dan Feist

[Dreadnaught]

Thanks @Dan Feist. Are you intending to buy one yourself? 

 

I wonder, how does one read "A+7/W35kW"; I am guessing "A" is air temperature and "W" is water temperature?

 

I am following this closely as this as potentially ideal solution for my forthcoming build, combined with a SunAmp.

 

Interestingly, R290 seems to be simply just propane gas (!) (CH₃CH₂CH₃) but it has a desirably "low Global Warming Potential". I believe that a qualified and therefore expensive gas-fitter is not required for installation.