Nick1c

Vaillant high(er) temperature ASHP?

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During the course of a conversation with a Sunamp agent they mentioned that Vaillant were bringing out a new ASHP which could deliver a good COP up to 70C (using CO2 as the refrigerant IIRC). Apparently it was launched in Europe recently & will be available April/ May in the UK and the price will be in the ballpark of their current offerings. Has anyone heard about it? The implications, if it’s as good as it sounds, would be pretty significant in terms of the options available for both heating and DHW. 

Edited by Nick1c
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I'm currently in talks with a few people to try and reinvigorate awareness of the possibilities for such devices in the domestic sector, and to get the CO2 ASHP's into the stock piles of the various manufactures / suppliers. Slow take-up at the moment as it's considered uber-niche. Good to hear Vaillant are on board.

I am trying to find some stray units in the UK to go into current, ongoing projects, where they would "do just nicely".

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Just now, Nickfromwales said:

Yip. 

 

 

I much likey. 

Sort it out please. :D 

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

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Just now, Nickfromwales said:

50 dollar?

 

Only if I get a happy finish :) 

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Issue with the CO2 units are that the refrigerant pressures are much higher and the engineers need to re-equip to service them. It is such a niche market that the uptake is very low. 

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Why the need to produce water at 70’ (apart from charging sunamp,s). @ProDave and I are happy producing water at 48’ and find the losses from our (slightly larger) DHW tank acceptable (losses are only true losses when the heating season ends).?

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I’m considering Sunamp, but they might also be used to feed standard sizes radiators, rather than having to fit oversized ones. 

The servicing might be an issue if @PeterW is correct - getting things sorted out 1 mile from lands end isn’t easy at the best of times....

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can't see servicing being an issue really. CO2 is Everywhere. Pubs, fire extinguishers etc. Just needs a new set of gauges...

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1 hour ago, dpmiller said:

can't see servicing being an issue really. CO2 is Everywhere. Pubs, fire extinguishers etc. Just needs a new set of gauges...

 

It's the pressures and they are significantly higher than normal which needs a lot more kit. 

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10 hours ago, PeterW said:

 

It's the pressures and they are significantly higher than normal which needs a lot more kit. 


how much are we talking? We can crowd fund a set for @Nickfromwales in return for special favours forum discount servicing.

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He would need all his FGas certs too .... it’s not the install as they are pretty much the same - I’ve had a Sanyo one for about 8 years - it is the servicing of the gas side.  

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23 hours ago, PeterW said:

He would need all his FGas certs too .... it’s not the install as they are pretty much the same - I’ve had a Sanyo one for about 8 years - it is the servicing of the gas side.  

 

Having been in a small plant room with  @Nickfromwales for numerous hours I can tell you he will have NO problem with F Gas! Arse like a sewer 😝 🤢

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23 hours ago, joe90 said:

Why the need to produce water at 70

It is really a by-product of changing to CO2.

From what I have read, the CO2 is kept in a super critical state, so basically relies on the energy levels of phase change.  This allows more energy transfer by volume.  CO2 does not like being a liquid.

The move to CO2 is to reduce the global warming potential of gas leaks, not improving the efficiency of the unit per se.

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Refrigeration change is the single biggest technology mitigation to climate change on drowdown so it's likely we'll see a number of changes in heatpump tech in coming years.

https://www.drawdown.org/solutions-summary-by-rank 

 

My mind does spin a bit at using CO2 to reduce GWP but it does make sense. I imagine a monobloc ASHP has much less GWP impact  than any split systems so I won't let this dominate my decision process.

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. 

Edited by joth
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19 hours ago, joth said:

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

There may be a different methodology used. So treat the numbers with caution.

Having said that, because of the losses from my cylinder being higher than my usage some days, I added extra insulation.

Not a hard job to do, if you make sure the box for the cylinder is in a sensible size i.e. not small.

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And the losses are only losses in the summer!.

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Re cylinder heat loss.

 

I think a lot of people don't insulate the pipes leading to the cylinder very well.  You need to insulate them ALL.  Even the over pressure / temp discharge pipe from mine is insulated, otherwise it was warm (by conduction from the cylinder) and losing heat.

 

The room the cylinder is in never seems any hotter than the other bedrooms so the loss from the cylinder cannot be very great.

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On 10/10/2019 at 11:54, joe90 said:

Why the need to produce water at 70’ (apart from charging sunamp,s). @ProDave and I are happy producing water at 48’ and find the losses from our (slightly larger) DHW tank acceptable (losses are only true losses when the heating season ends).?

Significantly higher when you heat the HWC via the immersion ( from excess PV ) where the cylinder will spend most of the summer at >70oC ;) 

 

On 11/10/2019 at 07:57, Barney12 said:


how much are we talking? We can crowd fund a set for @Nickfromwales in return for special favours forum discount servicing.

Fear not! I have 🤞 an F-Gas qualified fitter coming on board full-time in the next few months if all goes well ( and we can work together, e.g. he can deal with my OCD :D ).

 

19 hours ago, joth said:

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

I'd be VERY interested as to how those figures were arrived at......I'd bet my arse, no further comment required from @Barney12, that it was not in a real-life install with all the connected pipework in the equation.

You won't keep the losses lower than a Sunamp! Temp range vs losses are relative, so if you reduce the temp that the SA stored at you'd have even lower losses stated from that.

Apples with apples please!!

19 hours ago, joth said:

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.

Have you factored in G3 annual service / maintenance / inspection? Over the first decade you are set to invest a minimum of £1k in paying someone to come out and say "that's nice, whadduzitdo?"

FYI, A PROPER annual G3 inspection comprises of;

  1. Run off all of the stored hot water until the cylinder is cold.
  2. Turn the heating controls on and stand there whilst it heats back up again.
  3. Witness the temperature that the cylinder gets to / that the cylinder stat tells the heat source that the cylinder is satisfied and shuts off demand and that the zone valves etc are functioning correctly.
  4. Test all the pressure reducing / pressure relief valves ( which usually starts the PRV prematurely leaking after a few years e.g. so nobody ever does it!! ).
  5. Shut off and drain down the pressure in the cold water side and then check the pre-charge level in the expansion vessel. Not doing that is the #1 cause of early pressurised cylinder failure.
  6. See you the same time next year to do that all over again..........

Item 5 above is the only thing you have to do with the SA unit, and its easy to do that DIY ( e.g. you don't need to be G3 qualified ). In 20 years the SA will have paid for itself, and in 20 years the pressurised cylinder will have cost you 3x what it costs to buy. 🤔

 

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13 minutes ago, Nickfromwales said:
  1. Run off all of the stored hot water until the cylinder is cold.
  2. Turn the heating controls on and stand there whilst it heats back up again.
  3. Witness the temperature that the cylinder gets to / that the cylinder stat tells the heat source that the cylinder is satisfied and shuts off demand and that the zone valves etc are functioning correctly.
  4. Test all the pressure reducing / pressure relief valves ( which usually starts the PRV prematurely leaking after a few years e.g. so nobody ever does it!! ).
  5. Shut off and drain down the pressure in the cold water side and then check the pre-charge level in the expansion vessel. Not doing that is the #1 cause of early pressurised cylinder failure.
  6. See you the same time next year to do that all over again..........

1: I am buggered if I want someone wasting a tank of hot water.    If I do it myself I can do the tests just after someone has had a bath and USED the hot water rather than wasting it.

2: Heating from  cold with my ASHP will take about 2 hours. Partly because it only heats DHW in half hour bursts and then  waits half an hour.  I am buggered if I am going to pay someone to play on facebook on his phone while he waits that long.

3: My cylinder will stop heating when the ASHP's temperature probe in a pocket says it is hot enough.  You would have to add an EXTRA test, heat the cylinder even hotter with the immersion heater to confirm the cylinder thermostat clicks off at about 70 degrees and shuts the motorised valve.  That does NOT normally happen in normal use, but is there purely as a safety function.  The tester would probably not understand what is going on, and tell me it is "wrong"

4: easy

5: easy

 

I know I will incur the wrath of the forum, but I will stick to doing the tests myself.

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Just now, ProDave said:

1: I am buggered if I want someone wasting a tank of hot water.  

2: Heating from  cold with my ASHP will take about 2 hours. Partly because it only heats DHW in half hour bursts and the  waits half an hour.  IU am buggered if I am going to pay someone to play on facebook on his phone while he waits that long.

3: My cylinder will stop heating when the ASHP's temperature probe in a pocket says it is hot enough.  You would have to add an EXTRA test, heat the cylinder even hotter with the immersion heater to confirm the cylinder thermostat clicks off at about 70 degrees and shuts the motorised valve.  That does NOT normally happen in normal use, but is there purely as a safety function.  The tester would probably not understand what is going on, and tell me it is "wrong"

4: easy

5: easy

 

I know I will incur the wrath of the forum, but I will stick to doing the tests myself.

Check your building insurance as not having this in a block of flats left a L/L with a bill of over £30k to pay out of their own pockets.

1. Heating your tank will cost less than a quid, if you do it midday. I'll give you the quid ok ;) 

2. Up to you.

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

4. Your'e not qualified to do it.

5. See 4.

 

It's the wrath of your wife that'll see you 6' under if you have a failure and the insurance doesn't stump up ;) 

After all the money you saved building your own home, had you not factored  just paying for the things you have to pay for...........? 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Disclaimer;

I'm not actually going to give you the quid as I know you'll take it ! Ha ha.

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