SunAmp : Snog, Marry, Avoid?

[PeterW]

That would need to use peak power - my fag packet design allowed the use of E7 to fully charge the Sunamp overnight.

[Dreadnaught]

1 minute ago, PeterW said:

That would need to use peak power - my fag packet design allowed the use of E7 to fully charge the Sunamp overnight.

 

Ah I see. Good point.

[Jeremy Harris]

6 minutes ago, PeterW said:

@JSHarris I'm thinking for those that want to run an ASHP and a Hot Water Sunamp, so it is only being used as a booster to allow you to use just a SunAmp DHW on E7 alone but use the ASHP

 

4 minutes ago, Dreadnaught said:

 

Wouldn't it be better to have a PCM 34 Sunamp and the Steibel Eltron in line water heater between the Sunamp and the shower head?

 

Should work OK, and it would need the PCM 34 version, as the PCM 58 wouldn't get hot enough to melt with charge from an ASHP.  I originally fitted the instant water heater as a way to provide emergency hot water when we had the Sunamp PV, but then discovered that we never needed to use it, as the Sunamp PV always stored enough for our needs (unlike it's bgger, heavier and more expensive replacement).

 

 

Edited to add:

 

Sorry, typed the above before reading the later replies...

Edited February 27, 2019 by JSHarris
Added comment

[Barney12]

Why are we debating "work arounds"? The product should just do as advertised! It doesn't!!

 

"End of chat" (to quote a Welsh plumber from around these parts)

 

[Onoff]

14 minutes ago, Barney12 said:

Why are we debating "work arounds"? The product should just do as advertised! It doesn't!!

 

"End of chat" (to quote a Welsh plumber from around these parts)

 

 

Did you pay by credit card? 

[Gone West]

6 hours ago, recoveringacademic said:

For those of us contemplating fitting a SunAmp box, should we   SNOG, MARRY, AVOID?

I'm very glad I AVOIDED.

[Sue B]

Avoid

[joe90]

1 hour ago, Barney12 said:

Why are we debating "work arounds"? The product should just do as advertised! It doesn't!!

 

I agree, the product should be “fit for purpose” . I suppose @JSHarris sort of agreed to be a “tester” for them originally by giving feedback on performance but his original unit appears to have worked far better than the new one. I would be looking to get my money back if it were me (not to say the problem can’t be sorted out eventually).

[Ed Davies]

7 hours ago, recoveringacademic said:

Use the low power circuit to 'charge' the box (what does charge mean ?)

 

Same as with an electric battery: put energy in to get back out later. Just that the energy is stored as heat (sensible (actual hotness) or latent (phase change)) rather than the chemical changes which happen in an electric battery.

 

7 hours ago, recoveringacademic said:

The main selling point of the Sun Amp is the much lower standing heat losses than a HW tank.

 

I see the main selling points as:

 

1) Lower standing heat losses, as said.

2) Lower temperature of storage allowing charging from lower-temperature sources.

 

3) Smaller size.

 

As @ProDave says it would be better if the temperature was a bit lower than 58 °C when the source is an ASHP or, for that matter, solar thermal.

[Ed Davies]

5 hours ago, Dreadnaught said:

Would you be using the PCM 34 of 58? 

 

58 I assume. But, I wonder, is there a role for a PCM 34 cell too, @le-cerveau-style? Presumably not.

 

PCM58 for direct production of DHW. What I have in mind is preheat from a buffer tank as @JSHarris does. I did wonder about PCM34 for the buffer tank role up until I heard PCM34 was twice as expensive. Any heat loss from the buffer will be useful space heating, anyway.

[Jeremy Harris]

48 minutes ago, joe90 said:

 

I agree, the product should be “fit for purpose” . I suppose @JSHarris sort of agreed to be a “tester” for them originally by giving feedback on performance but his original unit appears to have worked far better than the new one. I would be looking to get my money back if it were me (not to say the problem can’t be sorted out eventually).

 

Probably worth restating the circumstances surrounding my acquisition of an early Sunamp PV, and our current Sunamp Uniq 9 eHW, as they are different, and although I think I explained my relationship with Sunamp back in 2015, that was on ebuild, not here, so is now probably lost.

 

I was introduced to Sunamp by Damon Hart-Davis, who told me that Sunamp were looking for "early adopters" for their Sunamp PV.  I entered into an agreement with Sunamp which meant we were supplied with an early production/pre-production Sunamp PV, on the understanding that I would report back to them on it's performance, would openly and honestly publish my experiences on eBuild and our build blog and agree to exchange the heat cells for replacements after two years, so that Sunamp could undertake a "post mortem" on them.  In return for this our Sunamp PV was supplied at a substantial discount (but it was NOT free, by any stretch of the imagination).

 

As it happens, Sunamp chose not to ask me to exchange the cells in the Sunamp PV when the 2 years was up, so we carried on using it.  The Sunamp PV worked very well, and I was more than happy to recommend it.  Not long after the Sunamp Uniq range was released last year, I decided that it would be useful to increase our storage capacity.  The Sunamp PV, with it's 5 kWh capacity, was perfectly adequate, but, as we can easily generate 20 to 30 kWh/day I felt that it would be useful to be able to store more heat, so that we had a reserve for days when there was little PV generation.  The idea was to be able to increase our self-consumption, and reduce out winter reliance on grid boost charging.

 

Sunamp agreed to sell me a Uniq 9 eHW at a discount, in return for me exchanging the Sunamp PV and providing them with a water sample.  I'm not able to say what the discount was, but can confirm that I paid well over £1000 for the Sunamp UniQ, plus the exchange of the Sunamp PV that had cost close to the same amount. 

 

To sum up, I agreed to be a tester/early adopter when I purchased the Sunamp PV, but not when I purchased the Sunamp UniQ.  I'm grateful for the discount from Sunamp, but overall I have paid them a fair bit more than the full purchase price for a Sunamp UniQ.

[Oz07]

I understand so little of this debate. It's almost a different language. Pcm 32 vs 58. My brain is scrambled

[Jeremy Harris]

1 minute ago, Oz07 said:

I understand so little of this debate. It's almost a different language. Pcm 32 vs 58. My brain is scrambled

 

TBH, that's very understandable, as the way these things work isn't something we've ever seen before in any domestic heating/hot water system.  It is a bit geeky, and to Sunamp's credit they have worked quite hard to try to simplify their promotional material, so as to emphasise the advantages that using a phase change material (PCM) offers.

 

We're all familiar with the core principle that these things use, though.  Ever noticed how large lumps of snow/ice hang around for a long time after the temperature rises well above freezing?  Part of that is due to the relatively high energy needed to melt ice (cause it to change phase from solid to liquid). 

 

The stuff inside a Sunamp uses the same principle, but with stuff that melts at either 34°C or 58°C (PCM 34 or PCM 58).  This property enables the Sunamp to store a lot more heat within a given volume than a water tank of the same capacity.  When "charged" a Sunamp is full of liquid PCM, when discharged it's full of solid PCM.  That change from liquid to solid releases a lot of heat, and it's reversible, with virtually no loss, so heating the solid to turn it into liquid absorbs a lot of heat.

[ToughButterCup]

19 minutes ago, JSHarris said:

[...]

The stuff inside a Sunamp uses the same principle, but with stuff that melts at either 34°C or 58°C (PCM 34 or PCM 58).  This property enables the Sunamp to store a lot more heat within a given volume than a water tank of the same capacity.  When "charged" a Sunamp is full of liquid PCM, when discharged it's full of solid PCM.  That change from liquid to solid releases a lot of heat, and it's reversible, with virtually no loss, so heating the solid to turn it into liquid absorbs a lot of heat.

 

Thank you.

[Onoff]

Presumably it's feasible to plumb for a TS/UVC in such a way it's a quick swap if SA ever sort the issues?

[Oz07]

Thanks too Jeremy. Still scrambled however. Do sunamp do a product to melt the ice on my windscreen or does it stop working when windscreen is 52% de iced 

[ProDave]

10 minutes ago, Oz07 said:

Thanks too Jeremy. Still scrambled however. Do sunamp do a product to melt the ice on my windscreen or does it stop working when windscreen is 52% de iced 

Not quite.  It won't start de icing until 50% of it is iced over.  Not much help if the 49% that is iced over is on the drivers side.

[Nick1c]

I hope that this is sorted out by the time we need to make a decision. The low standing losses and (at least notional) 'charging' flexibility is very appealing. 

This has been dissected in detail by minds far greater than mine but could someone explain why the following wouldn't work:

Pre heat water via an ASHP (Pv if possible) to a temperature that makes best use of the COP.

Feed the UFH if needed straight from the ASHP.

Use an electrical heater (powered by Pv when possible) to raise this waters temperature to charge the sunamp. 

In summer if cooling is needed there should be plenty of Pv available so use some for the ASHP in cooling mode and some for the electrical water heater. 

I wait to have the scales lifted from my eyes....

[ProDave]

14 minutes ago, Nick1c said:

I hope that this is sorted out by the time we need to make a decision. The low standing losses and (at least notional) 'charging' flexibility is very appealing. 

This has been dissected in detail by minds far greater than mine but could someone explain why the following wouldn't work:

Pre heat water via an ASHP (Pv if possible) to a temperature that makes best use of the COP.

Feed the UFH if needed straight from the ASHP.

Use an electrical heater (powered by Pv when possible) to raise this waters temperature to charge the sunamp. 

In summer if cooling is needed there should be plenty of Pv available so use some for the ASHP in cooling mode and some for the electrical water heater. 

I wait to have the scales lifted from my eyes....

I run my UFH direct from the ASHP with the flow temperature from the ASHP set at 39 degrees.  This seems to work well.

 

Several others run a buffer / pre heat tank at a similar level,

 

A modulating instant water heater similar to the Steibel Eltron one that I have would lift the HW from say 40 degrees to point of use temperature say 50 degrees.  

 

But why bother?  I run my HW tank at 48 degrees heated by the ASHP and it does that okay.  It won't be as efficient when heating to that temperature and under certain weather conditions will have to stop to defrost from time to time, but it will still be more efficient than resistance heating.

 

But this is all off topic which is about the Sun Amp's.

 

[Ed Davies]

9 minutes ago, ProDave said:

I run my HW tank at 48 degrees heated by the ASHP and it does that okay.

 

If a PCM48 existed it would be ideal for that use.

 

But how much hit does the CoP take if you run the ASHP at 60 °C, or a tad more, to charge a PCM58? It'd still be significantly better than one, I imagine. Bearing in mind that if you have a pre-heat buffer at your UFH temperatures then the quantity of heat you need to put in at the higher temperature would be fairly small.

[Nick1c]

In the absence of Pv there would be no/ much less point, but wouldn't Pv provide a 'free' boost for a large proportion of the year & E7 a cheap boost for the remainder with the sunamp acting as a low loss store until you need the heat?

[Nickfromwales]

I've sat outside these exchanges for a while as I have fitted a number of SA units and wished for the 'whole picture' to be freely discussed without my interjection. I think that's been exercised so time for a spanner in the works...….

For the majority of commentators, there is a wide knowledge and understanding of how the unit works, vs say Mr & Mrs Smith who know zero and just want hot water. So, I have fitted these units ( PCM 58 btw as PCM 34 is currently removed from sale until the bench test unit achieves the required number of cycles that will confirm it's longevity / robustness ) for a good few Smiths and so far so good.

I have fitted ones for pre-heat to combi boilers, one's which replaced a copper vented hot water cylinder and one's which do space heating & DHW combined. All I can do is offer my honest, impartial feedback to this exchange in order to answer the OP's questions, so FWIW;

One unit, a PCM 58 size 9 Hw+I, is in and working and has been for about 5 months. This is for a family of 3, and the SA is their only means of producing DHW. If there was any issue with this I would be the FIRST to know.

I have also fitted a size 6 and a size 3 in an architects house, ( the 6 doing the family bathroom / utility / kitchen and the 3 doing the ensuite only ), and likewise, as their only means of producing DHW, again, if there were issues I'd be getting shouted at accordingly.

I am being shouted at by neither, and both have given me testimonials for both the units and my services in fitting them with the latter asking me to go back to undertake further work there.

 

I felt I should comment to give some balance, and it should also be noted that I fitted the 2 units at @Barney12's home where he has had nothing but grief from day 1. Where the issues may possibly lay is in the history of these units meeting the 'adopters', where some folk were dealing with a company still in development, whereas now they refuse point blank to sell to the public, nor to respond to the public as they should have done ( or not done ) from day 1. Because they now only sell to resellers the buck stops with the installer, and the only installers permitted to buy and sell these units must prove their worth to SA and gain the necessary accreditation to boot. My point being this; that to specify and install these units you need to know how they work, what their USEFUL capacity is, and which unit is to be selected correctly for each instance. For eg; I have been asked to specify one for a client to replace a copper DHW cylinder and on paper a size 9 should suffice. As it will be heated by PV I have subsequently viewed the 9 as a 6, so at 50% depleted it would not have sufficient capacity to fulfil the needs of the household, so I have selected and subsequently recommended a size 12 unit for this particular instance. That unit will be fit and forget, and I will ever hear from them again, of that I am sure, but that is because I know how to specify these correctly. Simple.

The controller 'issues' are something that are best described as 'quirks', but are known and should have be considered by SA when stating the equivalent capacities in their installation manuals, especially when they knew they would end up in the hands of folk who couldn't decipher them properly. That point is NOW moot however as the units now being distributed should only be coming to 'the Smiths' via an approved SA installer so the 'thinking' would be removed, the quirks not causing any sleepless nights, and as above they should be fit and forget. The only remaining 'issue' then is the cost, where the client may consider this approach an unnecessary expenditure, eg where a size 9 on paper should suffice, and I recommend a 12 ( so an uplift in cost of ~£300 ), and the client has to bear that uplift for me to be able to recommend a SA...…..BUT...…..they'd never be aware of that mechanism as I would just be quoting for the size / type of unit which I calculated would be suitable for their needs and they would simply either accept or decline the quote. Ultimately SA is 'the loser' in that situation as I would have to make their product look expensive where it could / should be cheaper, but all this is early days in the grand scheme where most here probably do not know that SA have now pulled away from the public as aforementioned, in recent months, to ensure this kind of error cannot happen anymore. Credit to them for raising that drawbridge, albeit a little late in the day, but as the saying goes "pointless locking the stable after the horse as done a bunk" so they ( SA ) should really have been making more effort to remain in constant / constructive dialogue with their "early adopters" which it seems they haven't.

@recoveringacademic;

Should you be snogging this box of salty yogurt? I'd prefer not to have to bleach that image from my mind....

@mrsRA would be a bit pissed off if there were another in your marriage....

Avoid? No. 

Specify properly and install to suit? Yes.

 

Tin Hat suitably super-glued on and awaiting the flack...…..

[Nickfromwales]

34 minutes ago, Nick1c said:

In the absence of Pv there would be no/ much less point, but wouldn't Pv provide a 'free' boost for a large proportion of the year & E7 a cheap boost for the remainder with the sunamp acting as a low loss store until you need the heat?

Exactly the conversation I had today.

It needs to be implemented to make good use of it's capabilities, and today I told someone that it would be best to simply switch it off for 3 or 4 months of the year where there would be insufficient PV to charge the AC batteries AND offset the house base loads eg during peak winter. 

[paulmb]

In the discussion of using ASHP's with SA products, can someone clarify where the 'rHW' and 'rHeat' configurations fit?  I'm referring to the SA products:

 

• UniQ rHW Heat battery for domestic hot water only, which is heated by an external heat pump using the heat pump refrigerant circuit i.e. the refrigerant flows through the heat exchanger in the UniQ rHW store. (OEM only) 

• UniQ rHeat Heat battery for space heating only, which is heated by an external heat pump using the heat pump refrigerant circuit i.e. the refrigerant flows through the heat exchanger in the UniQ rHeat store. (OEM only) 

I'm not familiar in detail with ASHP's, but was told yesterday that there are some that require a 'refrigeration engineer' to install and service, and some that don't - so do the above SA models require a refrigeration engineer and hence why they're only available to OEM channels?  If that's the case, then is all other discussion of ASHP's here referring to ones that produce hot water as output?

[paulmb]

5 hours ago, Nickfromwales said:

... where most here probably do not know that SA have now pulled away from the public as aforementioned, in recent months, to ensure this kind of error cannot happen anymore. Credit to them for raising that drawbridge, albeit a little late in the day

 

I'm not sure that the above is completely the case - as just last week I innocently entered an enquiry on the SA web site which was responded to with a call from a SA business development manager, followed by an email containing version 2.3 of the Uniq Heat Batteries reference manual, and a couple of followup email exchanges.  It's gone a little quiet since I referenced the dialogue's on this forum to them...

Edited February 28, 2019 by paulmb