Sunamp heat battery

[oranjeboom]

15 minutes ago, JSHarris said:

Regarding charge time, it depends on the power output of the ASHP.  Our 6 kW ASHP would charge a 12 kWh unit in two hours, perhaps slightly less under ideal conditions when the ASHP can exceed 6 kW output, slightly longer under less ideal conditions when the output can drop a bit below 6 kW.

Thank you Mr Harris! As simple as that then. So then it comes down to how much heat is pumped out to the UFH which will be dependent upon UFH temp setting, duration and heat loss?

 

Wunda indicated the following for my setup which was based on 'current BuildRegs':

 

Groundfloor: Water volume: 129L; Estimated loading: 9.45Kw 
Upstairs on separate manifold: Water volume: 25L; Estimated loading: 2.03Kw

 

Not sure how they calculated the above, but how would I size a 12kWh SA unit for my UFH? My floor heat loss is:

 

Is that per sqm?

[Jeremy Harris]

If the UFH is considered to be the only form of heat energy input to the house (it won't be, by a variable amount depending on other incidental heat gains) then it needs to be able to provide the house total heat loss for any given temperature difference between outside and inside, which is on the spreadsheet.

 

In practice, you can knock around 80 W per occupant off that heating requirement, plus a couple of hundred Watts or so for the incidental heat gain from appliance heat loss (essentially everything in the house that draws power, from phone chargers, through lights to the TV and PCs).  There will be additional incidental heat gains from cooking, solar gain, showers, baths, hot water system standing losses etc, all of which will reduce the total heating requirement, so the total heat loss on the spreadsheet is very much a worst case figure.

[Nickfromwales]

22 hours ago, oranjeboom said:

Thank you Mr Harris! As simple as that then. So then it comes down to how much heat is pumped out to the UFH which will be dependent upon UFH temp setting, duration and heat loss?

 

Wunda indicated the following for my setup which was based on 'current BuildRegs':

 

Groundfloor: Water volume: 129L; Estimated loading: 9.45Kw 
Upstairs on separate manifold: Water volume: 25L; Estimated loading: 2.03Kw

 

Not sure how they calculated the above, but how would I size a 12kWh SA unit for my UFH? My floor heat loss is:

 

Is that per sqm?

Beware to separate what you need for immediate use, and what capacity you would require if 'charging' from PV or other 'short yield' energy sources like E10. Charging / storing is where the SA units excels, but as they're a substantial capital investment you really need to size accordingly.  

If you have an ASHP then why would you need to store anything for space heating, discounting DHW, plus a bit on top for DHW pre-heat? If this was all being charged off a huge PV array with short windows of yield then fair enough, but as you'll be able to match or exceed losses with the HP then the issue is greatly minimised. HP runs off PV so winner winner, and excess PV heats a PCM58 for DHW, with pre-heated water fed by the PCM34 buffer. Only problem is theres still no news on the PCM34 coming back to the market. @AndyT, any update ? 

 

The good news is that after a recent chat with AndyT, I can report that the 9kW SA units DHW capacity is boosted by over double when fed by preheated water at 38-40^oC, so a HUGE increase in capacity plus the brunt of DHW can be provided by the buffer temp water from the ASHP. So when theres enough PV for DHW but perhaps not enough to charge both the 58 and 34 cells, the ASHP can deliver with excellent CoP. 

I would seriously have to look at why I was spending on an ASHP ( and then paying to babysit it forever ) and not on masses of DIY PV and going all electric, as then you have a near zero maintenance 30 year solution that operates by pressing a button.......occasionally.    

 

[Jeremy Harris]

9 minutes ago, Nickfromwales said:

The good news is that after a recent chat with AndyT, I can report that the 9kW SA units DHW capacity is boosted by over double when fed by preheated water at 38-40^oC, so a HUGE increase in capacity plus the brunt of DHW can be provided by the buffer temp water from the ASHP. So when theres enough PV for DHW but perhaps not enough to charge both the 58 and 34 cells, the ASHP can deliver with excellent CoP. 

 

 

I can confirm that the same is true for the standard Sunamp PV we have.  The buffer tank is usually around 35 to 40^oC, and this preheats the cold water fed to the Sunamp via a plate heat exchanger, with the pump that pulls water from the buffer to the heat exchanger only coming on when a flow switch in the hot water feed operates, so it's "on demand" heated, much the same as the Sunamp.  The net result is that in practice the Sunamp PV can easily run a couple of decent showers, with enough capacity left over to meet the house hot water demands for the day.  I was thinking of adding another parallel Sunamp heat battery (essentially just the two heat cells from a Sunamp PV in parallel with the ones already fitted) but I can't see that it's needed, as long as the preheat system is working.

[Nickfromwales]

On 18/05/2018 at 08:47, TerryE said:

So what is the life expectancy and annual maintenance costs of your quoted eDual 12s?  I suspect 10 years and 5% might be a good ballpark, or roughly £1K p.a. amortised cost. My total annual energy bill is just over that with my twin SAs and Willis heater and no PV.  And we also have a largish 4 bedroom house with 3 ensuites and a bathroom and 3 occupants.

38,000 deep cycles in on the PCM58 with around 3-4% degradation.

Rough calculation : 

10 years x 2 full charges per 24hrs ( for eg ) = 7300 cycles. 

38,000 / 7300 = 5.2 years service 

5.2 years of service vs < 4% degradation to date  ( statistical info from SA from their bench test unit ) = the owner of the SA will typically die before the SA does.

Immersions are covered for 10 years via SA warranty. No other "moving" parts.

That laughs in the face of a HP and the cost of electric is offset by the maintenance and replacement costs over the lifetime. 

 

However, lol........ When youve finished digesting that lot, its still a no brainer to use a heat pump or gas in a larger dwelling unless youve got a ridiculously sized PV array and a bank of SA units to capture every glance of the sunlight that hits it.  

[Nickfromwales]

14 minutes ago, JSHarris said:

 

I can confirm that the same is true for the standard Sunamp PV we have.  The buffer tank is usually around 35 to 40^oC, and this preheats the cold water fed to the Sunamp via a plate heat exchanger, with the pump that pulls water from the buffer to the heat exchanger only coming on when a flow switch in the hot water feed operates, so it's "on demand" heated, much the same as the Sunamp.  The net result is that in practice the Sunamp PV can easily run a couple of decent showers, with enough capacity left over to meet the house hot water demands for the day.  I was thinking of adding another parallel Sunamp heat battery (essentially just the two heat cells from a Sunamp PV in parallel with the ones already fitted) but I can't see that it's needed, as long as the preheat system is working.

Ah, yes. I keep forgetting you have the 'pioneer' install with the preheat.  Its deffo a worthwhile endeavour to preheat if you have an ASHP, as it reduces the size and cost of the SA units significantly. 

[Jeremy Harris]

3 minutes ago, Nickfromwales said:

38,000 deep cycles in on the PCM58 with around 3-4% degradation.

Rough calculation : 

10 years x 2 full charges per 24hrs ( for eg ) = 7300 cycles. 

38,000 / 7300 = 5.2 years service 

5.2 years of service vs < 4% degradation to date  ( statistical info from SA from their bench test unit ) = the owner of the SA will typically die before the SA does.

Immersions are covered for 10 years via SA warranty. No other "moving" parts.

That laughs in the face of a HP and the cost of electric is offset by the maintenance and replacement costs over the lifetime. 

 

However, lol........ When youve finished digesting that lot, its still a no brainer to use a heat pump or gas in a larger dwelling unless youve got a ridiculously sized PV array and a bank of SA units to capture every glance of the sunlight that hits it.  

 

Shouldn't that be 52 years for 4% degradation at 2 cycles per day?

[Nickfromwales]

7 minutes ago, JSHarris said:

 

Shouldn't that be 52 years for 4% degradation at 2 cycles per day?

"Damn you decimal place!"  

Wheres @SteamyTea when you need him.  

 

Should have added the disclaimer at the bottom of that post about my shit maths skills.

 

Oh, and the point being......WOW! on the SA lifespan. 

 

[Guest Alphonsox]

3 minutes ago, Nickfromwales said:

38,000 deep cycles in on the PCM58 with around 3-4% degradation.

 

Just now, Nickfromwales said:

Oh, and the point being......WOW! on the SA lifespan. 

 

 

I've still seen no statement from SunAmp as to the cause of the degradation. If the degradation is unrelated to the number of cycles and is rather a simple time related wear out then the economic argument changes. (i.e 3-4% every couple of years rather than 3-4% every 38K cycles)

[Jeremy Harris]

There's a fair bit of evidence that sodium acetate doesn't degrade when stored in a sealed container, and that it's even pretty stable when in either supersaturated solution or as a crystallised solid.  Anecdotally that's supported by an old hand warmer pad I have, that was left "charged" (i.e. in supersaturated liquid form) in a desk drawer for a few years and when I found it and clicked the nucleator it immediately started to crystallise and heat up.  I recharged it and have stored it away, and will test it again in a few years, but I can't see any intrinsic reason why it should degrade, as it's an inherently stable compound.  As an example of its stability, it's commonly used as a waterproofing additive for concrete, where it remains stable enough to work for decades.

[Triassic]

Wasn’t the problem corrosion?

16 minutes ago, Alphonsox said:

 

 

I've still seen no statement from SunAmp as to the cause of the degradation. If the degradation is unrelated to the number of cycles and is rather a simple time related wear out then the economic argument changes. (i.e 3-4% every couple of years rather than 3-4% every 38K cycles)

 

[Guest Alphonsox]

3 minutes ago, Triassic said:

Wasn’t the problem corrosion?

 

 

There was a reported corrosion issue with the new PCM34 batteries, but no indication that this effected the PCM58 units currently in use.

[Jeremy Harris]

I have no idea what the compound in the PCM34 units is, but would guess that it will be something very different to the compound in the PCM58 units, which we know to be sodium acetate based.

[Nickfromwales]

@JSHarris

Bromide is causing the issue in the PCM88 ( not 58, a totally different compound ) and its the bromide in the 34 that's causing concern. Note the 34 isn't actually known to be suffering or to have failed, but the 88 has failed, catastrophically, so the 34 has been pulled temporarily as a precautionary measure. 

 

[Dreadnaught]

40 minutes ago, Nickfromwales said:

Bromide

 

On the nature of PCM34, as Andrew Bessell of SunAmp told us, PCM88 uses Strontium Bromide Hexahydrate. Source reposted by @Alphonsox from the previous forum here: 

 

In the letter from Andrew Bessell on the current issues re posted with permission by @le-cerveau in the thread below it says only that SU34 is a bromide with a different metal ion, i.e. not Strontium.

 

Edited May 19, 2018 by Dreadnaught

[Jeremy Harris]

1 hour ago, Nickfromwales said:

@JSHarris

Bromide is causing the issue in the PCM88 ( not 58, a totally different compound ) and its the bromide in the 34 that's causing concern. Note the 34 isn't actually known to be suffering or to have failed, but the 88 has failed, catastrophically, so the 34 has been pulled temporarily as a precautionary measure. 

 

 

 

Interesting.  Strontium Bromide is potentially more reactive than Sodium Acetate, which may well be part of the issue.

[Dreadnaught]

SunAmp's official announcement of their UniQ range is nigh.

Its next weekend at the Fully Charged Live show…

 

 

 

 

 

[Dreadnaught]

https://www.sunamp.com/fully-charged-live-2018/

 

Includes a link to a downloadable brochure on the new range.  

[Guest Alphonsox]

To save everyone searching....

https://www.sunamp.com/wp-content/uploads/2018/06/Leaflet-3-Introduction-to-UniQ.pdf

https://www.sunamp.com/wp-content/uploads/2018/06/UniQ-Modular-Scalable-Compact.pdf

https://www.sunamp.com/wp-content/uploads/2018/06/Leaflet-1-Sunamp-Dual-Port-Heat-Stores-Technology-Description-final.pdf

https://www.sunamp.com/wp-content/uploads/2018/06/Leaflet-2-Applications-Benefts-table.pdf

[le-cerveau]

Additional to this I have found the design and install guide that has much more detail on it on how to select what systems and how to mix and match:

 

http://www.bublshop.co.uk/files/pdf/pdf2040.pdf

 

I found my system in there though mine pre-dates the UniQ and the packaging is different!

[Nickfromwales]

7 minutes ago, le-cerveau said:

Additional to this I have found the design and install guide that has much more detail on it on how to select what systems and how to mix and match:

 

http://www.bublshop.co.uk/files/pdf/pdf2040.pdf

 

I found my system in there though mine pre-dates the UniQ and the packaging is different!

Yup. There have been some pre-final production changes for the better. 

Now a far more comprehensive range of products. 

 

[MrMagic]

As a complete newbie on Sunamp - can someone advise if the heating element in the electric only version is designed to work with something like a Solar iBoost wheres its power draw is proportional to 'spare' PV, as apposed to full 3Kw, all or nothing.

 

Considering using it to store any excess PV generation as either a combi pre-heat or with a solar diverter.

 

Edited June 26, 2018 by MrMagic

[Nickfromwales]

1 minute ago, MrMagic said:

As a complete newbie on Sunamp - can someone advise if the heating element in the electric only version is designed to work with something like a Solar iBoost wheres its power draw is proportional to 'spare' PV, as apposed to full 3Kw, all or nothing.

 

Considering using it to store any excess PV generation as either a combi pre-heat or with a solar diverter.

 

AFAIK, the 3,6,9 and 12 unit sizes ( with immersions ) employ 3x 1kW immersion heaters, not 1x 3kW. They also come with a little box of tricks to manage the 3 heaters, which IIRC are accompanied by 3x thermistors placed in ascending order which determine the state of charge. Any electrical input is deemed useful tbh, but the chemistry dictates at what temperature point the PCM changes state, so best consult with Sunamp before placing an order / designing the system.  

[oranjeboom]

For anyone on the verge of committing to purchase a Sunamp unit, you may want to bite the bullet sooner than later:

 

current 10% discount - or 20% for a fully-paid purchase by 29th June!

[oldkettle]

I know I've missed the discount (work and family commitments) but in case a good deal comes up again I have a question. 

 

We currently have a vented system with a relatively small hot water tank. Water is heated by a condensing boiler and there is an immersion heating element which we use regularly as washing long hair (not mine -:-)) takes a lot of time. The boiler short cycles quite often while heating water. We have hard water with no softener. 

 

As it a is not clear when we're going to get PP and following that builders to actually do anything I want to know whether it could be possible and feasible at all to buy a 12Kw Sunamp and hopefully directly replace the existing tank. Again, the idea is at some point it would be moved and the system would change quite a lot. Hopefully, the connections can be redone. 

 

Thanks in advance for any suggestions.