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Sunamp heat battery


Siochair

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There's a new presentation up on the Sunamp website: Andrew Bissell at Energy Storage & Connected Systems 2018 (Feb 8):

 

https://www.sunamp.com/sunamp-energy-storage-connected-systems/

 

https://www.sunamp.com/wp-content/uploads/2018/02/Sunamp-Optimising-Electrical-Systems-via-Smart-Heat-Batteries-PUBLIC.pdf

 

This drops some hints about their 3rd generation heat battery domestic product which is capable of use for hot water and/or heating, and is able to take AC input or DC (direct from your solar panels).

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Guest Alphonsox

Interesting presentation. The degradation curve is new information AFAIK, I'd like to see some more info on this. The statement is :-

"Previously undetectable degradation rate just becoming apparent after ~2.5 years and ~35,000 cycles"

 

I'd like to know whether this is primarily as a result of cycling or as a result of ageing of the PCM material. The subtext seems to be that this is a cycling effect leading to a capacity reduction of 25mW.hrs/cycle but it would be good to know there aren't other factors in play. @AndyT do you have any further details ?

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I have a single sample point for sodium acetate in a hand warming pack.  I came across this during our pre-move major clearout around Christmas time.  I can pretty much pinpoint when it was last used, which was November 2004.  I had charged it after use and put it in a drawer, where it sat at room temperature, in it's liquid phase, for over 12 years.  When I initiated the phase change it worked normally, turning into a solid and releasing the same amount of heat as it always used to, as far as I can tell.

 

The interesting thing for me was that it had stayed in it's higher energy state for that period of time.

 

Looking at the basic chemistry, but not knowing the exact composition that Sunamp use, I would doubt if there are any purely age related degradation effects, as long as the seals are good on the heat battery containers.

 

Be interesting to find out more, but I'm leaning towards the view that the thing will outlive me.

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Guest Alphonsox
4 minutes ago, JSHarris said:

Looking at the basic chemistry, but not knowing the exact composition that Sunamp use, I would doubt if there are any purely age related degradation effects, as long as the seals are good on the heat battery containers.

 

I tend to agree - But I don't know of any cycle based degradation effects either.

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10 minutes ago, Alphonsox said:

 

I tend to agree - But I don't know of any cycle based degradation effects either.

 

 

Just guessing here, but generally when you heat cycle any compound there will be some change, perhaps not an intrinsic property of the compound, but maybe a very small reaction that happens between the compound and the materials it is in contact with, for every heating/cooling cycle. 

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I still think, even with an acceptable degradation ( whether it be purely by cycle, or both cycle and life combined ), the degradation / lifecycle is still very economical vs the available alternatives. 

No multiple components failure like you suffer with gas boilers, or maintenance, other than a failure of the immersion to deal with so 'cheap motoring' AFAIC. Add to that no flue / ducting to outside etc etc, plus with the 3rd gen theres no integral pumps / additional wet plate heat exchangers / flow switches / TMV's / control wiring etc etc there's very little to go wrong.  

These are very impressive bits of kit :) 

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  • 3 weeks later...

Hi All,

Just as a "By the Way" - my Solar PV dashboard http://wattson.energyhive.com/dashboard/AndyT data has been taken off line for the moment while I do some testing two of Sunamp's latest prototypes.

 

Got all the plumbing done yesterday and as a result my conservatory looks like a Steampunk version of the engine room of SS W-s-M with meters gauges and dials everywhere.

Very akin to Willy Wonka's chocolate factory. Just got to do the electrics on Monday and then all it needs is the sound effects to go with it.

 

You can still access historic data on the dashboard by clicking the < and > symbols either side of the date.

 

Kind regards.

AndyT

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3 minutes ago, le-cerveau said:

These are my units (Still at SunAmp)  2 dual port cells with PCM34 and 2 with PCM58.  The one with the control box is the master the other the slave.  Still awaiting wiring details but they will be going in in a few weeks.

SunAmp.thumb.jpg.5522432a5600f9f3f4a40270af26efb7.jpg

Looking good you must be getting excited?

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1 minute ago, DenkiJidousha said:

What does  PCM34 and PCM58 mean?

 

As I learnt from this site myself, they are two different phase-change material compositions. And it relates to them being tuned to different input temperatures not output temperatures. For example input from an ASHP will be lower than that generated from PV electricity. 

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4 minutes ago, DenkiJidousha said:

What does  PCM34 and PCM58 mean? Is one handling your hot water and the other heating?

 

Different composition phase change materials that change state at different temperatures as I understand it. To cope with different heat sources.

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It's actually the phase change temperature, rather than the input temperature, in deg C.  So PCM34 changes phase from liquid to solid, releasing heat at 34 deg C.  Equally it changes phase from solid to liquid when heated to 34 deg C (actually a wee bit over).  Same for PCM58, but at 58 deg C.

 

The Sunamp PV uses PCM58, and the water temperature that comes out when it's running is pretty close to 58 deg C when it's got rid of it's residual stored heat.  The heat batteries store heat in two ways in the Sunamp PV.  One is by absorbing heat energy by changing the phase of the sodium acetate salt, the other is just heat stored conventionally by the heat capacity of the heat batteries.  The total storage capacity initially, when the heat battery is still hot, is a bit higher than the phase change temperature.

 

This means that when you draw hot water from one, initially the heat being drawn off is just that stored by the heat capacity of the heat batteries, then when it drops to 58 deg C, the salt starts to self-nucleate and change phase to a solid, releasing the heat from the phase change, plus a small amount of residual heat from the heat capacity of the material.  This means there is a variation in heat storage capacity that is time dependent since the last charge for a few hours.

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For clarity, on the subject of maximum output temperature:

  • if a SunAmp unit only has PCM34 cells then it can output any temperature up to about 34ºC (good for under-floor heating but inadequate for central heating with normally sized radiators or for domestic hot water)
  • if a SunAmp unit has both PCM34 and PCM58 cells then it can output any temperature up to about 58ºC (good for domestic hot water)

In each case, within the device the output can be blended down with cold water to any target output temperature below the limit.

In a unit with both types of cell in series, PCM34 cells can be used to preheat water for PCM58 ones. 

 

(It is worthy of note that I have not heard of a SunAmp unit in the wild  that has PCM34 cells alone).

 

if you would like even more splendid @JSHarris-style detail, I found this re-post by @Alphonsox from another forum of an entry by Andrew Bissell (SunAmp CEO) from September 2015 instructive — look to the seventh comment:

 

 

Edited by Dreadnaught
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7 hours ago, DenkiJidousha said:

What does  PCM34 and PCM58 mean? Is one handling your hot water and the other heating?

 

The PCM34 batteries will be charged by my ASHP at around 40oC and the PCM58 batteries will be charged by the boiler at around 65oC.

The UFH will take a feed from the PCM 34 batteries (same input as the ASHP).

DHW will be pre-heated by the PCM34 Batteries then the PCM58 batteries.

Effectively the PCM34 batteries are doing the same as @JSHarris buffer and the PCM58 batteries as is SunAmp PV.

plumbing diagram below:

Picture1.thumb.png.8991e268cfcbb84098d8f74933555a35.png

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2 hours ago, le-cerveau said:

 

The PCM34 batteries will be charged by my ASHP at around 40oC and the PCM58 batteries will be charged by the boiler at around 65oC.

 

I thought the Sunamp units were charged via electricity only?

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35 minutes ago, Visti said:

 

I thought the Sunamp units were charged via electricity only?

 

There are two different units,the Sunamp PV, which has a built in circulating pump and water heater to heat the batteries and the Sunamp Stack (and variations of it) that just have the heat batteries and some plumbing and control equipment, so they can be heated by hot water.

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37 minutes ago, le-cerveau said:

@JSHarris, in theory one of my PCM34 cells could be used to replace your buffer tank in your setup, though the cost is not insignificant.

 

Yes, and it would give me a significant advantage in terms of buffer heat capacity, but the cost and the nuisance factor of changing them over is a strong argument for me to stick with what I have for now.  Apart from anything else, I'd have to practically dismantle the airing cupboard, as the buffer tank is boxed in at the base of it.  I don't think that would go down very well right now!

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