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ebuild is sad to announce its closure - it has become too time and resource intensive to develop, manage and maintain.

However, ebuild will remain on-line in archive mode (ie no posting facilties) for several weeks so that users can use it as an information resource.

They Are Here, Place Your Order (Batteries), then moving on to phase change material storage units


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#121 DamonHD

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Posted 08 September 2015 - 09:25 AM

If the GB FiT for PV is killed then my ethical objections to the waste of exergy dumping electricity as low-grade heat is removed (for new installs), see my magnetite brain-fart elsewhere. You're not being paid to generate any more, so you can do what you like with energy you generate (at least until taxed, Spanish style).

Doesn't get me off the hook, since I am on FiTs already, but maybe I can flex my ethics*, and to that end today I had a very interesting conversation with SunAmp (http://sunamp.co.uk/) and I am sorely tempted to try out one of their pre-combi energy stores (http://sunamp.co.uk/products/sunamppv/). To my understanding their store should have essentially no standing losses beyond a 5W background consumption (being essentially phase-change) and at 4kW capacity should cover our typical daily DHW use from our PV in all but the depths of winter (3 months?). Not seasonal storage, and still suffers from my worries about waste of high-grade energy, but would cover half our household heat demand and not require masses of expensive insulation and have new and interesting H&S risks. And doesn't stop me doing something about the space heat demand later.

Halving my family's direct fossil fuel usage (eg gas) seems attractive.

And it would allow me to continue using my house as a test site for OpenTRV for another year! B^>

Thoughts?

Rgds

Damon





*Those are my principles, and if you don't like them... well, I have others.
Groucho Marx

Edited by DamonHD, 08 September 2015 - 09:33 AM.


#122 gravelld

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Posted 08 September 2015 - 09:55 AM

Er, how does it work? The brochure and website don't say anything really. It says it stores excess PV as heat, but how can they do that with no/very low standing losses?

Interested in the concept.

#123 SteamyTea

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Posted 08 September 2015 - 10:01 AM

View Postgravelld, on 08 September 2015 - 09:55 AM, said:

Er, how does it work?
Stores at room temperature maybe.

#124 DamonHD

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Posted 08 September 2015 - 10:05 AM

I have to understand more, and in particular the standing losses aspect, but it's at least likely to be be storing at no higher than (say) 45C or whatever the phase-change temperature is, which helps. But also consider those Sodium acetate heat warmers that sit at room temperature until you activate them explicitly. That's what I'm hoping is happening.

Rgds

Damon

Edited by DamonHD, 08 September 2015 - 10:05 AM.


#125 1anR

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Posted 08 September 2015 - 10:05 AM

If you go to the presentations page and watch the "Sunamp Heat Batteries" presentation you get a little bit of info.

http://sunamp.co.uk/.../presentations/

#126 djh99

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Posted 08 September 2015 - 10:19 AM

Do they have any technical information or specifications available? For example, what temperature does it sit at when it is fully charged? Is the 5 W Standby an electrical power draw or a thermal loss (which should be shown as a 24 hour standing loss under UK regs, no?)?

#127 DavidWright

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Posted 08 September 2015 - 01:30 PM

View Postgravelld, on 08 September 2015 - 09:55 AM, said:

Interested in the concept.
And in seeing what the prices are (if there are any on the website, or brochures, I missed them).

#128 djh99

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Posted 08 September 2015 - 02:05 PM

Quote

And in seeing what the prices are (if there are any on the website, or brochures, I missed them).
The brochure lists the price of a 4 kW PV system and the price of (a 4 kW PV system plus a sunamp) so it's possible to do a subtraction ....

#129 DavidWright

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Posted 08 September 2015 - 04:30 PM

View Postdjh99, on 08 September 2015 - 02:05 PM, said:

The brochure lists the price of a 4 kW PV system and the price of (a 4 kW PV system plus a sunamp) so it's possible to do a subtraction ....
So it does. Thanks.

#130 DamonHD

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Posted 08 September 2015 - 04:53 PM

And, oh joy, it looks as if a SunAmpPV unit would at least physically fit in the obvious space under our combi in the kitchen...

Rgds

Damon

#131 gravelld

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Posted 10 September 2015 - 09:28 AM

Let us know when you find out a little more...

#132 DamonHD

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Posted 10 September 2015 - 12:02 PM

I am hoping that someone from SunAmp might pop in here and explain more... Let me see if that is possible.

Rgds

Damon

#133 jsharris

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Posted 10 September 2015 - 12:15 PM

Be useful if they did.

Info is a bits sparse and I'd like to know some basics, like how long is the 5 kWh stored and what's the loss rate per day when it's not being charged by excess PV?

The obvious comparison is whether it makes sense to fit one of these units or just increase the size of an existing DHW tank/thermal store. Both would give a similar effect, but there are pros and cons of each that it would be nice to be able to compare, with some real numbers.

We know that the standing heat loss per day from DHW tanks/thermal stores is massively greater than the manufacturers specification, as I think enough of us here have done real measurements and added extra insulation and yet still failed to get close to the spec figures. What we need is hard data for the Sunamp PV, to see how it compares in reality, rather than in the mythical world of mandated specification testing.

#134 DamonHD

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Posted 10 September 2015 - 12:47 PM

In theory, theory and practice are the same. In practice, they are not. -- AlbertEinstein

#135 SteamyTea

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Posted 10 September 2015 - 01:39 PM

I emailed them, not had a sensible reply yet. They just asked what I wanted them for.

Energy and power density/volumetric would tell us a lot. As would the temperature ranges it can operate at.

#136 notnickclegg

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Posted 10 September 2015 - 07:21 PM

Search "sunamp" here:

https://patentscope....h/en/search.jsf

They have quite a few patent applications that might give you some clues about the sorts of things they're doing.

From the website, they seem to stack a load of PCMs with different phase change temps, then use valves to route warm water to the most appropriate layer in the stack for its temperature.

Jack

Edited by notnickclegg, 10 September 2015 - 09:00 PM.


#137 SteamyTea

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Posted 10 September 2015 - 08:52 PM

View Postnotnickclegg, on 10 September 2015 - 07:21 PM, said:

Form the website, they seem to stack a load of PCMs with different phase change temps, then use valves to route warm water to the most appropriate layer in the stack for its temperature.
Similar to what some people try and do with a water based thermal store. Should be more effective as they are discrete temperature units.

#138 1anR

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Posted 10 September 2015 - 10:06 PM

I've had some communication with them. I've been looking at energy storage options to counteract the upcoming FIT tariff changes.

The smaller Sunamp PV that stores up to 5kWh of energy can be charged directly via excess PV. This one has "certified" standing losses of 0.7kWh in 24hrs, an output temp of 55-58 degrees with a flow rate of 14l per minute.

The medium sized Sunamp Stack can be configured to store up to 40kWh of energy, and can have different temperature "layers". Currently this is designed to be "charged" by a high temp heat pump, although they are working on a resistive heater so direct PV can be used also. I was told this option may be available next year. Standing losses for the Stack are being tested presently.

The Stack is configured with up to 4 layers of 4 cells and each layer is the equivalent of 210ltrs of water. You can specify less than the maximum 16 cells.

I believe the Sunamp PV is intended to supplement an existing system, while the Stack is intended to replace thermal store and buffer tank.

edit: units corrected

Edited by 1anR, 11 September 2015 - 06:20 AM.


#139 SteamyTea

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Posted 11 September 2015 - 06:11 AM

kWh, not kW/h.

#140 jsharris

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Posted 11 September 2015 - 07:22 AM

If that 0.7 kWh/24 hours turns out to be accurate, then it's a fraction of the losses from even the very best thermal store or unvented hot water tank.

Taking my thermal store as an example, even with an extra 50mm of PIR foam sealed up pretty well all around it, it still loses 2.5 kWh/24 hours, and before the extra insulation it was losing 3.6 kWh/24 hours (against an official specification of 1.6 kWh/24 hours loss). My 260 litre thermal store is able to store around 6 kWh of usable energy for hot water at the temperature I run it, so not a great deal more than the Sunamp. Taking the losses into account, and making a very crude assumption that the thermal store or Sunamp is losing heat without free recharge overcoming the losses for 16 hours a day, so gaining heat for the remaining 8 hours per day from PV (crude, not valid on dull days, but it's a reasonable point to pick to make a standing loss comparison), then the losses from my double insulated thermal store would be around 1.67 kWh/day giving me a usable stored energy for hot water of 4.33 kWh. The Sunamp PV (assuming that it loses heat for 16 hours, gains heat for 8 hours, as for the thermal store) would have losses of 0.47 kWh and have a usable stored energy for hot water of 4.53 kWh, so slightly better than my thermal store.

So, it's pretty much a direct replacement for a very well insulated thermal store of around 260 litres. It's a lot smaller and would contribute less to the overall overheating in our services room, because of the lower losses, Combined with the 9.6kW instant boost heater I have in line with my DHW output, it would seem to be a much better solution for our hot water needs.

Definitely worth further investigation, if the price is reasonable.

Edited by jsharris, 11 September 2015 - 07:23 AM.