How do Sunamp heat batteries work?

70sbudgie

I also think that is its purpose. For all the properties that have combi boilers and no space for a HW tank. It is a high energy density storage solution that can be charged during off peak and used any time and the equivalent of a 150l tank takes up less space than a kitchen cabinet.

Solarchaser

Reed_Richards said:

Martyn1981 said:..... why?

My house has an airing cupboard that had fallen into disuse.  When I wanted to put a hot water cylinder back they had to take out a section of wall to make the airing cupboard a bit bigger in order to get the hot water cylinder and the associated pipework inside.  Something like that is not feasible in a lot of properties so a unit that performs the function of a hot water cylinder but is more compact has real utility.  I don't think there is anything more to it than that.

For example, @Solarchaser is heating their property using cheap rate electricity to charge some large tanks of water.  They are fortunate to have sufficient space to accommodate these water tanks and the necessary insulation.  With less space they might have been forced to use PCM thermal stores.       

And this is partly why I looked into and almost purchased a few sunamps.

Technically I didn't have room for the water tanks, I had to dig out a couple of cubic meters of dirt with bricks on my knees to accommodate the tanks under the house as the crawl space wasn't tall enough.
Sunamps are much smaller.

It definitely would have been less work with the sunamps, I just couldn't make them fit the bill, not enough heating power to charge fulky in cheap rate and too little evidence of full recovery/efficiency. 

It's a shame, if the evidence was more readily available I'd have given more serious thought to using an electric boiler to heat them, but it was just too much expense and commitment for something that seems... perhaps temperamental is the wrong word, let's go with finniky. And definitely unproven.

Reed_Richards

I've found an interesting thread on Sunamp here: https://forum.buildhub.org.uk/topic/13132-sunamp-issues/ .  Somebody who seems to know says they have a cold start mode necessary because the PCM is solid when the unit is cold.

Solarchaser said:

...too little evidence of full recovery/efficiency. 

It's a shame, if the evidence was more readily available I'd have given more serious thought to using an electric boiler to heat them, but it was just too much expense and commitment for something that seems... perhaps temperamental is the wrong word, let's go with finniky. And definitely unproven.

As I said before, I think the only physically possible way for them to be inefficient is by losing heat to their surroundings (I suppose they could leak their contents also, but hopefully not).  I think they have embedded elements for electrical heating, you would not need an electric boiler.   But I completely agree that they are unproven for any long-term operation and with a lot more things having the potential to go wrong compared to a tank of water.  My personal opinion is that they tend to be oversold and part of that involves not giving all the technical information you might want.   

Martyn1981

Reed_Richards said:

Martyn1981 said:..... why?

My house has an airing cupboard that had fallen into disuse.  When I wanted to put a hot water cylinder back they had to take out a section of wall to make the airing cupboard a bit bigger in order to get the hot water cylinder and the associated pipework inside.  Something like that is not feasible in a lot of properties so a unit that performs the function of a hot water cylinder but is more compact has real utility.  I don't think there is anything more to it than that.

For example, @Solarchaser is heating their property using cheap rate electricity to charge some large tanks of water.  They are fortunate to have sufficient space to accommodate these water tanks and the necessary insulation.  With less space they might have been forced to use PCM thermal stores.       

Yes, that's my conclusion too, it's a solution to a space problem, and that is a reasonable concern. But at quite a price premium.

But now I'm thinking that I'm being unfair placing the whole price premium as a negative, without giving them more credit for the space saving.

Horses for courses I suppose.

QrizB

Reed_Richards said:

I don't know how long a reusable handwarmer will last after you have boiled it up in that pan of water and let it cool.  Hours, days, weeks, months?  @QrizB ?  That would give some idea of how "permanent" the heat storage could be.    

Sorry, been busy ensewhere for a few days.

I've got a few phase-change hand warmers in the drawer here. Some of them I last recharged a year or more ago, but are still liquid.

(There are also a couple which have activasted themselves since last winter, so they're not entirely reliable as a long-term store of heat. But then I'd expect a £3000 Sunamp to be better engineered than a £3 hand warmer.)

70sbudgie

I had missed this from a couple weeks ago. Looks like SunAmp intend to use their thermal stores for longer duration storage than discussed above.
https://blog.rippleenergy.com/environment/sunamp-awarded-9-25-million-uk-government-funding-to-tackle-greener-heat-challenge/

Reed_Richards

If only we could persuade @Solarchaser that their "third tank" should be one of these Sunamp units we could get some first hand reporting on how they actually perform in practice.  Maybe we can crowdfund the purchase, I'd chip in a tenner.  

2nd_time_buyer

Reed_Richards said:

If only we could persuade @Solarchaser that their "third tank" should be one of these Sunamp units we could get some first hand reporting on how they actually perform in practice.  Maybe we can crowdfund the purchase, I'd chip in a tenner.  

I wonder if I can justify a basement swimming pool as a thermal mass?

Solarchaser

Reed_Richards said:

If only we could persuade @Solarchaser that their "third tank" should be one of these Sunamp units we could get some first hand reporting on how they actually perform in practice.  Maybe we can crowdfund the purchase, I'd chip in a tenner.  

Sounds good, I'd definitely be up for that.
They are £3300 for the 300L replacement. 
£3290 with your contribution. 

https://midsummerwholesale.co.uk/buy/sunamp-heat-batteries/sunamp-ehw-ipv-12

Just need another 300 contributers to this crowd fund and we will be rocking 😂😂🙌

1961Nick

Solarchaser said:

Just need another 300 contributers to this crowd fund and we will be rocking 😂😂🙌

Good news... we have 300 contributors.

You just need to find the other £3287 now.