Sunamp - Are They Worth It?

[Dougdrury22]

Hi All,

 

I'm looking at replacing my hot water cylinder, it's 100L but i'm looking at getting around 200L+ for my needs. 

 

Sunamp have caught my eye because they take up less space and by the sound of it they are much much more efficient & compact.  However, I have a few questions.

 

1. At the moment my cylinder is on a timer to heat up from 5am - 6am & 5pm - 6pm.  Using the grid Sunamp can I still control it on a timer and how long will it take to charge/heat up?  the assumption is, the heat battery is cold.
2. My cylinder takes about 30/60 mins to heat up and uses about 2KwH.  how much to the grid versions cost to run?

 

Sorry for the direct questions, hope they make sense and thanks in advance.

 

Thanks,

Doug

[SteamyTea]

You can run a SA exactly the same. Works best if it is just depleted before recharging, and that recharging is done at the phase change temperature.

 

If you want more hit water, why not increase the 100lt cylinder temperature, or charge it up more often, or for longer.

2 kWh is not much heating.

[ToughButterCup]

Seen this?

 

There are those of us who wouldn't touch a SunAmp ever, not no how, never never never never, and those of us who are happy with ours. It is  common to hear the argument that they are overpriced.

I have also heard the argument that  SunAmp insist that a trained fitter install them,  but at the same time allow their units to be sold in outlets where anyone can buy one. If thats the case, then SunAmp need to get their act together.

 

I think that in addition to the answers you get here, it would be an idea to ask the manufacturer the same questions you have above.

 

Mine is the 14kW version, absorbs all the pv I can throw at it (3.8 Kwp, northern England) , and is slowly repaying the outlay as forecast. For us space is at a  premium.  I have no idea how long it takes to heat up from cold.  

[Dougdrury22]

8 minutes ago, SteamyTea said:

You can run a SA exactly the same. Works best if it is just depleted before recharging, and that recharging is done at the phase change temperature.

 

If you want more hit water, why not increase the 100lt cylinder temperature, or charge it up more often, or for longer.

2 kWh is not much heating.

 

Thanks for getting back to me and thanks for letting me know.

I think I'm wrong with the cylinder only using 2KwH.  I can't remember were 2KwH fits into the cylinder's running costs, I need to re-visit calculations.

Sorry for the confusion.

[Dougdrury22]

6 minutes ago, ToughButterCup said:

Seen this?

 

There are those of us who wouldn't touch a SunAmp ever, not no how, never never never never, and those of us who are happy with ours. It is  common to hear the argument that they are overpriced.

I have also heard the argument that  SunAmp insist that a trained fitter install them,  but at the same time allow their units to be sold in outlets where anyone can buy one. If thats the case, then SunAmp need to get their act together.

 

I think that in addition to the answers you get here, it would be an idea to ask the manufacturer the same questions you have above.

 

Mine is the 14kW version, absorbs all the pv I can throw at it (3.8 Kwp, northern England) , and is slowly repaying the outlay as forecast. For us space is at a  premium.  I have no idea how long it takes to heat up from cold.  

 

No, I haven't seen that post but I'll have good read over it.

 

I did read about SA requiring an approved installer.  Sadly PV for us isn't an option, house faces the wrong and won't be worth it.

 

Thanks for the advise!

[SteamyTea]

23 minutes ago, Dougdrury22 said:

can't remember were 2KwH

You won't see that unit, think it means Kelvin times angular movement times capacitance.

kWh is what you mean.

[ReedRichards]

The Sunamp product is a thermal store.  A tank of water can be configured as a thermal store.  By comparison, the Sunamp unit is more expensive to buy but more compact and better insulated.  They are no more efficient than a tank of water except for the better insulation.  I am suspicious of heat loss ratings for thermal stores and hot water cylinders because they don't take into account heat loss down the connecting pipes which I suspect can be very significant.

 

H stands for Henry, the S.I. unit of inductance, not capacitance.   

[SteamyTea]

10 minutes ago, ReedRichards said:

H stands for Henry, the S.I. unit of inductance

The henry bit I remembered.

 

[martinwinlow]

Water requires about 1.2Wh of energy input to raise one litre by 1(degree)C.  Assuming 'cold' means 20C (room temp) and 'hot' = 60C, a 100 lire hot water cylinder (HWC) would use about 100 x 1.2Wh x (60C-20C=40C) = 4800Wh or 4.8kWh.  If you mean your immersion element is a 2kW one then it would take ~4.8kWh / 2kW = 2.4 hours to heat from 20C to 60C.  In reality, the water in the cylinder will rarely be at room temperature (unless you have just used it all, of course) and so the re-heat times will generally be less.

 

As ReedRichards says, there is little difference in the heating process efficiency between water in a cylinder and Sunamp's 'phase-change material', Sodium Acetate (a materiel used in the manufacture of potato crisps amongst many other things and therefore relatively cheap and non-toxic).  So, the amount of energy you put in will produce the same amount of hot water. However, the insulation of a typical HWC is pretty woeful (like everything else in our hopeless country - why are we all banging on about different and horribly expensive ways to replace natural gas for our hot water and space heating - which, together, amount for 2/3 of the UK's *total* energy use (?!) when we *should* be installing *way* better insulation?) and that of a Sunamp storage device way better.

 

As for the purchase cost comparison, if you carefully analyse the constituent components of the HWC Vs Sunamp store you will see that they are relatively comparable, likewise the construction process and so, like any new technology, in time the price will fall significantly with mass adoption.  It's a complete no-brainer (in the medium).