New Post Advanced Search
Important update! We have recently reviewed and updated our Forum Rules and FAQs. Please take the time to familiarise yourself with the latest version.

Heat Battery

edited 30 November -1 at 12:00AM in Green & Ethical MoneySaving
21 replies 5.3K views
2

Replies

  • SolarchaserSolarchaser Forumite
    597 posts
    500 Posts First Anniversary
    ✭✭
    I've been researching the sunamp.
    Possibly looking at two of the 6kwh models as they will fit in void at the cupboards in my kitchen, and the combi I have will run a 55c input, so pipe runs etc will be way simpler than a tank in the loft.

    https://midsummerwholesale.co.uk/buy/sunamp-heat-batteries/sunamp-uniq-6
    6kwh is around £2k, and the 12kwh is around £2.8k. But it's over a meter tall, so wont fit under kitchen worktops.

    Wondering if anyone has actual experience of using these, and any pluses or minuses to these.

    Planning on running them from surplus pv, and cheap rate leccy in winter to reduce gas use, hopefully in time expanding to cover heating too.
    West central Scotland
    4kw sse since 2014 and 6.6kw wsw / ene split since 2019
    24kwh leaf and Lux 3600 with 17kwh useable storage
  • mwinlowmwinlow Forumite
    14 posts
    Third Anniversary First Post
    Bit of an old thread, now but...

    I see at least one other company is selling a heat battery - Fischer 'Auqufficient' but I couldn't find any prices on-line.  I would think this is defo the water HW storage will go in the near future, obviating the need for last volumes of hot water storage and the expensive copper to contain it.  I have read recently that Sunamp's control system has some serious issues but should be fairly easily fixable.  It's very early days yet.

    Maybe the biggest market for this tech (as alluded to in an earlier comment) is huge heat batteries either 'charged up' using waste heat from industrial processes and then transported elsewhere to be used or (just one example) a Scottish distillery hosting one or more wind turbines to generate the electrical energy to heat the battery and then help provide the heat for the distilling process during calm weather.

    The costs of the units is pretty minimal and I would guess the Aerogel insulation (I'm assuming this is what is used as it is the best available) is the most expensive constituent in the box.  The 'active ingredient' ie the phase-change material is sodium acetate (yep, as used to make crisps) and is relatively inexpensive - probably about the same cost as the copper in an equivalent (heat energy) sized cylinder.  So, I would expect [rices to tumble significantly in time and with greater acceptance in the market.

    For those with long runs of pipework, consider small bore plastic pipe for your next installation - as long as the pressure is good - and assuming you have mains pressure hot and cold water - this will minimise 'dead water',  massively reduce heat transfer through the pipe wall and hugely increase the hot water delivery time.  Copper's thermal conductivity is very good, plastic not so much... by a factor of getting on for a thousand!  Not much use for bath filling, perhaps, but sinks, washing machines and showers, perfectly fine.  
  • michaelsmichaels Forumite
    25.2K posts
    Part of the Furniture 10,000 Posts Name Dropper
    ✭✭✭✭✭
    This sounds interesting to me if paired with a very cheap overnight electricity tariff, we use about 33kwh of gas every day just heating hot water but presumably heating this heat store using leccy at 4p a unit overnight would work out at a similar cost?  I wonder if they could choose a storage medium with a transition temperature more accessible to heat pumps and you could then 'charge it up using a heat pump at a higher COP than just a resistive heater?
    I think....
  • isvanaisvana Forumite
    2 posts
    First Post First Anniversary
    MoneySaving Newbie
    These sound like an interesting option... for hot water heating with spare solar energy. I am planning an extension and was thinking of a “heat battery” in terms of an underfloor set of bricks or blocks. A bit like these guys do... thermaray dot com
  • Hot_ToddyHot_Toddy Forumite
    1 posts
    Part of the Furniture First Post Combo Breaker
    MoneySaving Newbie
    I had 2 UniQ 6 heat batteries fitted in my flat 12 months ago to provide heat and hot water. Previously used electric heaters and immersion heater. Was told they were efficient would save money, blah, blah blah. I now pay twice as much and the radiators never get warm. Wouldn't recommend. Fischer only use Sunamp for heating water and so does the guy who fitted the batteries which so as I now know they are no good for heating
  • Pile_o_stonePile_o_stone Forumite
    159 posts
    100 Posts Name Dropper Photogenic
    Crikey, Hot_Toddy, you've been a member of MSE for over 10 years and this is your first post. Thanks for making it on the Ethical board! :)
    5.18 kWp PV systems (3.68 E/W & 1.5 E).
    Solar iBoost+ to two immersion heaters on 300L thermal store.
    Vegan household with 100% composted food waste
    Mini orchard planted and vegetable allotment created.
  • SolarchaserSolarchaser Forumite
    597 posts
    500 Posts First Anniversary
    ✭✭
    Thanks for sharing your experience. 
    Its good to know this technology is not useable for heating, saves me some money and some hassle
    West central Scotland
    4kw sse since 2014 and 6.6kw wsw / ene split since 2019
    24kwh leaf and Lux 3600 with 17kwh useable storage
  • Reed_RichardsReed_Richards Forumite
    649 posts
    Part of the Furniture 500 Posts Name Dropper Combo Breaker
    ✭✭
    Hang on a minute.  Your only hope to derive any running-cost savings from a heat battery if all-electric (and without solar PVs) is to use Economy 7 (or similar) to charge the battery at night with cheap-rate electricity.  You might just as well have a hot water cylinder and night storage heaters.  The only advantage that the heat battery offers over those is that it is more compact.  You would not expect any savings unless the old electric heaters that @Hot_Toddy replaced were instantaneous.  Also the standard heat battery heats water to 60 C.  That is too hot for Domestic Hot Water but colder than a typical boiler-driven radiator which aims for an average temperature around 70 C. 
    Reed
  • Martyn1981Martyn1981 Forumite
    11.5K posts
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    ✭✭✭✭✭
    Hang on a minute.  Your only hope to derive any running-cost savings from a heat battery if all-electric (and without solar PVs) is to use Economy 7 (or similar) to charge the battery at night with cheap-rate electricity.  You might just as well have a hot water cylinder and night storage heaters.  The only advantage that the heat battery offers over those is that it is more compact.  You would not expect any savings unless the old electric heaters that @Hot_Toddy replaced were instantaneous.  Also the standard heat battery heats water to 60 C.  That is too hot for Domestic Hot Water but colder than a typical boiler-driven radiator which aims for an average temperature around 70 C. 
    Yes. The selling point though is that they are more efficient as they don't leak heat. This was the approach the salesman used to 'sell' the idea to my sister and BiL, but when he suggested a price of about £2k, I explained it would take around 100yrs to get your money back against a high quality water cylinder with excellent insulation leaking about 1kWh per day. He really didn't like me only classing loses for 6 months of the year, as I said the 'loses' during the heating months are within the thermal envelope, so not an actual loss. When I pointed out that the price difference invested at 1% was greater than the annual 'saving' he really got pee'd off ...... then suggested these new super duper storage heaters from Germany ...... I asked if they had the 'magic clay' in them, and he gave up!
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Reed_RichardsReed_Richards Forumite
    649 posts
    Part of the Furniture 500 Posts Name Dropper Combo Breaker
    ✭✭
    Actually you could fill your night storage heaters with a phase change material like they use in a heat battery to make them more compact.  Possibly they would also perform better because all the heat is released at the phase change temperature.  So there you are, @Martyn1981, 'magic phase-change clay'.
    Reed
Sign In or Register to comment.

Quick links

Essential Money | Who & Where are you? | Work & Benefits | Household and travel | Shopping & Freebies | About MSE | The MoneySavers Arms | Covid-19 & Coronavirus Support