Pros & cons of Thermal Store.

Discussion in 'Plumbers' Talk' started by Allsorts, Sep 13, 2018.

  1. Allsorts

    Allsorts Super Member

    I think I know the basic principles, but wondered if there's more to it - pros and connies.

    The main 'idea' of them is that is acts as a large heat store which can then be used of DHW and CH. It's big pro is that is can be heated from numerous sources - solid fuel, PVs, solar panels etc. as well as a boiler.

    DHW is obtained from a heating coil inside the tank - cold mains water is passed through this coil and is heated 'instantly' as required?

    CH supply is taken directly from the tank - the tank essentially stores a large quantity of 'system' water?

    The tank is kept up to required temp - summer and winter - by the main boiler? In Summer only DHW is required, so there's still the need to keep a whole tank heated?

    Would you only ever consider one if you wanted more than one source of heating - eg PV panels powering an immersion, or a solar panel directly heating the stored water?

    And just how effective are they if supplied by PVs for example? I mean, if the PVs managed to get the store fully up to max temp during the day, just how much CH would that provide for the house in the evening?

  2. Richard_

    Richard_ Active Member

    As I understand it, the effectiveness is dependent on the input sources. They are useful if you have an excess of energy that you want to keep for use at another time, such as a back boiler on a fire, or perhaps a biomass system that creates more heat than you can use when you fire it up.

    If you are generating electricity (ie PV or wind) would it be economically better to put it into the grid and save the cost of the heat store?
    Allsorts likes this.
  3. Allsorts

    Allsorts Super Member

    Thanks Richard.

    That's what I'm trying to work out - at what point does it become a sensible option. As you say, I suspect it's only when you have a decent source of energy that might not be there when you actually want it.
  4. NoOhmToGoTo

    NoOhmToGoTo Screwfix Select

    Don't consider one unless you are in a soft water area or have a softener.
    I think their day was before unvented cylinders became mainstream.
    However, their usp is their ability to accept multiple heat sources simply, or, as you say when you have a decent source of energy that might not be there when you actually want it.
    Their moniker is sludge buckets!
    Allsorts likes this.
  5. Allsorts

    Allsorts Super Member

    It sounds as tho' it ain't worth it unless there was, say, a back-boiler also providing heat.

    The hoosie we are looking at already has a new unvented cylinder, so we could always fit a PV immersion or solar heating panel to that if we wanted to; hardly worth going 'Store I guess.
  6. Richard_

    Richard_ Active Member

    It'd be a very pricey toy if you have no need for a new cylinder!

    The folk on the green building forum are usually very helpful. You have to pay £5 annual fee to post, but reading old threads for free usually answers most questions.
    Allsorts likes this.
  7. Bob Rathbone

    Bob Rathbone Screwfix Select

    Thermal stores will only be of use when you have a wildly fluctuating heat source, such as thermal solar panels or a small CHP system that does not run continuously. Otherwise you are wasting your money.
    Allsorts likes this.
  8. DIY womble

    DIY womble Well-Known Member

    12v solar straight into water tank , don't go the whole hog
  9. Allsorts

    Allsorts Super Member

    Thank you Richard and Bob - that seems to be the consensus.

  10. longboat

    longboat Screwfix Select

    Are you planning to move somewhere in your locale or further afield, DA?
    Given the recent predictions, I'd be down sizing or moving north if I were you.
  11. Joe Burgess

    Joe Burgess New Member

    I once got a thermal store from this provider, I can say that it was pretty helpful, especially when controlling the distribution of heat from multiple sources. I think it’s a must if you have more than one heating source as it makes everything easier. As for solar panel CH production in the evening, I think that would depend on the amount of energy already stored as these panels won’t work at night, when no sunlight can be collected.
  12. nigel willson

    nigel willson Screwfix Select

    I have reported the above

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