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Freshwater DHW System

  • 07-10-2014 8:27am
    #1
    Old Jim
    Registered Users, Registered Users 2 Posts: 178 ✭✭


    For my new build the heating supplier has proposed a A2W heat pump with an integrated 180l tank feeding UFH.
    I have read about freshwater hot water systems where the DHW is fresh water heated through a heat exchanger by the water stored in the tank. The stored water and the fresh water do not mix. I like this idea, eliminating the risks with legionella and are apparently more efficient.
    Can anyone tell me how my system can facilitate this freshwater DHW setup? Would anyone know the name or link to the necessary hardware? My heat pump supplier doesn’t appear to be familiar with it.
    Thanks for any help


Comments

  • #2
    John T Carroll
    Closed Accounts Posts: 757 ✭✭✭John T Carroll


    Old Jim wrote: »
    For my new build the heating supplier has proposed a A2W heat pump with an integrated 180l tank feeding UFH.
    I have read about freshwater hot water systems where the DHW is fresh water heated through a heat exchanger by the water stored in the tank. The stored water and the fresh water do not mix. I like this idea, eliminating the risks with legionella and are apparently more efficient.
    Can anyone tell me how my system can facilitate this freshwater DHW setup? Would anyone know the name or link to the necessary hardware? My heat pump supplier doesn’t appear to be familiar with it.
    Thanks for any help

    This is something along the lines that you need Jim, I copied this sometime ago from a post on Boards.ie. Apparently the domestic hot water only passes through a coil which heats it to 40/45C, it doesnt have to be heated periodically to 60c to kill all these nasty bugs as its not deemed to be "stored" water.This enables the Heat Pump to run with a enhanced COP as it doesnt have to heat the water to 60C.

    As an aside, I assume that this is why Electric showers are acceptable as well, these only heat the water to 40/45C as well, even if you turn the "heat" up full the water still wont reach 60C as the overtemp stat(s) will trip the heating element(s). I just wonder is there any risk, however slight, when using a pumped electric shower as the temperature in the Cold Water Storage Tank can easily reach 22/25C in the summer, in which legionella might just live/survive??.
    http://power-options.fortro.com/assets/400/Latento4S2008EN.pdf


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