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Hot water cylinder for home and PV solar system

  • 08-03-2023 7:53am
    Registered Users Posts: 1,246 ✭✭✭

    Can anyone suggest a smart PV hot water cylinder?


  • Moderators, Home & Garden Moderators Posts: 5,912 Mod ✭✭✭✭graememk

  • Registered Users Posts: 1,246 ✭✭✭Scottie99

    A hot water cylinder specifically that can be used with PV and efficient. Mixergy has been mentioned but its quite expensive

  • Registered Users Posts: 8,511 ✭✭✭micks_address

    you can use an existing cylinder with immersion and run the immersion from a solar diverter like a myenergy eddii..

  • Registered Users Posts: 1,704 ✭✭✭Deagol

    As mentioned, any tank will work. As an example - I use a standard Joule 300ltr tank. It has 2 immersion heaters that connect to a myenergi Eddi that diverts excess solar to the heaters until setpoint temperature (65C) is met.

    The Eddi can be controlled / monitored from a phone. I have added the relay board to the Eddi and added 2x themocouples to the tank inserts so i can see the temperature of the bottom and top of the tank at any time.

    The tank also has twin heating coils for use with the oil boiler for when no excess solar. Plus, I could use the immersion heaters from grid power (you can boost the heat via the Eddi app) to heat water - not that I use that option as oil is cheaper and faster.

    Oh, and the water is useable for a shower (~50C) 48 hours after last being heated, so it's fairly well insulated.

    Not sure what else you could want but hope that helps OP.

  • Registered Users Posts: 4,460 ✭✭✭BoardsMember

    Has anyone done the numbers on combi rather than solar pv + tank? With no batteries. Seems like a cheaper option and with FIT being reasonably generous as fairly short payback time compared to batteries, eddi.

    We're thinking of going combi, so no tank. And using pv for general use and fit, and then charging ev (when we get it). Simple, straightforward, relatively cheap.

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  • Registered Users Posts: 8,511 ✭✭✭micks_address

    ive noticed the water doesnt stay hot in our copper cylinder for very long even with a heavy lagging jacket.. is there anywhere that shows the heatloss of various cylinder options? We have one electric shower so probably sticking with that anyway..

  • Registered Users Posts: 1,246 ✭✭✭Scottie99

    Unfortunately the existing cylinder had its element changed a few times. We were advised the last time around that the thread on the tank was deteriorating.

  • Moderators, Home & Garden Moderators Posts: 5,912 Mod ✭✭✭✭graememk

    With a FIT (and a smart meter) It usually doesnt make sense to go the eddi/New cyclinder route. If on a deemed fit, the math is different, but hard to tell how much longer a deemed fit is going to be around (my best guess is about 2-5 yrs) and will only be on day night meters.

    Once they have smart meters that can drop in directly in place of Day/Night meters thats when it will be wound down.

    Any new Cylinder will work, Id say about 1500 at a rough guess for a new cyclinder + eddi. Then labour on top to fit.

  • Registered Users Posts: 8,511 ✭✭✭micks_address

    im wondering at some point if it would be worth replacing my copper cylinder with an insulated one.. its fine at the moment and using eddii for heating for handwashing/dishwashing as we use an electric shower.. the advantage of insulated is i assume water would stay warm for longer

  • Registered Users Posts: 1,178 ✭✭✭kabakuyu

    A cheap fix at the moment would be a good lagging jacket well fitted, thats what I have, does the job, didnt want the mess/expense of fitting new cylinder.

    Edit. sorry just saw you have jacket already.

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  • Registered Users Posts: 867 ✭✭✭ColemanY2K

    I was quoted by a leading supplier a few months ago just under €4k+VAT for a 200/60 litre wellmaster - supply only.

    🌞 7.79kWp PV System. Comprised of 4.92kWp Tilting Ground Mount + 2.87kWp @ 27°, azimuth 180°, West Waterford 🌞

  • Registered Users Posts: 8,511 ✭✭✭micks_address

    its a reasonably new lagging jacket but i wonder are there 'best' ones out there that do a better job?

  • Registered Users Posts: 670 ✭✭✭bunderoon

    Are the flow and return pipes lagged?

    I overdid mine and it had a noticeable improvement.

    I've a 300 ltr Joule triple coil stainless steel cylinder and with the stove plumbed but when not used, the heat loss is more than normal which is annoying.

    Got a quote of 6k for 60 tubes & plus installation (I thought I needed 40, but the house orientation is NE/SW) and I'm seriously thinking of a dual immersion, dual coil 200Ltr and using PV instead. 6K would go along way towards the DIY PV road I want to go down.

  • Registered Users Posts: 839 ✭✭✭Boardnashea

    Throw a second lagging jacket on it. Especially over the top half.

    Is it in a hotpress? bit of extra insulation around that too, if possible, and as mentioned above, how are the pipes from the tank?

  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,554 Mod ✭✭✭✭2011

    Why do you think the FIT will be removed?

    Any links to support this?

    I would have thought that the FIT is here to stay, it was increased at the start of the year.

  • Moderators, Home & Garden Moderators Posts: 5,912 Mod ✭✭✭✭graememk

    Deemed FIT (ie Estimated/Calculated) wont be here forever. As in the one that you get if your currently on a Day/Night meter, which doesnt currently measure export.

    Day/Night meters are currently not being replaced with Smart Meters as they currently cant be configured as a "drop in" replacement for a day/Night. Ie a change of meter without moving you off the Day/Night tariff like they can with the 24 Hr meters.

    There is things happening to roll out a new version of the Smart Meter to do this.

    So if you refuse the smart meter, you stop getting the deemed FIT.

  • Moderators, Home & Garden Moderators, Technology & Internet Moderators, Regional East Moderators Posts: 12,554 Mod ✭✭✭✭2011