Upgrading my HW cylinder in preparation for a heat pump

Domestic Hot Water & Cylinders

Last Post by iancalderbank 3 years ago

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H2009

(@h2009)

New Member Member

Joined: 3 years ago

Posts: 2

Topic starter 07/01/2023 11:09 am

Hi Everyone I’ve come to this forum to look for some advice.

I’m looking to change my HW cylinder (300L) to a heat pump ready cylinder. Now I’m struggling to find a suitable cylinder if anyone can help, I Dont mind the idea of a custom cylinder but can’t tell if that’s a good idea or not.

My situation:

I want to upgrade the cylinder now because I can move this cylinder elsewhere and cover the cost.

I definitely want to get a HP going forward but I hate the idea of government grant which all that money is just a mark up on the installers cost. Generally speaking.

I want to retain my boiler 40CDI WB 7 years old system boiler - as back up.

I’m looking for the highest energy rated energy store.

I want to have as large coils as possible best heat transfer.

I need HW return loop.

Ideally I’m looking for a cylinder that has 28mm connections to my MPV which is all 28mm connections.

Questions:

I’m struggling to find someone who is recommend to carry out heat loss calculation in the South East, if anyone has recommendations.

Can anyone recommend a cylinder to meet the requirements.

On a flip side, (I know they aren’t generally available in the UK but I don’t mind importing it) a split refrigerant HW cylinder. But I so far I’ve been unable to find any unit that can accept a secondary heat source.

It then crossed my mind could I use the boiler to “pre-heat” or “after heat” the water using a plate heat exchanger? Only if needed that is.
Do these cylinder accept HW returns, from what I have seen they only have cold and hot outlets

A vented HP cylinder maybe more efficient as I can take 20c warm air all year round. But then have the issue as above with HW return and secondary heat source.

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iancalderbank

(@iancalderbank)

Noble Member Contributor

Joined: 3 years ago

Posts: 643

08/01/2023 6:03 pm

I put a 300L one from advanceappliances in 18 months ago as my old cylinder was dying. went for the heat pump grade coil in readiness (still have gas boiler). cylinder is bloomin awesome. Heat loss is next to nothing (once all the pipe work is lagged as well) - to the extent that mrs now complains that damp clothes can't be dried in the airing cupboard because its not hot in there any more. I don't know about HW secondary return as I don't have that in my house, you'd have to ask them if its an option. 300L more than enough for our family of four so long as the 16yo doesn't have 30 min (!) showers. I did think similarly to you about using a PHEX to get instant heat from my heat-only boiler into the DHW as well... as I was constantly running out with the old cylinder. but I decided too complicated and have never had the need in the end with the new cylinder. there's also quite a bit of discussion about cylinders on buildhub.org.uk - sometimes its about knowing which forum the people hang out on.

My octopus signup link https://share.octopus.energy/ebony-deer-230
210m2 house, Samsung 16kw Gen6 ASHP Self installed: Single circulation loop , PWM modulating pump.
My public ASHP stats: https://heatpumpmonitor.org/system/view?id=45
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