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Author Topic: alternate hot water  (Read 2937 times)
Moxi
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« Reply #15 on: March 26, 2019, 08:23:47 AM »

All,

I had thought about storage heating a bit back but not in terms of a storage heater exactly, the cottage is small and perfect for us but we literally don't have any floor space to spare. 

What we do have is a two to three foot thick stone wall that is more or less central in the house, this wall used to be the outside wall before the cottage was extended sometime in the early 1900's and I had wondered previously if I could attach to or insert some heating elements to this wall to use it as a thermal mass.  I know this works well in the lounge where the stove sits under an inglenook style stone lintel and which after a few days in the winter warms and holds heat lovely keeping the lounge warm overnight in between log fires. 

I think if I can figure out a safe sensible way of getting heat in to that wall I may have the basis of a sustainable development which would be a small battery system using solar panels and a small 300w wind turbine (our aspect does lend itself well to a small turbine) then after charging the batteries any dump load could be discharged to the wall or if not considered practicable / safe then I would consider a heat store located outside in a well insulated utility "lean to". 

Is there a thermostatic valve that will operate as a diverter valve so that the heat store would give hot water in priority to the boiler but when dissipated would switch the feed to the boiler to warm up OR would I need to use the heat store to pre heat the hot water feed via a thermostatic valve to minimise the gas needed to heat the water fully?

I am trying to find something that I can build in stages (modular?) and add to as and when funds allow hence the initial thoughts of adding to the existing wet central heating or the houses "mass" to maximise what we have in terms of infrastructure. 

An item I had forgot to mention is that the cottage has external wall insulation.

Andy
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chasfromnorfolk
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« Reply #16 on: March 26, 2019, 09:09:28 AM »

All,



What we do have is a two to three foot thick stone wall that is more or less central in the house, this wall used to be the outside wall before the cottage was extended sometime in the early 1900's and I had wondered previously if I could attach to or insert some heating elements to this wall to use it as a thermal mass...

....I think if I can figure out a safe sensible way of getting heat in to that wall I may have the basis of a sustainable development wheating or the houses "mass" to maximise what we have in terms of infrastructure. 

Andy

Had you thought (and maybe dismissed) the idea of u/f heating cable or wet u/f pipe let into the mortar courses?
Since folk walk in bare wet feet over electric u/f it should be safe and I believe connection can be as simple as a plug at one end, soit’s simple...that might be a goer. Rake out joints to a couple of inches and maybe set it in the proprietory flexible cement rather than normal mortar, to protect from chemicals, then repoint.
Even if the joints are handily wide, a wet system would be more of a wrestle - turns will be a pain and venting would have to be provided - but no risk to life.

Both have rather limited output directly in proportion to length - but you’re looking for gentle heat, and by drilling through you could do the other side sometime when time/money/enthusiasm allows.

Warmwall Bodge. Love it.

Chas
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brackwell
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« Reply #17 on: March 26, 2019, 09:28:42 AM »

Not quite sure which hot water you keep referring to as in my mind i like to segregate central heating from tap hot water (DHW)

I do not see solar PV being able to add anything to your central heating during the heating season although it could help with the DHW and i wonder what evidence you have that this is not the case.  You say it is a small cottage extrnally insulated but two fires struggle to keep it warm-difficult to compute?  Is the rest equally insulated ? You have not mentioned loft space.

Without storage or point of time use it is difficult to capture the PV.  So the bottom line in my opinion is that you need batts. The batts do not need to be in the house envelope. The batts will ensure that virtually all your PV is used and you can then power the house and your DHW with a help from E7 in winter (night rate leccy). Fit a instant leccy shower/inline water heater.  Stop using the LPG boiler as this is more expensive and inefficient but obviously keep it in case needs be. Whats not to like?

Ken
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Moxi
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« Reply #18 on: March 26, 2019, 02:16:42 PM »

Hi Ken,

I hadn't said the cottage is difficult to heat, indeed in my first post I actually said its warm and cosy, I'm looking to offset the cost of wood and LPG for heating (and DHW LPG only) using home generated electric.  My problem, as a few have you have commented on as I know only to well, is that the fuels I am using for heat and DHW are not readily replaced by PV electric at the time when the heat is required compounded by it also being a poor use of a electric.

As biff has indicated the small WT is also not likely to be able to do much but here my issue is that the ideal location for a larger W/T is in the front garden which is across a road and no readily available option for a cable transit to where the power is required Sad its a shame as we have a good windy aspect most of the time.

I've approached this problem a few times in the past and always arrived at the same conclusion that the set up is as good as can be managed without significant changes to infrastructure and since the boiler is only 4 years old I don't feel that I can change the DHW and CH system around sufficiently to incorporate other options as yet. 

Maybe its case again that having considered the options I have to accept that heating and DHW is LPG and Solid fuel based and focus on trying to make use of the electric generated to offset bought in electric using these savings to supplement the ever increasing cost of LPG until such time as the economics change and some form of ASHP pump becomes viable?

 Moxi
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Stig
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« Reply #19 on: March 26, 2019, 02:55:35 PM »

As biff has indicated the small WT is also not likely to be able to do much but here my issue is that the ideal location for a larger W/T is in the front garden which is across a road and no readily available option for a cable transit to where the power is required Sad its a shame as we have a good windy aspect most of the time.


Get an electric car and park it across the road when it's windy?   Smiley


I'll get my coat...
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andrewellis
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« Reply #20 on: March 26, 2019, 02:56:42 PM »

Those mole thingies can do under a road.  You just need a hole at either end and they then just thonk thonk thonk across.
« Last Edit: March 27, 2019, 08:27:39 AM by andrewellis » Logged

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Moxi
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« Reply #21 on: March 26, 2019, 03:10:41 PM »

My personal preference was a micro-wave death ray that I could focus across the road to a collector, thankfully we don't get double decker buses up where we live stir

I think the cost of a directional auger would be cost prohibitive but I am always on the look out for anyone doing trenches across the road in case I can lob in a 150mm duct for my personal use Smiley

I do think my options have shrunk to focusing on additional panels and a small battery bank with the option to dabble with the small WT.

Andy
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biff
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« Reply #22 on: March 26, 2019, 07:50:01 PM »

  Yes Moles are good,
                      Not hard to source either. Some have cameras on board.  It is an excellent idea from AndreWellis and should be seriously considered. Most cable gangs have them and a couple of hundred quids might tempt them to push a conduit under your road. You will not know until you try.
                                    Biff
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Tinbum
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« Reply #23 on: March 27, 2019, 10:07:17 AM »

The only thing with moles is you have to be certain what services are in the pavements / verges. I would like to do one here for drainage into the dyke opposite and also one so our phone line could be under the road but I would hate to hit the gas / water or telephone services. There would also be legal issues I would guess.
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85no 58mm solar thermal tubes, 28.5Kw PV, 3 x Sunny Backup 5048, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, Atmos wood gasification boiler, Brosley wood burner, 2000lt buffer tank and 250lt DHW
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