Can we run our heating/hot water system past someone?

[K44]

Is this the right place to post our idea for our heating/hot water system for people to comment on? (If not which topic should I put it under?) 

 

we are trying to work out an energy efficient, cost effective heating and hot water system. 
we have unfortunately had our plan for solar panels removed from our planning permission (barn conversion in Lake District national park) 

 

We want to use a stove (Ecco stove is the one we have decided on) for our heating. We have access to free wood and the house will be small and open plan and well insulated. 
 

For hot water we would like to use an electric shower and have an electric hot water tap in the kitchen because these things only use electricity when in use. 

We would like a hot water tank with a built in air source heat pump so that we are using our emersion heater less to heat water (for occasional baths and hot water in the bathroom sink) and we would like the tank to also have a feed from our stove (which would have either a flu boiler or slab boiler) 

Does such a tank exist?

 

We might use Solar panel batteries to store cheap energy at night for use in the day, and might eventually be able to get permission for solar panels but we have to work on the basis that we won’t. 
 

Does our idea make sense? 
Does anyone have a better one? 
comments welcomed 

 

[K44]

To recap.

- small, open plan barn conversion. 
- will meet current regulations on insulation. 
- access to free wood 

- can we get a tank with built in air source heat pump and feed from a stove? 
- Is using self heating appliances (such as showers, tap in the kitchen) a good way to use less electricity? 
- Is it worth us using Solar panel batteries without the Solar panels or is this an unnecessary upfront expense? 

[jack]

I've moved the post to this sub-forum since it doesn't fall squarely within one of the heating types.

 

Re: batteries, while it helps to have solar, a lot of people install them without. The right tariff can make them a very viable option. 

 

Take a look over on the relevant sub-forum for some ideas about what people are doing with batteries. You can consider them completely separate to heating.

[Conor]

Nothing wrong with what you are suggesting. Me, and a lot of sound evidence would suggest burning wood in a domestic ain't a good idea for your, or neighbours health. But nothing to stop you doing it.... Yet!

 

A small ASHP delivering hot water and UFH is the best, most cost effective way to go about it. Most people here will tell our the same. Direct electric heating of any type is the worst option. Including showers. If you are going to splash out on any sort of ashp, make it work as much as possible.

 

 

Stove is good as backup or extra source of heat. BUT, a stove installation in an airtight house to meet the required regs isn't trivial or cheap. That buys an awful lot of heatpump energy, free wood or not.

 

I'm saddened to hear you can't get solar panels. Do you have room for ground mounted solar panels or panels on an outbuilding that's not visible from the principle elevation? These would need separate planning but it's worth it.

 

Batteries are not cheap enough to make economic sense yet, especially if you are going to be a low energy user. Many here have them though and we better placed to advise than me.

[Nickfromwales]

9 minutes ago, K44 said:

For hot water we would like to use an electric shower and have an electric hot water tap in the kitchen because these things only use electricity when in use. 

There's your first very bad idea, sorry.

And here's why:

 

10 minutes ago, K44 said:

We would like a hot water tank with a built in air source heat pump so that we are using our emersion heater less to heat water

Why use the immersion less and heat everything else with other direct electricity? The water in the cylinder, via the heat pump, will be abundant and cheap as chips!!!! Do NOT fit an electric shower, or any other instant water heaters, as these are all the last resort when you have no possibility of fitting a hot water tank (or combi boiler).

 

12 minutes ago, K44 said:

we have unfortunately had our plan for solar panels removed from our planning permission (barn conversion in Lake District national park) 

Can you do a ground mounted array? I'll post some pics of one we've installed for clients previously, in an area of outstanding natural beauty, and a conservation area, and it passed with flying colours.

 

7 minutes ago, K44 said:

can we get a tank with built in air source heat pump and feed from a stove?

Yes, but it's messy, complicated, and I doubt 'sensible' when you have such cheap hot water already.

[Nickfromwales]

 

 

 

👌

[JohnMo]

Would need to read the regs, but I think the ones in the post by @Nickfromwales are exempt from planning rules, as they are basically portable. Just a shaped bucket filled with sand.

[ETC]

7 minutes ago, Nickfromwales said:

 

 

 

👌

Would look nice in green.

[K44]

RE solar panels, we have been told we would have to do a Biodiversity Net Gain report and mitigation. 
we are in the Lake District national park which is also a world heritage site

[Nickfromwales]

8 hours ago, K44 said:

RE solar panels, we have been told we would have to do a Biodiversity Net Gain report and mitigation. 
we are in the Lake District national park which is also a world heritage site

If this isn’t ’impossible’ or impractical I would definitely put solar at the top of the list, as using electricity for the rest of your days is going to happen, and only get more and more expensive to do   

 

Is there much of a cost impact to do the report? 

[Nickfromwales]

9 hours ago, JohnMo said:

Would need to read the regs, but I think the ones in the post by @Nickfromwales are exempt from planning rules, as they are basically portable. Just a shaped bucket filled with sand.

Annoyingly, anything ground mounted over 9m2 requires planning permission, but I believe this is waived if it’s on a raised framework which is then, technically, not a true ground mount ?!?

 

This country has some bloody weird and often obtuse rules and regs, and you’d think adding solar for the good of the environment would be less hassle!

 

Considering the massive solar farms we get to look at, and wind turbines, a ground mount of 9m2 (less than 3 domestic sized panels) is a garbage allowance.

 

For completeness, the above array went through PP first time with zero objections, as we planned and executed it as sympathetically as possible. 
 

The client reports that it is outputting some very high numbers all summer long. 👌👍

[Alan Ambrose]

@Nickfromwales I like the look of the array a lot.

[Bramco]

1 hour ago, Nickfromwales said:

The client reports that it is outputting some very high numbers all summer long

@Nickfromwales they will do but at that angle they'll do sod all in the winter and not much in the spring and autumn when it would be great to have more.

We found via PVGIS that an angle of 45deg gave about the same overall annual output but reduced summer gain and increased winter gain. Ours is a 6.5kWp (12 panels) system.

We're in the Green Belt, not as onerous as ANOB but our planning request was accepted without a problem.  No request for a biodiversity gain report.  Even if there were, most of these ground mount arrays go on a grassy patch.  In our case, we don't mow underneath the array, so you could argue that there has been a biodiversity gain, simply by not mowing and allowing that area to 'rewild'.

 

@K44 I'd do some searching on planning applications in ANOBs for biodiversity reports and net gains. There must be some out there.  Or if you intend to put up something like the commercial PV systems, simply put in a short statement that there will be no 'loss' as the area under the panels will still be there and that by rewilding that area, there will be a net gain.

[Nickfromwales]

1 hour ago, Alan Ambrose said:

@Nickfromwales I like the look of the array a lot.

Yup. He agreed to give it ‘very regular haircuts’ lol, so we agreed to ‘flush fit’ it down as low as possible.

 

He was concerned more about the ramblers, whom he had given access to cross his property to, regarding this not being an eyesore for them! Planning etc was almost a secondary concern lol.

 

Theres about 6kWp there, external inverter hidden in there, and AC was exported 135m back to the house.
 

Performing extremely well as we could pitch and orientate it to maximise irradiance.

 

There was zero chance of getting on the (diminishing course stone) roof of the 200 year old listed cottage…. We dared not even take the moss off it!

[Nickfromwales]

10 minutes ago, Bramco said:

@Nickfromwales they will do but at that angle they'll do sod all in the winter and not much in the spring and autumn when it would be great to have more.

I’d have to argue about that with you, as the numbers don’t lie.
 

I had feedback from the PV installers for the first years figures on just how “unbelievably well” the array was performing, the clients words and he was not a daft boy.

 

If you read my above, the remit was to have these installed so as to not bastardise the landscape, and if they WERE to be sat at a horribly unsympathetic angle of 45° then 1), they would have been quite ugly to look at and 2), they’d have needed MUCH bigger distances between rows to prevent the forward most panels from completely shading the ones behind them .

 

21 minutes ago, Bramco said:

We found via PVGIS that an angle of 45deg gave about the same overall annual output but reduced summer gain and increased winter gain. Ours is a 6.5kWp (12 panels) system.

A mono-pitch roof / array? Or 3 rows of panels banked one behind the other…..?
 

So for comments or a fair comparison, “apples for apples” plz.

 

How many Watts per panel are yours? I assume 540W per, by the rough maths.

 

These panels were German-made Solarwatt Vision 325’s, glass/glass, as the client wanted them to be as robust as possible and take impact from flying debris, otherwise we could have installed much higher output cheaper Chinese-made panels to boost the output. With a 30 year @ >90% performance guarantee the SW panels were a no brainer, as longevity of the installed equipment is paramount to preserve the indicative ROI. If the array fails early, goodbye payback. 
 

45° is a wonderful angle, I don’t disagree, but not here and not for this client. No 2 projects are the same, nor are any 2 remits, so we work to the client and their remit and treat each self builder / new client uniquely. No copy / cut / paste for me, as I feel that is just a lazy way to do things and quite a disservice. Discuss, summarise, discuss again, and only then do we crack on; eg only when the client has been given enough information and can then make their own informed decisions 🫡👌.
 

Also please understand that this was put through MCS etc, so anything less than admirable install wouldn’t have got through the software at the design phase  so it HAS to perform adequately, at the bare minimum, to get through these preliminary measures of due diligence; we do this on paper early on for every install, eg to firstly see if there’s a valid reason to NOT install PV etc. IIRC, less than 70% irradiance is a fail.
 

To combat the reduced irradiance of the shallower angle we designed this particular array to feature more panels than was required, peak summer, to offset the reduced output from the remainder of the ‘solar year’. Again, the numbers were known, discussed, and understood comprehensively by the client long before a deposit was taken.

 

Hence they have more panels than you, but less gross output than you.

 

As I said, this array is spewing out power for a lot of the year, and was placed to get sunlight from <08:00 - >18:00 peak summer; dependant on certain trees remaining crowned / surrounding (client-owned) woodland being managed.

 

Winter is a shitty time for any solar array, it is what it is, but numbers and results speak for themselves .

[Nickfromwales]

45° south facing arrays in populated areas can also cause inverters to shut down temporarily midday, due to over-volting the network. 

Always best to look properly at the whole picture, for anyone considering installing solar in a densely populated area / cul-de-sac etc, where most people may be out in work all day and exporting.

 

I wonder how well documented evidence of these instances are and how ‘problematic’ that actually is though.
 

Anyone? 

[sharpener]

11 minutes ago, Nickfromwales said:

45° is a wonderful angle, I don’t disagree, but not here and not for this client

 

With the current tariffs available it may make economic sense to export all your production rather than self-consume.

 

In that case it does not matter if the array is not optimised for year-round output or peak winter output. From the point of view of the planet it might be better to incentivise production in winter but (a) that hasn't happened yet and (b) it is usually so low at this time of year it would not make a lot of difference in the grand scheme of things.

 

 

So better to have any kind of panels than none at all.

 

 

Edited Wednesday at 09:49 by sharpener
Cross-posting

[Nickfromwales]

Just now, sharpener said:

 

With the current tariffs available it may make economic sense to export all your production rather than self-consume.

 

In that case it does not matter if the array is not optimised for year-round output or peak winter output. From the point of view of the planet it might be better to incentivise production in winter but (a) that hasn't happened yet and (b) it is usually so low at this time of year it would not make a lot of difference in the grand scheme of things.

 

So better to have any kind of panels than none at all.

Couldn’t agree more, but this was pre Covid, literally on the cusp of it, and the electricity market was a very different place back then.

[sharpener]

1 hour ago, Nickfromwales said:

45° south facing arrays in populated areas can also cause inverters to shut down temporarily midday, due to over-volting the network

 

Starting to look like a real problem. We are less than 200m from the sub-station and regularly see more than 250V.

If you are curtailed bc of high voltage at your meter presumably the DNO would have to do something about it. If however the issue is voltage rise between yr meter and the inverter then I guess you would have to install fatter cables and pray.

 

 

[Originaltwist]

A wood burner with a large heat bank looks like the way to go for you. I see you are keen on the Ecco stove but I can't see on their web site how it heats water. Can you explain please? I ask because many stoves have an integrated heat exchanger which can crack eventually and that will write off the entire stove.

[Nickfromwales]

48 minutes ago, Originaltwist said:

A wood burner with a large heat bank looks like the way to go for you. I see you are keen on the Ecco stove but I can't see on their web site how it heats water. Can you explain please? I ask because many stoves have an integrated heat exchanger which can crack eventually and that will write off the entire stove.

The issue with heat banks (thermal stores / buffer tanks) is that they need to be huge to have any useful effect or storage / stamina. 
 

I installed a 2600l Galu buffer on the above solar protect, with a log gasification boiler, and it just about provided central heating via radiators for a 24hr period if heated mid morning to late afternoon to 85°C. 
 

Anything smaller would have not made it through a 24hr period. 
 

Slightly difference if there’s a wood burning stove inside the house, as that will get heat to the surrounding rooms (if the doors are all left wide open and the fire stoked and burning well continuously) but to be storing that burn in a buffer tanks to carry you over needs at least 1000-1500L to scratch the surface. 
 

I’ve looked many times at banking heat for domestic dealings, and, as much as it sounds great, the sums just don’t work when you begin a design / concept and then realise just how quickly that size tank gets sapped of (useful) heat energy; anything below 50°C is pretty much useless in a standard home with radiators, so at 85°C you have a useful capacity only for that 35° of headroom. 

[Bramco]

3 hours ago, Nickfromwales said:

I’d have to argue about that with you, as the numbers don’t lie.

It's physics Nick, not numbers.  If your panels are at 20deg then they will get less irradiance than panels at 45deg.

 

And apologies if you thought I was dissing the whole installation - I wasn't, I know nothing about it.    I was simply giving an alternative view on the angle of dangle, which I thought might be useful to others....   Maybe 'sod all' was pejorative but it is true that you can get a better seasonal spread of output by setting things out at 45 degrees.  And FYI, currently we're getting well over 5kW from the 6.5kW ground mounted array in full sun at midday - which is great, means the batteries are topped up and we can do a dump out to the grid (15p) before the cheap rate starts again (7p). A lower angle wouldn't give us that option.

 

Anyway, this is all off topic for the OP.

[Nickfromwales]

51 minutes ago, Bramco said:

Anyway, this is all off topic for the OP.

 

16 hours ago, K44 said:

We might use Solar panel batteries to store cheap energy at night for use in the day, and might eventually be able to get permission for solar panels but we have to work on the basis that we won’t. 

Not entirely, lol, I think we got away either way it.   

 

52 minutes ago, Bramco said:

And apologies if you thought I was dissing the whole installation - I wasn't, I know nothing about it. 

Not taken any offence, I’m too stubborn and thick skinned to allow anything other than a round from a .50 to penetrate mate

 

The install was put in according to the clients wishes, would have been better on the 40° roof, but a compromise was struck, in a nutshell. 👌