Planning solar PV... maybe

Pulpdiction

Hi All,

As suggested I have started this thread to get some ideas, comment on my Solar PV system. Below is a picture of my roof so you can get an idea:



Looking to get a 4kw-ish system. South is directly south at the bottom of the photo and so the best roofs are the one facing southeast and the other one at southwest. The Southeat facing roof has a pitch of about 47 degrees, I can't get the pitch on the other one yet but it is less than that.

The ridges at the top of both roofs to the edge of the roofs are 8m in length approx (from the edge to where they meet in the middle of the house).

So, that's the problem.... is it a problem or should I be thinking about doing something else with my money?

Thanks in advance.

theboylard

15.55 at Newmarket, Noblest!!!

Off to the tip (rubbish, not betting!), be back later...

Pulpdiction

Thanks... I think.

Sorry, another question, most people seem to be talking in terms of a 4kw system, is this a limit on the FIT payment or could a larger, say 5 or 6kw system be fitted?

tunnel

4 kWp is the highest rate FiT limit, can you go bigger?....hell yes, I did but I made sure I stuck at 4k before adding. These days though the rates aren't too much different so if you have the room it makes more sense to go large(DNO permitting)


Looking at your roof you may struggle going over 4k so look to get quotes for a 4kWp split over the 2 rooves, I believe your going to need some sort of shade management, either solaredge or micro inverters as your SW facing roof will shade the SE in a morning and vice versa in the afternoon/evening. The one good thing going for you is you'll get a much longer sustained generation curve from the 2 rooves.

theboylard

theboylard wrote: »

15.55 at Newmarket, Noblest!!!

Off to the tip (rubbish, not betting!), be back later...

Came in 3rd, by the way!

Horse, not the rubbish tip.

Ectophile

theboylard wrote: »

Came in 3rd, by the way!

Horse, not the rubbish tip.

If it only came 3rd, that sounds like a rubbish tip to me

Has this got anything to do with solar panels?

Martyn1981

Pulpdiction wrote: »

Thanks... I think.

Sorry, another question, most people seem to be talking in terms of a 4kw system, is this a limit on the FIT payment or could a larger, say 5 or 6kw system be fitted?

Just to save a little time, if you have a read of this post (in full), a lot relates to your situation:

Martyn1981 wrote: »

Firstly, if you install more than 4kWp (even 4,001Wp) then the whole install will get the 4-10kWp FiT rate which is 10% less. That's not actually too bad, but you'd logically probably want to aim for 4 or 5+kWp, not anything inbetween.

Your rooves are going to be interesting/tricky. SE + SW would be a very nice mix, as T suggests. It all depends how much can fit on the SW roof as it's angled. Presumably the SE is a decent size. There's also the hipped end SE roof, but I suspect that triangle will be tricky, and 2 or 3 panels (if they fit) may look a bit ugly ...... not sure.

Then there's the NW front roof to fall back on if you have to/want to.

Definitely think you need shade management of some sort, as T suggests.

Mart.

Pulpdiction

@Martyn1981 - thanks, very useful, I guess if I put in a system of 4kw or just shy I could at some point, 3 or 4 years add to that (assuming I would need to get a slightly oversized inverter for day 1 - to cope with a later increase), would it only be at that point that my FIT rate would drop by 10% or would the whole thing be assessed against the FIT rate which applied at that time?

Thanks

Pulpdiction

Sorry, another question, one for a heating engineers maybe, I have a combi boiler so no water tank at the moment, and I understand that lots of people are using iboost to supplement the use of their existing immersion heaters, does anyone use iboost with a combi?

I would have thought that a header tank could be used with iboost which could then feed the combi boiler in effect allowing the combi boiler to take partially heater water into the combi allowing it to do less of the work and therefore use less gas.

Effectively heating water from 40 degrees to 55 for example rather than from 15 to 55 or less in the winter.

Does this make sense?

tunnel

Pulpdiction wrote: »

@Martyn1981 - thanks, very useful, I guess if I put in a system of 4kw or just shy I could at some point, 3 or 4 years add to that (assuming I would need to get a slightly oversized inverter for day 1 - to cope with a later increase), would it only be at that point that my FIT rate would drop by 10% or would the whole thing be assessed against the FIT rate which applied at that time?

Thanks

Your FiT rate for a 0-4kWp size system would stay exactly the same(+RPI) for the duration of the contract. Adding an extra system at a later date over 4kWp would then attract the next FiT rate up(4-10). At no point would your rate drop.
HTH

EricMears

Pulpdiction wrote: »

Sorry, another question, one for a heating engineers maybe, I have a combi boiler so no water tank at the moment, and I understand that lots of people are using iboost to supplement the use of their existing immersion heaters, does anyone use iboost with a combi?

I would have thought that a header tank could be used with iboost which could then feed the combi boiler in effect allowing the combi boiler to take partially heater water into the combi allowing it to do less of the work and therefore use less gas.

Effectively heating water from 40 degrees to 55 for example rather than from 15 to 55 or less in the winter.

Does this make sense?

Theoretically : Yes.

However, you'd need to supply the combi with water at or close to mains pressure so would either need a pressurised vessel as your 'header tank' or else install the header tank at least sixty feet above the boiler.

And another snag might be that if you were feeding your combi with very hot water (and unless it was a huge header tank, it would indeed get very hot) then your DHW supplies would be dangerously hot unless you put in a separate blending valve to mix combi output with cold water or perhaps used a thermostat to limit that tank temperature to 40 deg (and I don't think an immersion stat of that level is normally available ?).

Afraid there's every chance that doing all the above would make the project uneconomic !