The Great 'Get Paid To Generate Energy' Hunt

Dave_Fowler

zantos wrote: »

I have had solar PV installed and working quite happily now for over a month. Today suddenly my system won't synchronise with the mains supply and just shows "waiting" on the inverter display. According to the installer this is a problem with the local electricity supply and could be an over-voltage situation on the mains (I have measure thiis at 245v so seems unlikely), or a difference in phase between the two systems. Anyway they say it is the electricity boards problem as I am techincally generating electricity that just isn't going anywhere and as it doesn't show on the export meter I don't get paid.
Has anyone else had problems like this and if so how have they resolved them?

Dave

According to the manual, the Sunny Boy leaves the factory programmed to operate at the grid voltage and frequency expected in the country for which it was originally manufactured. It can be field programmed for other countries. If it were made for continental Europe (220V?) and not reprogrammed for the UK and then used at 245V the inverter could consider this to be a fault. I understand in the UK the grid voltage is gradually being reduced, area by area, from 240V to 230V. So 245V in an area which has not been converted would be nothing exceptional.

zantos

Dave_Fowler wrote: »

According to the manual, the Sunny Boy leaves the factory programmed to operate at the grid voltage and frequency expected in the country for which it was originally manufactured. It can be field programmed for other countries. If it were made for continental Europe (220V?) and not reprogrammed for the UK and then used at 245V the inverter could consider this to be a fault. I understand in the UK the grid voltage is gradually being reduced, area by area, from 240V to 230V. So 245V in an area which has not been converted would be nothing exceptional.

Could be the problem, the brochure I have states AC voltage 220-240 (UAC nom) so it could be the mains is higher than expected.although another printout taken (theoretically) from the SMA Installation Manual states
Nominal AC voltage 220v/230v/240v
Operating grid voltage 180....265v
So I don't know quite what you are supposed to make of that!

zantos

Dave
Just checked the side of the inverter and that says nominal AC voltage of 230v so I suppose it's all up to how much Sunny Boy allow the voltage to wander from the nominated 230v - at the moment I am still reading 248v with my meter on the mains.

green_as_grass

Albyota

People like your dad are my heroes with their home-made solar panels. Respect to him!

I'm afraid that with your own system your 'quite clever' controller is doing you a great disservice. Fine that it drops the temperature differential when the tank temperature is low, but I see no reason for it to raise the differential when the tank is hotter. Obviously I don't know your actual figures for temperatures (if your controller is the type that logs temperatures you might be able to substitute your own) but here is a made-up scenario for illustration.

Say on a fine day, with patchy cloud, (typical of a UK fine day) your tank gets up to 45 degrees by lunchtime. Your controller then switches to a bigger differential of 20 degrees. Your panel then has to reach 65 degrees before your pump will transfer the heat to your tank. Actual heat of your panel could vary between say, 55 and 64 degrees as it heats and cools and the clouds pass and the sun appears and disappears. This could go on for hours without the pump operating, until the sun is past your panels, wasting many hours of heat.

In effect you would need a day of blazing unbroken sunshine before the panels can heat the tank to a decent temperature.

I know you are resolved to remove your panels, but I urge you, even if it's just to try to prove me wrong, to set your controller to a temperature differential somewhere between 8 and 10 degrees static. Just for the next month maybe. And let us know your results. You could be pleasantly surprised.

green_as_grass

Cardew

Again you attack the character ('proponents have a vested interest') of the people you disagree with instead of using reasoned argument. (Sigh)

My main point is that the figures you repeatedly quote are based on an AVERAGE system, and that this average includes many poorly designed, poorly installed and over-priced systems. As the WHICH? report shows most solar thermal companies are either cowboys or incompetent, even some of the installers for the government-sponsored study were incompetent. This is the state of this industry in the UK. To be fair to the 'technology' the figures should be based on the best systems, well designed, competently installed, at the best price, not the average systems.

I feel I have made a tiny bit of progress in at least getting you to mention fuel price inflation. However your estimate of 5% is hardly more than the current rate of overall inflation. It is already above this rate. Perhaps you need to wise up to the Peak Oil issue (production rates are falling while demand is rising).

Here's a link that might help
http://video.google.co.uk/videoplaydocid=1196559543206316765#docid=4023216611691857334
Or it's easy to find your own if you type 'peak oil' into a search engine.

Sorry I can't give you figures. No-one can. It is impossible to predict fuel-price inflation or when exactly it will escalate at a drastic rate, but I intend to be ready when it does.

Cardew

green_as_grass wrote: »

Cardew

1. instead of using reasoned argument


2. Sorry I can't give you figures. .

Green as grass,

1. I have given a reasoned argument in all my posts.

a. I have quoted Government sponsored tests of 8 systems.

b. Quoted the April 2010 report by WHICH on solar thermal.

c. Quoted the technical manager of a national solar firm.

d. Albyota and Yakky 58 in posts above have given their experiences.

All of these are remarkably alike in their conclusions. That the savings will be between £30 and £80pa. I have given a reasoned explanation of the interest lost - £150pa compounded - on the capital invested.

Essentially you have rubbished the opinions all of these people and the only figure you have given is someone, who by dint of comparing gas bills, concluded that he had saved 1,824kWh in a Sep to Dec quarter. You then mused that it could have been for a swimming pool or abroad, despite using the gas price paid in UK as a basis for savings.

And you say I haven't given reasoned arguments?

2. Obviously you cannot give figures. However if the people above are wrong as you contend, then you must have some reason why you feel they are mistaken.

Equally, if you contend that solar thermal is viable, you must have made assumptions on which to base that contention. i.e. x thousand Kwh pa that you can use, pricing each kWh at ypence, future inflation at z%. You won't give those assumptions of course!!

It is also a perfectly reasoned argument to state that you are quite typical of someone who has bought solar and are determined not to face reality. That in itself is not a problem, but trying to persuade others on this forum to make the same mistake is regretable.

I am wondering if you are now in wind up mode, so I will leave you to tell Albyota how to set up his system - and perhaps you should write to WHICH and the DTI and tell them their experts are as deluded as the rest of us mere mortals.

albyota

green_as_grass wrote: »

Albyota

People like your dad are my heroes with their home-made solar panels. Respect to him!

I'm afraid that with your own system your 'quite clever' controller is doing you a great disservice. Fine that it drops the temperature differential when the tank temperature is low, but I see no reason for it to raise the differential when the tank is hotter. Obviously I don't know your actual figures for temperatures (if your controller is the type that logs temperatures you might be able to substitute your own) but here is a made-up scenario for illustration.

Say on a fine day, with patchy cloud, (typical of a UK fine day) your tank gets up to 45 degrees by lunchtime. Your controller then switches to a bigger differential of 20 degrees. Your panel then has to reach 65 degrees before your pump will transfer the heat to your tank. Actual heat of your panel could vary between say, 55 and 64 degrees as it heats and cools and the clouds pass and the sun appears and disappears. This could go on for hours without the pump operating, until the sun is past your panels, wasting many hours of heat.

In effect you would need a day of blazing unbroken sunshine before the panels can heat the tank to a decent temperature.

I know you are resolved to remove your panels, but I urge you, even if it's just to try to prove me wrong, to set your controller to a temperature differential somewhere between 8 and 10 degrees static. Just for the next month maybe. And let us know your results. You could be pleasantly surprised.

green as grass,

some basic physics.....

If no net heat flow occurs between two objects, the objects have the same temperature; otherwise, heat flows from the object with the higher temperature to the object with the lower one. This is a consequence of the laws of thermodynamics.

With my south facing panels, there is generally, this time of year, only an average of 9 hours during the day when the sun can 'work' on the panels, yesterday and hopefully today being very good yield days...however, the hot water cylinder is still warm this morning from yesterdays yield, the temperature at the bottom of the cylinder is at 35C, and from the probe two thirds up the cylinder reads 52C, and the panel temp as of 7-15am is at 24C, the ambient external is 23.8C.

Four of us had usual washes and/or showers last night, so the cylinder temperature this morning is where it would be normally. If the sun did not shine today, we would pretty much use the rest of that hot water through the day till it is cold, and then at 6pm (the sun has gone west) the air source heat pump would come on to heat the required amount of water for our needs.

The controller looks at the temperature differential from panel sensor to cylinder sensor, so with the cylinder at 35C.... the panels need to be higher than this to start the circulating pump, and by the law of physics, heat exchange in water happens above 11C. the hotter the water the greater the differential.... otherwise the circ pump will drag warm water from the cylinder and dissipate it outside.

I was lucky in that I purchased my setup and fitted it myself, pipe and fittings, insulation etc.. and scafolding hire came in at £2.5K.

In two and a half years since fitting (albeit, the least sunny for a long time and the coldest three winters) I could honestly say the amount of free hot water I have had, amounts to, at the most, £300.

Using gas, LPG, oil or direct electric, to heat the required amount of hot water for a family of four will cost between 40p and 60p a day. about £200 a year.
Lets be generous and say, here in the UK, the average amount of solar yield days is about 150.......150 days of maximum yield would be between £40 and £60 per year....and at my install cost of £2.5K that puts payback at 63 years....42 at best. OK the RHI at 18p/kWh (£250/yr) for 20 years may make a difference but at £3K to £5K (using MCS installer to qualify for RHI) doesn't make much difference to the payback / ROI.

in the time it took me to write this
the external ambient = 24.9C
bottom of the cylinder = 34C
Panels =29C
pump off

AL

albyota

Quote:
Say on a fine day, with patchy cloud, (typical of a UK fine day) your tank gets up to 45 degrees by lunchtime. Your controller then switches to a bigger differential of 20 degrees. Your panel then has to reach 65 degrees before your pump will transfer the heat to your tank. Actual heat of your panel could vary between say, 55 and 64 degrees as it heats and cools and the clouds pass and the sun appears and disappears. This could go on for hours without the pump operating, until the sun is past your panels, wasting many hours of heat.

If we only use, say, half a tank of water a day, then it is pointess heating the whole tank to a higher temperature, as the following day (if the sun comes out to play) there would be no differential between tank and panels, therefore the circ pump would not run. half a tank at 55C should be enough for most households.

albyota

Found this.....interesting

UNITED KINGDOM

England: the sunniest region in England is the south coast, which achieves around 1,750 hours of sunshine each year - an average of nearly five hours a day. Two resorts have traditionally battled it out for the hot spot: Eastbourne in East Sussex, and Bognor Regis in West Sussex. Eastbourne claims to have been the sunniest spot in mainland England last year, with a total of 1,868 hours, or five hours and seven minutes daily. But Bognor asserts that, over the past half century, it has been ahead of its eastern rival by a mean two minutes per day, with an average of 1,855 hours of sunshine annually.

Scotland: today, Lerwick in Shetland will enjoy four more hours of daylight than London. But its northern location, exposed to the full force of the Atlantic, makes it susceptible to cloudy weather. Glasgow takes the title for Scotland's sunniest city with an average of 1,400 hours per year (three hours 50 minutes per day). The country's sunniest destination is across on the east coast: Dunbar in Lothian enjoys 1,523 hours of sun per annum, or four hours, 10 minutes daily.

Wales: the hilly terrain and western location makes Wales cloudier than England. However, Dale Fort in Pembrokeshire achieves a respectable 1,718 hours of sunshine a year, which works out at four hours 12 minutes daily.

Northern Ireland: like Scotland and Wales, Northern Ireland has more cloud cover than England. Hillsborough in County Down has the most sun, reaching 1,340 hours per year (three hours 40 minutes daily). The sunniest months are May and June, with six hours of sun each day.

Channel Islands: the sunniest place in the UK is Jersey, with 1,914 annual hours of sunshine (five hours 15 minutes daily). Guernsey is a close second place with just three minutes fewer per day.

• 1 year ago

green_as_grass

Actually Cardew, I didn't say that you haven't given [any] reasoned arguments. That would be a global statement. I gave a specific example, ''proponents have a vested interest'. I acknowledge that you have given some reasoned arguments. But I noted that on that occasion you chose to attack character rather than argue with reason against my points.

Here's another example: I am 'determined not to face reality'. And you describe this as a reasoned argument!

I could happily overlook these if you did actually address my points.

You say 'you must have some reason why you feel people are mistaken'. Yes I do, and here are my reasons (again!).

a) The figures you keep quoting from WHICH? are based on average figures. The solar thermal industry in the UK is in a sad state with many cowboy firms and incompetent installations, as the WHICH? report highlights. The average performance of systems is therefore much below what well designed and installed systems can achieve. We need to base our decisions on the performance of well-designed and installed systems instead.

b) We need to protect ourselves against fuel price inflation (ref: peak oil issue). Fuel price inflation will make solar thermal even more economically viable.

I do not 'rubbish' people's opinions as you describe. But contributing to forums would be pointless if we could not include discussions, challenges and arguments (in a reasoned way) to other people's opinions. That is what I have tried to do.

As I've said before, I don't claim to be an expert. But I have found a small army of experts on the Navitron forum who have been extremely helpful to me and I've tried to point others to the same place. The suggestion I gave to Albyota was based on what I've learned from them.

I admit I tend to be sceptical of people who claim to be experts in solar thermal issues (until I've had experience of how good their advice is). It is too easy to claim to be an expert in an industry that is unregulated and has no specific qualifications to demonstrate competence.

I think the scenario I described to Albyota illustrates one way in which a system's efficiency can be compromised by a setting being out by a few degrees. No disrespect to Albyota, I'm aware he is more competent than me in many ways.

So, how about addressing my points?

Here's a link if you want to inform yourself about fuel price inflation:

http://www.telegraph.co.uk/finance/economics/7731212/Petrol-expected-to-fuel-inflation.html