Solar Panels and Unvented Cylinder anyone ?

[Gasguru]

Confirmation bias is a frequently applied term nowadays....and I can apply it to many customers that fall for eco systems especially when they've shelled out 1000s and the product must therefore being saving a fortune.
I also come across many customers that buy into the idea of eco products but have zero technical knowledge to assess the true efficiency/long term reliability and are nearly always looking at these options due to their own high carbon lifestyles. A customer the other day was thinking of buying an air source heat pump to replace their mains gas boiler (Greenstar Junior combi), the house is hopeless insulation wise so the COP would be hopeless....they holiday all over the globe .

 

[oldbutnotdead]

There is a new system in place now that pays a negotiated price per kWh for what is actually epxported, one has to have an export meter, and not paid on deemed export. Not sure if I made it confusing but that 963 kwh is times the the of Kwh of ones system .I generated 2900kwh so at 14ppKwh,thats £406 worth I didnt have to buy, plus I received £180.50 in Fit payment .

Ta for that- I looked at solar PV about 6 years ago, did the sums (at the time the FIT was quite high but so were system costs) and provided nothing broke and fuel prices continued to rise I'd have been in profit on year 8 or 9. It got a bit vague when I mentioned I was planning on renting the place out so I didn't do it...

 

[JohnD]

You're making assumptions here about what "worthwhile" means - so this is a gentle reminder that it means different things to different folk.

Enough for the value of the energy produced and used to exceed the apportioned cost of the investment.

 

[StephenStephen]

Enough for the value of the energy produced and used to exceed the apportioned cost of the investment.

Yes - that's exactly my point - it's a narrow definition of 'worthwhile' which makes pretty much every trip to the beach, holiday, planting of a beautiful bush, visit to a friend, purchase of art, turning on of a TV, playing of an instrument, walk in the sunshine, cup of tea shared, haircut, hobby, visit to the pub and social relationship not worthwhile.

None of those produce enough energy to exceed the apportioned cost of the energy, but I don't think I'd describe them as not worthwhile.

For me, the daily pleasure of showering from water heated by sunshine, of turning the gas boiler off for 6 months of the year, (and the smiley face on the immersion heater power diverter) the energy heading off to the grid, etc makes it worthwhile.
I also like that I've paid for all that electricity and hot water in advance, without that energy being subject to the vagaries of future energy price rises.

...and (I can't remember the maths but) I've probably saved money in the long run too

 

[JohnD]

(and the smiley face on the immersion heater power diverter) the energy heading off to the grid, etc

oh, so you are having solar electric panels (PV).

edit - sorry, my mistake.

 

[StephenStephen]

oh, so you are having solar electric panels (PV).

FYI @Gasguru

Yes indeed - and been very happy with them!
I have to agree with Gasguru - insulation may not be such sexy kit, but it makes a hell of a difference.

However, the perfect can be the enemy of the good, and I'm not completely convinced that inaction through fear of inconsistency makes the world a better (or less carbon producing) place.

 

[lostinthelight]

what temperature does your solar panel deliver AND what temperature do you have your gas boiler set to for the winte

Just taken the temp from the hot tap this morning after a running bath and shower ect.

 

[MeldrewsMate]

For what it's worth, I'm a fan of solar PV, with stored hot water heated by diverted electricity.
My system cost just short of £6000 with the immersion diverter in March 2014.
To date it has saved me about 15p per day in hot water savings, and some extra by reducing the electricity I have to import during the day to run the fridge, modem, and other base loads. I get a good feeling knowing that whatever I export to the grid saves a little coal or gas at the power station, plus it earns me about £500 a year in FIT payments by producing 20MWh to date (that's about 3000 kWh per year)...I know they're a 'false' earning, paid for by others' inflated bills, but as an economic argument for having them goes, it means my installation will fiscally pay me back at the end of next summer.

My system has a few, er, DIY mods, and the tendancy is to spend too much time thinking of new ways to use the solar power.
1. I built a better immersion heater diverter to divert more to hot water.
2. I turned my hot water cylinder-stat down to 40 C, that is just about warm enough for a shower, because I often get up before the sun! The immersion heater's 'stat is up around 65 C. Sadly it's a top mounted heater...maybe a Willis heater one day.
(there's a safety add-on that uses gas to heat it up to 60 C once per week if the weather has been dull, invoked twice over the last two years between May and October).
3. Diverted power also used to heat electric underfloor (150W) and towel warmer (300W) in the bathroom when the sun is out.
4. There have been no maintenance problems, apart from the eviction of several pigeons this year.

So is it worthwhile? If it lasts the rest of the year then yes fiscally, but worth more than that to me (carbon toe-print and all that), and though I'm guessing this next comment, I suspect the addition of solar PV has added to the house value nowadays, rather than being seen as a negative a few years ago.

I'd recommend solar PV, especially with a south facing roof, with the following addition; don't be limited to 4kW 'peak', mine is, and has never quite got there (16 x 250W = 4000W). The inverter will do the job of limiting the output to 4kW so as to meet regulations, but extra panels mean that your system will actually produce 4kW, and for several hours per day rather than just one (theoretical) peak. The limiting factor will be the maximum open circuit voltage that the inverter will tolerate, each panel typically can produce about 40vdc. So do your research.

MM

 

[MeldrewsMate]

...So is it worthwhile? If it lasts the rest of the year then yes...

Remind me never to do that again.
That post was written on 21st May while away from the house.
Unbeknownst to me, one of the 16 micro-inverters had failed the day before, tripping out all the rest!!!
The 16A breaker would not reset, and the generation meter was blank.
So no hot water on my return, and paying full price for a cuppa, even though the sun was shining strongly.

It gets better. Original installer has stopped trading, and had not issued the required insurance backed guarantee, so I'm footing the repair bill, which could be upwards of £800 if I bring a specialist in (scaffold and all that).

Faced with that I took a trip to the roof by ladder this week. Each of the 16 panels has a micro-inverter underneath it. As I have an east-west oriented roof I have 8 panels on each aspect, and managed to locate a roof mounted junctiom box where the east power joins the west power and the mains (yes, 240vac straight from the roof) cable runs from this down to the meter and breaker (connection to the mains).
I disconnected just the link to the east panels, and now I can reset the breaker and get 8 panels producing power. The next stage is to find and replace the (hopefully) single inverter on the west aspect which has broken down...they're Enphase micro-inverters, and they each connect to a 240vac 'bus' cable, so it really should be just a case of disconnecting each of the eight in turn until the breaker will hold in again; except that that bus connector seems to have a locking mechanism that I can't fathom (yet)...it look like special release tool time...and every soddin' connector is shielded by a 4' x 3' panel that needs to come off first.

Then there's the pigeon super-highway to be cleared, they seem to love nesting beneath my warm panels; can't think why? No doubt it'll be pigeon she-ite that's buggered the inverter.

MM