[Trillium]

Here are a couple of interesting videos if you're handy: Both are heating related.

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[Junie]

We have photovoltaic cells, we started using them in August, so just as the brighter summer days were coming to an end.  We have been rather surprised at how little electricity has been generated on overcast days, of which you will have many more in the UK! Bright sunny days are fine and we make lots of electricity.  We work on a different system here in that we pump all our electricity back into the grid, not just what we do not use, we gat about 3 times what we pay for it I think and we get paid once a year for what we have produced. It should pay for itself, we get a tax rebate which is almost half the cost.
We are keeping tabs on how much we use and make to see how it works out.  Our electricity bills are high, probably because we heat our water with it as this is the normal way in France - we hope to go solar for that at some time too - good job we have a large roof!

I am not sure that if we were in the Uk that we would go photovoltaic, unless there are lots of government incentives.
We will also go down ground pump at some time, air source pumps are more popular here than the Uk as they do Air Con too - which may be a bonus even in the UK.

[Trillium]

My mum and sister both have heat pumps where pipes are buried in connected lengths underground. Both installed this system because they worried about rising winter heating costs. The real kicker, that most folk forget, is that heat pump systems are useless without electricity, which is skyrocketing everywhere. What they saved in furnace oil is now replaced by electrical costs, moreso because both of them had in-floor heating installed and it takes a lot of juice to constantly push the fluid around large areas. There's no way to disconnect the in-floor heating system as all floors were tiled or had hardwood flooring or concrete (in basement)

[Spana]

  We have been rather surprised at how little electricity has been generated on overcast days,

Reading the energy forums that's one of the down sides most mentioned.  But most say the good days do compensate for the bad. 
Something that does seem to make a difference is keeping them clean.  This year a lot of people with them on their roof  had them covered in snow for days on end.  Ours will be mounted on the ground  at the top of a bank so will be easier to keep clean, I hope.

Another problem here seems to be getting your payments out of the company you sell to.

Junie, do you know what size system you have, do you keep daily records.

[John]

What they saved in furnace oil is now replaced by electrical costs, moreso because both of them had in-floor heating installed and it takes a lot of juice to constantly push the fluid around large areas.

According to the government, heat pumps make sense if you're on oil or LPG heating (in the UK - the equation may be different in Canada)

They're a big investment though so a lot depends on you having the initial capital to invest.

[Trillium]

I've not heard of any heat pumps in Canada run on oil or LPG; the point was to get away from true fossil fuels.

As for costs, my mum paid over $10,000 for hers, my sister, in a bigger house, paid closer to $15,000. And that was about 10 or more years ago for both. You definitely need deep pockets for this.

[Junie]

Hi, We don't keep daily records, but the equipment does keep some records, which I have just got the OH to show me how to get to.

On a cloudy dull day we will make about 1 kW hour
We had a bright sunny day last week ( from about 10am to 6pm)in which we made 8.4 kWhours
I have the monthly readings too here
August 222 kW hours
September 268 kW hours
October 200 kW hours
November 90 kW hours
December 100 kW hours
January 122 kW hours

Our system has 12 panels ( 1m x 1.5m multicrystaline). 
We face due South. 
We live about 50 km north of Toulouse.

We do have a quite a shallow roof, which does not make it optimal for winter use, but should really benefit in the summer, if you are putting it on the ground, it may be worth seeing about being able to adjust them them for winter and summer time.  ?My OH also mentioned reflectors which could extend the optimal time for your cells.
You will also need quite a bit of room for all the 'boxes' we will have to make a special cupboard for ours as they are in the hall.  I will post a photo later to show you what we have.


As far as our figures go
We very roughly paid 22000€
Will get €9600 back in tax rebate
The rest was a very low interest loan which is supported by government.
We receive 56 cents per kWh for every one produced
We pay 6 and 9 cents depending on time of day, so we get a normal bill and a yearly payment for what is put into the grid.

OH has worked out that we need to make 231 kWh hours per month to break even for the installation and cost of the system. That is not taking into account reducing the electricity bill at all.

We have talked about air source, but see them as quite inefficient compared to the ground source, although much cheaper to install. the thinking is that, when you want the house warm, the source air is very cold, when you want to cooler inside, the source air is hot, so there is always a large change in temperature required, which could be as much as 30 degrees going by last winter in the UK. This is surely going to cost quite a lot in power to get that heat.  With Ground source the ground maintains a roughly constant temperature of between 10-16 dregrees, so the change needed in temperature is far less and therefore less energy will be required.

I hope this has been of some help. Any more questions just ask and I will try to help!
June

[madcat]

there are a number of PV installations, ground and air pumps installed in the village through the local low carbon group.  There is no gas in the village, so the alternative fuel to on grid electricity is (gulp) oil or wood burning stoves.

the received wisdom seems to be that PVs are great on an unshaded south facing roof and generate more than enough for the household and to sell  to pay off the investment in a few (3 - 5 are generally mentioned) years.  However - there are a lot of sales organisations that will still sell you them for SW or SE facing roofs where they are a lot less effective, and you might be better just going for a cheaper water heating panel and forget the electricity generation.

The village wisdom on ground source pumps is only do it if you were going to remodel the garden anyway!  Air source on the other hand, I know 3 installations where the owners have been very pleasantly surprised at the amount of heat generated and the lack of fuss.  No complaints about noise.  In two of the cases they have PV generation so they are pretty self contained. 

[Bluedave]

I've not heard of any heat pumps in Canada run on oil or LPG; the point was to get away from true fossil fuels.

The point John was making is that in the UK it makes sense to change from oil/LPG to an electrically powered heat pump. This is due to the cost of oil/LPG, delivery and the space to store oil/LPG.

Also in terms of carbon, in the UK gas is roughly three times cleaner than mains electricity (this is due to the mix of fuels used to produce UK mains electricty - still a lot of coal power stations as well as gas, some biomass, some nuclear and a small proportion of Hydro (less than 10% last time I looked, mostly in Scotland)) which means that any electrically powered heating system needs to be at least 3 times as efficient - otherwise you may as well use gas.

Most air source heat pumps have a seasonal efficiency that is worse than this even though they state COP's (co-efficient of performance - the amount of heat/cooling you get from something for evey 1 kW of input electricity)of 3-8. There are a number of issues that affect the COP of heat pumps -

1. heating medium - standard rads in your home are sized at a flow/return temp of 80/60 degrees C and most operate at 82/71. A heat pump will only give you around about 45 degrees C flow temp. You can increase this temperature but the higher you go the lower the COP.  At 45 C the COP of the heat pump maybe 3 or 4 at 55C it will be less than 2. At 35 degrees it may well be 4or 5 - happy days. BUT my rads are sized at 80 - so i'm not getting the required heat ouput! Underfloor heating generally operates at 45/25 f/r temperature (or less) and so is perfect.

2. What is providing your domestic hot water? If your storing DHW (in a cylinder for example)you need to do this above 55 C due to Legionella. So a heat pump could do this but it would but the COP is low (less than 2 remember) it may also take a while to heat the water. A lot of these systems have an immersion top up for the DHW cylinder - so I'm back to using grid electricity to heat my water (which is 3 times dirtier than Gas).

3. Is the manufacturer stating seasonal efficiency? In the winter the heat pump will need to use energy to defrost the external coil - the COP obviously drops in this case.

So if I'm using grid electricity to heat my water, i'm not saving carbon and it's more expensive than gas (roughly 10-12 p/kWh compared to 3.5-4p/kwh).

So - if your on gas your probably better off both financially and in terms of carbon by sticking to gas or going for something truly green (if there is such a thing......).

If your on oil/LPG then heat pumps are for you! All the above applies to GSHP as well although they generally have a better COP than ASHP. It also applies to the UK market other countries have different tariffs and energy mixes.

If we clean up our grid generated electricity then heat pumps start to make sense from and environmental point of view (which is why they use them in scandinavia a lot where their grid electricity is all from hydro/biomass).

Going on far too long now!

[Bluedave]

the received wisdom seems to be that PVs are great on an unshaded south facing roof and generate more than enough for the household and to sell  to pay off the investment in a few (3 - 5 are generally mentioned) years.  However - there are a lot of sales organisations that will still sell you them for SW or SE facing roofs where they are a lot less effective, and you might be better just going for a cheaper water heating panel and forget the electricity generation.

3-5 years is optimistic - before the introduction of the Feed in Tariff (FIT), PV used to take 70 years to payback. Now, with the FIT I would say 11-12 years is about right - prices are coming down all the time though and so this will get shorter.

As to orientation -

The perfect orientation is due south with a 35 (ish) degree tilt (again, this applies to the uk - as latitude changes so does the optimum orientation). You get the maximum direct exposure and therefore maxium output (although if the panel gets too warm then efficiency drops off.......lol).

You should be able to generate approximately 800kWh of electiricty a year per installed kW in the south of the UK. This is the yearly average - most of this figure is achieved in the summer months.

So this will save you the most money (decreases payback period) and the most carbon.

You will still see some generation if you install the panels se/sw - probably 90% of this. If you install panels east/west you will achieve maybe 60% (probably slightly less) and if north maybe 20%. This smaller amount of generation still offsets grid electricity and so still saves carbon. It will of course take longer to payback - but if your interested in saving carbon and dont have a south facing roof then you can still do something.

You need to remember that the output will drop as the panels get dirtier and that the silicon degrades over time and so output will drop over the life of the panel anyway - there is no exact numbers to this that I am aware of but it could be as much as 5% every 5-10 years - just best guesses as nobody has had a panel installed over 20 years and bothered to check this yet!

[Spana]

Junie, Madcat and Bluedave.  Brilliant info.  :happy:

Thank you all for taking the time and trouble to post it. I've printed it all off for OH to read. :happy:

I had very mixed feelings  at first but getting quite excited about it all now.

We're going to see some air/ground source heat pumps working and will make a decision on which to go for after, but  have decided to invest in the PV panels to get us started.  We were hoping to have them in place for this summer but a lot depends on how quickly the planners move as we need  planning permission even tho its only a domestic system.

Junie, if you can get a photo of the meter boxes I'd be interested to see it.   thanks
The company say there will be very little mess in the house, can i believe them
How was it for you

[Junie]

Spana, Here are the photos
the first is the cells on the roof, we also had to have a white casing down the front of the house to go to the boxes ( you will not have that problem though! )

the second in the meter boxes etc, It is only those on the wall in front of you, not those on the left hand wall, which are our original meter and one of our rcb's.. One thing I did forget to mention was that it does make a buzzing noise when it is working, it was annoying at first, but we do not really notice it now!

[Spana]

Thanks Junie, its a lot more stuff than i thought it would be :blink: but it does look quite neat

Your house looks beautifully french

[Junie]

Hi forgot to say, there was no real mess in the house as everything was done on the outside in conduit, only one wire through the wall - which took sometime!!

Our house is certainly a classic looking farmhouse for this area! 

[Trillium]

TYour house looks beautifully french

I agree there