Sunamp anyone?

A place to discuss Renewable Energy and EV charging from Renewables.
Matt Beard
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Joined: Thu Oct 03, 2013 5:49 pm

Re: Sunamp anyone?

Postby Matt Beard » Wed Feb 15, 2017 11:03 am

noahs-dad wrote:£120 a year for gas! And they all have a standing charge too except for one supplier I am aware of (Ebico). If I could have found such a cheap deal, as all things green daft as I am, I would have been tempted to remain on gas. I'd guess Matt does not have kids, is not home much and uses thick jumpers and warm hat on system when home? (if so with the latter, I judge not!)

I think you have misread something - I am questioning Scally's figures, not quoting my own.

Matt Beard
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Joined: Thu Oct 03, 2013 5:49 pm

Re: Sunamp anyone?

Postby Matt Beard » Wed Feb 15, 2017 11:09 am

Scally wrote:I pay £12 a month for gas in the summer months - which is used purely for hot water. Those are the months I get lots of solar power.
My winter gas bills are £120 a month: that's when I need a lot of central heating, and there is almost no solar at all.
I'm afraid that Sunamp would save me around £100 a year, maximum, so the payback is 30 years.
I will look further at heat exchange systems - air or ground: they appear to have better potential.
I would also love to use my Leaf battery to power my home in the evenings, saving up to 50% of my electricity costs.

Erm... I have two issues with this.

1) Do you really get no power from your solar system during any of the days when you also require central heating? I was under the impression that solar PV still gave a moderate output in winter, and pretty good in spring and autumn.

2) I don't get how powering your home from your Leaf could save you money, unless:
a) You plan to charge the car using free public charging, then drive home and use the power to run your house. Less said about that the better! or...
b) You have (or switch to) Economy 7, where you could also probably save a significant amount by charging a Sunamp from an off-peak heat-pump and using it during peak times!

noahs-dad
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Joined: Wed Aug 06, 2014 5:36 pm
Location: Dunbar, East Lothian

Re: Sunamp anyone?

Postby noahs-dad » Wed Feb 15, 2017 12:00 pm

Yes Matt I have got you and Scally the wrong way around. Scally's gas bills are not even close to the norm clearly, so there must be either some misunderstanding on his part or specific and particular reasons how he can keep them so low.

If your not getting power from your Solar PV in the winter Scally, there could be many, many reasons why. There might be one or two faulty panels, they don't last forever and they can be tested. You generally want all your panels all facing the optimum direction too so you get them working to their maximum and at that same time. I see a lot of panels on those triangular type roofs and sometimes with apex sections, where their panel distribution is all over the place with them facing in 3 different directions.

In the winter in Scotland most areas have plenty sun, or even good enough daylight on many days to generate 0.5Kw for good sections of the day on a 4kW system. No idea what the design and size of your PV system is, but I would think you ideally just need more PV panels installed to improve your generation, particularly in Winter where overall generation is significantly reduced.

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Scally
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Re: Sunamp anyone?

Postby Scally » Thu Feb 16, 2017 1:18 pm

My 16 solar panels face 8 east and 8 west, on both sides of the roof ridge which runs north-south and is at a shallow slope of around 20 degrees.
Hence they do quite well in summer when the sun is high and travels all round the horizon, and very poorly in winter, when the south sun is too low in the sky to provide anything more than very oblique weak sunshine and filtered through bare but quite large trees.
My average solar gain in the Winter months is a miserable 0.2 kWh per day!
My gas bill is quite cheap in summer because I have a really good deal, and because we only use it for showers: the appliances all self-heat their own water. But the gas central heating is on most of the time in winter, and the house is well insulated.
Yes, we are on a Economy 7 tariff, and charge at night: so using spare eleccy from my car of an evening would cost me half the price of the usual rates. The spare capacity of my Leaf battery after a normal days drive is a lot more than the 5 kWh of the Sunamp!

noahs-dad
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Joined: Wed Aug 06, 2014 5:36 pm
Location: Dunbar, East Lothian

Re: Sunamp anyone?

Postby noahs-dad » Thu Feb 23, 2017 2:03 pm

I have planned a 3rd Solar PV system with my renewables installer which includes panels on a North facing roof, South facing roof, and East facing wall. Not the norm or done thing I know.

I would have done it 3 months ago or even tomorrow, but just don't have the funds. Anyway many of these panels will be on a garage roof which is lower than the house roof. Having monitored the light the various areas receive, I am in no doubt they will contribute a good all day round increase in generation. They will rarely all produce at the same time, but to significantly increase my solar hours and overall generation at any one time I think it is a good investment.

North facing solar installs in particular are not the norm, but they can work (I previously had evacuated solar thermal tubes installed on North Roof). Also walls are rarely used on the sides of houses, they can be a surprisingly efficient sweet spot for sunlight when not obscured.

I personally think there is almost always options and solutions when it comes to Solar PV, but I do confess to being a solar nut and enthusiast at the same time. I'd even consider constructing a permanent timber frame and roof structure at the back of my garden for facilitating Solar PV panels, if needed once we run out of roof and wall space.

Some ideas maybe?

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Buzby
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Re: Sunamp anyone?

Postby Buzby » Fri Feb 24, 2017 8:23 am

I have 4 PV panels mounted vertically on the side gable of my house. Not ideal, but they do manage to scoop up a lot of early winter sun from 1000 to 1500 daily (whilst it's there). I've found this more cost-effective than north-facing panels which estimates showed barely 4 months each year of reaching their potential maximum.... almost zero return on investment.
- Raymond (Glasgow)
EVAS Communications


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