Green Building Forum - Renewable Energy

Toothless rabbits needed

tony — Wed, 12 Aug 2015 09:11:59 +0100

All these solar farms seem to be going to run into problems with undergrowth, rapidly growing up and shading the panels.

We need toothless rabbits to eat the grass and keep it manicured, we could then eat te rabbits too. What else could eat the grass, our local one was supposed to be being grazed by sheep but that didn't happen,

Quote comparison

niallcook — Mon, 03 Aug 2015 12:40:42 +0100

Anyone like to comment on these three quotes for a 4kW PV system I've recently received:

Quote 1:
16 x JA Solar 250w Mono Modules
Ginlong Solis 3.6kW Dual MPPT Inverter
Â£4,630.00 inc VAT

Quote 2:
16 x Jinko JKM-250P Poly Modules
Solax SL-TL 3600T Dual MPPT Inverter
Â£3,999.00 inc VAT

Quote 3:
16 x UpSolar 250w Poly Silver Modules
Fronius Primo 3.6 Inverter
Â£5,382.46 inc VAT

Thanks in advance

Solar PV installers in South East London / Kent

richardelliot — Fri, 03 Jul 2015 11:07:38 +0100

The roof should hopefully start going on my build at the start of August and we are trying to finalise the PV installation. We contacted a company to get some ideas of prices etc... before planning and either we've lost their contact details of they have closed down as we can't find them anymore.

Can anyone recommend a PV installer in South East London / Kent? As it is a new build we are looking for one of the 'in roof' systems, where the solar panels sit flush with the tiles and not placed on top. (They are still panels and not the solar tiles.)

Any tips on what to look out for when installing would also be good.

Thanks,
Richard

Grunflos "alpha" or other self? modulating circulating pumps, how do they work?

orangemannot — Tue, 09 Feb 2010 10:49:48 +0000

As in I, from perusing the Grunflos webpage, figger that these pumps are controlled by pressure rather than temperature.Yes?
Reason I am asking is that we have a 40kw wood burner linked through a Laddomat to a 2200 litre buffer tank.
I can get the tank up to say 90 deg at the top & 80 at the bottom.
BUT when I start drawing off heat during the spring or autumn when my heat demands are marginal, I lose stratification,............ in the dead of winter no problems since I am lighting every day anyway.
So I reckon that I need a TEMPERATURE controlled circulating pump.
btw I pump straight out at max temp to hot cyl (in the house,) rads and also underfloor with its own self contained blending setup.
So I may need fit a blending valve as well? yes
though I am pleased with the higher temps at the rads,and indeed for domestic hot water, I simply run the pump for a shorter time.
cheers
M

Solar PV panels on a lean to pergola

Miked2714 — Sat, 19 Dec 2009 19:39:53 +0000

Hi all

I guess there will be a lot of solar PV questions in the next few months. We've just started to think about it for obvious reasons. Not a huge system ~1.4-1.8kWp. Doesn't seem to be many installers locally (S.Oxfordshire) so I contacted one with my plan which is as follows: install panels on a lean-to pergola which will be built to stick out onto south facing patio. We were planning to build this anyway, so can easily build it robustly to hold the weight and account for wind lift etc. Advantages of this approach (to me) are that the panels are accessible, can be at optimum angle, no scaffolding, electrics relatively simple as it's close to where I've got a spare main cable running back to the consumer unit, and we get some shading for free. The feedback from the installer was that this was highly unusual and they didn't do any installations which weren't on a roof or freestanding. I thought that we effectively had a roof without the tiles, but no go apparently. They were helpful and suggested that other installers might use a Shuco system, I checked their website, very nice, can supply custom canopies with built in pv panels, but it just screams â€œexpensiveâ€. Any suggestions on mounting sytems or installers to contact, feeling a bit down about the whole thing!

Cheers and thanks in advance

Mike

One small victory for rooftop solar

SteamyTea — Mon, 27 Apr 2015 19:39:44 +0100

In this quarters Renewable Energy Focus, the editorial was about permitted development being extended to 1 MWp roof top solar systems.

This is mainly for commercial installations, but good all the same.

.

tony — Wed, 29 Apr 2015 13:06:59 +0100

Water source heat pump map

tony — Thu, 09 Apr 2015 14:59:40 +0100

A map of places suitable for water source heat pumps has recently been published.

The idea that areas where there is high heat demand are close bodies of water and could therefore be suitable for district water source heat pump schemes may see a good one.

Warnings:-

District heating though popular in other countries have been very unpopular here in the UK.

High heat demand should be reduced in the first instance.

Taking vast quantities of heat out of bodies of water, especially rivers and lakes could result in them freezing!

Water source heat pumps need licences in order to use the water and the authorities responsible for these can put up a lot of expensive hurdles to overcome in order for such systems to be allowed.

Who owns the right to the heat in a watercourse is as yet undetermined in law, can I for instance take more than my fair share of heat out of my local river leaving my neighbour down stream at a disadvantage (this is akin to shading someone's solar panels with a new building).

Water source heat pumps, though very efficient, will loose some of their benefit if used to power a heat main.

To sum up we would do well to reduce our heat demand and we still are not paying anything like enough attention to this aspect of our energy policies.

SUDS for powergeneration.

renewablejohn — Mon, 27 Apr 2015 12:46:08 +0100

Have yet again been flooded out even though I live on a hill top.

Last winter our dam collapsed in the winter storms making our surge pool redundant which has protected us since it was installed. As a matter of urgency I will be reinstating the dam but now thinking of incorporating a power generating overflow using a stream engine. Has anyone experience of this was looking at a 4 inch overflow pipe and a 25 mtr head.

LiFeYPO4

dickster — Tue, 24 Mar 2015 16:08:27 +0000

Blimey, got my new PC up and running and found my way back to the forum.

Had the tree doctor in and reduced height of trees so am one step further forward towards goal of PV array and stonkin' battery storage using LiFeYPO4. Still struggling with all things Lithium, but have found a company called Balqon in the USA that sells Energy Storage Systems (battery banks) in a box with cell balancing and BMS spaghetti all pre attached. And the price for a 16kWh job, $8225.00 . Now divide by 3 multiply by 2 = Â£5483.33 + shipping + tax etc etc. Maybe Â£8K still waiting for email to confirm.

This is what I've been looking for. A decent price for decent gear for someone with not enough knowledge to be wiring up cell balancing/management stuff.

Mr Winston Chung (of Winston Thunder Sky etc) is involved in the company so they should know what they are talking about.

A typical LiFePO4 12v 200A = 2.4kWh battery in a well known blue box bought in the UK costs Â£2K.

A typical LiFePO4 yellow battery bank of 8 x 3v 1000A = 24kWh not in a box from mainland Europe costs around Â£6.4K with cell management and balancing as a DIY add on requirement + shipping.

So just thought you might want to check Balqon out.

PV; is this a good deal

Rex — Wed, 25 Mar 2015 15:02:11 +0000

What ho,

When we were building, I was investigating PV but decided that the money needed to be spent on the house and PV could be added later. As a result of those investigation, I have received a 'cold (ish)' call from Green Energy Electrical. With an ISA maturing and reinvestment rate of 1.6%, perhaps PV would be a better investment?

Salesman trying to sell me 3kWh of PV for either Â£10k cash or Â£16k with a Barclays loan which will be paid back by the FIT over X years. Both prices are a 'how stupid do you think I am' figure. Surprisingly, that price has now reduced to Â£7k and this morning, because of an order 'cock-up' we have 'surplus panels and can supply them, installed inc VAT for Â£6500.'

They are offering Canadian Solar panels, En-Phase micro inverters, a Solar iBoost for immersion heating and a voltage optimizer. My research tells me that I don't' need the VO but open to hearing opinions.

However, does anyone have any experience of Green Energy Electrical, based in Brentwood, Essex?

From what I can find out, Canadian Solar, En-Phase and Solar iBoost are well respected brands.

One other item that I don't quite understand, their price includes installation, in my case on a single story, flat garage roof, but it also includes installation on a normal, two story pitched roof. Installation costs cannot be the same.

Any comments would be greatly received.

Toodle Pip

Rex

Tomorrows Eclipse

SteamyTea — Thu, 19 Mar 2015 10:21:42 +0000

A couple of years ago we were discussing the amount of PV on the grid and how it may affect generation:
http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=9077&page=1

Well tomorrow is the day to find this out.
I shall keep an eye on the Gridwatch site and see what happens, there is a data column for Oil and Other generation types that are little used. I hope that the Other column shows PV, but not sure it does.
I suspect that gas will increase and it will all be well managed and nothing unexpected will happen.
I also hope the skies are clear, then I may be able to get some pictures.

Farm Anaerobic Digesters

owlman — Tue, 10 Mar 2015 18:08:08 +0000

I always thought that the main guiding principle for this technology and it's application was initially as a means of disposing of a waste product and turning it into something useful.
On small and medium farms and horticultural establishments it could usefully serve to dispose of otherwise "waste" matter.
It now appears we are turning good food producing land into feedstock for industrial sized digesters merely to capitalise on tariffs, or put another way as an investment tool for City get rich quick merchants, who are funding this. All this while food imports rise.
Is it beyond the wit of man to formulate rules that direct tariffs into true waste management? Is it a case of feed in tariffs distorting the scene.
It makes me think the Government really don't care and are only interested in ticking boxes before the 2020 GHG emission targets are due, irrespective of it's impact or morality.

.

Wattsun tracker control

GBP-Keith — Sat, 27 Dec 2014 11:33:34 +0000

Ok my fourth Wattsun tracker controller has popped its clogs so I think I have to come to terms with abandoning solar tracker technology as a big waste of time and money. Most of you knew that already i guess. The 40% estimated improvment in energy production is a valid claim but no advantage whatsoever if the kjt is going to pop everyfour or five years. With a replacment unit costing about Â£400 it has now become a big no-no.

Unless anyone on the forum knows of a uk manufacturer of something similar that could track the sun and send power to sattelite jacks. Wattsun has also been taken over by a larger firm since I last replaced the controller and it seems that their customer support has taken a dive with the merger.

Biomass Boiler Operating Manuals

browng — Tue, 03 Mar 2015 16:34:02 +0000

Has anyone experienced problems with trying to decipher operating manuals for biomass boilers especially those manufactured in Austria or German?

I am in dispute with my installer over the fact that the manual supplied for my boiler is not in plain english as required by the Renewable Energy Consumer Code (RECC). It is a poor translation from German and the grammar is appalling.

Would be interested to other's experiences

Gordon

Solar PV optimisation

aberned — Thu, 12 Feb 2015 11:07:52 +0000

I have a 10kW solar PV system and export around 71% of my generation to the grid. At the same time I'm running a 3 phase GSHP feeding a buffer cylinder and hot water tank. To extend the life of my heat pump, I want to make better use of my solar PV and am looking at installing some sort of optimisation system.

I'm quite keen on the Apollo Gem which I hear good things about. Unfortunately I'll need 3 of these (1 for each phase) and each independently feeding an immersion on one of the 2 tanks. Including the immersions and other bits and pieces, I think I'm looking at around Â£1,000 all in. Worth it?

Does anyone have any experience of the gem or other products?

PV panels on the move

the souter — Sat, 21 Feb 2015 11:37:44 +0000

It appears that securing PV A-frames to flat roofs by using Jewsons gravel bags as ballast, is not a twenty year fix

Not hearing the happy hum of our inverter t'other day, I ventured into the attic to discover zero production. Strange; it was sunny. Out on the roof, one cable was disconnected, another so taut it was acting as a guy line to a bank of four panels. They had marched a foot towards the edge of the flat roof...

Last year, on our other flat roof, I had inserted cut-up old paving slabs into the rear flanges of the frames. This seemed a good substitute for the bird-pecked, splitting, uv degrading clear plastic bags slumped over the bases. Did I then immediately go purchase new slabs and swap out the bags on the remainder? Labelling myself a bit of an eco warrior, I disliked the idea of fresh concrete slabs; surely some would crop up soon from a job? Then it was Christmas/ raining/ had a cold/ etc. Just plain dropped the ball.

I accept this is 'school of the flipping obvious' stuff but if you have any doubts about the security of your panels, please listen to that little voice and avoid a potentially disastrous scenario. As it was, I only lost perhaps 15 kw/h production and some pride.

To your ladders!

Swedish report wood burning causes 1000 premature deaths per annum.

Chris P Bacon — Sun, 08 Feb 2015 18:50:39 +0000

May be of interest to some here.

A new report from the Swedish Environmental Research Institute and the Department of Public Health and Clinical Medicine at UmeÃ¥ University has concluded that residential wood burning caused just over 1000 premature deaths in 2010.

The report can be downloaded from the link below:

Primarily in English, just scroll down past the summary in Swedish.

http://www.ivl.se/download/18.41ba7c1514a956c967d64d/1422532458711/IVL+B2197_Exponering_2010.pdf

Cut in speed of large turbines

CWatters — Thu, 05 Feb 2015 19:12:56 +0000

Nearby wind farm has two sizes of turbines 100m and 130m. All this week (light winds I think) the smaller turbines have been running but the larger ones have been stationary. I thought the cut in speed for larger turbines was lower? Anyone?

Simax PV Panels

g4piq — Sat, 31 Jan 2015 18:33:20 +0000

Does anyone have any experience with Simax PV panels? We have received 3 quotes and the one using Simax panels is substantially cheaper than the others. However, there is very little information that I can find on the internet of people using them in anger, and if like to have some confidence that they don't take to many manufacturing shortcuts.

Thank you

Andy

SolarPV and inverters

albacore — Sat, 30 Jul 2011 20:59:39 +0100

We are planning an installation of PV panels on our bungalow on two roof aspects, just off of S.E and S.W orientation. I seem to remember reading that installations in different orientations should be connected to seperate inverters. (I can't remember where I read it,and can't now find relevant information by googling) Is this correct? and is there any accessible source of information online on such technical aspects of PV installation? I would also like to learn about issues related to cable length, and cables passing through insulation.

Thank you for your help.
Albacore

Should solar pv panels face West?

tony — Sat, 11 Oct 2014 16:03:32 +0100

Not my question but we are being drive totally by financial considerations in always wanting them to face South.

West facing panels produce more energy during the peak period, indeed for this reason alone it could be argued that they all should face west!

Dutch Company Powers Streetlights With Living Plants

Chris P Bacon — Sat, 17 Jan 2015 11:33:27 +0000

"The process involves plants growing in modulesâ€”two-square-foot plastic containers connected to other modulesâ€”where they undergo the process of photosynthesis and convert sunlight, air, and water into sugars. The plants use some of the sugars to grow, but they also discharge a lot of it back into the soil as waste. As the waste breaks down, it releases protons and electrons. Plant-e conducts electricity by placing electrodes into the soil."

http://www.yesmagazine.org/planet/dutch-company-powers-streetlights-with-living-plants-will-your-cellphone-be-next

Proven 2.5 wind turbine

GBP-Keith — Fri, 26 Dec 2014 20:51:45 +0000

Hi.my turbine has suddenly taken it upon itself to start triggering the trickle dump which is built onto the top of the controller box and it is triggering at very low voltage-about 25.5 volts. Has anyone else come across this phenomena? I'm wondering if it is a result of the lightning storms at the end of November. The lightning wrecked my tracker too.

Best 'black box' to redirect solar pv to immersion

tony — Wed, 17 Dec 2014 23:19:02 +0000

Which one of these is the best to get?

Genersys

jmcca — Wed, 17 Dec 2014 12:05:11 +0000

I had 'Genersys' Solar panels installed at my home about five years ago. I might be having some work done on my roof so need to investigate puchase of flashing parts/ weather seals etc in case anything gets damaged during the work. However 'Genersys' website seems to indicate they're no longer in business. Can anyone advise please? Is everthing OK with Genersys or have they shut down manufacture worldwide completely, or just in the UK? Or perhaps franchised out their UK business?

Any information welcome please?

second hand solar PV - any pitfalls?

hairydude — Tue, 28 Oct 2014 15:53:54 +0000

Hi all,
A client had just purchased a house which has a 2yr old 4kw solar array with Sunnyboy Inverter.
His wife hates the appearance (old property in conservation area) and whilst roof is being repaired/altered, the solar system is being removed.

Now, I was about to install a system on my own house anyway (have been quoted Â£5200 Inc VAT for an MCS registered system) but my client has offered me the 2nd hand system for Â£600.

My questions are:

1. Can I register for FIT with a 2nd hand system?
2. What is likely cost of installation by MCS registered installer?
3. Is Â£600 a decent price? Obviously saves me capital cost but potentially lose FIT long term.
4. Any other pitfalls I should take into account?

Thanks in advance.

Technologies for coping with a fluctuating energy supply

kev67 — Sun, 04 Dec 2011 22:56:02 +0000

Storing larges amounts of electrical energy has always been difficult, which makes it tricky to match power supply to demand, particularly when that supply comprises some widely fluctuating renewable energy sources.

Electric cars have been mooted as being useful for regulating power supply. The idea being that vehicle batteries can be charged up on windy nights. The batteries may even assist in supplying the grid at times of peak load. Personally, I am sceptical. People are not going to be happy if they can't drive their cars in the morning because it's not been very windy recently.

It's been suggested that in future that some home appliances could be fitted with chips that would allow them to be switched off for short periods of time at peak load: freezers, washing machines and that sort of thing. I would think that was more a short term measure though. It might help level energy demand during commercial breaks in world cup matches, but I doubt it would be very helpful for making use of a fluctuating wind resource.

Water heating or storage heating are other options, I suppose.

We could connect a cable to Scandanavia to pump their hydro.

I wonder if certain industries could be incentivised to help. For example, the Haber-Bosch process for manufacturing nitrogen fertilisers usually relies on methane for its source of hydrogen, but it could use electrolysis. Fertilisers can be stockpiled. I imagine these days the process is highly automated, so labour costs associated with employees standing around idle or having to work anti-social hours would not be such a consideration.

What else is there?

most reliable inverters

Fred56 — Wed, 26 Mar 2014 06:57:12 +0000

I'm canvassing for practical experience with PV inverters. The inverter on our system has just died at 25 months. It was an Eversolar which is now called Zeversolar and is part of SMA. It's in warranty but clearly a life of only two years is completely useless. I'm thinking about replacing it with a better unit. Our system is a 2kWp. Whta are the most reliable inverters?

NB we did not choose the original, it was what the installer supplied. Internet searches illustrate that the Eversolar stuff fails at around 2 years.

Inverter/Charger has high voltage at battery terminals?

crosbie — Tue, 09 Dec 2014 09:47:58 +0000

I've got a new 12V->220V inverter/charger and it works fine, but I've noticed that whilst its chassis/cabinet is earthed, there is a potential difference of over 100V between either battery terminal and earth.

Is this normal?

Paris bans wood fires

CWatters — Sat, 06 Dec 2014 22:22:37 +0000

Small article in todays papers...

Wood fires are to be banned in the French Capital from January 1 to tackle pollution.

12 or 24 volt lighting

Triassic — Sat, 29 Nov 2014 18:09:14 +0000

In another thread the following was suggested

Posted By: ringiAt least for someone with PV, once local stored energy systems becomes cheaper, the energy should be stored in the home, topped up with PV, and then at time of least demand if not enough PV.

Maybe even sending 12v or 24v direct to all the LED lights without converting to 240v.

So I'm planning a new build, if I had solar panels, just how difficult would it be to have 12 or 24v lighting?

The Future of Electricity in Domestic Buildings

Triassic — Fri, 05 Dec 2014 08:41:05 +0000

Thought this report may be of interest to some of you who look to the future

by Andrew Williams --BRE

This paper reviews some of the key issues surrounding the supply, distribution and use of electricity in domestic buildings. Its primary aim is to consider the electricity system in a holistic, albeit simple, way and identify some of the inter-relationships and inevitable compromises that inherently arise. By adopting a â€˜horizontalâ€™ system-wide review the hope is that the paper stimulates an integrated, system-wide debate surrounding how electricity in domestic buildings will evolve in the future. Only by doing this will electricity generation and consumption be harmonised with national targets and future consumer lifestyle need.

http://www.designingbuildings.co.uk/wiki/The_Future_of_Electricity_in_Domestic_Buildings

Link to the report, all 91 pages ! http://www.designingbuildings.co.uk/w/images/b/b7/The_Future_of_Electricity_in_Domestic_Buildings.pdf

SPF calculation charges?

gustyturbine — Tue, 02 Dec 2014 09:29:51 +0000

Hi All,

Well here is a short question on the RHI GSHP SPF calculation.

I recently requested that my installer calculated my GSHP SPF for me as in my opinion the default 3.1 was a bit low. The results have come back and the SPF for my unit is apparently 4.1 so that was good news.

My question is this though. I went back to my installer as they know the system and we have a good working relationship etc. I knew that this calculation would not be free but the actual invoice has been sent as follows-

Carrying out SPF calculation of your heat pump system and registering the SPF with Ofgem as requested Â£400-00
Carrying out Heat Requirement Calculation as requested Â£85-00
Plus VAT Â£582-00

Now to me that seems very expensive.
What is the general opinion on this as I feel they are just cashing in on my back.

Thanks.

Wind Power Storage with Molten Aluminium

Doubting_Thomas — Tue, 02 Dec 2014 13:57:09 +0000

In Germany (of course) they are trialling an interesting technology.

Rather site specific - I'd hate to think it gets used as justification for an unwarranted increase in Aluminium consumption elsewhere, but quite a clever use of the metal as a storage medium:

http://www.bloomberg.com/news/2014-11-27/molten-aluminum-lakes-offer-power-storage-for-german-wind-farms.html

PV, off-grid, ground mounted

carrotandturnip — Sun, 30 Nov 2014 19:05:35 +0000

Hello, and please can I ask for comments. I'm thinking of (diy) installing a small ground mounted off-grid pv system, to help with dhw or for a little space heating. The important questions are probably the ones I don't even know to ask.

It's to have six panels of the common size, about 1.65m x 1m, arranged landscape, 2 wide x 3 deep, so overall about 3.3m wide x 3m deep. The site is rocky, a sort of amphitheatre, facing SW. I propose to make the frame of scaffold, with concrete flags and/or lintels as ballast weights.

There are some photos of the site and of a model of the frame, and more description of details at
https://www.flickr.com/photos/89810542@N02/sets/72157649544482805/

How long will scaffolding last, and is there a good way to stop the clips and tube going rusty?

The ground is difficult - at the back is very uneven solid rock, but it cleaves and tends to crack, and would need quite long fixings to be secure. I propose lintels for ballast, since they will rest on just a few points of rock. They will not be fixed, relying on the braced frame to prevent them sliding.

At the front the ground is very stony earth - a 30mm masonry drill will not push the stones out of the way, so I don't think it would be possible to hammer in spiral ground anchors. I can dig it with a pick. There is no access for machinery. So I propose a stack of two or three concrete flagstones at each side, part below ground level to hold them in place.

The four ballasts will be fixed to the front and back bottom tubes with 100mm wide x 6mm thick strip and 16mm threaded rod, all stainless steel.

The total panel area is about 10 sq m, and the total weight of the frame and ballast about 550kg, biased to the front. Exposure is moderate - the site is windy, but the installation is protected by trees and rising ground.

More questions about the electrical side but I'll stop there. Any suggestions will be welcomed, particularly about the frame and ballast. Please let me know if details are not clear.

Google engineers - Renewable not enough

CWatters — Tue, 25 Nov 2014 12:18:46 +0000

Google engineers calculate that renewable energy won't save us. They consider the scale of what else we need...

http://spectrum.ieee.org/energy/renewables/what-it-would-really-take-to-reverse-climate-change

Even if every renewable energy technology advanced as quickly as imagined and they were all applied globally, atmospheric CO2 levels wouldnâ€™t just remain above 350 ppm; they would continue to rise exponentially due to continued fossil fuel use. So our best-case scenario, which was based on our most optimistic forecasts for renewable energy, would still result in severe climate change, with all its dire consequences:

To bring levels down below the safety threshold, Hansenâ€™s models show that we must not only cease emitting CO2 as soon as possible but also actively remove the gas from the air and store the carbon in a stable form.

Harvesting energy from thin air - Graphene will make it possible.

Chris P Bacon — Thu, 27 Nov 2014 07:46:26 +0000

http://www.independent.co.uk/news/science/scientists-predict-green-energy-revolution-after-incredible-new-graphene-discoveries-9885425.html

Story on the front page of today's Independent reporting on a study published in Nature that states that:

"Researchers have discovered that graphene allows positively charged hydrogen atoms or protons to pass through it despite being completely impermeable to all other gases, including hydrogen itself.

The implications of the discovery are immense as it could dramatically increase the efficiency of fuel cells, which generate electricity directly from hydrogen, the scientists said.

The breakthrough raises the prospect of extracting hydrogen fuel from air and burning it as a carbon-free source of energy in a fuel cell to produce electricity and water with no damaging waste products.

â€œIn the atmosphere there is a certain amount of hydrogen and this hydrogen will end up on the other side [of graphene] in a reservoir. Then you can use this hydrogen-collected reservoir to burn it in the same fuel cell and make electricity,â€ said Professor Sir Andrei Geim of Manchester Univeristy."

Still only small scale and probably many years work involved in realising this on a commercial scale but it looks very positive.

PV vs solar thermal for low grade heat

Ed Davies — Sat, 15 Nov 2014 12:45:00 +0000

In another thread:

http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=12791&page=1#Comment_213286

FosterTom wrote: â€œThere must be a crossover, when with increasing insolation ST begins to produce 'something' while PV produces more, and at some point they equalise even for same collector area, before ST races away to produce much more for same collector area. Any 'feel' of where that equalisation point lies?â€

This is my page with the closest relevant results: http://edavies.me.uk/2012/01/solar-per-area/ The bottom graph is slightly less horrible to look at.

Taking just about producing heat at 25 Â°C above ambient the relevant lines are the ~~darker blue~~ green for flat plate and light blue/cyan for evacuated tube. PV is pretty much temperature independent so its single muddy-brown line is the one which applies.

Going on rough insolation read off the graph:

[Edit 2014-11-18: corrected to use the appropriate line for flat plates. More detailed and output-temperature-specific graph added. Oops.]

< 40 W/mÂ²: nothing works.
40 to 75 W/mÂ² the PV produces a trickle of output.
75 to 95 W/mÂ² the PV produces a bit more and the ETs begin to produce a bit, but less than the PV.
95 to 125 W/mÂ² the ETs produce steadily more than the PV.
125 to 145 W/mÂ² the ETs then PV are still winning but the flat plates are beginning to produce.
145 to 185 W/mÂ² the order is now ETs, FP, PV.
> 185 W/mÂ² the order is FP, ET, PV.

Looked at like that it seems that the region where PV wins is very narrow. There are a few things to bear in mind:

1) That's an important and common region at the times of year when the performance of space heating is critical; any old system will do in the summer but if you want to extend well into the heating season then you need to tune things more carefully.

2) This is based on area. Solar thermal is more than twice as expensive per mÂ² compared to PV. When you go on price the break points are different (http://www.edavies.me.uk/2012/01/pv-et-flat/).

3) This is about producing relatively low temperature outputs for space heating. Solar thermal is penalised significantly compared to PV when higher temperatures for DHW are required.

Thinfilm PV panels or strips

Fjord — Tue, 18 Nov 2014 10:15:39 +0000

I'm looking for some updated info on Thinfilm PV products. I'm looking for a very discreet installation on a 200m2 roof surface. This surface can be seen by properties located higher up the hills and we're not allowed to have normal shiny, ugly PV panels installed on the roofs because the architecture of the neighborhood has to be preserved. I would like to find a product that simply gives the roof a black matte look with no references to normal PV panels. Does something like this exist? :)

PV energy storage

owlman — Mon, 17 Nov 2014 12:04:28 +0000

Interesting no? Anyone got any experience?
http://www.samsungsdi.com/ess/residential-commercial-solution

general info on solar thermal

pgrbff — Sat, 15 Nov 2014 07:15:01 +0000

I'm in Italy so I have , or rather had before 2014, good access to sun.
I have a 500l Akvaterm solar plus which will be dedicted to DHW using my two other 2500l accumulators in winter.
I have virtually no knowledge of the various types of solar panels, can anyone offer any general advise?
Solar PV is not an option.

Forgot to consider Solar

pgrbff — Thu, 30 Oct 2014 06:45:17 +0000

I have moved to Italy and having considerable timber available am about to install a 60kw gasification boiler and 5000l accumulator.
I had always taken the view that the accumulators, 2 at 2500l each were too big to use with solar but failed to take it any further.
I now need to incorporate solar dhw and have no idea if it is better to buy a third smaller accumulator and heat this with a combination of solar and primary water from the other accumulators or buy what I would consider a standard sealed hot water cylinder and heat this with a combination of solar and and primary hot water from the larger accumulators.
Any thoughts? Would one be more efficient than the other?

PV, is MCS worth it?

PeterStarck — Wed, 08 Oct 2014 08:42:38 +0100

I have an area of single storey roof at 30Âº which faces SSE. It is 5.3m by 3.7m and is unshaded. If I installed PV myself rather than through MCS could I
a) claim FITs, I guess not!
b) export electricity and be paid for it?
c) have it signed off under Part P?
d) is DIY PV worth it?

Best use of our solar heat?

Phil.Chaddah-Duke — Tue, 07 Oct 2014 10:03:43 +0100

Hi guys, well I have at last completed our solar system including the 2nd hand Riomay tubes I got from James on the forum (canâ€™t believe that was a year ago), see pic. As we have a 250l DHW and 1000l UFH TS, I am wondering the best way to configure it.

During the summer I have just been heating DHW before it swaps over to TS as a heat dump really but now heating switched on I need to decide what to heat first and to what temperature. The gas boiler tops up both tanks to required temperature when required. The UFH heating only needs 40 degrees so in terms of energy use, is it better to heat the TS with the freely available lower grade heat first or try and get the DHW tank up to temp but that means solar is waiting to pump longer trying to reach the higher DHW temp or does it make no difference as energy is energy whether itâ€™s the solar or gas and whether its low or higher temps?

Ikea's online PV panel calculator

Chris P Bacon — Fri, 03 Oct 2014 08:58:07 +0100

There was a piece in the papers here in Sweden during the week about how IKEA are now selling PV panels in the UK. According to IKEA's figures the average payback period in the UK is now 8 years.

So I just had a look at the ikea.co.uk website and they are selling in partnership with another company Hanergy, "Ikea family" members get a 15% discount. I clicked through to their online calculator and the results it gave were utter rubbish. It reckoned that a south facing 3.84kWp array at 45deg pitch in central Edinburgh would produce over 7000kWhrs a year. PVGIS reckons on 3400kWhrs which is much more believable.

It would be interesting if others tried this also for their actual locations to see if it was just a single bad result or a calculated attempt to suck people in.

N.B. The online calculator won't let you see the result until you input Name, telephone and email address. I just used nonsense values for all, Fred Bloggs will be getting a lot of sales calls later today!

Ikea's start page for solar panels can be found here.

http://www.ikea.com/gb/en/campaigns/solar-panels.html

feedback on solar thermal

Jeremy S — Sun, 10 Feb 2013 08:37:10 +0000

Hi,

we've had some trouble finding a heating engineer locally with sufficient experience of solar thermal, so I'm hoping for some feedback on our proposed circuit (attached as PDF).

We've overspecified the collectors and the store in order to a) gain a greater winter contribution, and b) to offset the lower contribution on frequent cloudy days in western Perthshire.

We've been heating our well-insulated and air-tight 57sq.m 2-bedroom cabin with the occasional use of a 2kW electric radiator on the cold (sub-zero) nights - installing a 4kW solid fuel stove (c/w 1kW back-boiler) will a) reduce reliance on electricity, b) contribute to DHW, c) improve air-flow (via window trickle-vents), and d) be cosy!

Due to roof pitch and topography, we're intending to install the collectors on a shed some 25m from the store (see below); 12vDC thermal differential control, pump, expansion vesel, and pressure relief will be in the shed, with solar PV alongside the collectors. Thermal store, other valves, and heat exchanger for stagnation-preventing heat dump will be in the cabin.

Any comments are welcome, bur specific questions are:
1) can anyone recommend a H.E. in 50-mile radius of Crieff?
2) are there any safety concerns with the proposed schematic?
3) how does a 'filling loop' work? what's the procedure and hence, required plumbing?
4) for the 25m run, we thought to not use std s/s corrugated due to pressure loss; should we go for copper and just deal with thermal expansion somehow, or instead use s/s tube at extra expense?
5) suggestions for valves?

Links to kit:
Thermal store: http://jouleuk.co.uk/Cyclone_Thermal_Stores/299
Collectors: http://www.kingspansolar.co.uk/products/16/df100.aspx
Stove: http://shop.salamanderstoves.com/small-stoves/hobbit-stove
Pump: http://www.solarproject.co.uk/page2.html
Thermal differential controller: http://www.reuk.co.uk/buy-SOLAR-PUMP-CONTROLLER-CIRCUIT.htm or http://www.solarproject.co.uk/controller%20detail.html
Plate heat exchanger: http://www.ebay.co.uk/itm/Stainless-Steel-Heat-Exchanger-Plate-Heat-Exchanger-20-Plates-44-kW-/330867777183?pt=UK_Home_Garden_Hearing_Cooling_Air&hash=item4d09419e9f

In the longer term, I'm looking to investigate programming a dedicated 12v Linux 'intelligent' controller using Raspberry Pi (http://www.raspberrypi.org/) - see: http://www.raspberrypi.org/phpBB3/viewtopic.php?t=31455&p=272911

best wishes - Jeremy

kerosene from concentrated sunlight

Triassic — Sun, 24 Aug 2014 13:57:30 +0100

SOLAR-JET aims to ascertain the potential for producing kerosene from concentrated sunlight, CO2 captured from air, and water.

http://www.solar-jet.aero/

Sounds like an interesting EU funded project !?

Anaerobic digestion and CHP

owlman — Sun, 17 Aug 2014 14:36:46 +0100

Anybody familiar with this technology, what does it entail?

Your views welcomed! Planning application would shade our solar panels

RobinB — Fri, 01 Aug 2014 07:31:52 +0100

Objecting to planning application for a building that would shade our solar panels - any precedent?

Has anyone come across this before?

I don't want to stop them from building - I just don't want a building so tall and close to our southern boundary that will cut out all the sun from our largely south facing windows, garden and solar panels.