Green Building Forum - Renewable Energy

Heating with wind turbine

CWatters — Wed, 13 Mar 2013 22:20:46 +0000

Any advice for this poster on another forum? In particular how to meet SAP when using the output from a turbine to drive an immersion heater. Is the SAP assessor correct?

http://www.ebuild.co.uk/topic/11828-advice-needed-please-re-heating-with-wind-turbine/

Quote:

The SAP assessor has just informed us that the house will fail as it stands, because of using an immersion heater. It would only pass if we either installed an air source heat pump or:

To enable the dwelling to pass using electric space/water heating the following would be required:â€¢Electric under floor heating throughout

â€¢Electric instantaneous water heating

â€¢100% low energy light fittings

â€¢Pressure test at 3.8

Solar PV slates

Triassic — Wed, 13 Mar 2013 14:25:12 +0000

I live in National Park and I'm looking to replace our dilapidated bungalow at some stage, so I'm starting to plan the replacement.

At Ecobuild I noticed a company selling solar PV slates, sand blasted to a matt dark grey finish so as to blend in with the surrounding natural slates. Unfortunately I failed to get the companies details. As our proposed PV will be on the front of the house facing the road, I have a feeling the planner will have something to say and my wife hates the shiny look of standard PV panels, I was thinking of using matt PV tiles to reduce the visual impact.

Anyone got any thoughts on sand blasted panels, will the matt finish affect the output, are sand blasted panels a good idea?

PV cold calls

Nick Parsons — Tue, 05 Mar 2013 13:19:37 +0000

A cold-caller has just told me that I could make up to Â£1700 p.a. from 'solar panels'. I have not yet calculated the size of array which would be required to generate that sort of FiT income, but I am sure my roof is not big enough..... Interestingly, they hung up as soon as I told them I was aware of the dramatic reduction in FiTs.

RHI

SteamyTea — Wed, 06 Mar 2013 22:26:33 +0000

Just seen this about the new rules being proposed for the RHI, looks like it is not going to be quite as good as people hoped:

http://www.treco.co.uk/blog/2013/03/06/

"Other changes to the RHI announced on Wednesday include flexible tariffs to control the budget of the scheme, sustainability requirements for new and existing biomass installations, tariff reviews, and the simplification of metering requirements."

Seems to me they can pull the plug on it if they feel like it.

Also heard on the news that there is going to be a review about biomass in general (Scotland has already had a debate on it)

http://www.foe-scotland.org.uk/news150113

All interesting stuff going on.

Solar decision and other technical questions

Pile-o-Stone — Thu, 07 Mar 2013 10:10:14 +0000

I wonder if the knowledgeable folk on here can help.

I live in a listed building and so I can't put solar panels on the south facing roof of the house. I can however put panels onto an outbuilding at the rear of the house, but its roof is east west facing. The roof is also shaded by the house in the winter months when the sun is low, I guess from November to Feb. I have a heatbank connected to mains gas and to a multi-fuel stove. The heatbank has an unused solar coil installed.

The questions are:

1. Am I better to install solar water heating connected to the solar coil (with a buried solar duo pipe between the house and the outbuilding, or better to install solar PV with a buried cable between the house and outbuilding?

My thoughts are that solar thermal is a much more efficient way to heat water, but PV gives me a wider range of uses and I can export unused electricity to the heatbank via an immersion heater (there is an unused immersion heater boss low down on the heatbank that I could use - separate from a higher immersion heater connected to mains).

2. The west facing roof of the outbuilding receives sun for about an hour longer, so should I go for panels on both sides of the roof or just on the Western side?

3. If I opt for solar water heating, does anyone know if I would have problems with heat loss by burying the solar duo pipes underground between the house and outbuilding? I measure the run of the pipe to be 20 meters underground.

Waste Inceneration Plants

tony — Wed, 24 Oct 2012 19:18:10 +0100

I am scared rigid by the pollution and air quality of these plants yet they seem to be getting the thumbs up.

Solar PV kit for Spain

colin440 — Sun, 24 Feb 2013 11:52:31 +0000

Which companies in the UK are recommended to buy the complete Solar PV kit from? I see Navitron mentioned a few times, but curious on any others.
I don't skill or knowledge (or time!) to research and build the kit myself so looking for a good supplier. This is for a house in Southern Spain and would be shipped out with some other items from the UK.

The Solar requirements would be to power lights/TV/laptop/ but more importantly run the water pumps for the underfloor heating (and I think I will need an electric pump for the 24 tube solar collector for DHW (as can't really be positioned above the thermal store on 2nd floor). I think I need around 2500Wh/day from a system, but any advice is appreciated. thanks

Free heat from PV inverter

jms452 — Fri, 15 Feb 2013 15:05:16 +0000

When our PV was fitted we decided to put the inverter inside the house (rather than the in the loft).

At the time this was because lofts can get hot and many of the failure modes of inverters seemed to be due to over temperature. It also made fixing/replacing the inverter easier (and hopefully cheaper) if and when it breaks.

However I have since realised that between October and March we get about 100kWh of heat from the inefficiencies within the inverter.

I know this is small fry but given our (i.e. GBF's) tendency to worry about things like air leakage through key holes 100kWh is actually quite a lot of free heat. To put this into perspective 100kWh over 6 month is ~20W - The same power consumption as a decent MVHR...

SAP2009 asks if the central heating pump is within the heated space (presumably for this reason) but doesn't care about the PV inverter.

Is this detail ever considered - I think it should be.

Discuss!

Wood Gasification (Log) Boiler Experience?

edwinvanek — Fri, 14 Sep 2007 12:33:18 +0100

Over the last 6 months we have been considering the replacement our old oil fired central heating boiler with a log boiler as both our tank and boiler need to be replaced over the next few years. We have compared alsmost every manyfacturer available (Dragon, Atmos, Vigas, Froeling, Hoval, Baxi, Mescoli, Viesman, ETA, Herz, Biotherm, Treco, etc) and haven''t been able to make a decicion yet. Recently we started thinking about keeping the oil fired central heating and adding two wood stoves, one connected to the warm water tank.
My preferde boiler would be the Austrian ETA boiler which I have seen in operationa t various locations in Germany, but the boiler itself without heat store and other component, flue and installation is close to 6K, which is too much. The middle way would be a Baxi Solo Inova. Does anybody have any experience with Vigas and Atmos boilers, which are the most economically priced boilers. The pros are: renewable ennergy, affordable fuel the cons are: costly, not as instantly controlable as oil and gas, bulky and expensive to install.

Before finally making my mind up I was wondering weather anybody who has already installe a log gasification boiler would be willing to share their experiences and or frustrations?

Edwin

Outstanding solar thermal collector performance too good to be true?

Jeremy S — Sat, 21 Jul 2012 09:45:47 +0100

We are in the middle (or, hopefully, near the end!) of specifying a solar thermal installation for a new build - we're pretty much decided on 5-15sq_m of collectors (scaling over time), with PV powered 12V DC pump and controller as indirect supply to 800L store (with future contingency for wood/pellet stove). DHW will be mains via coil in store, with top up from in-line electric heating (Zip CEX).

I've been researching collectors - both flat plate and evacuated tubes - and using efficiency as a function of mean panel temperature [Tm: 10-90degC] and global radiation [G: 300-1000W/sq_m] as a means of comparison (calculated from eta0, a1,& a2 per method in EN12975/Solar Keymark). As might be expected, the resulting plots exhibit two main trends corresponding to tubes and flat plates and, generally speaking, there's not a great deal to choose between the particular models in each group, although some (older?) models are definitely perform more poorly...

EXCEPT: there is one product that appears to perform as well or significantly better than it's competitors, being a clear outlier on the graphs; comparing efficiency, across the ranges I've looked at, against the mean of the other 27 units, one product exhibits between 0 & 60% better performance.

So, why isn't everyone raving about Baxi Solarflo tubes?

Since this is a clear outlier, I was initially sceptical; the data I've used are drawn from product brochures; in some cases manufacturers publish the actual EN12975 reports. I obtained the EN12975 report from Baxi and the test results are indeed as presented in the brochure. When I've figured out how to do it, I'll put graphs and data up; in the meantime, anyone who cares to check my calculations (please), get in touch and I'll email the spreadsheet (.ODS format, but can do .XLS). Currently I've gathered data for: Navitron, SusTech, AES, BAXI, Worcester-Bosch, Genersys, Clearline, Dimplex, Consolar, Thermomax, SonnenKraft, & Gasokol. If anyone cares to suggest others - or better still: post eta0, a1, a2 - I'll add them to the mix; for completeness, the parameters I've collected are: type (plate/tube), aperture area, eta0, a1, a2, IAM50_long, IAM50_lat, H, W, D, kg.

Finally, I'd welcome advice on other important performance measures, e.g. when does stagnation temperature become critical? should we be lobbying for all manufacturers to present the off-axis correction factor (IAM50)?

Best wishes - Jeremy

Solar Thermal Panels

mark jackson — Sun, 10 Feb 2013 16:12:07 +0000

We are looking to install thermal solar panels to our south facing roof. There is so much information to look at and we just need some basic honest advice on type/style and any other info that we may need. Can anyone help?:shamed:

PV-T Hybrid system

abogas — Thu, 03 Feb 2011 19:24:51 +0000

Hi, Has anyone any experience of a PV-T hybrid system being offered by a uk firm (the only one that is MCS certified)

Cheers.

Wind Turbine "blown over"

candlemaker — Wed, 30 Jan 2013 17:12:29 +0000

A 35 meter high wind turbine has collapsed in Devon:

http://www.telegraph.co.uk/earth/energy/windpower/9837026/Wind-turbine-collapses-in-high-wind.html

Faulty bolts (my guess)? Reported gusts of 50pmh seem no more than it must have faced over the last 3 years. Again a shame that these things happen and then get blown (excuse the pun) out of proportion. it will be interesting to see what really caused the failure.

Gravity Light

jamesingram — Mon, 10 Dec 2012 16:09:56 +0000

Nice little idea for lighting without power , lift up a weight ( earth filled bag/ plant pot) and the light runs for 30 minutes (not sure what lumen output is ?)
Possible benefit for those in developing world

http://www.indiegogo.com/projects/282006
"Following the initial inspiration of using gravity, and years of perspiration, we have refined the design and it is now ready for production. We need your help to fund the tooling, manufacture and distribution of at least 1000 gravity powered lights. We will gift them to villagers in both Africa and India to use regularly. The follow-up research will tell us how well the lights met their needs, and enable us to refine the design for a more efficient MK2 version. Once we have proved the design, we will be looking to link with NGOs and partners to distribute it as widely as possible. When mass produced the target cost for this light is less than $5."

Should i stay on mains water.

woodgnome — Wed, 23 Jan 2013 21:31:44 +0000

My current water bills are about Â£25 to Â£30 per month, on a meter. I have a good spring feeding a large pond, which seems to run all year, even in the hot summer...distant memory.
My new build will be not too far from it. I was considering using the pond for my GSHP, but still to be decided. If i don't do this, i was thinking about using the spring for our water supply, subject to testing.
Anyone done this? Any ideas on cost of pumps and filters etc. is it worth it?

Thanks

Evoco wind turbines

windymiller — Wed, 23 Jan 2013 16:59:40 +0000

Does anyone have an update on what is happening with Evoco wind turbines?

I had heard that they were all switched off (In November last year http://goo.gl/HocLp ) and that there was an owners meeting scheduled before Christmas, but I haven't heard anything about what is happening now. Are people back on? Have any changes been made?

I'm a bit surprised that there haven't been lots of angry posts about this....

Solar thermal on outbuilding?

Noodle — Wed, 16 Jan 2013 18:31:57 +0000

Just a quick question,

As my house is listed and in Dartmoor, solar thermal or PV on the roof is a big no no. I am planning an approx 4kw pv array on one the outbuildings - direct south aspect.

Question is can I do the same with solar thermal? Would too much heat be lost over pipe run outside - estimate approx 10 - 15m from outbuilding to proposed location of thermal store. Obviously would propose to highly insulate the pipe run, even bury it 4ft underground it recommended? I assume the solar thermal doesn't "have" to be higher than the store as its pumped round isn't it?

Perhaps daft questions but would be useful to know the answer.

Thanks!

Confused? What is the main reasons to Buy Renewable Energy

peterpanel22 — Tue, 08 Jan 2013 12:05:07 +0000

Hello,

I have been debating over why people buy into renewable technology when it is so expensive especially without grants and incentives?

I know it depends on house type and usage, but I want a discussion based majority of people. I have a typical semi detached house with 3.5 bedrooms (32% houses in UK), gas for heating, and normal electric meter. I have a central heating system that is say 7 years old. I have 2 teenaged kids and in my early forties. I have paid 50% of my mortgage, paying it off comfortably (current low interest rate) and have some savings about Â£20K. We pay about Â£700 in Gas and Â£500 (if that) on electric. Using it generously.

Are people buying because of incentives attached, or are they really looking at longterm energy security? 10, 20 or 30 years? To me personally I am looking at less than 10 years, god knows what I will be doing after this, I may move.

Is the industry eagerly waiting for the new RHI incentive? to motivate people to buy or a people really ready to pay 10-15K and hope to see a return after 15-20years.

What is your situation how much would you spend, what would be your max payback time.

Is renewable energy mostly beneficially to heavy users?

I think we owe it to confused people and misleading sales people to have a thorough break down.

Products I have looked into

Solar PV - Electricity
Solar Thermal - Heating and Hot Water
Biomass - Off Grid heating and water
Air to Air - Looks like simple system, for mainly open space living
Ground Source - Not sure about this
Air to Water - Looks new heats house and water
Auto Energy Monitoring System - Does this only help monitor electric or gas? cost/benefit raito?
Infrared Panels - New tech, movable, fairly cheap, DIY install
Thermodynamics - heats water and now home, no RHI
VO5 - Cost/Benefit ratio?

What is the average cost range, payback period, savings amount, is it retrofit, grants available, is it now a good time to buy or wait?

I know this is massive, but choosing something is confusing, people keeps saying it depends on this and that. Please help me, please help other people.

did your PV generate less in 2012?

sarahhughes — Mon, 07 Jan 2013 10:05:24 +0000

I'd be interested to know if people have compared their 2011 and 2012 power generated - it felt like the sun hardly appeared at all in Manchester last year and it's putting some people off considering solar pv installations ... anyone got any relevant generation figures?
thanks
Sarah

PV futures

Ed Davies — Thu, 03 Jan 2013 13:25:00 +0000

Currently PV panels are pretty cheap. E.g., Navitron are doing Scheuten 235 W panels at a tiny smidge over 51p/W, incl VAT, so less than 43p/W after a new-build VAT reclaim. MCS approved Kinve panels of the same size are a little more expensive at about 57p/W incl. Maybe they'll get a bit cheaper but I can't help thinking the price can't get much lower unless the design is changed radically (stick-on thin-film or something).

At Â£100/mÂ² they're already cheaper than windows by area, I think. Windows are similar technology but with more oxygen and less doping in one of the layers and no backing plate :-).

So, it seems to me that if you can use them immediately then there's no point in waiting - buy now. If, on the other hand, you can't use them for a while it's a difficult question when to buy. Delaying might save a small amount of money but it's entirely possible that the current glut will dry up or EU anti-dumping threats will be acted on or something so the price would go up resulting in bigger losses.

Anybody got any up-to-date thoughts on what prices are likely to do this year?

UK solar PV

owlman — Thu, 03 Jan 2013 19:28:08 +0000

I received this email today I can't vouch for the validity, but interesting nontheless.

http://www.evoenergy.co.uk/i/uk-solar-pv/?utm_medium=email&utm_source=Evoenergy&utm_campaign=2024458_Newsletter+January+2013+Domestic+Prospects&utm_content=infographic&dm_i=QTQ,17E2Y,4IKGSU,42MYU,1

energy worth

williedrumliah — Wed, 02 Jan 2013 23:48:39 +0000

Does any body know what this is worth if you generate 20000 kwh and export same amount what is this worth, and then do you deduced amount used at what rate.

Micro Hydro from spring water powering GSHP

Pile-o-Stone — Thu, 13 Dec 2012 16:45:41 +0000

Hi,

Opposite our home is a former mannor house that used to have its water provided by a natural spring. The manor house was connected to the mains many years ago and so the outlet was severed and now empties into a stream that is at the rear of our garden. I've been monitoring the outlet for the last 3 years and it seems to have a constant flow regardless of the season. I'm seriously thinking of using the water to power a turbine and was wondering if anyone had information on how this can be done technically?

We currently have a heatbank connected to a woodburning stove and ma9ins gas condensing boiler (solar is an option but due to shading could only provide HW in summer) and I was wondering if the hydro could be connected to the heatbank either by emersion heater or GSHP?

Which would be the better option? I know that GSHP are supposed to have a RHI payment next year and the micro hydro would have a FIT, so would this be the most cost effective solution? What sort of power output would the micro hydro have to produce to power a GSHP?

Wind turbine for immersion

Si.min — Sun, 09 Dec 2012 12:47:48 +0000

Hi I am attempting to form a long term plan for further additions to house (cost and time to save etc) I would like to know if you can buy a wind turbine to make a direct connection to an immersion heater, heat dump to be used would be the central heating - store is 320litres. I like the "idea" of a 2kw turbine max 3kw output connected to a 3kw immersion with thermostat removed. I am not skilled in electronics oscilloscopes and rectifiers etc so if complex wiring, soldering required I would seek the help of an electrician, but before I get too far ahead of myself and throw other factors in to the mix like location, average wind speed etc Im just trying to see where they are at, it would be great if you could be sold a kit for an immersion connection with no batteries etc and then get an electrician to complete the setup. Other forums I have read so far forums seem to talk of installations by people with expertise who have made up there own units with gains on windy days. ok thanks

The "California Array"

jon — Fri, 07 Dec 2012 10:19:16 +0000

I'm (finally) starting to work up concept details for the spherical solar arrays: Took some time as got bogged down in the historical link.

The idea is to form bays of segmented mirror spheres to generate high grade heat to supply turbines for day demand. Excess heat and electricity production can be sent to air fuel synthesis or compressed air storage (for night-time demand). I've put up some 3-D Google Earth concept models in the link below (great fun to play with but not easy to transfer from AutoCAD format)

http://flyingoven.blogspot.co.uk/2012/12/concept-drawings-california-array.html

The spherical idea is inexpensive and good from a land-use perspective. From the figures I got from our test prototypes (long time ago but they're on the forum somewhere), this could potentially supply the USA or Europe with its energy needs (in the future sometime). Technically, there's no dispute about whether or not it could work (largely because a variant on it is already operational at the Auroville Solar Bowl: http://solarcooking.wikia.com/wiki/Auroville_Solar_Bowl)

Can anyone see a fatal flaw with the arrangement.. a reason why it couldn't work better than the various other large scale solar projects which are being tried?

Insurance for small wind turbine

windy lamb — Sat, 28 May 2011 10:17:23 +0100

I'm just about to have a Gaia 11kW turbine installed and maybe I should look at insurance!

Don't need it for the installation as that is covered by contractors but does anyone have any pointers to where I should look for operation insurance?

PV module test

djh — Sat, 24 Nov 2012 17:55:18 +0000

A link to a useful looking test of PV modules was posted on the AECB forum:

http://www.pv-magazine.com/pv-test/#axzz2Cxjzfx8x

What happens to FiTs if you change electricity supplier?

stones — Tue, 16 Oct 2012 17:53:01 +0100

Just received the dreaded letter from npower notifying me of a 15.5% price rise. A quick check shows i could save by switching. All good so far. Problem is, I had solar pv installed in July and registered with npower for the FiTs. In their conditions it says must be a npower customer to have them as FiT supplier. A search online would seem to provide contradictory information. Various sites say that FiT provider and electricity supplier can be different, yet other sites state that the 'big 6' can tie you in so that you have to take your electricity supply from them if they provide the FiT. FiTs can be switched as I understand it, Does the tariff remain the same as I assume the system will be registered centrally with the regulator, or is there a risk you would have to sign up to lower FiT rates? Anyone have direct experience and can advise?

How secure is Great Britainâ€™s electricity and gas supply

jamesingram — Sun, 11 Nov 2012 15:25:09 +0000

CIBSE Annual Lecture 2012: How secure is Great Britainâ€™s electricity and gas supply over the next decade?
http://vimeo.com/53144064
"The 2012 CIBSE Annual Lecture, held on 7 November, gave Alistair Buchanan, Ofgem's Chief Executive, a chance to review the UK's rapidly changing energy supply landscape. Maintaining energy security of final supply was emerging as a key issue. It could offer new opportunities for the energy demand side to play a key future role.
In his lecture "How secure is Great Britain's electricity and gas supply over the next decade?" Alistair Buchanan looked at the complexity of energy supply and planning for the future, He touched on existing resources and the potential of shale gas, which has helped the US move towards self sufficiency, from a European-wide and UK perspective."

Grabbed from a poster on AECB facebook page. http://www.facebook.com/groups/theaecb/
"I would urge all to take a hour of your life and watch this lecture. If the CEO of OFGEM is saying we are running out of energy we should take note! Towards the end he says the UK in the winter 2010/11 was two days away from running out of gas. I can validate this as over that same period Northern Gas Networks had us on formal notification of supply interruption for weeks. The future is not Orange, but bleak!"

Renewable Rescue - Dorset

moulesnfrites — Thu, 08 Nov 2012 16:22:30 +0000

Have a look at the install pictures on this site ..... http://www.renewablerescue.co.uk/

the wall of shame is worth a peek as well !

Its enough to make you :cry:

The case for winds farms is all but lost - Delingpole

martint — Thu, 01 Nov 2012 12:52:27 +0000

Wind energy claims are just a lot of hot air
The case for winds farms is all but lost, as the Tories inject a welcome dose of reality into the debate

<>

LibDems get hoisted with their own vane, again. (Or is that vain?)

Fuel for the 21st Century?

tony — Thu, 23 Dec 2010 19:00:55 +0000

I dont think so! ---- Biomass is too polluting, not sustainable, AND NOT ZERO CARBON!!!!

How can it be called sustainable when it is NOT sustainable --- do you want to a Britain looking like some parts of Africa with no trees?

How can it be called safe when other countries are not allowing it because of the toxins in the emissions?

I am not sure about it being energy secure for sure there will be fights over wood in the coming years may be even wars!

I have heard tell that the UK wants to import vast quantities of biomass so how is that local?

I know I am being harsh but I hate pollution and worry about smogs and poor air quality in our urban environments and do not think that Biomass is the way to go -- sorry.

A bit of sense on biofuel at last

SteamyTea — Wed, 17 Oct 2012 21:38:40 +0100

Seems that some scientists are getting the message though at last.
http://www.bbc.co.uk/news/world-europe-19982214

Air Fuel Synthesis - Petrol from air.

Chris P Bacon — Sat, 20 Oct 2012 11:42:33 +0100

Surprisingly can't seem to find any mention of this on here.

The boys from Darlington producing petrol from air and electricity.

http://www.airfuelsynthesis.com/

http://www.independent.co.uk/news/uk/home-news/company-that-made-petrol-from-air-breakthrough-shudders-at-prospect-of-oil-industry-approaches-8218812.html

seaweed as fuel

RobinB — Fri, 19 Oct 2012 08:19:29 +0100

What do we think of this?

http://www.seaweedenergysolutions.com/

Solartwin

ingleside — Fri, 17 Aug 2012 14:18:05 +0100

We've had a Solartwin panel for years and been very happy. Thought about buying another one, but realised we'd need a bigger HW tank, so did nothing. HW tank now needs replacing, but Solartwin have just 'ceased trading'. Does anyone have any ideas about whether it is going to be resurrected, or whether equipment will be sold off, or - really - any information at all?
Thanks
Tony

DIY or professionally fitted?

Jonti — Wed, 10 Oct 2012 03:14:38 +0100

If I were to look at fitting solar panels to my roof for the purpose of generating electricity would I be better to purchase the stuff myself and use local tradesmen to fit it or get one of the professional firms in?

Any advice gratefully received:bigsmile:

Jonti

spinning solar cells

RobinB — Thu, 04 Oct 2012 19:58:42 +0100

I like the idea that they run cooler, not sure I'd want one on my roof.

http://inhabitat.com/v3solars-photovoltaic-spin-cell-cones-capture-sunlight-all-day-long/ !

"The V3 Spin Cell is currently undergoing refinement through collaboration with industrial design team Nectar Design before it is made commercially available. Once refined, the company believes that the Spin Cell could be a game-changer in its market. On their website V3 explains that if one places a 20x solar concentration on a flat, static solar panel then â€œthe temperature quickly reaches 260 degrees F, the solder melts within ten seconds, and the PV fails. With the same concentration on the Spin Cell, the temperature never exceeds 95 degrees F.â€ "

Liquid Air Could Be The Fuel Of The Future

jamesingram — Sun, 07 Oct 2012 20:22:34 +0100

http://news.sky.com/story/991949/liquid-air-could-be-the-fuel-of-the-future

"British scientists developing the technology say normal air can be used to store energy by cooling it to -190C, turning it into a liquid.

When the liquid air is later warmed, it rapidly expands into a gas, creating high pressure that can drive the piston engine of a car, or generate electricity in a turbine.

Dr Tim Fox, of the Institution of Mechanical Engineers, which has organised the summit of experts, said: "We're coming out of the cave blinking on this one and we're only just getting an inkling of how great the energy storage benefits of liquid air could be."

One company, Highview Power Storage, has built a pilot plant next to a power station in Slough to prove the technology works.

At times of low demand for electricity, the plant uses the excess energy from the power station to suck air through refrigerator-style compressors turning it into a liquid, which it then stores in an insulated tank.

When consumer demand spikes, the energy is returned to the national grid. The tank, which stores 60 tons of liquid air, can power 6,000 homes for one hour."

Seems they're doing it just round the corner from me , sounds interesting form of energy storage, anyone heard more?
http://www.bbc.co.uk/news/science-environment-19785689
"IMechE says this process is only 25% efficient but it is massively improved by co-siting the cryo-generator next to an industrial plant or power station producing low-grade heat that is currently vented and being released into the atmosphere.The heat can be used to boost the thermal expansion of the liquid air."
"Highview believes that, produced at scale, their kits could be up to 70% efficient, and IMechE agrees this figure is realistic."

DIY LED Exterior lights...

James Norton — Sat, 06 Oct 2012 17:44:45 +0100

I have a few places I was going to use exterior LED lighting:

Over a front door
On a small balcony
On a deck / some steps

You know the sort of thing, normally you'd have a couple of 100watt CFL jobs and 10 or so 30watt halogens that
kind of business...

Now I know you can get off the shelf stuff, but I presume without 10 hours of blazing summer sun it will be an embarrassing disappointment.... therefore wondered about knocking up something a bit more hardcore...

Say v.efficient low power LED light(s)
Decent PV panel (s)
Maybe a small wind generator
12v leisure battery
DC/DC constant current driver(s)
PIR / occupancy / day night control (to keep demand low)

Any thoughts...?

J

solar thermal: mixed flat plate and evacuated tube collectors

Jeremy S — Thu, 27 Sep 2012 01:03:01 +0100

(trying to bump this by reposting here, rather than Heating and Cooling)
Hi,

so, here's how I understand things:
1) evacuated tube collectors (ETC) maintain efficiency at higher inlet temperatures;
2) flat plate collectors (FPC) are more efficient at low inlet temperatures;
3) ETC are more expensive than FPC by both per joule and per sq_m.

what's to stop us trying to optimise using the benefits of both in a mixed system?

I'm thinking: 6-8sq_m of FPC in series with ~2sq_m of ETC.

Is there any technical constraint that would prevent this being viable? (apparently the MCS certificate can't handle it but that's bureaucracy, eh?)

best wishes - Jeremy

Can PV Solar make your grid meter run backwards!?

JTGreen — Sun, 09 Sep 2012 15:02:39 +0100

Just doing my meter readings for The Carbon Account, and my electricity meter is reading lower now than at the start of August. Is it running backwards due to PV solar? Surely that's not how it is meant to work? (Since we also have generation meter for purpose of FiT.

PV on free standing domestic garage

tychwarel — Sun, 23 Sep 2012 14:34:10 +0100

I have a domestic garage approx 6m from the house which at present has a flat steel sheet roof.
Its is also the best site for domestic PV, no overshading, existing electric spur from the house distribution board, easy access, etc

What I would like to know is :-
1 would I require planning permission to place PV units on this roof (free standing units designed for flat roof)
2 Would the fact that it is not integral to the dwelling influence the FIT rate.

(I am in Wales if it makes any difference

Other wind generation

MikeRumney — Fri, 31 Aug 2012 09:13:47 +0100

Anyone thought about, or come across, what I like to think of as an original idea that probably isn't!

A "Treebine" ... Cable from a "Dynamo" on the ground to top of a wavy branch.

(If you've seen a pole lathe in action you'll get this straight away.)

Lots of variables I'm sure, and only just beginning to think about it, so all observations welcome (except "can't see it working" which never got anything built) :bigsmile:

Off-grid PV wiring, fuses etc

Nick Parsons — Fri, 07 Sep 2012 15:19:13 +0100

Someone has just rung me to ask if I know a local (Sheffield) supplier of big fat DC cables and big fuses for an off-grid set-up. Not big - just to run his garage. It's only one panel, but I did not have the wit to ask what wattage!

I don't, though I suggested that Navitron might be able to help.

Anyone know of useful suppliers? Of course the supplier doesn't have to be Sheffield-based, as long as it's OK with mail order.

Thanks for any help.

Nick

Poorest performing Wind Turbine

tony — Mon, 27 Aug 2012 15:16:04 +0100

Which operational wind turbine in the UK produces the smallest amount of power compared to it rated output?

WHATS GRANTS ARE AVAILABLE IN THE UK

TOTALPLUMBING — Thu, 14 Aug 2008 14:47:18 +0100

I HAVE A CUSTOMER WHO WANTS EITHER A WOOD PELLET BOILER OR A WOOD GASIFICATION BOILER FITTED. I AM NOT SURE OF THE GRANT SITUATION AND IF THERE IS A LARGER GRANT FOR THE PELLET MODEL DUE TO IT'S CARBON ADVANTAGES, CAN ANYONE HELP?

I MAY ALSO HAVE TO LINK SOLAR TO THE SELECTED SYSTEM, IS THERE A SEPERATE GRANT FOR THAT?

Any downside to this offer?

Joiner — Wed, 14 Mar 2012 11:10:36 +0000

http://www.tecg.co.uk/domestic/solar-heating/solar-heating-panels.aspx

How good is your FIT supplier?

YouGen-Cathy — Thu, 02 Aug 2012 15:07:56 +0100

I reckon I get more complaints and questions about FIT suppliers (that's the energy company that administers your feed-in tariff) than any other thing. So I've set up a survey to try and find out what people really think of their FIT suppliers; what the problems are; and which ones are giving the best service. Its only 9 questions so will take a couple of minutes to reply (unless you choose to write an essay), and as a bribe, we'll put everyone who responds into a draw for an Amazon voucher. I'll also share the results with you all, to help newby microgenerators to pick a good one. The survey is here: http://www.surveymonkey.com/s/X6LFVMK

Â£75 FIT Data Processing Charge Introduction!

SteveZ — Wed, 22 Aug 2012 11:13:25 +0100

Along with my latest FIT Levelisation (?) Invoice for the last quarter came a letter announcing the introduction from next March of a charge for actually processing the FIT claim. They say that since OFGEM have reduced their contribution towards the cost of processing these, my FIT licensee will have to charge Â£75 annually (index-linked) if I wish to stay with them.

Has anyone else had anything similar or heard any rumours about OFGEM removing their subsidy?