There’s a lot going on such that I can see the house project progress stalling for a bit. This is also an opportunity to reflect on the progress to date and see if anything can be improved.
Category Archives: Eco Strategies
PV > House use = Water Heating
There seems to be a new entrant to the market for setting it up so that if your house solar panels (PV) are generating more electricity than the house is using, this gets auto diverted to an immersion heater to heat up your water.
So you use the water tank as an energy battery of sorts.
In the UK, you get paid via the Feed-In Tarriff system if you export to the grid or not. Plus a rate for what you do export, but that is a lot less than the rate at which you buy electricity if you need to. So these systems are said to save around £300 a year.
- http://www.immersun.co.uk/
£350 from http://www.biggreentechnology.com/green-energy/immersun-free-hot-water-from-solar-pv/immersun-free-hot-water-from-solar-pv.html?source=FroogleForum discussion about this at http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=10577&page=1#Item_0
- Powerdiverter.com, apparently £399 with “free UK delivery, wireless and easy to install.”
Get a bath “cast in iron from recycled brake discs” !
http://www.thewatermonopoly.com/baths
I’ve already ordered the bath, but If I hadn’t I’d be looking at these. Stunning and recycled materials 🙂
£50,000 printed house released by WikiHouse
From: http://www.technology4change.com/page.jsp?id=312
Looking at the details in the PDF, a lot of the ideas are similar to those being used by ecofab for my project:
– see some screen grabs below.
From the article:
WikiHouse has released the design for a £50,000 printed house for the UK that could help tackle problems like urbanisation, climate change and inequality, say creators.
The design is the latest creation from the non-profit project that has been developed to help produce low-cost, high-performance houses that are suited to local needs.
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The project, called WikiHouse, is an open source construction system which makes it possible for anyone to design, share, download, adapt and ‘print’ houses.
Users of the system can ‘print’ house parts from a standard sheet material like plywood, and the main structure assembled in about a day without the need for conventional construction skills, say creators.
“The open secret is that in reality almost everything we today call architecture is actually design for the 1%,” said WikiHouse co-designer Alastair Parvin of London-based design studio 00.
“The challenge facing the next generation of architects is how, for the first time, we will make our client not the 1% but the 100% – to radically democratise the production of architecture.”
He added: “We are moving into a future where the factory can be everywhere – and increasingly the design team can be everyone.”
WikiHouse is currently under development, with a growing community of teams and is seeking collaborators and funders.
Wall panel layers:
Assembled wall panel:
Best explanation of the Passive House ever. (Mildly NSFW)
A fun video to explain the principles of Passive Houses.
Although the Silver Spray isn’t to Passive House, it is following the Passive House principles.
Recycling
A bunch of the windows and doors have gone to new homes.
A bunch of the wood is either going into local log burners or being set aside for furniture etc.
A lot of the roof tiles have been set aside for somebody or to be made into place mats etc.
A chunk of the metal was taken to the scrap metal dealers, where the lead, copper and other metal got a bit over £200 !
Thermodynamic Panels :: Happy Irish Customers
The Irish firm LVP Renewables have been installing Thermodynamic Panel systems in Ireland for a while. Their site has a big list of happy Thermodynamic Panel customer testimonials including:
We are a family of six-two adults and four children ranging in age from 13 to 21 years …. Having now had the system in for 10 months we are delighted with it and there have been no problems to date. We are never in need of hot water as we have had a constant flow since the systems installation in October 2011
Their FAQ page has a few interesting items:
Does this system need a back-up heating system during the winter?
No, this is the only solar panel heating system that will provide you with 100% of your hot water. Also our cylinders come with a mini-emersion inside that can be turned on manually if needed. However if you would like to incorporate a back-up heating system there is a provision for a secondary heating coil in most of the systems we provide (call for specific information on tanks). If you decided that you wanted the secondary coil in the tank then we would advise you to put a manual leaver on the system and only use it if necessary.
What is the difference between an Energie Solar Panel System and Solar Tubes or Plates?
Unlike traditional solar panels (tubes and flat plates) the Energie system offers:
- No unnecessary annual maintenance checks. In order to maintain the maximum efficiency of tubes and plates they must be serviced annually.
- LVP panels are lightweight (weighing only 8kg) and roof structures do not need to be reinforced. Conventional solar panels are heavy-weighing anything from 40-300kg
- Energie Solar Panels absorb heat from both sides unlike traditional panels which only capture radiation on one side
- One Energie panel (80cmx200cm) will provide a family of up to 6 people with all of their hot water needs. With traditional solar a large amount of panels is needed to provide similar quantities of water
- Energie panels need no back up from oil or gas. Other solar panels need an auxiliary energy source when the sun isn’t shining or when in high demand
Is the system provided with any device to treat bacteria such as Legionella?
Yes. In accordance with current legislation, it is provided with a circuit to rise the temperature up to 70 Degrees, which is manually activated and automatically disconnected
What happens if we install 2 panels on the roof?
The heating time will be reduced by half
Thermodynamic Panel Case Study :: Cork (Ireland) water and space heating
Their site also has case studies including one for a central heating and domestic hot water system in Cork (so SE Ireland).
Most are about water heating only (no heating) with positive comments.
The Cork water and space heating was for:
- 235 sq m 2 storey stone cottage with a large extension that has:
– 4 bedrooms, 3 bathroom (1 en suite), 1 kitchen, 2 sitting rooms, 1 large hallway, 1 utility.
The Silver Spray property is 281 sq m (4 bedrooms …. - Radiators (not under floor heating)
– average water temp to the radiator circuit 45 degrees C input, 35 degrees average return temp.
– the radiators give the property a 1000 litre water buffer ! - 300 litre water tank.
- I can’t work out what the figures mean !
Thermodynamic panel :: A happy user
One of the long GreenBuildingForum threads on Thermodynamic Panels has had some comments from somebody that installed one on their property in Northern Ireland, 18 months ago:
- “I have had a thermodynamic panel installed for 18 months now and so far I can’t find fault with it.”
- “It provides all the hot water requirements that is asked if it.”
- “I have never switched on the built in immersion even when it has been -10 degrees outside and the panel has had an inch of ice on it.”
- “I couldn’t justify solar as lets face it who wants something that only works well 7-8 months out of 12 then you need an additional piece of kit as back up, or pay £3000 per bole hole for a ground source heat pump when you don’t have enough land for slinkies or have their own personnel forest to supply a log boiler.”
Installed System
- £4,100
- Panel
- 280 litre cylinder
- pump and fittings
- County Down, Northern Ireland
- “Currently there are 4 showers every morning, plumbed to dishwasher and washing machine, and and usual washing in the sink when items don’t fit in the dishwasher.”
Beware of Thermodynamic Panels ?
I’ve been sent a scan of a one page article in the Clean Slate publication by the Centre for Alternative Technology (CAT, www.cat.org.uk) that has the title:
Think Twice about thermodynamic panels
Compared to an air source heat pump, a Thermodynamic panels is a heat pump connected to a flat panel instead of the heat exchange unit.
The article is concerned that:
- Panel collectors might work well in some conditions, but badly in others.
- That air flow can be poor around them,
- That they can ice up.
- That there are no studies on year round performance to back up marketing claims.*
- They don’t qualify for the Microgeneration Certifciation Scheme (MCS). So, pending any updated clarification as what they are (heat pump?) they won’t qualify for the Renewable Heat Incentive (RHI).
* I’ll have to check, but a few companies and Internet sources do seem to have put their year round data on-line. OK these aren’t independent studies, but there is data about.
If the panel is running at low efficiency, then you have a low or zero coefficient of performance or COP. The article points out that consequent running costs at such times could be more expensive than gas (or even oil).
The report quotes an “Energie” thermodynamic system consuming 4.1 kWh of electricity to heat 250 litres of water from 10°C to 55°C with 15°C ambient temp. The 2.7 COP is “no better, financially or environmentally, than a modern gas boiler).
They say a conventional solar water heating system would use less energy and so cost less. The report references the Energy Saving Trust field trial ( I Google found the link).
The reports concern is that:
- In winter a boiler would be more cost effective.
- In summer a conventional solar water heating system will be better.
A conventional solar hot water heating system uses almost no fuel.
The CAT advice sheet on conventional solar water heating systems is here.
Confused Conclusion for Silver Spray Water Heating
The end solution for Silver Spray isn’t clear.
- No mains gas.
- Next to the sea (so an air source unit will fail and need major component repairs and replacement within 5 years.)
- Cliff top and narrow plot, plus slope etc means ground source by buried pipes or vertical drilled holes both seem unrealistic.
BUT:
- There are going to to solar elec PV panels.
- The house is going to be highly insulated and sealed, so there will be a low space heating requirement.
So if Thermodynamic panels can have a good chunk of their winter electricity from the PV panels, they could still be the best solution.
Green Roof & PV
From the Winter 2012 copy of Green Building Magazine (volume 22, No3).
Two green roof studies. One, carried out in Berlin, where green roofs had been installed in the 1980’s. They varied the PV arrays to find the most efficient:
- Over 5 years, PV panels over a green roof Vs a bitumen roof has 6% higher yields.
- If over a green roof AND on a swivelling stand that tracks the sun, then 10% higher.
So green roofs boost PV productivity AND as they insulate the roof, they decrease the amount of energy needed for heating and cooling.
The second study looked at planting schemes. The most popular current choice is sedum, du to high resistance to draught. Sedum was compared to Stachys byzantian, Hedera hibernica and Bergenia corifolia.
Stachys byzantina (commonly known as Lamb’s Ear) outperformed the other species in terms of leaf surface cooling, cooling the substrate beneath it’s canopy and even the air above it’s canopy during short intervals over hottest periods, when soil moisture was not limited.
The conclusion was to not choose the best plants for a shallow substrate, but those that provide the best all round environmental performance, including bio diversity. This may involve deeper substrates and some form of irrigation.