This is the second in a series of blog posts by the architect Mark Stephens on taking a traditional Irish cottage off grid. The first post is here.

OK, so here's the first main blog post - where are we going to do it? I'm going to concentrate on an actual built structure rather than the other forms of off-grid living such as yurts, camper vans etc which are discussed in Nick Rosen's excellent book How to Live Off-Grid .

The first form of structure I'll be looking at is the derelict, traditional small cottage which would have been prevalent across the whole of Ireland, though most are now are disintegrating through decay because of exposure to the elements.

There are two stages in making such a structure habitable before we even consider how we then get that dwelling off-grid:

1. Increasing the size. Although we don't want to return to the McMansion sizes of the Celtic Tiger days, we will still need to increase the floor area to make it a more practicable solution for the family of today. Normally the biggest 'traditional cottage' size would have been a single room either side of a communal eating, living/sleeping space. So unless you are a very small family you will need to increase the house by at least another bedroom, and frequently these derelict cottages were without bathrooms, so a new bathroom will also need to be included.

Some older cottages would have been even smaller — I am currently restoring two cottages that were just single rooms where entire families were raised!

I'm not going to discuss here the problems associated with planning for converting properties of this type into habitable dwellings; for more details on this visit my website .

2. Upgrading the buildings fabric to a current standard.

The standard I would suggest trying to achieve is the passive house standard, devised by the Passive House Institute in Germany. Again going into depth on this standard is beyond the scope of this blog post but we can have a look at typical insulation standards that will need to be achieved in order to get close.

The roof should be the most straightforward area as typically the roof will have to be reconstructed anew with new rafters, slates etc. This is generally because the increased weight of slating the roof (frequently the roof would have been metal sheeting that would have replaced thatch) requires the rafters to be increased in size; larger sections of timber would have been impossible to obtain when the house was originally constructed.

This means that we can create a roof with the desired level of insulation. The u-value for a certified passive house  is less than 0.15 W/(m2K), which could be achieved with a warm-roof construction with sufficient insulation between the rafters, and then further insulation under them to prevent cold bridging. The amount of insulation needed will vary depending on the type used.

The walls of the cottage will be more problematic. A typical U-value for a 2' stone wall is over 2 W/m2K; to achieve 0.15W/m2K will require a rendered external insulation of around 200mm of EPS (expanded polystyrene). The good news is that cottages of this type would have been normally been rendered with a lime render and white lime wash which is not a million miles from a modern white, mono-couche external render.

As well as calculating the U-values you should also take care to avoid the risk of condensation; the correct way to do this is with a dew point graph which graphically shows the area in any construction build-up where condensation can occur. A condensation analysis  can be carried out using simulation software such as WUFI, which is based on EN 15026, a European standard for simulating condensation risk.  

Any new structure that extends the existing cottage will be easier to insulate to a high standard as we are constructing anew as per the roof.

The next logical step in thinking is to jump from the derelict cottages that are dotted throughout the country to the derelict houses in the ghost estates throughout every county. Theoretically they should be easier to upgrade to a better standard than the older cottages but their poor location and lack of infrastructure will remain an issue.

So, we have somewhere to live in to conduct our off-grid experiment — the next step is obtaining heat and power to the house. Trying to obtain passive house standards will drastically reduce the heat requirement for the house but it will not eliminate it entirely. The next blog post therefore will address this key aspect of off-grid living.

A quick round up of interesting stories you or may not have seen:

According to SEAI, the organisation is approving 1,000 Home Energy Saving scheme grants a week, at an average of €2,900. Press release and full report (down the bottom) are here.

Permission sought for Ireland's first geothermal energy electricity generation facility. But Richard Tol is skeptical.

Work on Dublin's Metro North to begin in April

Profile of a nine story timber-frame apartment building, including a time-lapse video showing its construction. Construct Ireland previously profiled Ireland's largest timber-frame building, the Navan Credit Union.

Beetlecrete: making use of timber that's been infested by the pine beetle.

Article and audio report on an office built out of shipping containers, which seem to be growing in popularity in the US. How long before an Irish building uses one?

Is green building causing a "real estate revolution" in the US?

Britain is banning inefficient boilers

The New York Times has an in depth feature on passive houses

The Infrastructurist asks why we (or more specifically the US, in this case) are still so afraid of nuclear power?

Some cool aerial photos of urban sprawl in the US (they're after the first few aerial photos of prisons)

The world's biggest offshore windfarm has been activated in the North Sea

More than a thousand applications for Home Energy Savings (HES) scheme grants are being approved every week and 98.5% percent of recipients say they would recommend the scheme to others, according to the Sustainable Energy Authority of Ireland (SEAI). The survey also revealed that over 68,000 grants have been awarded since the scheme began in April 2009.

In May we profiled the Nottingham House, an entry into Solar Decathlon Europe designed by a team from the University of Nottingham that featured an insulation system from Isover Ireland. The Solar Decathlon challenges university teams to design and build homes that maximise the sun's energy. This was the first year of the European competition - the US version is well established. 

Anyway, here's a video from the University of Nottingham documenting the build process.

[video:tp://www.youtube.com/watch?v=KP6vQnATckk] 

Hi everyone, the new issue of CI has gone to print and should be out by early next week. Having just caught up on what's been happening in the green building and energy world for the first time in a few weeks, here's some stories that caught my eye. 

How to get the most from your heat pump: Treehugger

Fascinating profile of Honk Kong's rooftop villages: Sustainable Cities Collective

Top ten green building prioties: No 10, make it easy: Green Building Advisor

Green buildings may boost occupants' health and productivity: Green Building Advisor

The US's first certified passive house retrofit: Green Building Advisor (more here

San Francisco unveils striking-solar powered stadium: Inhabitat

Report questions whether rainwater and greywater harvesting are really green: Energy Saving Trust

Should building regulations be less impenetrable and more consumer-friendly? Energy saving Trust

Paris to heat buildings using metro: Guardian

Profile of Britain's first recycled theatre: Guardian

The architect Mark Stephens begins a series of guest blog posts on going off grid

Welcome to this first in a series of guest blog posts that came about following the many enquiries and questions I receive as part of my everyday work and through the Ask the Architect service. This particular question came from Sylas Harper with the basic premise being that people haven’t got much money at the moment but they still need somewhere to live, and that throughout the country there are derelict houses that could be turned into homes. What I’m talking about here is living off-grid — a home that is not connected to mains electricity, water, gas or sewage. A home that is self-sufficient, sustainable and lowers the demands placed upon the planet. Once the enclave of the hippy or the hermit; the concepts behind living off-grid are now completely mainstream; solar panels and wind turbines are now commonplace and it is essential that we look for ways to lower our carbon dioxide emissions and to live a more sustainable life. As a theoretical experiment it may not be possible to adopt all of the points I’ll raise, but some of the aspects could be adopted by anyone seeking a more ecologically aware existence.

Now the initial question was posed thinking of the traditional Irish cottage wrecks dotted throughout the country, but with the recent news on the ghost estates throughout Ireland I came to the opinion that these ghost estates are the modern day equivalent of the derelict homes left to rot and be visible for generations to come. Surely there’s some way of getting ghost estates back into the hands of the ones that should be owning them - ie the people - especially now that all these homes are now effectively owned by the Irish tax payer via Nama. The Irish cottage concept is equally valid, and the points raised in these guest blog posts will equally apply to all types of housing.

Maybe it’s too big a jump to ask to get these ghost estates occupied and in-use? The argument could be made that living off-grid is possible for a sole dwelling but for an entire community of people? Well, Nick Rosen in his excellent book How to Live Off-Grid (ISBN:978-0-553-81819-2) discusses thoroughly the arguments and concepts for off-grid living and through his off-grid journey meets individuals and entire communities living beyond the constraint of national services. I cannot recommend this book highly enough —  if you’re interested in off-grid living in any way, buy it now!

So what are we talking about here? We basically have four facets to living off-grid:

1. WHERE

We need somewhere to do it; that is an enclosure that gives us protection and shelter from the elements; a defendable space that we can call our own - a private space to retreat to and a public space to interact with others.

This will be the argument behind the first main blog post — I’ll be looking at what you will need to look for to provide your ideal off-grid dwelling. This blog post will also incorporate passive house concepts; a dwelling adhering to passive house concepts (airtightness, high levels of insulation etc) will obviously require less energy to heat than a more conventional house.

2. POWER

We will need to provide power to the houses without relying on the national grid. It’s too much to ask people to live in houses powered by candles, to go to bed as soon as it gets dark or wander around your house with LED lamps strapped to the head. The dwellings will need to be powered in a reliable yet sustainable way.

Therefore, the concept of this second blog post will be investigating methods of providing enough energy to adequately provide light and heat to the house and providing hot water for baths and showers.

3. WATER & FOOD

Each dwelling will also require a potable water supply, and the third blog post will investigate what will be required to bring water to a site with no discernible, potable water supply. I will be looking at methods of extracting water from the ground (wells) and water harvesting/purification to provide water for drinking as well as the ‘grey’ water for flushing toilets etc. I’ll also be taking a little detour to see how any land associated with the dwelling (or even communal land) can be used to grow vegetables/fruit and again contribute to a more sustainable and self-sufficient life.

4. EFFLUENT

Each dwelling will need to safely dispose of its effluent; this will probably be the biggest problem (as evidenced by the current strict
standards regarding obtaining planning permissions involving a new septic tank). But equally this theoretically should be the easiest problem to solve as Ireland doesn’t have a national sewage infrastructure and the use of individual septic tanks and effluent treatment units is well established (ground conditions permitting). I’ll also be looking at composting toilets and reed bed systems.

The plan is to do one of these guest blog posts every week, so hold onto your hats for an interesting ride and a theoretical experiment in off-grid living with the first blog-post looking at where we are going to do it.

Comments welcome.

Mark Stephens RIBA MRIAI is a UK and Ireland trained chartered architect, based in Foxford, County Mayo, Ireland. He specialises in one-off, residential houses, extensions, restorations and refurbishments. His slant is a modernist approach using traditional forms and materials; his work also combines a contemporary architecture with an ecological and sustainable soundness.

Sorry for the slow stream of blog posts recently, I've been out of the office a lot. I spent yesterday looking at some innovative home systems for dealing with wastewater in Dundalk, and I'll try to blog about that soon. But for now, here's a bumper bunch of links.

Interesting profile of a small Welsh town designed in 1925 with some green principles in mind: Sustainable Cities Collective

Vapour profiles help predict whether a wall can dry: Green Building Advisor

The pyramid of energy efficiency — is this a useful tool for approach energy upgrades? Treehugger

How Britain's homes could make cost free emissions cuts: Guardian

Insightful interview with renowned green architect William McDonough on "cradle-to-cradle" design: Forbes

Improving the energy efficiency of buildings — IIEA conference in Dublin, Sept 3. IIEA

London's new "green" Strata tower named ugliest building in Britain: Treehugger

If the grid didn't exist, would there still be a need to invent it? Infrastructurist

Top 20 urban planning successes of all time: Public Servant Blog

Some vertical farms could actually get built says the SSC. George Monbiot, writing in the Guardian, thinks it's an absurd idea.

RIAI course on designing low energy retrofit in association with Joseph Little Architects: RIAI

Profile of a pay-as-you-save scheme in the UK: Guardian

 

 

The best green buildings of the last 30 years: Architect Magazine

Stunning eco apartments in Switzerland: Treehugger

Is it acceptable to allow some air infiltration through a building structure as a means of ventilation? Green Building Advisor

Renowned green architect Michelle Kaufmann blogs about a discussion with architect and passive house expert Walter Unterrainer: Michell Kaufmann Studio

China's incredible "car straddling" bus: Infrastructurist 

Architecture's ten biggest failures of the past 25 years: Infrastructurist

Can heat be stored in the sand beneath a house? Green Building Advisor

Interesting post on the challenges of selling a new passive house in a tough US property market: Green Building Advisor

 

Frank Gehry's Novartis building in Switzerland (at centre). Photo by Brad P .

Renowned architect Frank Gehry appears to know more about green building and architecture than he originally let on. Back in May, Gehry criticised the cost of green building as well as Leed, the US's environmental rating system for buildings. I covered his comments at the time and was quite critical writing: "Gehry has designed some of the most iconic buildings of our times, but I think his comments are reflective of a wider lack of understating among many architects when it comes to green building and architecture."

Thankfully, Gehry has now given an interview with US broadcaster PBS in which it becomes quite clear that he knows a lot more than his initial comments let on. He's actually quite insightful. Some highlights are below, but I'd highly recommend reading the full interview - Gehry goes on to speak about green materials, minimising construction waste and using stationary bicycles to provide energy in one of his projects, among various other topics.

Some choice quotes from Gehry: 

A lot of our clients don’t apply for the LEED certification because it’s complicated and in their view, they simply don’t need it.

There are other ways to encourage green building. For example, we did the Novartis building in Switzerland.

They don’t use the LEED program over there, the government just says this is what you can and can’t do, and things have to be built in a sustainable way. So really it’s a political thing: People taking responsibility on an individual level combined with government programs that give mandates that say “this is how we’re going to require people to build.” Our federal government is trying to take steps in that direction. I just met with someone from the Obama administration, they are trying to enact tougher standards, but they’re having some trouble.

...The Swiss government said the Novartis building couldn’t be air-conditioned. So we had to come up with another way to regulate the temperature. We built it entirely out of glass and cooled it with a geothermal system. The roof panels were made with photovoltaic glass that generates energy. And there is an opening at the top that lets hot air out — like a teepee. In the end, there’s no one way to do it, you have to be creative.

...Maybe you need the point system to energize this type of building, but I’m not sure it’s necessary.  The best way would be a political initiative that requires people to address these issues in order to get a building permit. Then the government can incentivize sustainable building through subsidies and various other things. But this is a global issue, so you need programs that not only we agree on but also that the Russians and the Chinese agree on.

...On certain projects, on big public projects, people definitely are interested in making them greener, but on smaller projects with tight budgets it can be harder. People don’t feel like they’re making enough of a dent for it to be worth it.

 

 

 

The new issue of CI hits the shelves this week. Here's a round up of some interesting stories that have broken while we've been away from the blog, working on the latest issue.

Irish green tech firm Solar Print to create 80 jobs: Irish Times

Major BBC investigation suggests the global asbestos industry is targeting developing nations: AFP

British homeowners to pay higher stamp duty for energy inefficient homes? Daily Mail (yes I know it's the Daily Mail - unfortunately they were the only news outlet I could find who weren't running this story behind a paywall)

Isover launches Irish energy efficiency awards: Silicon Republic

How SEAI's Accelerated Capital Allowances scheme has helped one Irish firm reduce the running costs of its data centre by 30%: Silicon Republic

European Commission publishes voluntary green public procurement for product categories including thermal insulation, CHP, street lighting and floor coverings: Envirocentre.ie

Bord Na Mona grows its renewable energy portfolio: Silicon Republic

Worldwide PV market to double in 2010: Wordofrenewables.com

Empire state building to get $20m green retrofit: Guardian

Is this the US's first passive house retrofit project? Jetson Green

Up to ten energy management interns are being recruited in Louth: SEAI

Brief profile of the new apartments at Arsenal FC's former ground Highbury, which have earned a BREEAM 'very good' rating: Building Design News

Green-minded architects and builders are familiar with the Forest Stewardship Council (FSC), which certifies timber as sustainable. It's attracted its fair share of criticism, as a quick look at the blog FSC Watch indicates (the blog even has a section devoted to certification in Ireland). Still, FSC certification is one of the few ways specifiers have of knowing how well a forest is managed when they're choosing timber.

Now another certification scheme, the Programme for the Endorsement of Forest Certification (PEFC), is getting up and running on these shores. In an email to Construct Ireland, PEFC Ireland 's William Merivale wrote:

There are two distinct areas of our work.  Firstly we are involved with drafting an Irish forest management certification standard which we expect to be ready for submission to PEFC International for endorsement by late summer/early autumn, and once endorsed both State and private forest owners will be able to apply to have their forests certified by PEFC.  (You may be aware that in the UK the Forestry Commission and a significant area of  private forest managed by Scottish Woodlands/Tilhill have recently opted for dual certification to both FSC and PEFC and we are confident this will happen here as well.)  Secondly we promote chain of custody certification to as wide a range of businesses involved in the manufacture/supply chain of wood-based products, and to their consumers.

Hopefully the arrival of PEFC will improve awareness of forest certification further - I've been surprised once or two recently, talking to people who work in various parts of the timber industry, at their lack of awareness of these certification schemes. Saying that, one architect I spoke to made the valid point that certification marks like FSC or PEFC discourage specifiers from doing detailed research on where timber comes from and deciding based on that - he argued they encourage laziness in timber selection, essentially. It's a reasonable point, but he also acknowledged - rightly - that the likes of FSC and PEFC are necessary for the many specifiers who want a green product but don't have the time or motivation to do serious research.

Most flat plates and some vacuum tube systems show efficiencies of around 80%, but when you look at the EN certificates for most popular Chinese vacuum flask systems, they are often in the mid 60s or less. Many people assume that this reflects poor quality Chinese manufacture, but in fact it is a quirk in how we measure “zero loss efficiency” which is at noon, and ignores the effect of the sun facing tubes at different angles at different times of the day. This factor is included in test results, described as transversal incidence angle modifier, or IAM.

The efficiency of a panel is usually given for noon when the sun is directly facing the panel. With a flat plate panel, efficiency falls off either side of noon, but with vacuum flasks, the efficiency actually increases. There are two reasons for this.

Firstly, the curved surface of a tube passively tracks the sun. Secondly, whereas at noon, the sun shines between tubes, as the sun moves towards 40 degrees off due south, there is increased reflection from tube to tube, dramatically increasing absorption.

The effect of this change in incidence angle modifier is measured as part of the test procedure for EN12975 certification. To show efficiency at any particular time of the day, the zero loss efficiency should be multiplied by the IAM.

The following chart shows a comparison between the IAM of a typical flat plate system and an Ecologics 58mm flask system at different angles as the sun moves from Noon to evening. A mirror image of this graph happens between sunrise and noon.
 
At its most extreme point, with the sun at an angle of 60 degrees, the output of a flat plate would be reduced by 10%, whereas the flask system’s efficiency is actually increased by 44%.

The difference between flasks and tubes
Chinese vacuum flasks are like a thermos flask with two layers of glass and a vacuum between these layers. There are many advantages to this:

• The vacuum element is a single piece of glass, whereas many other vacuum systems have a single layer of glass with a join between the copper heat pipe and the glass forming a seal to maintain the vacuum. With extreme temperatures, especially in stagnation, this seal can fail.
• Flasks are modular. When they lose their vacuum (typically expected after 15 - 20 years) only the flask itself need be replaced. Tubes require the replacement of tube, heat pipe and collector as a single unit.
• Replacement flasks are in common sizes of 47mm and 58mm diameter, produced in numerous plants in China, so you are not reliant on one supplier for spare parts. By comparison, most tube systems are not interchangeable. 
• Replacement flasks are typically about €5 each, whereas replacement tubes are considerably more expensive. 
• Chinese flask systems may be more sustainable than either tube or flat plates. Flat plate panels usually have a life expectancy of about 35 years after which the entire panel needs to be replaced with enormous disruption. An aluminium or stainless steel manifold on a vacuum tube system should last as long as the roof, with just a requirement to exchange flasks every fifteen to twenty years. This also dramatically reduces the embodied energy of the components required to maintain the solar water heating system over the lifetime of the house.
  

 
For these and other reasons, Chinese flasks have been widely adopted, and many – but not all – are of excellent quality and durability.

BER assessments
Modern houses with their improved energy efficiency could benefit more from vacuum systems because the central heating is operating for a shorter season, and vacuum systems have a longer operating season which complements this nicely.

A problem arises when you try to use the figures for vacuum flask systems in DEAP for BER assessments and Part L compliance. Commercial solar simulation software takes the IAM figures into account, but despite requests to SEAI going back almost two years, there is still no way to incorporate IAM in Deap.

You might think that you could simply take the ratio between the two average IAMs as a multiplier. The reality is more complicated because the multiplier should reflect the amount of time that the sun spends at each angle, and efficiency will also change as fluid temperature and ambient temperature changes throughout the day. You also get different effects depending on the roof pitch, orientation, and the amount of sunshine.

We ran identical panels through simulation software with each of the IAM curves shown in the graph, using various roof pitches and locations in Ireland. These showed a net increase in output of between 16 and 19% as a result of the altered IAM.

Not all vacuum flask systems have the same IAM curve, and it would be difficult to develop a formula that would reflect the effect. However, it would seem reasonable to allow BER assessors to increase the zero loss efficiency used in Deap provided they or the panel manufacturer can produce documentary evidence supporting this change for the conditions.

In the case of the example shown in the graph above, the multiplier would bring the zero loss efficiency from 66 to 78.4%. When you take into account the true efficiency, combined with the improved heat loss coefficient of vacuum systems, it becomes apparent that vacuum flask systems are extremely efficient at all times, often at a lower capital cost, and with lower long-term maintenance costs.

IAM for tubes with an enclosed flat plate
Lastly, it should be stated that this situation does not apply to vacuum tube systems which have a small flat plate inside a single glass tube. Their IAM more closely resembles that of a flat plate panel.

Quentin Gargan is a lecturer on the Fetac solar training in Cork Institute of Technology and is a founding director of Ecologics Solar Solutions. He has worked with both vacuum flask systems and Austrian flat plates, and would argue that commercially he has no axe to grind.

You may remember the Solar Decathlon, a US competition that challenged university teams to design the best solar-powered house. We previously profiled the competition in a lengthy photographic feature.

The sliding metal shutter shades of the Lumenhaus can be used to protect the house from glare and overheating, or pulled back to let sunlight in fully

For the first time this year a separate Solar Decathlon was held in Europe - Madrid specifically - and Virginia Tech's Lumenhaus (above), which also entered the US competition, emerged victorious. Green Building Advisor has more on the Lumenahus, and the official website has lots of information on all the houses (just click on the boxes). Team Finland won the architecture award at the competition (more info on the house here), and there's loads of info on the University of Florida's traditional-looking but ultra-modern house here. There's also an in-depth profile of the University of Nottingham's house in current issue of Construct Ireland.

Sorry for the brevity here on a subject that deserves much more attention - we're getting down to the heavy work on the July issue of the mag, so updates to the blog and news section might be sparse over the next week or two. But we've got an exciting issue coming up, with profiles of a couple of stick-built timber frame houses (including one that is staggeringly air tight), a piece on the most sustainable way of dealing with ghost estates and an opinion piece by Bord Gais CEO John Mullins on the company's green plans. 

 

For your reading pleasure:

Open House 2010 Dublin Highlights announced: Irish Architecture Foundation

Solar assisted air conditioning comes to market: Treehugger

Slideshow of the Cooper-Hewitt national design awards in the US: Treehugger (some of the products and buildings are quite green)

Profile of the first legal third party appeal of a LEED (Leadership in Energy and Environmental Design - the leading US environmental rating system for buildings) rating: Green Building Law

Profiles of nine "near carbon neutral" communities: Jetson Green

Solar PV integrated into ceramic roof tiles: Jetson Green

Sustainable Industries' top ten green building products of 2010: Sustainable Industries

Altering clocks in winter "could cut carbon emissions": Energy Savings Trust

Dubbed the Infrax building, this is the new headquarters of the West Flanders Energy Company in Belgium, and I'm posting it for the simple reason that it's quite stunning and reasonably green. I've taken the info that follows on the building's technical features from the website of architects VK.

...The West Flanders Energy Company commissioned the building of a new high-quality office in Torhout, complete with a warehouse and storage space. WVEM wanted its new premises to be sustainable and have low energy consumption to underscore the example the company sets for society…

...The office building has three levels, with ground level extension used as a communal dining hall. The building covers 4800 m2…

…Extensive insulation of the building shell and the use of high-quality insulated glazing gave the entire building an overall insulation level of K35. The building is heated at low temperature by concrete core activation on the upper levels and floor heating at ground level. Small low-temperature convectors are used to fine-tune the temperature in each zone. The offices on the upper levels do not have lowered ceilings. In summer the concrete core activation provides very comfortable and energy-efficient cooling of high temperatures. The calculations for the design were produced using detailed comfort and energy simulations of the office….

...Soil was integrated in the design as a sustainable source of energy. A borehole energy storage (BES) field combined with a high-performance water pump provides basic low-temperature heating in the building in winter…

…At ground level the building has mechanical ventilation, while the upper levels are equipped with a hybrid ventilation concept, because for 60% of the office time a building can be ventilated naturally without compromising on comfort. A hybrid ventilation concept means the building is ventilated mechanically in winter and summer and naturally at other times of the year. The result is a significant saving of energy. Heat recuperation occurs in the central air group…

…The hybrid ventilation system has been integrated in an intelligent facade concept. This concept is a highly integrated design of architecture and engineering. The ventilation facilities have been integrated in a double facade system, comprising an insulated inner shell and a glazed outer skin. The cavity between the two can be drenched with outdoor air. Outside summer and winter, the cavity air heated by the sun is used to deliver fresh air to the offices by manually opening 'viewing windows’. 'Light windows' allow ample daylight to penetrate deep into the offices. The windows are set well back in the intelligent façade to shield them from direct sun radiation. What's more, the double facade structure provides better acoustic insulation between the busy ring road and the offices...

…Photovoltaic solar cells integrated in the facade provide the energy required to drive the primary pump of the BES field. This makes it possible to cool the offices by means of the BES field and concrete core activation without extra energy consumption. The offices have been equipped with energy-efficient lighting fixtures, complete with daylight control and presence detection sensors…

...The office building has been equipped with water-efficient sanitary furniture and plumbing to minimise the demand for water.  Rainwater captured on the roof is reused in the building to flush toilets and urinals. The parking spaces for cars are pervious. Water originating from the metalled surfaces is infiltrated on site in green basins integrated in the car park landscape.

Sorry for the lack of blog updates last week - I had some trouble with our blog software and a blog post I published seemingly disappered. Anyway, here's a quick round up of recent links to get things kick-started again, mostly courtesy of Inhabitat and Treehugger.

Database will detail money saved from green retrofits in New York: Inhabitat

World's fastest train rolls off production line: Inhabitat

Work starts on UK's largest prefabricated straw bale building: Inhabitat

Can we use biomimicry to design cities? Treehugger

Toyota working on electric vehicle with Tesla: Inhabitat

University of Nottingham unveils solar-powered house: Inhabitat

A profile of Finland's entry into Solar Decathlon Europe: GreenBuildingAdvisor.com (Construct Ireland previously profiled the US Solar Decathlon here)

Green roofs now mandatory in Copenhagen: Treehugger