Posts Tagged ‘Heating and cooling’

The great PV break-through

15/03/2012

Ross McGuinness is Area Sales Manager for Kingspan Insulate and Generate. In this guest post, he celebrates the unprecedented take-up of solar PV, but warns it’s too early to break out the Champagne just yet…

The massive expansion of solar PV capacity in the UK has passed another milestone recently. Just a couple of weeks ago, SPV broke through the symbolic barrier of 1,000MW of installed capacity.

Sunset reflected in a solar panel, by ToGa Wanderings on Flickr

This growth has been rapid: in April 2010 there was a mere 26MW installed nationally. 23 months down the line and the industry has topped 1GW, which is a stunning result. The driver behind this seismic shift towards green, renewable energy is without a doubt the government-backed Feed-in Tariff (FiT).

This is all very positive news, and with the announcement from the Department of Energy and Climate Change some weeks ago stating their wish to have 22GW installed by 2020, you could be forgiven for thinking that everything is rosy in the SPV garden.

This announcement of several weeks ago has set out something of a roadmap for PV, but key questions need to be addressed before the industry will come out and support the new policy.

The government has destroyed any trust it may have had with the sector and it will take quite some time to repair what has become a fractious relationship. Continued court actions and appeals mean that, in the short term at least, a cloud hangs over SPV in the UK right now.

Looking at what is proposed by government, many industry insiders believe that it will be challenging to convince consumers to invest in SPV at the new rates. One of the main drivers of SPV has been the willingness of investment firms to “fund” SPV, hence the plethora of “free” installs whereby the end user got the benefit of free or discounted electricity and the funder got the Feed-in Tariff.

The new FiT rates will make it unlikely that similar funding models would be viable from an investor perspective. Funders look for an IRR of a minimum return of 7%; anything less and they simply go elsewhere for their fix. The government is on record as stating that they envisage returns of ca. 5% and will strive to ensure they do not go any higher by linking the price of PV modules to the FiT rate.

On the face of it this is a good proposal and should go some way to preventing the “Boom and Bust” that has beleaguered the industry. The mechanism has the potential to provide a sustainable and controlled future for the FiT.

In the long term, this is a positive for the industry, but short term – bearing in mind the skepticism and mistrust about the government’s attitude, and also bearing in mind the further cuts announced for July – you can understand why many are not cracking out the champagne just yet.

Solar panels in a low-tech setting: Breckenridge, Colorado

The belief is that Westminster is out of touch with where the industry is at, but most crucially and disappointingly, they fail to see where the industry can go. The Minister of State for Energy and Climate Change tweeted a couple of weeks ago that the Germans had just announced big cuts to their FiT scheme, implying that he was actually correct in pursuing the cuts here – blissfully ignoring the fact that Germany has had a Feed-in Tariff for the past decade, has a total installed capacity close on 25GW and operates on a completely different scale to the UK.

Under the new rates, the German government is proposing to pay €0.135/kWh for ground-mounted solar farms with a capacity of 10MW or less, and for rooftop installations that are 1–10MW in size. Germany is lightyears ahead of what is currently viable in this country.

There are, however, some reasons to be optimistic. The Chinese government last week directed the leading polysilicon and solar cell manufacturers to increase production, which should see prices continue to fall. That’s good news for consumers and probably bad news for non-Chinese manufacturers. China really does seem to be attempting to establish itself as the SPV equivalent of the Middle East. Continued downward pressure on price of SPV definitely looks set to continue in the short-to-medium term.

The great PV breakthrough should achieve one thing, however: SPV will at least now receive the recognition it deserves as a viable and high-quality alternative to fossil fuels. The SPV industry deserves recognition in Government energy strategy.

There is simply no reason why, if there is willingness on behalf of the powers that be, that by 2020 the UK cannot have the 22GW of solar capacity that government says it wishes to have.

Ross McGuinness, Area Sales Manager, Kingspan Insulate and Generate

Twitter: @rossmcguinness   Email: ross.mcguinness@kingspan.com

Spotlight on solar air heating

15/03/2012

Andrew Brewster leads the Renewables Design Team for the CA Group – a specialist building envelope manufacturer and installer. In this guest post, he puts one of the lesser-known solar technologies under the spotlight:

Solar air heating is a proven technology that has been developed specifically for heating large spaces. With high-profile advocates including The Royal Mail, Marks & Spencer and Jaguar Land Rover, the technology is increasingly expected to become part of the sustainability strategy of those companies leading the charge for environmental responsibility.

Harnessing sunrays to heat large spaces

What is solar air heating?
Solar air heating works by harnessing the sun’s energy via a Transpired Solar Collector (TSC), or SolarWall®. The SolarWall® technology pre-heats fresh, outside air, which is then actively drawn into the building’s heating system, contributing considerably to a reduction in the need for fossil fuels.

The technology is 100% renewable and has the effect of dramatically reducing a building’s overall heating requirement, providing significant savings in energy consumption and carbon emissions.

SolarWall® in action
CA Group recently installed the world’s largest SolarWall® on a single building for Marks & Spencer, at the retail giant’s 80,000m² East Midlands Distribution Centre (EMDC) in Castle Donington. The 4,500m² Transpired Solar Collector is expected to reduce the building’s heating requirement by somewhere in the region of 30%, by generating more than 1,135,000kWh and saving over 256t of CO2 per annum.

The SolarWall® can be seen in action at the Jaguar Land Rover training academy in this video:

The benefits
The revolutionary solar air heating system has the lowest capital cost and the highest known efficiency of any active solar technology in the world (up to 80%), generating in excess of 500 Watts of thermal energy per square meter on a clear day [Dr. Chuck Keutcher, U.S. National Renewable Energy Laboratory (NREL)].

It also offers the quickest return on investment, with an estimated payback period of three years on new build and eight years on retrofit applications. So as well as being an excellent option from an environmental perspective, it is also one that makes good commercial sense.

Global recognition
SolarWall® has been available for almost 30 years and is used in over 35 countries globally. A number of companies have tried to emulate the system but, due to a lack of understanding and third-party testing, they have been unable to replicate SolarWall®’s level of system performance.

In the UK, as part of its ongoing development and accreditation, the technology has received the independent endorsement of five leading authorities: Oxford Brookes University, the Welsh Assembly, Cardiff University, BSRIA and BRE.

CA Group has seen a significant uptake in the technology because of the very tangible results it delivers. As awareness of the technology’s capabilities increase, the Group anticipates that solar air heating will become part of the sustainability strategy of more and more companies looking for cost-effective ways of making the biggest impact on their CO2 emissions.

CA Group’s interactive Renewables Guide offers further information on solar air heating and other renewable options geared towards the generation of power and heat for commercial, industrial and distribution centres.

Green covers from Down Under: an Australian designer’s summary of green roofs

05/03/2012

Our ‘Australian Correspondent’, Mark Iscaro of First Angle, is in the process of specifying a green roof for a client’s building. In this guest post, he takes a closer look at the concept, components and benefits of living roofs.

San Francisco Academy of Sciences, by Osbornb on Flickr

“This blog will be focusing on a new Green Building initiative in Australia that is slowly making its way into the mainstream. Currently a growing trend around the world, the idea of having a green roof is gradually catching on. Even one of my own clients has finally given in and allowed me to put a green roof on their new building in Marysville.

So what is a green roof?

A green roof is a partially or completely covered roof containing a growing medium and vegetation. These are positioned over a waterproofing membrane and can include water retention, drainage and irrigation systems. There are two main forms of green roofing available in Australia: intensive and extensive, the difference being as follows:

  1. Intensive roofs (roof gardens) contain over 300mm of plant growth and can include a wide variety of shrubs, grasses, tree species and even kitchen herbs. They are also more akin to a park or garden, with easy access for recreational purposes.
  2. Extensive roofs contain less than 300mm of growing media, and so are generally lighter in weight. They are suitable for harsher growing conditions and require minimal irrigation, using hardy, low-growing plant and ground-cover species. These roofs can handle slopes up to 30°. Extensive roofs are usually only accessed for maintenance.

Commercial green roof installation, by Arlington County on Flickr

What are the benefits of green roofs?
• Reduce heating (by adding mass and thermal resistance value).
• Reduce cooling loads on a building by 50 to 90% (by evaporative cooling), especially if it is glassed in so as to act as a terrarium and passive solar heat reservoir: a concentration of green roofs in an urban area can even reduce the city’s average temperatures during the summer.
• Reduce stormwater run-off.
• Natural habitat creation, promoting biodiversity.
• Filter pollutants and carbon dioxide out of the air, which helps lower rates of diseases like asthma.
• Filter pollutants and heavy metals out of rainwater.
• Help to insulate a building for sound: the soil serves to block lower frequencies and the plants block higher frequencies.
• Increase agricultural space.

So now that you know a bit more about these wonderful creations and the benefits they provide, why not look at one for either your current home or perhaps your next project?

Note: Information was gathered from Wikipedia & Green Roof Technologies.”

Mark is active on Twitter, and details of his projects can be found on the First Angle design and planning website.

For more facts and figures on green roofs in the Southern hemisphere, Green Roofs Australasia is worth a visit. A good variety of extensive, intensive, semi-intensive and brown/biodiverse roofs can also be compared over at ESI.info. If you are looking to plant a facade rather than a roof, have a look at what’s available in terms of living walls and vertical gardens.

PassivHaus: the devil is in the detail

07/10/2011

The PassivHaus concept is quite a simple one: create an airtight, super-insulated structure, install mechanical ventilation with heat recovery, address thermal bridging, and find yourself with a building that can essentially be heated by a hairdryer. However, as with most things, the devil is in the detail…

Here, I take a look at the following questions:

What does a PassivHaus look like?

PassivHaus is really a design and build process, as opposed to a particular style of architecture. Whilst we may have preconceived ideas of a PassivHaus-certified building’s aesthetics, it could (at least in theory) look pretty much like anything – especially given that existing buildings can be retrofitted to PassivHaus standard.

100 Princedale Rd, Paul Davis + Partners

This was done at 100 Princedale Road – a Victorian house in a London conservation area – by Paul Davis + Partners and contractor Philip Proffit of Ryder Strategies Europe Ltd. This house was the first of its kind in the UK to achieve PassivHaus accreditation, meeting its target to reduce carbon emissions by 80%. (Granted, with the subject of the retrofit starting out as a drafty, four-story old house, there was plenty of scope for improvement.) In other words, a passive house can be anything from a large, new office building to a centuries-old, traditional house. Below are some examples:

Single-family residence in Brooklyn, NYC | Gregory Duncan

Eurogate Sozialbau, Vienna – Europe’s largest PassivHaus settlement? | Tiger46 on Flickr

Passive house office building in Austria | Tõnu Mauring

What does a PassivHaus cost?

The Footprint article on the Princedale Road Retrofit for the Future project includes an interesting breakdown of the cost / payback time / bills before and after completion, making a comparison between refurbishing to PassivHaus or Decent Homes criteria. The Green Building Store, in conjunction with Building magazine, has also provided a breakdown of costs for the Denby Dale PassivHaus in West Yorkshire.

What about air quality?

The more passive (or other enclosed, airtight and sealed) houses we construct, the more important it is that we keep monitoring and assessing the quality of the air circulated in these buildings. Are we avoiding moisture build-up? Is the air too dry? Is there enough of it? Will we see a concentration of emissions inside these buildings, over time, from the building materials used? What are the potential positive/negative effects on occupants’ health and well-being? Housebuilder’s Bible author Mark Brinkley experiments with air quality and CO2 levels in this House 2.0 blog post, relating his findings to PassivHaus standards.

To ensure a good level of fresh air supply, most passive houses are ventilated and heated by mechanical ventilation with heat recovery (MVHR). Heat from the warm air that is being extracted is passed to the incoming fresh air through a heat exchanger – with the result that heat loss is minimised and heating costs are reduced. Ducting is an integral part of this: “Marion Baeli, the architect on the [Princedale Road] project, stressed that in a retrofit with MVHR, the coordination of ductwork requires considerable design attention, and should be integrated right from the start.” (Footprint)

Airflex Pro suspended ceiling ductwork installation (Airflow Developments on ESI.info)

Which products are used in a PassivHaus?

The PassivHaus Institut provides a list of certified building components, products and systems suitable for use in PassivHaus construction. Presumably, as this concept gains popularity and awareness, the list will grow. We have already looked at ventilation. Other important components are energy-efficient windows, airtight seals and thermal insulation.

But of course, a component is only as good as its installation. As well as architects who know how to design a successful PassivHaus, and manufacturers who can make products suitable for this type of construction, we need contractors with the right skills and experience. (PassiveHouse Builders, Passivhaus/LCC, Passive Development and Viking House are some of the firms I have come across.)

Project Green Home, Palo Alto | Mark Hogan

What is it like to live in a PassivHaus?

Bill Butcher, the construction manager of the Denby Dale house, kept a 17-instalment diary during the building process. But what happens post-occupancy? How does the building perform, and how does it shape the lives and behaviours of its occupants? In a separate post, I have taken a closer look at the realities of living in a passive house.

What is the next big thing after PassivHaus?

In the absence of a unified, international environmental standard for buildings, there is a certain amount of ‘competition’ between the different accreditations. There is no shortage of acronyms to choose from, and there are almost as many opinions on which accreditation makes the most sense as there are design-and-build professionals. (For a sensible take on PassivHaus vs the Code for Sustainable Homes, see “The Bout of the Decade” by Sustainable Homes.)

Andrew Holt heads the practice Architectopia in Norway, and also runs a course on sustainable architecture. He has worked extensively on PassivHaus developments. In an Arkitektnytt.no article, he talks about what the next big thing after PassivHaus might be. Mentioning BREEAM, zero-emission housing and “plus houses”, Andrew emphasises the importance of tailoring the standard to the individual project, using different tools to come up with a package that is fit for purpose. He comes to a refreshing conclusion (my translation):

What follows ‘after’ the PassivHaus standard should be a variety of different possibilities, so that our ambitions are based increasingly on the individual project and its local climate and conditions. This would facilitate greater innovation, creativity and cross-disciplinary co-operation. This approach demands a high level of competence within the project team.

An understanding of what the PassivHaus standard is, is a prerequisite for high-quality construction within the energy-efficiency sector. An understanding of what the PassivHaus standard isn’t, is a prerequisite for moving forwards.

PassivHaus office in Langenhart | Train.bird on Flickr

The realities of living in a PassivHaus

07/02/2011

Thermal image of a PassiveHouse (Young Germany)

Once the scaffolding is down and the blower door test has been passed, what is it actually like to live in a PassivHaus? How does it feel to occupy a house that is kept warm using only your own body heat; a house that is completely airtight and needs no conventional heating system? How does it change your behaviour, needs and habits?

PassiveHouse as a concept

The concept of the passive house (or PassivHaus for the internationalists amongst us) is becoming increasingly well known amongst British architects, contractors, developers and clients. It has moved from being yet another forward-thinking construction method that is adopted in mainland Europe but largely ignored in this country, to being championed by a number of UK built environment professionals.

Information abounds when it comes to PassivHaus certification requirements, test results, design detailing, building physics and heat capacities. The Passipedia website is a good resource in this respect. It also gives an interesting historical review of  passive houses from the past. Did you know, for example, that Fridtjof Nansen’s 1883 polar exploration ship Fram functioned like a PassivHaus? Nansen wrote:

(more…)

Breton architecture – a sense of place

06/08/2010

Paul Gauguin painted in Pont-Aven, moving from Impressionism to "synthetism"

Staring at the dreich, Scottish rain outside my office window, it is hard to believe that I have just come back from two sun-drenched weeks in Brittany.

I am trying to recall the sights, sounds and smells of Nevez, Raguenéz, Pont-Aven and Bénodet: the rough granite coastline and shimmering sea, the super-salty surf that the kids were gleefully dodging, the sudden and short-lived rainfalls drumming onto the roof of our tent. (Not to mention the local cider and caramel au beurre salée…)

A windy walk along the beach in Bénodet

Houses on the hill in Pont-Aven

I was struck by how closely the area’s many new-build houses resemble centuries-old Breton homes. While introducing some new features (maritime-style, circular windows were popular), the designs stayed close to the regional vernacular.

The buildings were  tall, wide and shallow structures, with thick masonry walls in white or cream render – good thermal mass for keeping warm in stormy winters and cool in blistering summers.

Windows were often small and placed mainly on south-facing facades, and roofs were steeply pitched slate or thatch with elaborate dormer window detailing. Gardens had sparse planting, clusters of pine, and the ubiquitous pink-and-blue hydrangea.

From Dol-de-Bretagne (Wikimedia Commons)

I assumed this uniformity to be a result of tight planning regulations – or is it self-enforced by Breton clients, architects and builders? Either way, the distinct architectural style helps preserve and reinforce the region’s identity.

Nevez cottages (Breizh33 on Flickr)

As much as I hate seeing innovative, brave design being stifled by overly conservative planning control (and royal interference…), I do enjoy spending time in places where new-builds retain a sense of history and local context. A difficult balance to strike, perhaps. Do you have any examples of places where they have got it right?

Maria (11) setting up 'home' in a big Breton pine

More than two ways to skin a building: smart facades

01/04/2010

tanakawho on Flickr

How does an architect approach the design of a brand new building? What are the primary considerations – function, form, structure, materials, setting, sustainability?

Each designer will have their own priorities, but to the public – outsiders, neighbours and visitors – a building’s cladding forms a large part of our first impression. The cladding is the building’s face, and we often take it at face value.

Increasingly, though, new technologies are allowing a building’s skin to have functions beyond weatherproofing and decoration.

Smart skin: translucent insulation

Impression of a SmartSkin zero-energy building

Dutch architects and engineers Jon Kristinsson and Andy Dobbelsteen have released details on a new smart skin system for zero-energy buildings, conceived by Dr Noor van Andel and Mr Peter T Oei. Tests on prototypes have shown promising results.

‘Smart skin’ is a new concept: a thin translucent skin for buildings instead of walls. Groundwater is used to buffer the temperature difference between night and day and even between summer and winter. Most often, technicians think that energy losses can only be reduced by using thick insulation, or at least high-performance insulation. ‘Smart skin’ is a typical Dutch idea from a wet country with an averagely mild climate and high groundwater level. ‘Smart skin’ is not a well-insulated wall, but uses the thermal mass of groundwater for heating or cooling.

A PDF outlining the project can be downloaded here.

Smart skin: building-integrated wireless access

In another project, Ji Hoon Jeona, Woonbong Hwang, Hyun-Chul Park and Wee-Sang Park have researched the buckling loads of smart-skin composite panels, in this case for use with wireless LAN systems. Here, thin-strip antennas are incorporated into laminate cladding for building-integrated wi-fi access.

Smart skin: biomimicry

MRA's Kepos eco-hotel

An Ecofriend blog post brings details of MRA‘s Kepos eco-hotel. Designed by John Naranjo, the hotel absorbs solar and wind energy through an open skin. The double-skin building facade is meant to replicate a forest canopy:

The technical and sustainable attributes that are being reinforced by the biomimicry concept include learning from the life-supporting aspects of our living environment, obtaining energy, recycling and reclaiming resources and materials. The main component that will be applied to the building’s exterior canopy will be a special layer developed by SMIT called GROW. This canopy incorporates a combination of photovoltaic and piezoelectric technologies in one system that will absorb both solar and wind energy in one open skin.

Smart skin: carbon absorption

In a previous post, we have glanced at how living algae facades can be used to absorb CO2 from the atmosphere. We have also (in our very first, tentative and terribly short blog post) looked at the emergence of living walls.

Smart skin: this is just the beginning

Through nanotechnology, biomimicry, photovoltaic energy generation, dynamic facade technology, membrane development and a growing emphasis on ‘intelligent’ building materials, building facades will increasingly have to work harder, becoming more than just a pretty face.

Cladding images, specification details and case studies can be found on ESI.info:

Dezhou – a technology hub for solar energy

18/02/2010

Following on from our earlier post on Trondheim’s strategy to create a ‘supercluster’ for maritime knowledge and research, here’s a look at Dezhou, in Shangdong Province, China, which has developed itself as a ‘world solar city’.

Dezhou is hosting the 2010 International Solar Cities congress in September. It is home to 100 solar enterprises with 586 solar product patents, and five solar scientific research programmes belonging to National Plan 863.

China Solar City

China Solar City

Called China Solar Valley, the Dezhou cluster covers an area of 330 hectares of research and manufacturing facilities, including the world’s largest solar water heater production plant. Around 800,000 people work in the solar panel industry.

There has also been a determined effort to ensure that solar technologies are put to spectacular use.

The Sun-Moon Mansion is a 75,000m2 solar-powered building (office space / exhibition centre / R&S centre / hotel) with over 2000 solar collectors above its roof.

The Sun-Moon Mansion

The Sun-Moon Mansion

Seasonal heat storage, solar heating and cooling, and geothermal heating are used to supply hot water, cooling in summer, and heating in winter, whilst photovoltaics generate energy and provide lighting.

Energy saving glass, sun-shading panels, external wall insulation, roof gardens, rainwater collection and water treatment systems also feature.

But there’s also the more mundane, but probably more important, schemes that address the needs of the local population. As a result of the One million solar roofs project more than 80% of the urban buildings are covered by solar water heaters.

Solar bathrooms in hundred villages is another project.

ESI references: