Better on both sides

Just a quick post regarding an interesting innovation in PV panels introduced to me via a CPD in the office last week from a company named Renewable Resources Ltd based in New Lanark in Scotland. Our attention was brought to a new product available on the market called Solyndra. These panels operate in much the same way as the standard flat panel models; however these panels consist of cylindrical models mounted off any flat roof surface allowing solar radiation to be captured on the panels entire 360 degree surface, and the installation of a white coated roof surface allow light to be reflected back and converted into electricity. Combined with direct and diffuse sunlight, these panels can also be placed closer to one another than standard PV panels (which usually require tilting) allowing for a significant increase in the electricity produced.

The panels are installed horizontally, and there are small gaps between the cylinders which allow for wind loading requires and the panels are self-ballasting – reducing the labour and parts costs and installation time associated with mountings for tilted models. These small gaps also provide natural cooling to the panels reducing heat loss and providing higher energy production.

This model would be of particular interest in large scale commercial buildings, with a lot of flat room space to put to use – or perhaps on the aforementioned Shrubhill House building. Another point highlighted by the engineer was that even during the heavy winters that we have experienced in the UK in the previous years the Solyndra panels, unlike conventional models, would continue to produce electricity, as the albedo from any snow underlying would continue to be absorbed by the cylinders. Pretty impressive stuff…

Demolishing the Future

The current prolonged downturn has seen a tranche of mothballed sites around many city and town centres, leaving gaping holes within streetscapes. Whilst some sites sit entirely empty, with mounds of topsoil gradually being overgrown with weeds, others contain whole derelict buildings derided by locals as an eyesore, a constant reminder of the cash strapped times we now find ourselves in. Right leaning think tank The Policy Exchange has put forward the idea of transforming our redundant high streets into housing (another gem from the ‘greenest government’), conflicting directly with the forming of sustainable communities with a range of mixed used developments. Combined with a drop in petrol prices, this would indeed be the final nail in the coffin of the high street as we know it, as householders jump into their cars to do their weekly shop at the nearest out-of-town shopping centre. This in turn would also lead to the further erosion of any local services and social cohesion associated with popping down the shops and bumping into a few people that you know – and all done without planning permission no less... and yet I feel they have hit upon something.

SUSTAINABLE_SOLUTION

There is definitely scope for regenerating derelict areas, providing that it is done to reinvigorate and not further deteriorate. Shortcomings within areas (i.e. housing, shops, workplaces, public buildings) should be identified and developments geared towards this, with the goal of strengthening communities and reducing travel distances. We should be making better use of run-down building in prime locations rather than leaving them to rot or knocking them down. There advantages to this are pretty obvious – reduced planning costs, reduced construction costs, and a reduction of pressure on resources involved with new building. All of which could be carried on to the end user as low cost housing. The main obstacle would be in persuading local opinion that monstrous decrepit buildings could still have a part to play in their area. However this in turn represents a chance for architects to once again gain the trust and respect of communities following their recent public batterings. It would also represent an excellent opportunity to create exemplars of green building technologies.

SHRUBHILL_HOUSE

I pass one such potential site on a daily basis. The Shrubhill area of Leith Walk in Edinburgh was until the last decade home to local council offices (Shrubhill House) and a bus depot. To go even further back reveals the area’s history as one of the original sites of the botanical gardens within Edinburgh – eventually moved to Inverleith due to increased traffic levels on Leith Walk affecting the growth of plants. The red-brick bus depot buildings have been almost entirely been demolished spare a couple of buildings to the west boundary and a tall chimney which all formed part of the old power station which provided power to the old tram network that once ran through Edinburgh. Although these buildings are run-down, their Victorian/Edwardian industrial era architectural merits are easy for all to see. To the north of the site lies several typical Edinburgh colony flats (all Grade B listed and part of a conservation area, including Middlefield House) and to the south traditional tenement blocks adjacent to an existing railway track serving nearby waste incineration works. Still standing on the south boundary of the site is an existing masonic lodge constructed of 1970’s style steel frame and metal cladding. On the sites west boundary stands a section of the now derelict Shrubhill House, a 1960’s concrete clad box which served as offices for council staff. To say it is ugly would be an understatement, and the local community would surely be content at seeing the building raised to the ground. Local council planning statements also encourage this. However it is in this unsightly building that I see some potential for sustainable development and a starting block for the site as a whole.

Planning permission has already been granted for the demolition of Shrubhill House and construction of multi-storey student housing by Unite in association with Acanthus Architects. The existing master plan for the site includes further low density housing to the rear of this, with underground car parking provided, and a scattering of landscaping (mostly hard landscaping) throughout. The old bus depot buildings and chimneys have been sensibly retained and provide a good lure to increase permeability through the site. However once people realise these buildings are converted housing, that appeal may be short lived.

ALTERNATIVE_PROPOSAL

Having obtained existing plans from the local planning portal, I have decided, beginning with Shrubhill House, to develop an alternative scheme, one that makes perhaps better use of the site for the area as a whole, supplying not only housing but commercial and public service opportunities, whilst providing more green space and attempt to encourage a more sustainable transport network – all at a scale suitable to the site. I will also use any designs as a springboard for learning more about the green technologies that are available and their suitability. So far I have broken down the site and surrounding area to represent existing building uses, permeability and green spaces, as shown below:

I’ve also began working on a scheme to convert Shrubhill House into medium density housing, with commercial units on the ground floor. This is very much a work in progress at the moment, but the intention may be to have some kind of solar buffer within each apartment and either attempt to have natural ventilation or go with a Passivhaus Standard (u-values not exceeding 0.15 W/m2/K for building envelope, 0.8 W/m2/K for glazing) which would mean incorporating mechanical ventilation with heat recovery. I’ll update more as I work through ideas, but here are a few sketches that I’m working on.

The danger is that the longer a site is allowed to deteriorate, the lower the expectations are for any development that would be eventually constructed – something is better than nothing. But this in turn leads to a cycle of unsuitable unsustainable building resulting in more demolition and redesign in another generation. This is a cycle we cannot afford, financially and environmentally.

New Songdo City

As one of the many coursework’s I have undertaken for the ‘Sustainability in Civil Engineering’ module of my masters, the CEEQUAL analysis was certainly one of the most enlightening. CEEQUAL, or Civil Engineering Environmental Quality Assessment and Award Scheme (think they may have to work on that acronym) provides participating developers or clients with an assessment and subsequent award with regard to their sustainability credentials for a specific project. With the aim of driving up environmental and social awareness of developments, CEEQUAL works in a similar way to a BREEAM assessment, though perhaps on a broader basis. The assessment itself is split into twelve separate sections, each containing a number of questions which the assessor must award points or scope out where relevant. The tally of these points for each section are then displayed graphically, and pitted against the potential points available to highlight shortcomings. The final award is then based upon the total points given from all sections. The final award is rated in the following order: No Award, Pass, Good, Very Good and Excellent. The assessment is usually carried out post completion; however an interim award is also available. Although not a statutory requirement, its award and required ambition to reach this award is sold as good PR and as an improvement to efficiency and best practice. So as part of our course we were given a variety of projects to choose from, and using the CEEQUAL assessment tool Version 3 (there is now a new improved version 4 available)perform an assessment of the projects sustainability credentials from the information available. Coming from an architectural background, I chose New Songdo City, Central Park in South Korea using the report descripting the project provided by its engineers Arup, which can be found here. Here are some snippets from my analysis of the results of the CEEQUAL assessment:

New Songdo City is citied by its developers as an exemplar in sustainability and green urban planning on a massive scale. One key aspect of this is the utilisation of almost 40% of its master-plan for the development of green spaces, the largest of which being Central Park. On the basis of the material available, New Songdo City has received a Good pass award with an overall initial score of 53.8% post construction. The majority of points awarded were achieved through effective project management, consideration of water issues and the development of a sustainable transport strategy, all of which resulting in a high award for community relations. There was however scope for the whole project rating to achieve an excellent award, should the developers have placed more emphasis on effective land use, reduction of energy consumption levels and ensuring that sustainable materials were selected and sourced locally.

Sustainability was obviously one of the key objectives of this development, something that has been undertaken by considered project management. The inclusion of sustainability consultants within the design team reflects this ambition. Points have also been gained through the consultation of local design teams and academic institutions, ensuring that most environmental impacts have been identified early on, and that the development meets local design and construction standards. This has also supported an attempt to balance the parks design with the natural surroundings of New Songdo City and respect historic Korean construction traditions. Rigorous consideration has also been given to the design, maintenance and water quality of the canal. Although this is in part due to the desire to maintain a reliable canal service route, praise should be given to the developers attempts to incorporate SUDS and the inclusion of an Operation & Maintenance plan. Consideration has also been given to the impacts on soil and groundwater and correct analysis and sustainable use of existing water bodies. The successful planning and development of new transport networks via new footpaths, cycle ways and a ferry service on the canal heavily contribute towards the park award, all attempting to encourage a reduction in car usage and minimise traffic impact. One of the perceived bonuses of building on reclaimed land is that there are few, if any, local communities to engage with, which although reducing the possibility for conflict also could encourage complacency within the developments design.

However it could be argued that while sustainability has been integral to the overall master plan of New Songdo, the same attention has not necessarily been paid to the actual construction of the park. This is reflected in the choice of materials and the consumption and generation of energy with the parks associated buildings (i.e. car park, boat stations) where little mention of sustainable local sources or renewable energy generation is made. Although difficult to achieve with the development of a park, it would appear that no whole life costing has been carried out with regard to the canal, park and associated buildings. It should also be noted that the production of an Environmental Impact Assessment (EIA) could have resulted in the resolving of several unknown factors, with possible impacts on the final award. Korea suffers from Geographical restraints, with limited land resources due to large central mountainous regions resulting in either huge cut and fill developments or land reclaiming programs. However there is little evidence substantiation the necessity of the land reclamation here, or proof that alternative solutions have been fully considered which may have had a zero or minimum impact on the existing wetlands habitat so crucial for local wildlife. Consideration has also not been fully paid to the impacts of climate change, with the potential destruction from rising sea levels and the increased capacity of extreme weather to hit the region.

Below is Radar plot of my score award to New Songdo City. As part of the coursework I also carried out a critique on the CEEQUAL assessment itself, which I may post parts up at a later date…

Northern Exposure

Unfortunately it has been a while since I have added to the blog – this was due to balancing my workloads between my current employment and my part time masters. Alas the combination of coursework, lectures and exam preparations got the better of me regarding time; however I now have a lull for 3 months in classes and will soon update the blog with some recent activities and thoughts on the course so far. For now however I will cast my mind back to August last year, and to Scotland’s Housing Expo, where I took the opportunity to view some of some Scotland’s most revered architects attempts to create innovative modern low energy housing designs, constructed of sustainable local materials.

The site contains in total 52 houses, a mixture of bold designs and realistic solutions. Several units were incomplete due to the impact of the financial crisis, and snagging required to others but considering the current state of the construction industry in Scotland this is understandable. Around 20 of these homes are affordable rent or low cost home ownership with a shared equity scheme, delivered by the Highland Housing Alliance in conjunction with Albyn Housing Society Ltd and Cairn Housing Association.

MASTERPLAN

In attempting to avoid the traditional cul-de-sac of the neighbouring developments, master planners Cadell2 have considered the Scottish environment and climate and how to respond to the sensitivity of the Scottish landscape. The individual housing sites are located perhaps more closely than normally associated with traditional housing schemes in an attempt to recreate the more socialable, dense, tight knit communities of Scotland’s past and moving away from detached properties by including a couple of possible terraced house solutions. The site makes good use of its outdoor spaces, including a wide village green and play area avoiding the usual accompaniment of uninviting railings and hard landscaping, as well as a gentle sloping avenue enticing people to a wooded area north of the site. The two main streets through the site have also been located to incorporate the existing waterways on the site. Although efforts have been made to reduce car numbers, an opportunity to make the site entirely car-free has been missed. The Expo in particular could have been a great exemplar of how cars can be separated from housing design, emulating several housing developments around Europe that the Expo perpetrates to admire. According to the site plan however the site is not linked up the surround housing schemes, possibly restricting permeability, although access to walking, cycling and public transport routes are provided at the south of the site.

AFFORDABLE_TERRACE

Although not initially overwhelmed by its metallic exterior and its vernacular house shape, on reflection ‘The Timber House’ by John Gilbert Architects certainly avoided the pitfalls associated with unrestrained double-storey glazing that so many of the other house designs seemed to submit to (i.e. overheating, privacy, carrying of odours and expensive). That’s not to say that there is a lack of natural light. After negotiating the semi-detached house’s slightly awkward entrance, the spacious lounge area is naturally well-lit by an extensive corner glazing incorporating timber double-glazed argon filled doors. This is a sentiment that is continued in every room, with generous but understated glazing provided to the kitchen and first floor bedrooms.
The combination of warm timber internals and natural light is backed up by the timber framed external wall construction, consisting of 95mm cross-laminated timber frame pre-fabricated from Sweden (do they not make this in Scotland?) enabling quick erection and a high thermal mass. Ventilated corrugated aluminium sheeting insulated with 200mm hemp is then attached to this frame, avoiding overheating from insolation in summer and keeping the house cosy in winter. The aluminium façade is continued in the pre-fab roof build-up. I would question the use of aluminium here, being that as a material it has an extremely high embedded carbon levels so should really not be considered when conceiving a ‘low carbon’ house. Aesthetically, it also doesn’t really work here, and in time the walls could become reminiscent of the many decaying out of town shopping warehouses that blight the landscape around most cities. In terms of its use of reflecting solar radiation in the summer, several other materials and coatings with high albedos are also available, and the use of suitable coloured paint can add to this as well as getting away from the gloomy grey pebbledash housing that we are so accustomed to in Scotland. The architects might not have pushed the boat out when it comes to taking design risks; however its modest attributes could make it attractive to private housing developers and with heating bills as low as £73/year (54 KWh/m² energy consumed, heating only) it has the potential to appeal to the social housing attempting to combating fuel poverty.

SECRET_GARDEN

Isle of Skye practice Rural Design’s Secret Garden plot was a great example of how space within a dwelling can be used resourcefully without stifling design inventiveness, and providing the added bonus of a large outside space required for a sustainable lifestyle such as food production. By strengthening a traditional highland house design, the architects have created a modest yet welcoming environment with a balanced room layout.
On entering the detached property, the staircase to the upper level is carefully tucked away removing its use as a feature but freeing up more space. The large living/dining area overlooking the stretch of garden to the rear of the property, clearly connected by large single storey full height glazing (with a slight overhang from above) and roof lights within the lounges sloped ceiling section. By separating the footprint of the two levels within the property, the architect is then able to make use of the room space over the lounge area, giving the room a more spacious and inviting feel again achieved in conjunction with timber internal finishes. The 3 bedrooms upstairs all face the rear of the property, maintaining privacy, and once again making full use of roof space to increase the perception of space. The use of roof space generally here does have its short fallings though, as indicated in the houses low carbon credentials slightly especially in comparison with its neighbouring sites. With an annual energy bill for heating of £320 (126 KWh/m²), its timber frame with 350mm insulation will need to be complemented perhaps by ensuring that the building is air-tight (perhaps built to Passiv Haus standards) and possible use of heat recovery technology.

MISHAPS_OTHERS

These two designs, although not perfect, stood out for me particularly. However there were also a number of successes and mishaps scattered around the development as a whole, each with their own nugget of value. As previously mentioned, several designs opted for full height double storey triple-glazing designed no doubt to increase heat gains from solar radiation. Twin Peaks by Joseph Thurrott highlighted the flaws associated with this feature when not correctly positioned, by creating too much roof space leading to expensive energy bills and smells directing from the below kitchen towards upper bedrooms, not to mention inadequate shading to prevent overheating. The Apartment by Keppie Design displayed an interesting solution to this problem by providing every apartment with a glazed balcony and retractable doors between this space and the living quarters, allowing more flexibility and the potential to warm air during the day ready for release within the property in the evening. Timber was present in most of the buildings, mostly prefabricated but not always sourced locally which was a let-down. Black was also present in a lot of buildings, no doubt due to its heat absorption properties however it remains to be seen how popular this tone is with buying customers. JM Architects went one step further with specifying black rubber to the outer face of their terraced housing on Stealth Terrace, although they attempted to balance its impact in the long term by introducing climbing ivy. NORDs Stone House made excellent use of local Caithness stone and the building form created a uniquely shaped lounge area. However the houses room layout seemed at odds with conventional wisdom, placing the dining and kitchen area on different floors (the dining area with it’s very on en-suite bathroom?) ensuring that any residents life would be spent firmly on the stairs. Visitors were equally confused by the abnormally high storage spaces provided in the bedrooms of the terraced housing scheme Three on Nine by Graham Mitchell Architects. Workspaces generally seemed to be an afterthought in most designs, many placed within hallways or redundant upper floor space created by vast glazing.

CONCLUSIONS

So what can be taken from the once dubbed ‘Highland Housing Expo’? The now defunct name at least explains its location in Inverness, not exactly the most accessible venue to promote quality design around Scotland. Low Carbon and Zero Carbon houses are always going to be a hard sell on their own, with higher purchasing costs clients will find it hard to visualise where all that extra money is going when so many of the advances are coming in energy generation technology and hidden away thicker insulation. The clients and architects at the expo have recognised this, and acknowledged that there is a need to re-evaluate the design of houses to give the client something more tangible for their buck. The designs also show the lack of a silver bullet for house design, each with their own appeals and snags. Sacrifices are always made. At the heart of any solutions though is a combination of very plain detailing and innovative use of new technologies and techniques, not a bombardment of gadgets. In this respect better information could have been on display regarding the energy saving devices spread around the sites. I was also genuinely surprised at the number of families and ‘average punters’ attending the expo. Participating architects could have learned a lot from spending some time eavesdropping on their prospective inhabitant’s thoughts, perhaps making use of those hallway workspaces they neglected to integrate properly into their designs….

My definition is this...

Surprisingly, the UK’s zero-carbon housing policy is one of the most stringent in the world. Policy however, is perhaps the most fragile of promises any governments can make, and turning it into a reality is the real intricacy. With the UK legally committed to reduce its carbon emissions by 80% by 2050 compared to 1990 levels, new homes are to play a vital part (though arguably a high level of savings could be utilised through retrofitting the countries existing housing stock) with the objective that all new homes should be zero-carbon from 2016, and non-domestic from 2019. I was therefore surprised to discover that after years of consultations, there is yet to be a clear definition of what is actually meant by zero carbon.

The closest thing we have to date as a definition is from Level 6 of the Code for Sustainable Homes. Although this has seen a number of exemplar houses by various architects and developers, all have proved difficult to role out into mainstream house building. Any new definition must take into account the difficulties that have been experience through this experiment. This in turn has led to a rethink from the current level 6 requirements. So what is being done to finalise a new definition? The Zero Carbon Hub (ZCH) was set up by the previous government to drive the delivery of zero carbon homes. It aims to deliver across 5 separate areas: energy efficiency of buildings, energy supply, gathering examples, developing skills and consumer engagement. The most immediate step in its remit is to provide a definition, which is expected to be delivered later this year. It is believed that the proposed definition would allow house builders to make half of the emissions savings by improving the fabric of the building and on-site generation technologies.

Defining Energy

In an impressively bold move, the most challenging aspect of zero carbon houses is that emissions should be reduced by not 100%, but actually 150%. Perhaps not the most easily comprehensible or arithmetically correct statistic, but the thinking behind such a figure is admirable. For the first time the measuring of carbon emissions from any new home will include unregulated energy as well as regulated energy. So what are the differences between the two? Regulated energy use includes all forms of energy currently covered in Part L of the building regulations, i.e. fixed lighting, space heating, water heating. Unregulated energy use includes all forms of energy use not currently covered in Part L of the building regulations, i.e. cooking, TV’s, computers, plug-in appliances. Carbon emissions from both must be zero by 2016.

A typical average-sized house built to 2006 building regulations releases just over a combine regulated and unregulated 3 tonnes of CO² every year. This figure is the sum of a buildings regulated (2 tonnes) and unregulated (1 tonne) energy use. Two thirds (2 tonnes) of a typical houses C0² emissions come from regulated energy use – to meet the standard this will need to be reduced to zero (100% reduction). The other tonne, produced from unregulated energy use will also require to be reduced to zero. In the end, overall emissions will need to be reduced by an incredible 150%.

A series of regulatory steps proposed by the government aims to lead the industry towards this goal. Maximum regulated emissions will be gradually lowered from now until 2016, the first of which will see amendments to Part L this October, requiring a reduction of 25% in regulated CO2 emissions (2 tonnes to 1.5 tonnes). In 2013, a further reduction of 44% of 2006 levels, to 1.1 tonne of regulated CO2. Then in 2016, everything must drop to zero, including unregulated emissions.

Zero Carbon Pyramid

The new zero carbon definition will be based on a ‘carbon pyramid’, the foundation of which is the reduction of energy demand. For example, the less energy required for heating, the less dependence on on-site renewable technologies. An airtight and well-insulated home will use little or no energy for space heating.

Energy Efficiency

A specialist task force within the ZCH was set up to advise on a minimum building fabric standard, a

ttempting to keep greens and developers happy alike. The resulting standard describes the maximum energy demand per square metre of floor area per year re

quired within the fabric design. For apartment blocks/mid terrace housing this value is 39kWh/m²/year. Detached, semi and end of terrace houses, where heat lo

ss of is greater, is 46kWh/m²/year.

Carbon Compliance

Additional reductions will come from building based low and zero carbon compliance i.e. photovoltaic panels, solar thermal water heating and heat pumps, biomass boilers, combined heat and power systems (CHP). Carbon compliance covers these technologies that are already available, but which have not yet been forced upon people.

Allowable Solutions

Energy efficiencies made through building fabric improvement and with carbon compliance should reduce a building’s regulated emissions by 70%. That still leaves 0.6 tonnes of regulated emissions, and 1 tonne of unregulated emissions. Still the haziest of responses for this further reduction is a form of offsetting entitled ‘Allowable Solutions. While exactly what these offsets entail is still being determined, current proposed solutions include:

• Carbon compliance beyond minimum requirements, i.e. fabric energy efficiency
• Credits for energy efficient appliances and building control systems to reduce use of appliances
• Exporting low carbon or renewable heat from a development
• Credit for contribution by the developer towards local low or zero carbon infrastructures.
• Improving the energy efficiency in local existing buildings
• Investment by developer into LZC infrastructure – ownership passing on to purchaser of the house.
• Credits for emission savings relative to grid electricity where offset renewable energy is connected directly to the development.

In Conclusion

In a recent conversation with one of Scotland’s largest housing developers (Stuart Milne) regarding the outcomes of their trial Sigma zero carbon home design, they were refreshing honest with regards to the issues that the industry is currently facing. There appears to still be a large disparity between manufacturer’s products performance and efficiency in comparison with their actual results on-site. This combined with an inability to maintain cost efficiency means that we are still a long way off from meeting these future targets. Cost is also incredibly hard to determine in 8 years time. Any new definition must be technically achievable and cost-effective for house builders, which in itself is very difficult in today’s climate where the focus of many house-builders is to stay afloat.

The more time allowed to the construction industry to prepare for what will be extremely stringent building standards, the better. Unfortunately funding for the Zero Carbon Hub has been cut post-definition, in line with every other public department. It is therefore yet to be seen as to whether the level of investment into research and development (and even government financial incentives) required will be in place to translate the zero carbon policy into reality.

Breathing easily

Many buildings currently consume unnecessarily high energy levels ventilating and cooling inhabited spaces, whilst simultaneously producing uncomfortable and unhealthy environments for their inhabitants. Clearly an important factor in energy efficiency is ensuring that buildings are as airtight as possible (current revisions to Part L of the Scottish Building Standards now ensures that air-tightness testing is compulsory) which in turn also increases our attention towards ventilation and cooling. The ‘Build Tight – Ventilate Right’ mantra is becoming evermore vocal, however important lessons must be absorbed from the over-use of mechanical systems and as a consequence of which has seen rising levels of sick building syndromes created by unhealthy indoor environments.

Current issues with MV/NV

The current incentives to avoid mechanical ventilation (MV) and air-conditioning are obvious – both consume high levels of energy, with ventilation alone consuming 5-15% of a buildings running costs. If badly maintained, both systems can also be a source of pollution. That is not to say that natural ventilation (NV) provides an all encompassing solution – poorly designed systems can be very difficult to control, also leading to the introduction of pollution and can be a waste of heat energy. With neither method providing an energy-efficient, clean, controllable and easy to maintain system, a mixed mode or hybrid is becoming the more favoured alternative.

Design Solutions

Passive Stack Ventilation
This approach uses a combination of cross-ventilation, buoyancy and suction enhanced by chimneys or outflows into zones of negative pressure to provide the most effective system of natural ventilation. Cool air is introduced into rooms via opening windows or inlets at low level, and is then heated by solar gains (or other internal heating systems in winter) and gradually rises where the warmed air is extracted through stack chimneys where multiple openings at roof level automatically close on windward and open on leeward sides. Careful consideration must be given to the amount of solar gains provided by glazing, with effective solar shading installed to give sufficient control, and window openings should be designed to ensure that over-ventilation is not an issue. Atria can also perform a similar function to chimneys when using a cross ventilation strategy. Mechanical ventilation does have a part to play when improved air flow requirements are necessary.

Night Cooling
Night cooling is a process which involves harnessing the lower night time external temperature to reduce the temperature of the building fabric, therefore reducing the internal temperature for the following day. Attention however must be given to security and window orientation which can aid lowering the ambient temperature and delay the use of energy consuming cooling equipment.

Culvert systems
Culvert systems exploit the constant temperature of the ground to facilitate buildings with warmer or cooler air which in conjunction with proper controls, solar gains and cross ventilation can also provide internal spaces with a regulated desired temperature. The average temperature of the earth at a depth of 2 metres below ground level is 10°C throughout the year. Air flowing into the ground via a wind tower and distributed to the building via an underground system where the warmed/cooled air can then be introduced and employed to warm or cool rooms. This system can also function in combination with heat recovery.

Conclusions

Reliance neither fully on MV or NV, but the introduction of natural means where possible and restrict where possible the use of mechanical equipment to the role of supporting flow and maintaining comfort levels. Any mechanical ventilation should incorporate lower vent rates and lower specific fan power (i.e. energy required to move a certain quantity of air) to ensure high energy efficiency.

Passive systems of cooling should take precedent over mechanical cooling, again with any mechanical cooling acting as a balancer – any heat should be recoverable too.

Hit the Hütte

Well if you’re going to start somewhere, might as well start big. This is based on an article I recently spotted in the May 2010 (English edition) issue of Detail Magazine – Green Issue. Many hill walkers will be familiar with the concept of bothies or Biwakschachtel to our German friends. Essentially a basic shelter providing hill walkers or farm workers with free basic accommodation in remote areas, several are scattered around the Scottish Highlands and within secluded areas of the Alps. Within the Swiss Alps, 3000m above sea level and 8km as the crow flies from the nearest road fit for traffic, lies the newly constructed Monte Rosa Hütte. Locations for construction do not really get much more isolated than this however you would struggle to find a better example of what architecture can achieve without compromise.

Brief + Design

Swiss Architects Bearth + Deplazes certainly had a task on their hands taking on this brief. Working on an initial design by architecture students from various colleges as part of a four term 'Studio Monte Rosa Hütte' the site provided a number of challenges; no electricity, running water or sewage to tie into and no infrastructure ensuring that transport logistics would be a key issue. The end result is a boulder shaped 3-storey structure that looks as if it has been deposited at random by a slow moving glacier, and further shaped by the extreme weather conditions. The autonomous design allows the building to perform the dual task of blending in with its picturesque surrounding landscape whilst acting as a landmark and orientation point for visitors to the area. This orientation point is continued inside with an internal winding staircase hugging the inside face of the external wall, accompanied with a strip of glazing allow the occupants to constantly consider their relationship with their surroundings. The 6.5million Franc Hütte provides temporary accommodation to over 120 visitors per year, and is only staffed in its most prolific season - between March and September.

Construction + Services

Built in short time windows in spring and summer, construction consisted of a timber prefab frame with a highly insulation facade supported on a star-shaped steel assembly platform. Due to logistical problems, all parts had to be transported on site via 3000 helicopter flights and erected by a team of 35 committed craftsmen living for 5 days at a time in the old Monte Rosa Hütte - weather obviously affecting the program.

Electricity is provided by shimmering 84m² photovoltaic panels placed on the south-facing elevation. Electricity generated is then stored in batteries (200kWh) for use with cooking (with a gas back-up), lighting and running various equipment.

Solar collectors (I had to double check the difference between solar panels and solar collectors – panels are for generating electricity, collectors for generating heat) placed as a band around the base of the structure have the added bonus of reflection from the surrounding snow. This energy is then used to heat water and warm air. In combination with this, the glazing accompanying the internal sweeping staircase has been designed to follow the line of the sun thus maximising the passive radiant heat which is then distributed around the building by minimal ventilation plant. The warm air created is delivered to individual rooms via floor level slits in the doors, and extracted directly above the door (reducing ceiling thickness and minimising lengths of ducts). CFD (computational fluid dynamics) simulation showed that circulation bypass would not be a problem. Extracted air is then channelled to a heat recovery system, and reused to heat water for the four hot showers in the guest quarters. Back-up energy is provided by a combined heat and power system which burns on rapeseed.

Melt water is collected in a cave 40 metres above the hut with a storage capacity of 200m³, thus creating enough water pressure - no pressure booster required. Water is then used for cooking, washing, cleaning and personal hygiene. Microfilter treats sewage, producing „grey water“ which is then reused for flushing toilets or for washing and released into environment in a purified state.

Green Credentials

With most of its energy coming from renewable sources, the building is 90% self-sufficient in water and energy terms (or 60-70% with cooking) ensuring only 10% of the huts energy is flow in by helicopter, which obviously makes a large dent in the carbon footprint. All components and equipment must be market-tested, robust and reliable, as maintenance would be an issue, minimum valve and pumps - less to replace.

A model predicted control system was created to increase efficiency further – an energy management plan monitored that is controlled remotely, in this case the system in controlled in a small office in a far-off town in Switzerland. Due to the fluctuation in the buildings occupancy levels, an intelligent energy management, rather than a system only being aware of the present situation of the building was required. Here is my understanding of how this works: First the scenario – A busy weekend where the hut is at full occupancy, all guests leaving on a Sunday evening and the building is left with a full septic tank and half empty batteries. The weather during the following week is terrible to start with, but improving later in the week. Using a normal control system, treatment of sewage tank would begin, emptying the remaining batteries which in turn signal the backup power to kick in. Using a predictive regulation system (which includes weather forecasting and predicted visitor numbers) knowing that few people will visit during the week and of improving weather later in the week, delays sewage treatment, allowing the batteries to charge fully and empty the septic tank without using heat and power plant backup therefore doing without the use of a back-up generator and saving energy.

Obviously the requirement for constructing any structure in such an isolated location is questionable, particularly when it involves 3000 helicopter flights (almost half of the total kg Co2 for the building over a 50 year period, however total for new building is only a third of the existing hut). However what cannot be overstated is the declaration that this building makes. 70% (two thirds of that being renewable energy) of the huts accumulated energy use goes towards running it, with 30% (just over half renewable) towards construction and eventual demolition over a 50 year period. By good design and overcoming such obvious unyielding issues it provides us with irrefutable evidence that we must challenge the way in which we view solutions to problems, and indeed how we takes these challenges for granted, not seeing them as the opportunities they are. Opportunities which allow us make better use of our surrounding environment and how we can make better use of the waste energy that we produce.