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Monday 17 November 2003
Welcome to the first issue of “Get Sust!” - an e-mail newsletter for undergraduates, post-grads, researchers and professionals with an interest in sustainability and the built environment.
This is a “special” issue, focussing on the Worldwide CIBSE/ASHRAE gathering of the building services industry in Edinburgh at the end of September 2003. The event took the theme of “Building Sustainability, Value and Profit”.
Thanks to:
The Chartered Institution of Building Services Engineers (http://www.cibse.org) for access to its Edinburgh Conference.
WMDs - coming to a town near you!
Bush and Blair may still be scouring Iraq for weapons of mass destruction (WMDs), but CIBSE President Terry Wyatt already knows where they are - we’re all sitting in them!
Buildings are responsible for around half of all emissions of carbon dioxide, the main greenhouse gas, and Mr Wyatt says that this summer’s heat-wave should be seen by all as a wake-up call: climate change is upon us.
Why should this concern you? Well, as students of the built environment you have the power to influence the design and performance of the next generation of buildings - buildings that will have a life-span of 50 years or more, and buildings that will have to provide comfortable conditions for occupants in an increasingly hostile environment. UK government-backed predictions say that even if we manage to reduce global emissions of greenhouse gases, we can still expect hotter, drier summers and stormier, wetter winters.
We all know that everyone can do their bit to save energy and thus play a tiny part in slowing down the climate-change juggernaut. But for construction professionals there are other factors at play, as Richard Riley, ASHRAE President pointed out: in the wake of the September 11 disaster and more recent power supply failures in New York, clients around the world are beginning to take the issue of risk very seriously. Who wants to invest millions in a building that can’t stand up to the rigours of life in the 21st Century?
But building performance isn’t the only issue here. Buildings are for people, and if the people aren’t happy, the building will not reach its full investment potential.
Healthy buildings are happy buildings
There is mounting evidence that poor design contributes to sick-building syndrome (SBS), and that uncomfortable and unpleasant buildings have a direct impact on the performance of the people who work in them. Delegates to the Edinburgh event heard two entertaining and informative presentations that highlighted the need for designers to think carefully about healthy indoor environments. The first, by Dr Richard Hobday, engineering consultant in solar design for health, discussed “the healing sun” - the link between architecture, medicine and daylight.
Dr Hobday was a wealth of interesting facts. For instance, the benefits of sunlight were appreciated as far back as 2500 BC, when the Egyptians used the sun for healing, but it was just 100 years ago that scientist Niels Finsen was awarded the Nobel Prize for his work to established the scientific link between sunshine and health. From the middle ages to the 1800s window taxes, taxes on glass, and poor quality buildings deprived citizens of their sunlight, and the wasting disease “rickets” was rife. There is an old Italian/Roman saying: “Where the sun does not go, the doctor does”. But the connection between rickets and lack of daylight was not made until 1921.
These days we are aware of the health benefits of daylight. For instance, sunny hospital wards help depressed patients recover more quickly, and have fewer bacteria. However, we now spend around 90% of our time indoors, and Dr Hobday says there is a danger that some “energy efficient” buildings can actually reduce solar access.
The second health-related presentation came from Professor Tadj Oreszczyn, Director of the Bartlett School of Graduate Studies, University College London. He described a major government-backed research project - the WarmFront Scheme - part if which is investigating the health benefits of improving the energy efficiency of homes. The team have monitored 1500 homes for energy consumption, fabric heat loss, airtightness, mould growth etc, and they are now in the process of comparing their findings with feedback from occupant surveys that looked at thermal comfort, income, health and the habits of the occupants. Their aim is to find out whether improving the building’s airtightness, insulation levels and heating system actually made some health problems, such as asthma, worse.
Prof. Oreszczyn confessed that he has become something of an expert in the life-cycle of house-dust mites - the tiny pests whose droppings cause sneezing and breathing problems. He explained that the mites are extremely sensitive to changes in temperature and relative humidity. They thrive in humid environments; and if the temperature increases only slightly the creatures mature much more quickly and the population can increase dramatically. The lesson for designers is to provide adequate ventilation and to ensure that occupants understand the need and have the means to reduce humidity (e.g. a specific place for drying wet clothes). Full details of the study will be published early in 2004.
(As an interesting aside, Prof. Oreszczyn also mentioned that, in terms of air pollution, burning one joss-stick is equivalent to smoking 20 cigarettes!)
Taking responsibility
Which all goes to show that there’s more to sustainability than meets the eye - it’s not just about windmills and composting toilets! Indeed, sustainability is an issue that is raising its head at board meetings across the land in the form of “corporate social responsibility” (CSR). This “buzz word” is doing the rounds at the moment, but it’s one that construction professionals should take very seriously. Government initiatives such as Action Energy have been promoting the idea of energy efficient and environmentally sensitive buildings for over a decade. But new legislation and a better-informed public are forcing companies to think hard about the environmental impact of their operations. Early next year, ASHRAE will publish guidance on “green buildings”; the aim is to encourage engineers and designers to persuade clients that it is in their own interest to put sustainability at the top of their priorities list.
Student action
And what of the conference itself? If you have never been to a professional conference before, then the CIBSE/ASHRAE gathering is an excellent place to start. They made a big effort to welcome students, and hosted a special session to introduce them to the event. Tim Dwyer of London Southbank University and Ant Wilson of FaberMaunsell described the exciting employment prospects for building services graduates, and two students from Sheffield University and Imperial College talked their colleagues through the conference programme.
With 26 sessions over 2 days, plus a supporting exhibition, there was something for everyone. Papers presented at the conference have now been published on CIBSE’s website, and the rest of this newsletter summarises a few highlights.
Learn more:
 |
• | http://www.cibse.org |
| • | http://www.ashrae.org | |
| • | http://www.healingsun.com | |
| • | http://www.bartlett.ucl.ac.uk | |
| • | http://www.actionenergy.org.uk | |
| • | http://www.lsbu.ac.uk | |
| • | http://www.fabermaunsell.co.uk |
| © Melanie Thompson 2003 |  |
Can you cut it?
CIBSE has launched a major design competition that will be particularly beneficial to students. The “CIBSE Carbon 60 Competition” calls on practising designers and built environment students to draw up a plan to cut carbon dioxide emissions at CIBSE’s London headquarters by 60% - the tough national target set by the Royal Commission on Environmental Pollution (RCEP). The competition will have two short-lists - one for practitioners and one for students. The four student teams that reach the short-list will be paired with a major building services company to gain help with calculations and detailed planning. This is a great chance to gain experience of a real project - and to see your plans put into action.
The deadline for entries is 31 March 2004. For full details and an application pack contact Karen Ortiz at CIBSE. E-mail: kortiz@cibse.org Tel: 020 8772 3676.
Low-tech solution shows true performance in the classroom
There’s a lot of enthusiasm for computer modelling of building performance, but sometimes a “low-tech” solution can be more persuasive, as the CIBSE/ASHRAE Conference discovered when Professor Andrew Woods and his team from the BP Institute and CMI Cambridge University demonstrated the performance of naturally ventilated buildings using water-bath models.
Natural ventilation has proven benefits in that it reduces emissions of greenhouse gases, cuts energy costs for the building and avoids the health problems sometimes associated with air-conditioning. The physics is simple to understand too - warm air rises, and very small pressure differences between the inside and outside of a building can be harnessed to successfully drive the system. Adding “stacks” to the design gives extra height, and can increase air-flow by up to 40%, while “solar chimneys” heat the air further to improve out-flow.
Prof. Woods explained that although customised software using computational fluid dynamics (CFD) calculations can be used to check the detailed performance of a building (right down to an individual occupant’s sensation of hot or cold), such programmes don’t always show a true picture because they have been programmed to spotlight particular issues. His live demonstration, using dolls-house-sized models in a water-bath quickly illustrated the importance of getting stack heights and positions correct. One notable example was of a design for a classroom with an atrium. Water-bath analysis revealed that the original design would have left the poor teacher feeling hot under the collar, because in some weather conditions, instead of fresh warmed air entering the classroom via the atrium, the ventilation system could accidentally reverse, drawing expelled air from the pupils straight to the front of the class.
And he also explained how natural ventilation can achieve impressive constant comfortable conditions - whatever the outside temperature - citing the example of a naturally ventilated brewery in Malta, where outdoor temperatures can reach 40 degrees Celsius but the beer inside must remain at a constant 24 degrees.
Learn more:
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• | See http://www.bpi.cam.ac.uk |
| • | See also “The pros and cons of simulation”, below |
| © Melanie Thompson 2003 | |
Cladding to clean up cities
Researchers in Scotland have developed a cladding system that not only reduces energy usage, it cleans up polluted urban air.
Known as the “smart breathing wall” the system is being developed by a team led by Dr Mohammed Imbabi of the Environmental Building Partnership Ltd, King’s College, Aberdeen. The system uses conventional building materials such as fibre-based insulation and rain-screen material to create a panel that can be used on new or renovated buildings. The panel insulates the building but at the same time it filters pollutants from the outdoor air, and enables the clean air to move seamlessly through to the indoor environment. Theoretical models suggest that the panels could satisfactorily filter out many common pollutants for up to 60 years.
The key to the success of the system lies in the design of the “support structure” for the insulation material - without this the filtering system would eventually fail because the insulation would gradually move. The team have applied for a patent on their panels, which incorporate an egg-carton-like support system. Conventional natural ventilation - caused by the difference in internal and external pressure - does the rest. An added advantage of such panels is that air inlets could be located anywhere on the wall.
Test rigs have been set up in London and Aberdeen to verify the theory. The team are also investigating the possibility of incorporating low-pressure hot water pipes into the panels to heat the incoming air, enhancing flow through the panel and acting like a conventional radiator in the room.
If all this sounds too good to be true, there is one proviso: for the system to operate correctly, infiltration or leakage flows through gaps, cracks, leaky doors and windows must be reduced as much as possible - a significant challenge for today’s building contractors.
Learn more:
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• | Download a full report on the development of the panels from http://www.cibse.org/conferencepapers/ (Session 8c) |
| • | Visit http://www.environmental-building.com |
| © Melanie Thompson 2003 | |
The pros and cons of simulation
Building performance simulation has been around for some time, but is mainly used by specialist consultants. Now architects and engineers are getting in on the act, with some surprising results.
Many architects call in simulation experts to verify specific decisions at the scheme- or detailed-design stages of a project. But sustainability is not a “bolt-on” option: decisions made at the start of a project - even basics like orientation and positions and numbers of openings - can have a significant impact on the final product.
Brian Spires of HLM Design told the CIBSE/ASHRAE Conference how this architectural practice has made a determined effort to take full advantage of building simulation, bringing it to the architects’ desk-top at the concept design stage. The main problem they faced was with the simulation software itself, which can prove complex for the uninitiated. However, government funding helped the practice to develop an “outline design stage” (ODS) interface so that design data could be entered by team members who are not simulation specialists. Now, HLM Design use the system on all projects. Having entered raw data about the building and its location, the design team can run a simulation and quickly find out the ‘intrinsic’ annual energy consumption and assess likely thermal comfort for the basic design. For example, they recently used it to compare the performance of the Health & Safety Executive’s new office development in Liverpool against good practice energy benchmarks.
Despite the many advantages of simulation, David Palmer of The Campbell Palmer Partnership, did sound a small warning bell. As with any software package, it is important for the users to think about real-world issues too. Mr Palmer, a consulting engineer who uses simulation to analyse energy usage in existing buildings, told a cautionary tale about a factory used by textile manufacturer. The roof was old and needed to be refurbished, and the building often overheated. Upgrading the roof would introduce additional insulation (to meet current Building Regulations standards) and that would make the overheating problem worse. Simulation using the client’s data suggested that air-conditioning - at a cost of some £100,000 - was the only solution. But a quick look outside revealed that, of the 125 fans on the old roof, only four were working properly. It turned out that the fans had not been maintained for decades: no wonder the factory was overheating! Once the true facts are revealed, the simulation could be re-done, and the model proved to be correct.
Learn more:
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• | Download Brian Spires’ presentation from http://www.cibse.org/conferencepapers/ (session 7a) |
| • | The case described by David Palmer was a Design Advice consultation under the government-funded Action Energy scheme |
| © Melanie Thompson 2003 | |
The little building with a lot of features
We read a lot about large-scale “sustainable” construction schemes, but 80% of buildings in the UK are “small”, so let’s hear it for a little building that packs a big environmental punch.
The new Environment Centre at Skelton Grange in Leeds is owned by the British Trust for Conservation Volunteers (BTCV). Completed in June 2003, it is a teaching space, mainly for primary school children, with an office, workshop, kitchen and toilets.
Matthew Hill, Energy Consultant at Leeds Environmental Design Associates, explained to the CIBSE/ASHRAE Conference that the client was determined to use the building as a demonstration of its environmental credentials. The design team used this, and the need to accommodate movement of groups of people into and out of the centre, as the main drivers behind the initial design concept. They decided to use an unheated “buffer space” in the building to act as a passive solar collector, a draught lobby big enough to accommodate 30 children, and a plant conservatory. They also chose a pre-engineered, modular timber-frame building, which minimised on-site waste and made good use of natural resources. They then incorporated:
|
• | a small wind turbine |
| • | roof-mounted photovoltaics and evacuated-tube solar panels | |
| • | a ground-source heat pump to supply under-floor heating | |
| • | argon-filled double-glazing with a soft, low-emissivity coating | |
| • | a rainwater harvesting system to supply toilet cisterns | |
| • | high levels of insulation - phenolic foam for the walls and “IsoGras” (made from grass cuttings) for the floor and roof (all originally specified as “Warmacell” shredded newspaper, but lack of registered installers forced the change). |
The design team was well aware that renewable energy sources cannot be simply “bolted on” to a conventional design to make a building sustainable; they need to be fully integrated with other systems, and this demands an analysis of all energy used and energy generating equipment to assess their impact on the prospective annual energy balance. This includes usage often overlooked by services engineers such as passenger lifts, maintained emergency lighting, kitchen equipment, and even fire alarms.
This integrated approach proved particularly important when it came to the heat pump. It was important to achieve a high co-efficient of performance, and the team took full advantage of two site features to maximise the benefit of the system. First, using adjacent land as a “leachfield” for drainage meant one area of land would be kept moist (providing improved heat transfer). Second, there was a 275-kV underground cable feeding West Leeds running across the site. The cable owners gave permission to the team to install heat-pump pipework 50 cm adjacent to this cable, so that it could benefit from the heat generated by the cable resistance.
The 2.5-kW wind turbine, sited 100 m from the building on a 9-m mast is predicted to provide 3500 kWh a year; and a 2.0-kWp photovoltaic panel array fitted on the south-facing roof will provide approximately 1520 kWh per year.
Although the design raised some cost issues, construction methods helped to keep down costs. The pre-engineered building system allowed, for example, electrical containment in walls to be fitted within the factory-assembled modules, significantly speeding up installation on site.
Learn more:
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• | Download Matthew Hill’s presentation from http://www.cibse.org/conferencepapers/ (session 3a) |
| • | Visit http://www.leda.org.uk |
| © Melanie Thompson 2003 | |
