Buildings have a significant impact on energy use and the environment. Commercial and residential buildings use almost 40% of the primary energy and approximately 70% of the electricity in the United States (EIA 2005). The energy used by the building sector continues to increase, primarily because new buildings are constructed faster than old ones are retired. Electricity consumption in the commercial building sector doubled between 1980 and 2000, and is expected to increase another 50% by 2025 (EIA 2005).Buildings have a surprisingly profound impact on our natural environment, economy, health, and productivity. In the United States, the built environment accounts for approximately one-third of all energy, water, and materials consumption and generates similar proportions of pollution.
Integrated building thermal and airflow modeling is an enabling technology for the design of high energy performance and green buildings.
Buildings represent major investments in the future delivery of further and higher education. We dedicate money, time, creativity and many natural resources to their construction and ongoing maintenance.
Buildings provide shelter for human activities so that society can prosper; and good buildings represent the best that a generation can achieve in terms of skill and beauty.
Buildings can also be significant contributors to global problems such as polluting emissions, climate change and the depletion of natural resources. It is in this arena that we must focus our greatest skill, knowledge and creativity when making the longer term investment decisions that buildings demand.
The sustainable design and construction of both new and refurbished buildings can minimise negative impacts through, for example, more efficient use of energy and water, or the utilisation of renewable energy and materials. All universities and colleges will eventually do this – driven by a mix of rising energy costs, tightening regulations and changing stakeholder expectations.
Experience shows that these benefits can be achieved without, or with minimal, increases in capital costs if:
- Sustainable construction processes and practices are embraced from the start as a key performance requirement; and
- The design and procurement process is managed effectively – with clear responsibility for, and timely decision-making to meet, all the institution’s long-term requirements, including sustainability.
Designing and sizing building systems and equipment on the basis of well-understood needs, and careful modelling of their interaction, rather than ‘rule of thumb’ assumptions, can result in reduced capital and operating cost, easier maintenance, and lower energy consumption.
Optimised use of daylight, in bright, airy, buildings with views of the outside, has positive psychological effects on most users; creates a sense of connection with the natural world and the diurnal cycle that has measurable effects on learning outcomes in teaching rooms and libraries; reduces eyestrain and other adverse effects of artificial lighting; and has low electricity consumption for illumination.
- Use of natural ventilation, rather than mechanical ventilation or air conditioning, reduces the costs and environmental impacts of energy consumption; and the maintenance burden associated with complex equipment.
- Maximum use of natural, sustainably produced, materials reduces environmental impacts; has positive psychological effects on most users; and avoids the harmful emissions associated with some man-made building materials, finishes and cleaning materials (e.g. in adhesives, solvents and plastics).
- A high level of metering and monitoring highlights opportunities to reduce energy and water consumption; identifies problems in building operation; and can provide rich information for use as a teaching resource in undergraduate and specialised postgraduate courses.
High performance, well-designed, buildings should synthesise all aspects of how a building functions, including aspects usually associated with ‘green issues’ and ‘sustainability’. They are achieved by using:
- Structures and layouts that deliver highly productive and adaptable working conditions;
- Practices and materials that are designed to safeguard occupants’ health and well being;
- Very low energy solutions and low carbon resource inputs;
- Low water consumption systems; and
- Effective use of scarce material resources.
The term ‘green’ building can be interpreted in many ways, and can be mistakenly associated with buildings that are more expensive to build, or buildings which emphasise environmental aspects of design at the expense of other, equally important, issues such as functionality and aesthetic. To avoid such confusion, for the purposes of this guide, the alternative term ‘high performance building’ is used in order to emphasise a more holistic attitude to design that incorporates sustainability at an intrinsic level; and to focus attention on the following key features:
- Firstly, the importance of adopting a holistic design process that optimizes the performance of all the key features of the building with the result that any environmental or ‘green’ features are fully integrated and do not conflict with other design aims, such as capital and operating costs, comfort, high utilisation and flexibility;
- Secondly, avoiding the risk of delivering a ‘low performance building’ with the associated risk of dissatisfied staff and students, high energy and water costs, lack of attention to ‘future proofing’ in terms of adaptability and flexibility, and high maintenance costs; and
- Thirdly, redressing the perception that energy and environmental issues are technical issues that can be addressed at a late stage in the design process.
Experience shows that the cost of dealing with sustainability issues effectively rises with time. By considering them strategically, and as key design requirements, costs can be minimised and opportunities for associated benefit maximised. This approach also firmly places sustainability at the centre of a design process that focuses on high performance over the whole life of a building. Over this period, the salaries of occupants, and other operating costs, will significantly outweigh the initial capital expenditure. Improved sustainability therefore creates very large whole life benefits from:
- Lower rises in utility costs; and
- Lower sickness and absence rates, improved occupant productivity and performance (arising from naturallighting and ventilation, and higher indoor air quality through use of toxin-free materials).
A ‘whole life cost’ perspective of this kind avoids the common trap of missing large opportunities for long-term financial and environmental benefit because of a short-term focus on relatively small amounts of capital spend.
A research study undertaken by the US Green Building Council concluded that: “Many green buildings cost no more to build – or may even cost less?- than conventional alternatives because resource-efficient strategies and integrated design often allow downsizing of more costly mechanical, electrical, and structural systems.
The biggest barrier to specification and delivery of high performance buildings is the perceived lack of connection between capital and revenue budgets. Usually the building’s ‘prospective occupiers’ (e.g. a university department) are focused on getting the most, and best, accommodation available for a given capital sum. Running cost responsibilities fall to another budget, which is usually the responsibility of the Estates Department, and these are therefore often less ‘visible’. This explains why environmental measures with reasonable payback periods are often not implemented.
Rapidly rising utilities costs are major items of controllable expenditure. Hence, unexpected variances from a projected budget can have significant implications for financial performance and flexibility, especially when budgets are tight. By reducing overall consumption of energy and water, high performance buildings reduce the scale of these risks. They also avoid the risk of future associated difficulties and / or the need for costly retrofitting if new regulations are applied to existing buildings – as is increasingly the case as Governments try to meet their long-term targets for reducing carbon dioxide (CO2) emissions.
All utility infrastructure has a maximum capacity, and in most cases this is far above predicted actual demand. Hence, incremental increases in demand within a building envelope appear to require very?low capital investment, often involving only some extra cabling or pipe work. However, once maximum capacity is approached, further expansion can be very expensive. Additional infrastructure will be needed, such as construction of new electricity sub-stations, and upgrading of transmission cables to provide adequate electricity supply. High performance buildings reduce the risk that a need for additional, and expensive, utility infrastructure will constrain future expansion. This point is especially important for refurbished buildings, which should aim to work within the utility ‘footprint’ of the existing structure.
The building avoided high profile green features in favour of a simple but effective, and well implemented, design which includes:
- A narrow plan, allowing high levels of daylight to reach all spaces;
- High insulation, with 200mm of insulating material in wall cavities, and triple-glazed, argon-filled,windows (that open when ventilation is needed);
- Detailing which avoids air leakage and cold bridging (and whosesuccessful construction required clearexplanation to site workers, and detailed checks before being concealed);
- Use of concrete hollow core floor slabs, and a Termodeck heating and cooling system, to stabilize internal temperatures;
- External and integral blinds in the windows to minimise solar gain in the summer; and
- Pressure testing for air leakage, prior to occupation.
The steps of Integrated Design Process:
- Consider right building size and use;
- Consider orientation, form, thermal mass h
- High-performance building envelope;
- Maximize passive heating, cooling, ventilation and use of day-light;
- Install efficient systems to meet remaining loads;
- Use renewable energy sources as much as possible;
- Ensure that individual devices are as efficient as possible; and
- Ensure proper commission of systems
A net zero-energy building (ZEB) is a residential or commercial building with greatly reduced energy needs through efficiency gains such that the balance of energy needs can be supplied with renewable technologies.
A good ZEB definition should first encourage energy efficiency, and then use renewable energy sources available on site.
- Net Zero Site Energy:
A site ZEB produces at least as much energy as it uses in a year, when accounted for at the site.
- Net Zero Source Energy:
A source ZEB produces at least as much energy as it uses in a year, when accounted for at the source. Source energy refers to the primary energy used to generate and deliver the energy to the site. To calculate a building’s total source energy, imported and exported energy is multiplied by the appropriate site-to-source conversion multipliers.
- Net Zero Energy Costs:
In a cost ZEB, the amount of money the utility pays the building owner for the energy the building exports to the grid is at least equal to the amount the owner pays the utility for the energy services and energy used over the year.
- Net Zero Energy Emissions:
A net-zero emissions building produces at least as much emissions-free renewable energy as it uses from emissions-producing energy sources.
The other way to market penetration.
- ventilation and use of day-light;
Use renewable energy sources as much as possible; Some countries have set zero targets for building codes:
- Denmark: all new buildings must be plus energy plus strict reductions of consumption
- France: all building public buildings plus in 2020
- UK: residential buildings zero carbon in 2016 and ?commercial / public buildings in 2018/19
- European Union: all building codes must be close to zero in 2020 (EPBD directive)
- California energy commission: residential buildings zero in 2020 and commercial in 203
Conclusion Building Codes
- Passive design and zero energy buildings play central role in the work to realize the large potentials.
- Such buildings must be supported by active policies.
- Innovative building code is a central policy.
- The whole European Union is on this track.
- But will all countries implement in time ?
The basic steps of Integrated Design Process (IDP):
- Consider right building size and use;
- Consider building orientation, form, thermal mass;
- Specify a high-performance building envelope;
- Maximize passive heating, cooling
- Install efficient systems to meet remaining loads;
- Ensure that individual energy-using devices are as efficient as possible, and properly sized; and
- Ensure proper commission of systems & devices
- National Trends and Prospects for High-Performance Green Buildings, Based on the April 2002 Green Building Roundtable?And Prepared for the U.S. Senate Committee on Environment and Public Works By the U.S. Green Building Council
- Zero Energy Buildings:?A Critical Look at the Definition: P. Torcellini, S. Pless, and M. Deru
- National Renewable Energy Laboratory
- Buildings energy efficiency in global climate perspective
US Passive House Conference
5-7 November 2010, Portland
IEA, International Energy Agency, Jens Laustsen