- Количество слайдов: 27
Building performance Nils Larsson, MRAIC Executive Director
Why should we aim high ? n The building and construction sector is the biggest single sector responsible for energy consumption, emissions and waste; n But it is also the elephant in the room - we are all so familiar with buildings, roads and bridges that they do not appear to be good prospects for reducing climate change effects; n The fact is that, in most countries, it is easy to reduce energy consumption in buildings by 40%; a reduction of 60% can be achieved with some work, and a good hard effort can reduce consumption and emissions by 75%; n A compelling reason for high performance is that there are no losers owners and operators have reduced operating costs and risks, designers have a new market, and occupants have healthier and more comfortable indoor environments; n The strongest argument in developed countries is that we must set a very good example to have credibility when developing countries are asked to control their emissions; n There is no option: we can and must begin immediately.
A practical definition of specific performance aspects relevant to GB and SB n n n Social and economic considerations Urban / planning issues Green Building n Sustainable Building n Fuel consumption of non-renewable fuels Water consumption Land consumption Materials consumption Greenhouse gas emissions Other atmospheric emissions Impacts on site ecology Solid waste / liquid effluents Indoor air quality, lighting, acoustics Longevity, adaptability, flexibility Operations and maintenance
Performance Levels Regenerative Bring ecosystems back to full health Sustainable No negative impact on ecosystems Green Substantial improvement in environmental performance Good Practice Performance levels achieved by top 25% Regulation Minimum performance according to regulation and/or industry practice Community scale Building scale To be explored High densities, mixed uses, mainly public transport & pedestrian oriented, green space Very high performance, feed electricity to grid Emphasis on higher densities, mixed uses, control of car, provision of public transport Best practice performance - 75% reduction from norms Community planning follows conventional suburban path. 50% reduction from norms (probably top 25% of current). Transport, water, sewer etc. seen as quite separate Some emphasis on energy performance, but not much else
Triage of existing building stock Existing building stock Viable for energy retrofit and located near public transport No intervention required or hold for later action Not viable for energy retrofit and located in low-density areas Demolish / dismantle High performance infill projects High performance energy retrofits Materials for re-use or recycling New high density and high performance projects
Energy consumption isn’t only from operations
The vicious circle Global mean temperature GHG Local ambient temperature A. C. heat rejection Power generation Cooling Increased indoor temperature Building indoor temperature / occupant comfort
CO 2 emissions by fuel type in the UK; note the high rate of emissions for grid electricity Source: UK Gov’t.
Specific factors related to performance n The main issue from a climate change perspective is greenhouse gas emissions that are generated from non-renewable fuel sources, over the life-cycle of the building or structure; n Some other performance issues, such as ecological impacts, water consumption, indoor environmental quality are also of high importance; n Performance varies widely within regions and within building types; n Actual performance is often significantly different from potential performance; n The most effective levers are sticks (regulations and financial penalties) and carrots (financial or other incentives); n The use of an integrated design process will foster system integration and can help to achieve goals; n Use of a rating system can tell the market of the achievement; n Operating efficiencies can be crippled by poor operating procedures.
Design and Construction is quick; Pain or Gain is long-term Risk and expense of initial investor Benefits and costs to future owners and occupants Developer / Owner 1 Owner 2 Pre-Design Construction Owner 3 Refit Owner 4 Owner 5 Demolition or Disassembly Refit O p e r a t I o n s Perhaps 20 generations of occupants ? 1 10 20 30 Years 40 50 60
Refer to following detail sheets
A smaller slice
Details of one element of integrated system effects: Part 1
Details of one element of integrated system effects: Part 2
It is easy to make bad decisions early in the process According to Jiang Yi, this design for the new CCTV building in Beijing resulted in the center of gravity of building being outside the main body, thereby greatly increasing the structural complexity and first cost. Also from Jiang Yi, this design for an Olympic stadium had “heavy steel consumption” for a movable roof and would cost 2 to 3 times more than similar stadia.
Which building performs well?
Many architects ignore the fact that each side of a building faces very different conditions
Unsuccessful solar control strategies
Problems in daylighting – bad lighting control or nonacceptance by occupants
This library in the UK is elegant but, according to the library staff, dysfunctional because of thermal stratification and noise transmission problems.
Progress in Dubai Source: Khaled A. Al-Sallal Dubai World Trade Center, 1979, 278 k. Wh/m 2 Emirates Tower, 2000, 560 k. Wh/m 2
This is the Canadian Dream of 10 years ago; now the house is much larger and the garage has room for 3 cars
Specific barriers to the widespread adoption of sustainable building practices n Limited market demand for high performance buildings; n Actual or perceived cost of building to a high level of performance; n Lack of simple funding mechanisms to pay for incremental performance; n Difficulty of measuring environmental performance in an objective and reliable way; n Increasing requirements for specialized skills and knowledge in the design process; n Skills deficits in small design firms; n Making bad decisions early in the design process.
A different approach: What if… n …key actors sat around the table to discuss alternatives and objectives before the concept design is developed? n …we could make use of the experience and knowledge of engineers, building operators and even users, early enough to influence the design? n …we developed at least one alternative design? n …we used simulation programs to predict how the designs will perform? n All of this is common sense, but rarely followed.
Contacts & Info n http: //www. iisbe. org n http: //www. sbis. info n Nils Larsson, [email protected] org