“No ka wsiemu privikajet czelowiek” – is the first sentence in the Chekhov book. Years ago, when I have already mastered the letters used by Greeks and Russians and I started to learn the language, it took me almost ½ a day to translate the first sentence. To all things human being becomes accustomed, says the sentence but why is there the word “No”. Does it mean that human can become accustomed to only some things not the others? The next day I got through a ½ page and so my understanding was increasing until after some months of work I was able to read technical books in Russian. (You may not know that building physics was written first in Russian and much later in German and I was decided to study this new discipline of science from the source). A few months later I understood that the role of the first “no” is simply an emotional reinforcement. So, this my introduction to the fact that emotions are part of our life and part of our judgements.
It also helped me to understand that all young people react stronger to emotions than older people and having less experience in judgement they often assume that all “green” actions must bring about the sustainable future. While the term “green buildings” has become a buzzword for environmentally driven impulses it is, however, not equivalent with the term sustainability. To make this discussion more focused I will call the contrast between green actions and sustainable buildings as the “paradox of sustainability”. Wiki encyclopedia says: A paradox is a statement which seems contradictory yet suggests a truth. An example of one can be found in John Donne's "Death Be Not Proud" in which the author states that death has no right to be proud, for it is merely a slave to wars, murder, accidents, etc. The poem goes on to say that while humans do not truly die but only experience a "short sleep" before eternity, death is the only thing to die once nothing is left (as everything else has already ascended to a higher state of existence). The last line "Death; thou shalt (will) die" in this classic poem is a paradox.
Figure 1, quoted from Mattock[1] provides the definition of sustainability.
[1] Chris Mattock: building scientist, engineer and teacher; works in British Columbia and various places in China.
Figure 1: Definition of sustainability (From Mattock)
In Mattock’s presentation, technology is linkage between society and economy. Perhaps Confucius inferred relation between buildings and society years ago when he said “walls reflect culture”. So if we follow the ASTM E2114 definition of sustainability:
“a building is that provides the specified building performance requirements while minimizing disturbance and improving the functioning of local, regional, and global ecosystems both during and after construction and specified service life”.
We may see a broader picture in which technology has linkage with all three elements of sustainability. Why is there a paradox when dealing with the sustainability? In my opinion, the paradox of sustainability is that
"to design and build sustainable buildings one must have a lot of experience in the balance of ecological, social and economic considerations with a proven construction technology and to master construction technology one must design or construct many sustainable building whose performance is proven by monitoring for at least one full year."
With other words, it is not enough to claim computer model calculations but the monitoring of the field performance (at least the energy efficiency) must be the basis of accepting construction technology that has already been examined from ecological, social and economic points of view during the design.
Effectively, the paradox of sustainability requires closing the circle of a design by a verified field performance. The latter requirement may appear trivial but it took us a lot of social pressure on a leading US “green building” programs to introduce mandatory monitoring of the energy efficiency. We considered it of the paramount importance because in the 2007 US survey, 41% of all respondents defined a green building as one with a specified percentage of green materials and 46 % stated that green buildings must follow criteria established by a national program.
Another term, namely “high performance building” was defined in the US Energy Policy Act of 2005 as follows:
The term “high performance building” means a building that integrates and optimizes all major high-performance building attributes, including energy efficiency, durability, life cycle performance, and occupant productivity.
Expanding this to all buildings we could replace the words “and occupant productivity” with words “indoor environment, occupant well being and productivity”. Yet, for the highly technical people, every building must address all those aspects of performance. Unless the statement of building objectives states otherwise, every building should be treated as the high performance building.
Evaluation of systems not materials
It is important to place emphasis on performance of the whole building and built assemblies instead of emphasis on materials used in those assemblies. We realize that dealing with materials is easier. Building codes and standards always ascribe a specific function to a specific material because this is the only way that a prescriptive code can work. We have WRB, water vapor retarder, air barrier, thermal barrier (fire), rain-screen, where functions and materials are mentally coupled. But one material, e.g. closed-cell spray foam, can also function as insulation, a rain-screen, WRB, water vapor retarder or air barrier.
The outcome of an architectural design is modified by interactions between different materials and the trades involved in installing them in an assembly. Architectural design and construction are holistic processes that involve highly specialized people – how should they collaborate during this process? This aspect of design is so important that we stress the importance on mock-up testing and the continuous QA and/or commissioning as separate activities in the construction process. This is to ensure that the design concept is buildable and that all the trades learn what they must do for ensuring the required building performance.
So far we have established that the future belongs to green buildings. Let us now review the critical components of the complex called, for simplicity, the “green value” of a building.
Key components of “green value” during the design and construction of buildings
The list of typical components of “green value” includes:
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Design for durability
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Design for energy efficiency and efficient use of material
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Separation between ventilation/air distribution and heating/ cooling systems
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Integrated hot water systems
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Review and if possible increased use of day lighting
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Improved indoor environment (with view to occupant health and productivity)
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Greater design flexibility, i.e., lower costs associated with changing space configurations
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Design from cradle to cradle, i.e., considering if the existing components can be used in the next generation buildings and re-use of materials in building enclosure systems
3. Design to the passive house standards (design must be efficient enough to justify economic use of renewable resources)
- Use of adequate tools for performance evaluation of building enclosure
- Improve control of inter-zonal and interstitial air flows
4. Building and testing the mock-up of building enclosures for commercial buildings
5. Using the commissioning process as a part of the design and construction process (from design objectives, through the construction and post occupancy tests)
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Trouble shooting study of design drawings is the first step in commissioning
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Testing air flows during construction
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Testing air quality of occupied space (after occupancy on working level)
Number one in the green value complex is the issue of durability (long-term performance). If one can extend the service life of a building, say by 20% longer than a typical construction, one reduces the annual costs. One can postpone the use of materials needed for replacement of the building so that materials and energy can be used for other productive means and for rehabilitation of existing building stock. In this process the direct savings on replacement materials and energy provides a multiple effect that may be compared to injecting 3 to 5 times more money into the local economy.
The second most important consideration is to increase all possible passive energy efficiency measures that lead to energy savings before progressing to (active) energy generating measures. The passive measures that are often neglected, even though they offer the most value for the invested money, are (Pope[2]):
1. Simple building shape and mass placement integrated with air re-distribution measures (saves capital and energy)
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Increase airtightness (cost little, saves lots)
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Increase insulation values and reduce thermal bridging (costs but saves energy)
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Reduce window area (saves capital and saves operating cost)
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Improve windows and wall-window interface (costs capital but saves operating cost)
The above may serve to produce a list of additional requirements, as follows:
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Use solar preconditioning of ventilation air
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Use geothermal preconditioning of ventilation air
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Use solar hot water heating
These are requirements are followed by other, more complex technical measures ranked for their energy saving potential:
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radiant or hydronic heating and cooling
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heat and energy recovery ventilators
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diagnostics for malfunctioning of a system or component in service
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dedicated ventilation system (direct outdoor air and air redistributing system)
In short, we stress that highly insulated, airtight building enclosures are a pre-requisite for the next generation of HVAC and lighting systems. Those measures can dramatically reduce thermal loads which in turn would encourage the use of the distributed HVAC. Locally operated small exhaust fans in each room are becoming popular in some European countries.
One can observe a trend for building enclosures to become multi-functional. Dynamic envelopes can be used to pre-heat or pre-cool indoor air; and by using filters and dehumidifiers these enclosures can modify the indoor environment. Advances in glass and window technology permits use of increased day lighting. With reduced thermal loads several technologies previously discarded in research are becoming more economically viable. Those include effects of thermal mass and phase change materials – even though these effects are climate dependent – they are coming back as significant improvements in the technology mix.
Effectively we can distinguish three stages in design of low energy buildings:
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Follow the passive house standards (development started by Prof. Feist and Adamson more than two decades ago)
2. Incorporate solar thermal collectors and geothermal energy sources with physical storage of thermal energy
3. Decide what fraction of PV (photovoltaic) will be constructed initially (the remainder will be done later during the service life of the building)
Conclusion
If it is not in equilibrium with social and economic considerations the green action is still not a sustainable solution.
[1 Chris Mattock: building scientist, engineer and teacher; works in British Columbia and various places in China.
[2] Steve Pope – a presentation from the National Resource Council of Canada to Ottawa BEC, May 20, 2008