By: Architectural Institute of Japan (AIJ)
Reported by: Sheau-Chyng Wong (M2)
Chapter 2 / The Vision and How to Make and Use (part 1)
Summary
Chapter 2-1, comprising six sub-chapters, introduces the various concepts on integrating buildings into their natural and urban environments.
Bioresource Sciences Professor Itonaga starts the chapter providing backgrounds and definitions of ecosystems and ecological design. The concept of Compact City is then introduced by Sato as an ideal “to construct the urban elements in an efficient, organic way, but within compact limits”. The motives for constructing Compact Cities could be threefold: to reduce energy consumption; to revitalize traditional city centers; to restore cities to a human scale, i.e. to promote better lifestyle at a local level. Two examples of Compact City are given; Utsunomiya and Tsuruoka, both of which are old castle towns in Japan.
Chapter 2-2, which focuses on ‘how to conserve energy’, begins with an emphasis on the importance of designing buildings that are “in tune with the local climates” by Prof. Sakamoto. In particular, buildings that are well adapted to local climatic conditions reduce the need for external heating and cooling, thus saving energy. In this regard, greater attention should be given to traditional houses, which have typically evolved and adjusted to the native conditions; even though they may not meet the latest performance standards, the building styles or materials could provide valuable lessons for the employment of ‘passive design’.
In the subsequent sub-chapter, the linkage between urban environments and heat island phenomena was discussed. According to Professor Hoyano (of Tokyo Institute of Technology!), the main causes of urban heat island phenomenon are: changes in ground cover, massive energy consumption and air pollution. Several examples, using thermographic images, are then presented to demonstrate that: i) the surface temperature of urban areas with little greenery are much higher than the atmosphere; ii) the fluctuation in surface temperature of green areas is very low from day to night; and therefore, iii) greeneries could help mitigate urban heat island effect.
Professor Yoshino provides a brief overview of the status of housing energy consumption in Japan before presenting the energy conservation measures for homes. The three classifications of energy-saving measures are: i) improvements in building design, e.g., sufficient thermal insulation, optimal use of sunlight; ii) improvements in efficiency of mechanical equipment; and iii) lifestyle changes, e.g., turning off lights between use.
Thereupon, Prof. Sakamoto introduces the Japan’s energy conservation standards for housing and non-residential buildings. Both standards were put into effect in 1980 based on the Energy Conservation Law (or Law concerning the Rational Use of Energy) which was enacted a year prior. The standards were subsequently revised in 1992 and 1999. Due to major revisions to the standard for housing, the 1999 version was called the “Energy Conservation Standard of Next Generation for Housing”. The table below outlines the main energy performance indicators of the ‘Next Standards for Housing’ and the Energy Standards for Non-residential Buildings.
Table 1: Energy Performance Indicators of Energy Standards
| Next Standards for Housing | Energy Standards for Non-residential Buildings |
1) Energy-saving:
2) Air-tightness:
3) Provision of Dew-proofing Layer for Walls 4) Provision of Ventilation system |
1) Perimeter Annual Load (PAL)- To measure thermal load generated from perimeter zones of a building by improving the ‘skin’ design.2) Coefficient of Energy Consumption (CEC)- To measure energy performance of air-conditioning equipment, hot water supply system, ventilation system etc. |
The energy consumption of a building can also be examined based on its life-cycle stages, as explained by Ikaga. Using a typical office building as an example of how energy is consumed during each life cycle stage: 1) Design Stage – energy is consumed in the design office and staff transport; 2) Material Production Stage – energy is consumed in gathering materials, manufacturing and transportation, and depends on material type and site; 3) Construction Stage – energy is consumed in the assembly of construction parts and business activities; 4) Operational Stage – energy is consumed for direct energy use inside buildings (air-conditioning, lighting etc.) and building maintenance, and could occupy up to 60% of the total building life cycle energy; 5) Refurbishment Stage – energy is consumed for replacement of equipment and exterior/interior finishes; 6) Disposal Stage – energy is consumed in reclaiming/recycling of used materials and their transportation.
Ikaga and Kodama close this sub-chapter by introducing the concept of ‘active design’ and ‘passive design’. ‘Active design’ generally indicates the utilization of artificial technologies such as air-conditioning equipment and lighting. Strategies to reduce energy use and improve indoor environment include variable-air-volume air-conditioning system, thermal storage, automatic lighting control system, and automatic escalator operation system. In contrast, ‘passive design’ refers to “the system that performs heating, cooling and lighting by utilizing the flows of natural heat and light in a building… objective is to design a building as a whole and its parts, conforming to the local characteristics of the climate”. Strategies of ‘passive design’ include passive solar heating, passive cooling, daylighting and passive ventilation. As opposed to ‘active design’ which typically results in substantial energy consumption, ‘passive design’ utilizes the natural potentials of the local environment therefore lessening the needs for artificial mechanical systems.
Reporter’s Own Thoughts
The Energy Conservation Law of Japan apparently does not carry any specific penalties or legal obligations, but the author remarks that the energy conservation standards are making overall positive impacts. In my opinion, it would be quite difficult to assess or justify the said impacts, particularly from the perspective of the users, designers, builders or community in general. This rather lax attitude towards ‘law enforcement’ is quite different from that of most developed countries, in which a law is usually accompanied by strict penalties and regulatory systems.