ARCH 501SIMA NABIZADEHSTUDENT NUMBER: 096033

THE GLOBAL WARMING PREVENTION STRATEGY FOR

HOUSING IN JAPANBy Ken-ichi Ishida

Open House.Vol2, N3, page12 t0 24

Japan signed the Kyoto Protocol to reduce the nation`s carbon dioxide (co2) emission by 6% below the 1990 level.

The housing industry is no exception being required to reduce the negative impact of the housing delivery on the environment .

Today , all newly-constructed detached houses being built by Sekisui House Ltd. are designed to alleviate the societal pressure, accompanied basically with the following techniques or technologies:

1-The reduction of energy use relating to air-conditioning by improving the houses `insulation performance to meet Japan's energy saving standard set in1999

2-The reduction of energy consumption that drives from domestic hot water by applying a high-efficient water heater

3-The micro-power generation by the installation of solar photovoltaic (pv) power generation system

4-The cooling effect achieved by tree shading

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN, By Ken-ichi Ishida

:Abstract

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

INTRODUCTION

An average energy consumption of a house in Japan is much less than that of the United States and European countries. specifically the heating energy consumption in Japan is only 30% of that in US and 20% in Germany.

The energy use for supplying domestic hot water is considerable ,Japan is experiencing the gradual expansion of the heating time and space in order to improve the house`s living comfort.

Domestic energy consumption profiles of Japan, the US and European countries selected(Japan productivity center for Socio-Economic Development 2004)

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

INTRODUCTION

There is a need for the homebuilding industry in Japan to establish strategies that help reduce the co2 emission in housing and achieve the Kyoto Protocol target.

Sekisui House Ltd. is known as the largest housing manufacturer in the world, producing 56000 houses annual where its industrialized building system is brought into effect.

The average life expectancy of a house in Japan is 30 years ,however, the industrialized houses are often designed to stay physically sound even over 100 years as the longer durability of housing environment.

In fact, the survey of the homes delivered by Sekisui House Ltd(1999) indicates that 70% co2 emission relate to housing operation and 30% derives from the construction and abandonment, when the lifespan is considered to be 30 years.

The company practices the co2 zero emission in the factory production and site construction; however, it admits that the actual co2 zero emission over the lifespan of housing may hardly be achieved without the user`s cooperation.

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

co2 emission reduction to the kyoto target

Fig2:The target of the co2 emission reduction

The investigation of energy use under the actual condition of detached houses built in 1990 and 2000 was conducted.

The house`s floor area, structure and thermal insulation are in to consideration while the energy sources.(fig2)

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

The market consciousness to global warming prevention

–The market consciousness to global warming –prevention:

–The public awareness of global warming has been increasing as it is often warned by mass media in Japan.

–However, this seems a little impact on homebuyers buying decision.

Public condition to cooperate in global warming prevention

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

The overview of ”Action Plan 20”

4:co2 emission ratio and measures according to usage 5:The schematic diagram of Action plan 20

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

co2 emission reduction percentage

–The simulation as to the house's operational co2 emission suggests that the combination of a high efficient boiler and a high thermal insulation leads homes to the drastic reduction of co2 emission and the achievement of Kyoto target.

6:The schematic diagram of Action Plan 20

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

Thermal insulation and air-conditioning

7:Thermal insulation applied to southern areas of Tokyo

8:Panelised wall structure equipped with thermal insulation material

Thermal insulation and air-conditioning

9:Hybird ventilation system10:Operational patterns of the hybird ventilayion

system

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN

Cooling effect by shading

14:The cooling effect by shading

15:Measurment of summer-day street temprature at 1 o`clock

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN111

Verification of co2 emission reduction effect

Table1 :( 1990,2000 and 2005 survey of energy sources in housing)

THE GLOBAL WARMING PREVENTION STRATEGY FOR HOUSING IN JAPAN111

conclusion

In this study the effect of energy sources and thermal insulation performance levels on the co2 emission reduction in housing operation was analyzed.

In short, homes need to be well insulated before costly advanced technologies that to some extent reduce the operational co2 emissions are applied.

The Action Plan 20 introduces a number of energy-efficient housing measures and it can be considered as a practical global warming prevention strategy for delivery of low-carbon housing that meets the Kyoto target in Japanese context.