‫ە‬Research trends and resultsStudy on light environments in LCCM housing and lighting
energy reduction effects
MIKI Yasuhiro, Senior Researcher
Residential Environment Planning Division, Housing Department

Research trends and results(Keywords) LCCM housing, daylighting, artificial lighting

1. Introduction
LCCM housing (“Life Cycle Carbon Minus”
housing) has been proposed as “housing that creates anegative (“minus”) CO2 balance throughout its long
lifetime, including CO2 emissions during construction,by striving to reduce CO2 as much as possible during
construction, use and demolition, and by creating
renewable energy using solar panels and the like” 1). To
study this LCCM housing, a joint research organization
called “Research on Zero Energy Housing” has been
established under an initiative by the Building
Research Institute, and the National Institute for Landand Infrastructure Management is taking part in this.
The author has compiled a report on light environmentsin this housing as well as its lighting energy reduction
effects, and gives a brief outline of the content here.
2. Study on the light environment of LCCM housing
When studying the light environments of LCCMhousing, the author first proposed a concept2) based on
knowledge of light environments obtained from low
energy housing with validated efficiency (a type ofenergy-saving housing), among others, then enlisted
the collaboration of academic and professional experts
in simulating daylight lighting and lighting designers
for artificial lighting. Bearing in mind that daylighting
could conversely cause an increase in lighting
consumption, since the introduction of daylight causes
glare or the room interior is felt to be dark in contrast to
the brightness around the windows, we used the highly
precise daylight environment simulation software“Radiance” in our study. We mainly studied the impact
of south-opening louvers at different time and seasons,and taking account of the daylighting simulation results,
compared the results to the initially drafted plan andincorporated them in later versions of the plan (Fig. 1).
As for artificial lighting, the study was based on therationale of distributed multiple-light arrangement
harnessing the characteristics of LEDs, i.e.
compactness and long life2). We obtained a working
brightness in accordance with specific domestic
activity by using distributed light, even if the averageluminosity was low, and planned balanced lightingwith less contrast and no sense of discomfort.

Fig. 1 Daylighting simulation example
3. Study on the lighting energy reduction effect ofLCCM housing
The total energy consumption by artificial lighting in
LCCM housing was around 480W, and the annual
lighting power consumption was around 530kWh(primary energy consumption around 5.1GJ). Bearing
in mind that, with LED, CO2 emissions when in use
account for almost the whole of the life cycle, it should
be possible to reduce environmental load while
adequately forming light environments including
lighting effects.
4. Conclusion
A demonstration version of LCCM housingreflecting the results of this study will be built inside
the Building Research Institute. It will be completed inFebruary 2011, and after completion, verification trials
reproducing the living conditions of residents will beheld. In future, we plan to measure artificial lighting
consumption volumes and take actual measurements oflight environments.
References
1) BRI NEWS Vol. 52, Advanced eco housing for thelow-carbon society: LCCM housing
2) Y. Miki, Proposal of distributed multiple-lightarrangement using small high efficiency lamps,
National Institute for Land and InfrastructureManagement, Annual Report (2005), 84-85