Head on this page.
Head on this page.
The Japanese government announced the target of reducing greenhouse gas emissions by 25% from the 1990 level by 2020*1. In response to this announcement, the Ministry of the Environment started projects in 2010 to publicly seek and support projects that will use strategies to effect a 25% reduction in CO2 emissions in a local area, aiming to revitalize and create local areas that have less environmental impact. Tokyu Corporation applied one of these "Challenge 25 Campaign" projects, and was authorized by the ministry. The company selected Jiyugaoka Station, located in the south of Tokyo’s Meguro Ward, as its field of operations. The station is shared by the Tokyu Toyoko and Oimachi lines, and is daily used by about 140,000 passengers.
We installed 1,174 highly efficient LED lighting fixtures on the platforms and in the concourses, station administration offices and travel center. In the passenger zone lighting plan, we repeated, thorough energy-saving simulations using "Feu," our spatial brightness-level index, to evaluate the luminous environment. Additionally, for platform lighting, we developed a special fixture equipped with a light-control system that enhances the brightness of platforms while controlling glare that effects train conductor. A new structure with a ceramic substrate was adopted for the LED used in this project, thus achieving a high quality light environment.
We have introduced a lighting control system that allows the brightness and hue of concourse lighting to be flexibly controlled according to a time schedule. It automatically controls the luminance and color temperature of LED lighting according to the biological "circadian" rhythm of humans. A stark white is the basic tone in the morning, while a warm sedate tone is created in the evening onward. We have aimed to achieve comfort and eco-friendliness by creating station lighting that matches each situation.
Organic electroluminescence (EL) lighting fixtures were installed as general lighting for the station facilities. This was the first practical installation in Japan*2. Because an organic EL lighting device is very thin and is a surface-emitting light source with low brightness, its widespread use as an alternative to fluorescent lighting is highly anticipated. Although its performance does not currently exceed that of an LED, we plan to replace the current lighting with more upgraded organic EL lighting in fiscal year 2013.
At the platforms of Jiyugaoka Station, we have introduced a highly functional lighting control system that is tied into illumination sensors and proximity sensors in addition to a yearly scheduled timer control. This lighting control and lighting improvement have led to a reduction in power consumption by a total of approximately 400,000 kWh per year. As for CO2 emissions, we aim to reduce emissions by approximately 131 t-CO2 per year*1.
The aim of this project is to change the concept of urban development as well as people's perceptions, by focusing on stations where people gather, in order to realize a low-carbon society. In the future, we will carefully implement energy-saving measures by tuning up the control system that we have introduced. We will create more comfortable, eco-friendly lighting environments for stations, further promoting the initiative to "achieve comfort and eco-friendliness" at stations nationwide.
This is a new lighting index that quantifies the brightness that people sense in a space. Currently, the lux, a unit created 120 years ago, is used as the standard measure of lighting brightness. It indicates the brightness of illuminated plain surfaces. In general, it expresses the brightness of horizontal surfaces such as floors or desks. However, when we view a space, we not only look at the floor but also the ceiling or walls. The Feu is an index that quantifies the brightness that we sense in a space by comprehensively assessing the effect of the light that illuminates the walls or the light reflected from the floor.
“Circadian” means “approximately a day” in Latin. “Circadian rhythm” is a term used to describe how the physiological characteristics (deep body temperature, the autonomic nervous system and the endocrine system) and behaviors of living things change according to a daily cycle. For example, the internal functions of living things, including humans, change over an approx. 24-hour cycle in time with the day-night alternation caused by the Earth’s rotation. If we create a lighting environment that does not disturb our biological rhythm, we will be able to provide a physically and psychologically stable environment.
Since organic electroluminescent (EL) lighting devices are very thin and act as surface-emitting light sources with low brightness, there are high hopes for their increasing use as an alternative to fluorescent lighting. Applications to signboards or displays are anticipated, since EL lighting devices can be bent easily. However, EL lighting, since it has low brightness, is not yet a good replacement for LED lighting. Performance improvements are required, such as for light flux and product life cycle.
Return to Top