Daiwa House Constructs Energy-saving Office Building

2014/04/15 14:51
Kiyotaka Nakanishi, Nikkei BP CleanTech Institute
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Daiwa House Industry Co Ltd announced that its office building having an environmentally-conscious design has been completed April 11, 2014, in Toyoma City, Japan.

The building, "Daiwa House Toyama Building," has been built on the site of the former "Ginrin" Japanese restaurant. And the Toyoma branch of Daiwa House will have an office in the building. The building was selected for the "Net Zero Energy Building Verification Project," for which Japan's Ministry of Economy, Trade and Industry called for proposals from the public in fiscal 2013.

A total of 24.5kW of solar panels (20kW on the roof and 4.5kW on walls) were installed. Also, Eliiy Power Co Ltd's 15kWh Li-ion rechargeable battery was employed for peak shaving and BCP (business continuity plan).

In normal situations, the battery is used to store nighttime power, and the stored electricity is used for peak shaving during daylight hours. In case of power outage, the battery stores solar electricity so that electricity can be used during nighttime hours. As an exterior material, Daiwa House employed a multifunctional exterior frame on which plants can be grown.

According to Daiwa House, it is possible to reduce CO2 emissions by about 50%, compared with normal buildings in 1990, by (1) combining the "active control" and "passive control" and (2) utilizing BEMS (Building Energy Management System) to optimally control power consumption. The active control makes use of solar power generation facilities, storage batteries, LED lighting equipment, etc. And the passive control takes advantage of natural energy with window shades using light-diffusing films, which enable diffused transmission of direct light from the sun, and windows equipped with dimming films.

Daiwa House evaluated the building based on the "CASBEE New Buildings 2010" standard, which is for evaluating buildings for their overall environmental performances, and concluded that it was equivalent to the "S (highest) rank."

Daiwa House has been promoting the "Smart Eco Project," which is aimed at reducing the amount of CO2 emitted through the operation of an office building to zero by 2020. As a first step toward that goal, the company commercialized the "D's Smart Office" environmentally-conscious office, which enables to cut CO2 emissions by up to 50%, in July 2011.