WORLD Expo Shanghai turned 100 days old yesterday with attendance climbing as the temperature dropped after last week's heat wave.

More than 37.8 million people have visited the Expo site since it opened on May 1. Yesterday's attendance was more than 390,000, the second busiest day of this month.

But even with the temperature dipping to about 34 degrees Celsius, people still find themselves rushing into pavilions to enjoy air-conditioned environments after long waits in the sun.

Still, many are surprised to feel so comfortable in some pavilions at the Urban Best Practices Area as they don't use air conditioning.

The temperature inside the Hamburg Pavilion, or the Passive House, remains a constant 25 degrees Celsius, no matter how hot it is outside. It does this while saving up to 90 percent of the energy needed by ordinary buildings to maintain the same temperature.

This is achieved by a ground source heat pump, which lets heat flow in a natural way throughout the house via pipes, keeping the house cool in summer and warm in winter.

Liu Jing, 17, a student from Shanxi Province, told Shanghai Daily yesterday that it's not hot at all inside the Hamburg Pavilion. "It's amazing that the house can cool itself."

Besides the heat pump, the pavilion's windows are triple glazed to keep heat out during the summer and in during the winter.

While at the Eco home, Shanghai's UBPA case, visitors can feel the wind, indoors. The building's design took into account the direction of Shanghai's prevailing wind and certain windows will automatically open once poor air quality is detected.

Dense plants on walls, empty areas and the roof provide natural shading and prevent hot air from entering the home.

The home was inspired by an energy-saving building in Xinzhuang Industrial Zone in Minhang District.

The Eco Home is expected to become an "ordinary home" in about five years.

The Alsace Pavilion was inspired by the solar wall at Bouxwiller High School in Alsace, France. It uses solar energy to keep interior temperatures at a comfortable level with a waterfall helping to keep things cool.

The solar wall is controlled by computer, which responds to changes in the outdoor temperature and sunlightintensity.

• yesterday [´jestədi] n.&ad.昨天；前不久 (初中英语单词)
• passive [´pæsiv] a.被动的 n.被动性 (初中英语单词)
• constant [´kɔnstənt] a.坚定的；坚贞的 (初中英语单词)
• energy [´enədʒi] n.活力，精力；能力 (初中英语单词)
• maintain [mein´tein] vt.维持；保持；继续 (初中英语单词)
• province [´prɔvins] n.省；领域；范围 (初中英语单词)
• amazing [ə´meiziŋ] a.惊人的；惊奇的 (初中英语单词)
• account [ə´kaunt] vi.说明 vt.认为 n.帐目 (初中英语单词)
• industrial [in´dʌstriəl] a.工业的，产业的 (初中英语单词)
• interior [in´tiəriə] n.&a.内部地(的) (初中英语单词)
• computer [kəm´pju:tə] n.计算机；电子计算器 (初中英语单词)
• sunlight [´sʌnlait] n.日光 (初中英语单词)
• pavilion [pə´viljən] n.大帐篷；亭子 (高中英语单词)
• indoors [,in´dɔ:z] ad.在屋里 (高中英语单词)
• waterfall [´wɔ:təfɔ:l] n.瀑布 (高中英语单词)
• intensity [in´tensiti] a.激烈；强度；深度 (高中英语单词)
• automatically [ɔ:tə´mætikli] ad.自动地；无意识地 (英语四级单词)
• hamburg [´hæmbə:g] n.汉堡 (英语六级单词)
• triple [´tripəl] a.三倍的v.增加到三倍 (英语六级单词)
• prevailing [pri´veiliŋ] a.占优势的；主要的 (英语六级单词)