Keeping your cool at the Expo

It's hot and getting hotter. Shi Jing explores what pavilions and organizers are doing to keep the temperatures down.

Children play at a fountain inside the Expo Garden. Jing Wei / for China Daily

Weather forecasters are predicting the wet weather that Shanghai has endured the last few weeks will soon end. But with the end of the humid rainy season, will come the stifling and sometimes unbearable heat, which could cause problems for visitors at the Expo 2010 Shanghai.

Officials at the Expo Garden have, and are still, coming up with solutions to the high temperatures, while pavilions have introduced innovative ways to keep visitors cool.

As temperatures reached 35 C in June, the Bureau of Shanghai World Expo Coordination responded by utilizing sunshades and misting fans. According to Hong Hao, director of the coordination office, 12,000 sunshades have been installed throughout the Expo Garden. There are also more electric fans and ice cream vendors in the Expo Garden.

The coordination office even started providing paper fans to visitors. Refreshing traditional Chinese food that is much favored during summer time, such as the sweet mung bean soup, will probably be provided in the Expo Garden soon, said Ding Hao, deputy director of the coordination office.

While the coordination office is taking further measures to confront the heat, some pavilions have won praise from visitors because designers already planned for the high temperatures by providing fans that blow pleasant breezes and are environmentally friendly.

The Madrid, Hamburg, Alsace and other pavilions in the Urban Best Practices Area (UBPA) are frequently referred to as "summer resorts" in the Expo Garden, weaving environmentally friendly technologies into the original designs and providing shade to visitors in natural ways.

The Air Tree at the Madrid Case Pavilion is perhaps the most notable and practical summer resort in the Expo Garden. At the top of the steel decagon structure, a draft fan 7 meters in diameter allows for better ventilation in the building. Together with the many plants in the Air Tree, the difference in temperature from inside to outside the tree can be as much as 8 C.

"Some of the air-conditioned pavilions are too cold for visitors who are only wearing T-shirts. We may catch a cold due to the sharp temperature difference. Therefore, I prefer to take a break under the Air Tree," said a visitor sitting under the Air Tree on a hot summer afternoon.

At first glance, some pavilions in the Expo Garden may seem to cool visitors with little or no effort. The Hamburg Case Pavilion may leave some speechless as it can amazingly maintain a room temperature of 25 C throughout all four seasons without air-conditioning or heating.

The secret is that all the open spaces and the building itself face north to avoid excessively high temperatures that come from direct exposure to the sun. The exterior of the building, such as the roof and the windows, was built with an insulation system that refreshes visitors upon entering the pavilion.

A young girl plays in a mist spray area. Wang Jianwei / Xinhua

Similar examples can be found in the Makkah Case Pavilion, which features the tents of Mina. The pavilion is made up of these tents, known for their ability to keep out the heat and keeping the temperature comfortable without air-conditioning. The tents, made of a special material that is fireproof, windproof and anti-corrosive, only let in 10 percent of sunlight to ensure a comfortable temperature.

Designers of the State Grid Pavilion, who helped design the National Stadium, or the Bird's Nest, for the 2008 Beijing Olympics, seem to be more experienced. Through precise calculations, the designers concluded that there will be about 901 hours during the Expo that visitors will feel uncomfortable to due direct sun exposure, which accounts for about 20 percent of the total time of the Expo. To make sure that visitors were not uncomfortable lining up outside the pavilion, the designers lifted the building so that its framework would provide shade to visitors.

To allow better ventilation in the queuing area, designers adopted an enhanced ventilation system in the State Grid Pavilion. While the solar energy collector heats the air in the patio, a heat difference grows within and generates a flow of natural wind that keeps blowing at a speed of 0.12 meters per minute, keeping visitors cool with a constant breeze.

More technology was employed at the China Aviation Pavilion to reduce heat. The pavilion, in the shape of a cloud, is clad with a layer of Polyvinylchlorid (PVC) fabric, which has formed a cavity a meter thick, resembling a sunshade. On top of that, an air deflector was installed in the cavity to reduce solar radiation and cool the pavilion.

Throughout the Expo Garden, mist spray has been the most widely adopted cooling measure. At the Japan, Australia, Denmark, China Aviation and some of Expo's other favorite pavilions, mist sprays cool visitors queuing to enter.

Some visitors prefer more natural ways of cooling down, and a visit to the three parks in the Expo Garden is a good choice. With the green areas and spray devices visitors may be inclined to linger around for hours.

The most important thing is to be prepared for a day at the Expo Garden. Expo granny Yamada Tomiyo, 62, from Japan, who has gone to the Expo every day, knows what to bring.

"I will always bring a tangerine with me. It is easy to eat and helps to add vitamins to the body, which can relieve fatigue," she said.

"The most important thing during summer is to keep hydrated. Therefore, I bring orange juice and self-made plum water to the Expo Garden to make up for the lost sweat," she said.

Visitors should have basic items, like umbrellas, water, fans and hats, at all times. Sunscreen is also useful in July and August, Tomiyo said.

"Some girls will choose to wear T-shirts and shorts in the Expo Garden. Of course it is cooler, but they will very likely to get sunburned. So I suggest that every visitor take a coat to block the sunlight. And remember to apply some sunscreen cream 30 minutes before you leave for the Expo Garden. That's the secret for my not turning darker after one month in the Expo Garden," said Tomiyo.

A group of Expo workers enjoy the coolness of a mist spray area. Yong Kai / China Daily