A new material can cool buildings without drawing power or using refrigerant. It costs 50¢/square meter and 20 square meters is enough to keep a house at 20°C when it's 37°C outside

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A new material can cool buildings without drawing power or using refrigerant. It costs 50¢/square meter and 20 square meters is enough to keep a house at 20°C when it's 37°C outside