MAKKAH: Two of the world’s largest cooling stations are set up in Makkah to provide chilled and fresh air to pilgrims at the Grand Mosque, an official told Arab News. Sultan bin Ati Al-Qurashi, undersecretary-general for Technical, Operational Affairs, Maintenance and Facilities Management, said one is in Shamiya, which is 900 meters from the Grand Mosque and consumes energy of up to 159,000 refrigeration tons. The other one is in Ajyad, 500 meters away and can consume energy of up to 39,000 refrigeration tons. Al-Qurashi said the stations work by cooling water in the system to about 4 or 5 degrees Celsius, which is then sent to the Air Handling Units, where hot air from the mosque passes over the chilled water. The cool air that is created is then pumped through air purification systems and into the mosque. The agency renovates the air conditioning units periodically and replaces all heat exchangers and air purification filters with new ones, he said. Al-Qurashi explained that the air is purified through air handling units after natural air is extracted from the surface of the Grand Mosque. It is done in several stages through high filtration technology, which prevents dust and other small particles from entering the air-conditioned environment. It is then sterilized with ultraviolet light that kills all types of bacteria. The General Presidency for the Affairs of the Two Holy Mosques oversees the operation of the coolers, which are operated by several highly qualified and experienced Saudi engineers and technicians. The technicians also balance the amount of air pumped into various areas of the Grand Mosque, depending on the number of visitors. Al-Qurashi said that 25 percent more workers are deployed to the Grand Mosque during the Hajj period, to ensure the best services for pilgrims.