ISHVAC (the International Symposium on Heating, Ventilation and Air Conditioning ) is first launched by Tsinghua University in 1991, which is a very influential international meeting in the international and domestic HVAC industry. In the past ISHVAC got support and sponsorship from international and domestic societies and associations, such as IIR (International Institute of Refrigeration ), WRO (Word Energy Organization), ASHRAE(American Society of Heating, Refrigeration, and Air-Conditioning Engineers), CAR (Chinese Refrigeration Association), CBA-HVAC (Chinese Building Association-Heating, Ventilation and Air Conditioning), CAIEH (Chinese Association of Indoor Environment and Health), NHVSEA (Nordic Heating, Ventilation and Sanitary Engineering Association), JACHA(Japanese Air Conditioning and Health Association), and SKIEA(South Korea Indoor Environment Association). ISHVAC has been successfully hosted six times, which was held every four years from 1991 to 2007. From the year 2007, the scientific committee decided to change it into every two years. Each session of ISHAVC is hosted by one of the domestic universities and co-organized by Tsinghua University to integrate resources of domestic universities and to improve the level and quality of this international conference. ISHVAC had been hosted in Beijing, Shenzhenand Nanjing. In 2013, it will be hosted in Xi'an, a historical and cultural city of China, and be organized by Xi’an University of Architecture &Technology. So, welcome to ISHVAC 2013, and welcome to Xi’an University of Architecture &Technology.