Abstract: The hospital clean operating room has the higher requirement on indoor cleanliness、tempreture and moisture, the four-pipe-water system has been increasingly applied in the operating room construction because of its high load adaptability、good accommodative facility and can be better satisfied the clean operating room's control requirement.The cold and heat source is the key factor of the four-pipe-water system.The article combines the engineering constuction examples,supplies four types of the cold and heat sources,and hopes to give some references to the designers.

Key words: four-pipe water system, cold and heat source, air cooled heat pump, air sourceheat pump, multifunction cold hot water unit