The energy consume of air conditioning system is a big part in the total energy consume of building. So energy saving is a insistant mission for the engineer of HVAV and architecture. So

the best energy saving measure of the water system in central air conditioning engineering consider not only the system circulate under full-load condition

but also under patr-load condition. The variable water volume of the chilled-water and cooling water system make refrigerating machine saving more energy under part -load condition. The single loop variable chillled-water volume system is better than the first and the second loop variable water volume system.