Now a days havc requirement is increasing regularly. Everyone want to be optimum solution in hvac to reduce space, electricity consumption, initial cost, maintenance, and control. if we required all advantages in single package then we are suggesting Primary Variable Chilled water system.This system is maintaining constant temp at outlet of load by variation in flow. The flow variation will helpful to reduce electricity and constant leaving temp give better COP. This type of system is simple in design and very less pump requirement so that initial cost will be reduced. pump will be variable speed so electricity will be saved with better COP. Entering and leaving constant temp will be reduce complex automation requirement.