Control Valve Selection For Hydronic Systems PDF

Water is one of the primary distribution media for heating or cooling energy in large buildings. This energy is imparted through heat exchangers (coils), normally part of an air-handling unit. The traditional method of control is to throttle the flow of water, air or both in proportion to space or air-handler discharge air temperature. When water flow is throttled, a control valve performs the function. This article discusses some of the effects of the valve in operation and ideas for proper valve selection. Understanding control valve performance is required to operate the system efficiently, tune temperature controllers, minimize interaction effects on other parts of the HVAC system, reduce operating cost and keep people comfortable.