What’s the difference between a Double Regulating Valve (DRV) and a Pressure Independent Control Valve (PICV) in HVAC systems?
The main distinction is how flow regulation reacts to variations in system pressure.
A Double Regulating Valve (DRV) is a manual valve that helps balance the flow of air in HVAC systems. It is often found on the return line of chilled water coils. It lets technicians establish and keep a specified flow rate by hand (for example, 2.4 GPM per ton). Flow is determined via pressure drop across the valve or coil, utilizing equipment like ultrasonic manometers. But DRVs depend on pressure, therefore if the pressure in the system varies, the flow rate does too, which may suggest that the system needs to be rebalanced.
A Pressure Independent Control Valve (PICV), on the other hand, is a smart, dynamic valve that keeps the flow rate the same no matter what the pressure does. It has the functions of a balancing valve, a control valve, and a pressure regulator all in one unit. PICVs can also change the flow based on the temperature in the room and turn it off when heating or cooling isn’t needed, which saves electricity. These valves are great for buildings like hotels or hospitals that have sophisticated, variable flow systems where the pressure changes a lot.
PICVs cost more up front, but they work better, need less maintenance, and save energy over the long term compared to standard DRVs.