Item ID: 269
Pressure-Independent Flow Control Valves
Hydronic Systems: Pressure-independent Valves vs. Conventional Valves
Replacements for conventional two-way valves used to control the flow of heated or chilled water through coils.
Pressure-independent control valves (PICVs) are replacements for conventional two-way valves used to control the flow of heated or chilled water through coils. Actions, such as changing pump speed or adjusting a valve, affect pressure in the distribution system. A traditional actuated ball or globe valve changes the flowrate through the valve as the pressure changes in the system. This may change the temperature in a conditioned space. If the zone had been satisfied and then the flow changes, the actuator responds to this change by opening or closing the valve, which can lead to hunting and excessive equipment cycling.
PICVs do not react to the operation of other equipment on the system. By stabilizing heating and cooling coil flows and maintaining flow balance, more space can be heated and cooled with less equipment. Most HVAC projects employ multiple technologies so it is difficult to isolate the energy savings solely due to use of PICVs.
PICVs can be part of any installation that uses adjustable speed drives (ASDs) to vary fluid flow through a hydronic loop and can be specified in an ASD retrofit. PICVs should be bundled into HVAC optimization measures that includes ASDs, differential temperature control, super efficiency ECPM motors, and other HVAC energy optimization techniques. PICVs are recommended for use where balancing at reduced loads is needed, such as in office buildings, schools or hotels; where temperature variance cannot be risked, including hospitals or laboratories; where longer actuator life is required; or where the primary variable flow system needs to be optimized.
Energy Savings: 5%
Energy Savings Rating:
Comprehensive Analysis What's this?
|1||Concept not validated||Claims of energy savings may not be credible due to lack of documentation or validation by unbiased experts.|
|2||Concept validated:||An unbiased expert has validated efficiency concepts through technical review and calculations based on engineering principles.|
|3||Limited assessment||An unbiased expert has measured technology characteristics and factors of energy use through one or more tests in typical applications with a clear baseline. |
|4||Extensive assessment||Additional testing in relevant applications and environments has increased knowledge of performance across a broad range of products, applications, and system conditions. |
|5||Comprehensive analysis||Results of lab and field tests have been used to develop methods for reliable prediction of performance across the range of intended applications.|
|6||Approved measure||Protocols for technology application are established and approved.|