APPLICATION GUIDE Achieve your design intent and energy savings with Siemens PICV usa.siemens.
There is a better way to have your boiler and chiller systems operate more efficiently and maintain hydronic balancing easily so that the right comfort level is achieved throughout the building, leading to happy occupants and energy savings. This application guide covers PICV basics, sizing and selection, common PICV applications for Hydronic Flow Optimization and how much less effort PICVs are, which in the long run, leads to no callbacks.
1 PICV Features and Operation An Easier ∆T Solution 3-in-1 Control Valve The Siemens pressure independent control valve is a three-in-one device. The main difference with Siemens is that the field adjustable flow limiter is independent of the valve stroke. With other PICVs, the way that flow is adjusted is by adjusting the valve stroke. So, by reducing the flow, the valve stroke is reduced.
2 Fast and Easy Sizing and Selection of PICVs Pressure dependent valves are more complicated to size requiring multiple calculations Drawbacks of traditional variable flow systems There are a number of steps that need to be taken when selecting traditional control valves. Sizing and selecting traditional control valves is complex and requires several calculations. To calculate the Cv and properly size a valve, the design flow of the coil and the design pressure drop are needed.
Less Effort with PICVs Required system balancing is labor intensive Pressure dependent valves require more commissioning time: 1. It is common to do three passes for proper balance when using conventional control valves. 2. A change to a valve in a branch results in changes to the flow through the rest of your system. Why pressure dependent valves require more commissioning time: Typically, a balancer would start with the first valve and control loop on the right.
Smaller install footprint No matter how complicated the pipe network, Siemens PICVs are the right fit. Siemens PICVs combine a control valve and a balancing valve functionality into a single device. The traditional control valve and balancing valve require almost twice as much space. To properly pipe this configuration, almost twice the amount of space is needed.
PICV applications for Hydronic Flow Optimization Air Handling Unit with PICV direct control Air Handling Unit with PICV injection circuit AHU Applications Injection Circuit Secondary Side Injection Circuit Primary Side S S R R Air Handling Unit Room Controller PICV Primary Pump Metering Station Air Handling Unit Room Controller Circulation Pump PICV Primary Pump Metering Station Air Handling Unit with PICV direct control Air Handling Unit with PICV injection circuit This is a common us
Chiller / Boiler Examples Fixed Speed Chiller – Plant Room with PICV control Fixed Speed Chiller – Plant Room with PICV control Condensing Boiler – Plant room with PICV control Siemens flanged PICV up to 6” can also be utilized in mechanical/plant room applications.
Plate Heat Exchanger with PICV control Fan Coil Unit Application with PICV control Fan Coil / Plate Heat Exchanger Examples Fan Coil Unit Application with PICV control S Flow and Return Secondary Side Flow and Return Primary Side R SS RR Fan Fan Coil Coil PICV PICV Metering Station Metering Station Room Controller Index Room Pressure ControllerPICV IndexPrimary Pump Pressure PICV Primary Pump Plate Heat Exchanger Room Controller Temperature Sensor PICV Secondary Pump Fan Coil Unit App
Achieve Design Intent with Energy Savings Multiple Air Handling Units with PICV direct control AHU Energy Savings Case Study • 50 story high rise • Study conducted over 4 weeks • Conducted in 6th floor plant room • Total 40 AHUs in building • Compared PICV vs Globe valve • Two week run time of each valve type on AHUs then swapped out S R Air Handling Unit Room Controller PICV Primary Pump Metering Station Multiple Air Handling Units with PICV direct control A study was conducted in a high rise to
Better Performance with PICV In this middle chart, the impact PICV will have on the relative flow control of the circuit compared to globe valves is apparent. There is a much tighter spread in flow percentages right around the desired levels compared to the globe valve. Over/undershoots are also much smaller in comparison with smaller times of adjustment between periods These three charts below capture the significant difference in performance between the pressure dependent globe valve and the PICV.
Energy Savings at the Pump(s) Pump Affinity Laws ( ) qPICV NPICV = qGlobe NGlobe HPICV NPICV = HGlobe NGlobe Where: q = water flow N = pump speed 2 H = pump head ( ) BHPPICV NPICV = BHPGlobe NGlobe 3 BHP = pump power The pump affinity laws can be used to gauge the impact of using a PICV in place of a globe valve on the distribution system.
Rely on Siemens for the best possible system performance. The right HVAC device matters to make your perfect place a reality. Achieve your design intent with hydronic flow optimization. Choosing the right devices in a hydronic system up front can lead to greater energy efficiency and significant savings in first costs, maintenance costs and performance costs.
