Hydronic Balancing Using Automatic Balancing Valves to Dynamically Balance Hydronic Systems Sean Kalman – Hays Fluid Controls
Dec 23, 2015
Hydronic Balancing
Using Automatic Balancing Valves to Dynamically Balance Hydronic Systems
Sean Kalman – Hays Fluid Controls
Automatic Balancing Valves
Agenda
Methods of Hydronic Balancing How Automatic Flow Control Works Automatic Flow Control Saves Money Where to Apply Automatic Flow Control Valves Selecting an Automatic Flow Control Valve
Automatic Balancing Valves
Methods of Hydronic Balancing
Balancing Valve Type Information
Ball Valve Inexpensive & Inaccurate
Circuit Setter Moderately Priced & Somewhat Accurate
Venturi Higher Priced with Improved Accuracy
Automatic First Cost eqivalent to Venturi, Lower TAB Cost
Automatic Balancing Valves
How Automatic Flow Control Works
When the Differential Pressure increases, the diaphragm presses up to and flexes against the orifice plate. This limits the area for the water to flow through.
When Differential Pressure decreases, the diaphragm relaxes, and increases the area for the water to flow through.
Flow
Automatic Balancing Valves
Automatic Flow Control Valves Save Money
Less Valves Required in System Higher Accuracy Lower Installation Cost Lower Test, Adjust & Balance Cost Lower Long Term Maintenance Cost Lower Pumping Capacity Requirement Can Be used in Variable Flow Systems
Automatic Balancing Valves
Typical Manual Balancing System
•Circuit Balance Valves required at all terminal units as well as riser.
•System to be rebalanced when new terminal unit brought on line.
Automatic Balancing Valves
Automatic Flow Control System
•Automatic Flow Control Valves only required at terminal units.
•No system rebalance needed when new terminal unit brought on line. AFCV dynamically adjust to maintain flow.
•No AFCV required on riser.
AFCV offers unmatched flexibility for your design.
Automatic Balancing Valves
Automatic Is Accurate
Most manual valves give somewhere between ±15% to ±25%
Automatic valves increase your accuracy to ±10% as a general rule
Automatic Balancing Valves
Lower Installation Cost
17 Components21 Connections
5 Components1 Package4 Connections
Automatic Balancing Valves
Less Valves Required with AFCV
In this manual system, 26 manually adjusted flow control valves are required. In the same system using automatic valves, only 18 valves are required.
Automatic Balancing Valves
Less Valves Required With AFCV
No balancing valve required in bypass with AFCV
Automatic Balancing Valves
Lower TAB Cost
Because AFCV are pressure independent, they are balanced from the time the pump is turned on. Thus, only flow verification is needed, saving as much as 60% over outdated manually adjusted valves.
1.5 Hrs to manually balance 1 coil.
$50 / Hour LaborX1.5 Hrs$75 Per CoilX100 Coils$7500 Balancing Cost
.5 Hrs to verify flow on AFCV.
$50 / Hour LaborX.5 Hrs$25 Per CoilX100 Coils$2500 Balancing Cost
Automatic Balancing Valves
Less Energy Consumed With AFCV
When your building load changes, AFCV can dynamically change to maintain your flow requirements.
When the ΔP decreases, the valves open to maintain a constant flow rate.
When the ΔP increases, the valves close slightly to maintain a constant flow rate.
Manually adjusted valves cannot adjust to the changing ΔP to maintain a constant flow rate. If ΔP increases, so does the flow, if ΔP decreases, so does the flow.
Automatic Balancing Valves
Less Energy Consumed With AFCV
Application:
In an office building on a Spring day, the building may not be calling for less chilled water than what it was designed for. Except for a cafeteria which is at 100% capacity. By using AFCV, you can reduce your pump speed to meet only the chilled water need you have. With manually adjusted valves you do not have that luxury. In turn, reducing your pumping cost and saving money.
Automatic Balancing Valves
Less Energy Consumed With AFCV
Automatic Balancing Valves
Less Energy Consumed With AFCV
How Flow balancing cuts HVAC energy costs. (Use .06 kwh-hr cost) Flow Parameters Unbalanced Flow Balanced Flow
Flow, GPM 1050 870 Pressure, ft of head 62 75 Power, BHP 21.8 19.8 Power Consumptioin, KWH 18.2 16.4 Cost Per KWH $0.06 $0.06 Annual Electrical Cost $7098 $6396 Annual Savings $0 $702 Annual Savings Percent 0% 9.9%
Automatic Balancing Valves
AFCV With Variable Speed Pumps
Automatic Can accommodate changes in system.
Only AFCV can change to maintain exact flow rate.
For use with 2 position valves is excellent application.
Automatic Balancing Valves
AFCV With Variable Flow Systems
Control Valve has complete authority except when fully open and flow is beyond design.
Prevents “Overflow” of coil. Aids in preventing valve cavitation. Aids in preventing premature erosion of control
valve body.
Many engineers have suggested that AFCV is not suited for variable flow systems. Here are some reasons they are perfect for the job:
Automatic Balancing Valves
Cost Savings With AFCV
27 Circuit Setters = $729Installation Labor = $675
TAB Labor = $2,025Total Installed Cost = $3,429
18 AFCV = $954Installation Labor = $450
TAB Labor = $450Total Installed Cost = $1,854
In this example, we saved $1575 first cost alone.
Automatic Balancing Valves
Where to use Automatic Flow Control Valves
Water Source Heat Pumps Fan Coils VAV Box with Reheat Coils Air Handlers Unit Ventilators Cabinet Heaters Radiant Floor Heating Systems Hydronic Baseboard Heaters Cooling Towers Chillers
Automatic Balancing Valves
Automatic Flow Control Placement
In most applications, it is best to place the AFCV on the return side of a coil. This ensures that your water tube is full and providing maximum heat transfer.
Supply side will work, but is not ideal as too much air or turbulence may occur.
Automatic Balancing Valves
Automatic Flow Control Placement
In an open system, the AFCV must be on the return side of the coils to ensure that the tubes are flooded and ensure maximum heat transfer.
In an closed loop system, the AFCV can be on the return side or the supply side of the coils. The best practice is still to have your AFCV on the return side.
Automatic Balancing Valves
AFCV For All Applications
A small inline valve will work in tight spaces
A multipurpose valve provides unlimited options.
Larger valves accommodate high flow rates.
Automatic Balancing Valves
Choosing The Right AFCV
Choosing the right AFCV is very important. Here are some items to consider when choosing an AFCV:
•Operating Range:AFCV have a PSID range that they will operate within. Make sure the one you choose meets your needs.
•Flow Rates Available:Most AFCV manufacturers provide several flow rates to choose from. Some have a better selection than others. Make sure you are getting the flow rate you need.
•Hassle Free Operation:Ask the manufacturer if there are maintainance isssues with their valves. Will you have clogging problems or noise problems?
Automatic Balancing Valves
Automatic Flow Control Valves
SATISFIED
CUSTOMER
Inst
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Valve Selection
No
Cal
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Balance
Automatic Balancing Valves
Conclusion
AFCV are a good application in all types of systems.
AFCV saves money on both installation and operation of system
AFCV are best option for balancing of Hydronic HVAC systems.