Presentation Transcript
Slide1 : Booster System Basics: Constant Speed Systems
Pressure Booster Systems : WHAT IS A BOOSTER SYSTEM?
BOOSTER SIZING REQUIREMENTS
BOOSTER SYSTEM CONTROL
ENERGY SAVING STRATEGIES
DRAWDOWN TANKS Pressure Booster Systems
What is a Pressure Booster System? : All components mounted on a common base, tested and calibrated to site conditions What is a Pressure Booster System? Pumps Control Panel Headers, Piping and Isolation Valves, Pressure gauges, Solenoid Valve, Aquastat and copper tubing Pressure Reducing Valves
What you need to size a booster system? : What you need to size a booster system? Calculate the total flow requirement for the building
Number of Domestic Water Fixtures
Type of fixtures in the building
Type of building (residential, public, heavy use)
Special services
Total Flow = Total Fixture Units : Total Flow = Total Fixture Units
What you need to size a booster system? : What you need to size a booster system? Calculate the total flow requirement for the building
Calculate the total pressure required for the building
Static Pressure : Static Pressure Based on the vertical boost required above the packaged system manifold
This component never varies
Fixture Pressure : Fixture Pressure Required pressure to operate fixture at farthest point from system.
Must overcome valve “start-up” pressure (i.e. 25 PSI min. required for flush valves to operate)
Never varies, this is always required as a minimum
Packaged System Losses : Packaged System Losses Systems are designed to have no more than 5psi loss from suction manifold to discharge manifold
This must always be added into pressure calculations
Available Suction Pressure : Available Suction Pressure Typically varies by about 10-30 PSI
Can vary over time due to growth
Can also vary due to municipal re-structuring
Friction Losses : Friction Losses Usually calculated at 10% of total static requirement
Typically a very small boost pressure component
Can be larger as in the case of boost over a “campus-style” area or large low-rise building
Pressure Requirement : Pressure Requirement
Pressure Requirement : Pressure Requirement Pump Boost Pressure (TDH)
= Fixture Pressure
+ Package Losses
+ Static Head
+ Friction Head
- Supply Pressure
Pressure Requirement : Pressure Requirement Boost Pressure
= System Pressure - Supply Pressure
Significance of System Flow in Booster Systems : Significance of System Flow in Booster Systems Flow impacts system demand, not pressure - as demand increases, flow must increase at a constant output pressure
Flow governs pump actuation - therefore, flow should govern pump sequencing and actuation
System capacity matched to system flow requirement is most efficient and cost effective for domestic water pressure boosting
What are the most popular methods of booster pump control ? : What are the most popular methods of booster pump control ? Flow meter or flow switch
Instrument is in contact with corrosive water therefore requiring more maintenance
What are the most popular methods of booster pump control ? : What are the most popular methods of booster pump control ? Flow meter or flow switch
Pressure Switch
Requires non-overloading (NOL) motors
Requires a pressure drop across operating range
Can be unstable in operation resulting in “starving” the system of water (end of curve operation)
Mechanical switches increase possibility of failure
Effect of Suction Pressure : Effect of Suction Pressure
Effect of Suction Pressure : Effect of Suction Pressure
What are the most popular methods of booster pump control ? : What are the most popular methods of booster pump control ? Flow meter or flow switch
Pressure Switch
Current or kW Sensing
Current Sensing : Current Sensing As the flow increases, so does the pump load
The motor must match the pump load
Current / Power draw for motors is proportional to the load (pump flow work)
Current - Flow Relationship : Current - Flow Relationship
Effect of Suction Pressure : Effect of Suction Pressure
Effect of Suction Pressure : Effect of Suction Pressure
Effects of Voltage Fluctuations on Motors : Effects of Voltage Fluctuations on Motors
Current Sensing : Current Sensing Motors sized to match the power requirement
Current sensing allows flexible pump sizing to match the system load profile and energy requirement
Duplex:
Triplex:
33% - 67% capacity split
20% - 40% - 40% capacity split
Slide27 : Duplex allows up to three steps of sequencing Current Sensing
Current Sensing : Current Sensing Triplex allows up to five steps of sequencing
Typical Daily Demand Curve : Typical Daily Demand Curve
Duplex Booster - 50/50 Split Conventional Split : Duplex Booster - 50/50 Split Conventional Split
Duplex Booster - 33/67 Split 3 Step Control with No-flow shutdown : Duplex Booster - 33/67 Split 3 Step Control with No-flow shutdown
Energy Consumption : HP = GPM X Feet (Head) Energy Consumption Smaller pump at lower flows will be more efficient and consume less energy
Smaller motor is more efficient at lower loads 3960 X (Pump Eff) x (Motor Eff)
Energy Savings Conventional vs. 33/67 Split : Energy Savings Conventional vs. 33/67 Split
Slide34 : Total Energy Savings = 19%
Energy Cost = $0.12 / kWhr
Savings per Year: $2,280
Energy Savings Conventional vs. 33/67 Split
What are the most popular methods of booster pump control ? : What are the most popular methods of booster pump control ? Flow meter or flow switch
Pressure Switch
Current or kW Sensing
VFD with pressure transducers
No-Flow Shutdown and Tank Sizing : When do you use it? Where should you install it? What size should it be? No-Flow Shutdown and Tank Sizing
Sizing and Selecting Drawdown Tank : Sizing and Selecting Drawdown Tank Tanks are to be used in systems that do not have a continuous water demand
Tanks should NOT be sized according to booster size
Tanks should be sized to store 20 - 30 Gallons of water (2 - 3 GPM leak loads)
Tanks maintain pressure in piping system and supply small demands to allow pumps to be shutdown
Sizing and Selecting Drawdown Tank : Sizing and Selecting Drawdown Tank Tank Storage Volume is governed by the Ideal Gas Law
Solving for storage volume gives:
Vstorage = Pdifferential x VTotal Tank (PTotal +PAtmosphere)
3 factors must be considered
Tank Volume : Tank Volume
Vstorage = Pdifferential x VTotal Tank (PTotal +PAtmosphere)
The bigger the tank, the better the storage
Differential Pressure : Differential Pressure Tank storage Volume is proportional to the difference in the cut out and cut in pressures of the pumps
The larger the pressure differential the more water that will be stored in the tank
Vstorage = Pdifferential x VTotal Tank (PTotal +PAtmosphere)
Pressure Differential Calculation : Pressure Differential Calculation
Pdifferential = Pstop - Pstart
Pstop = Pressure at the tank when the system shuts down
For adjacent or package mounted tanks, this means the suction pressure plus the shutoff head of the pump
For remote mounted tanks, this is simply the normal system pressure at the location of the tank
Pressure Differential Calculation : Pressure Differential Calculation Pdifferential = Pstop - Pstart
Pstart = Pressure at the tank when the system starts again down
For adjacent or package mounted tanks, this means the setting on the no flow (call on) pressure switch
For remote mounted tanks, this is simply the system pressure at the location of the tank when the call on pressure switch brings the system back on
Total Pressure : Total Pressure A lower Total Pressure will yield larger water storage for the same pressure differential
Lower Total Pressure allows for lower tank pressure rating
Vstorage = Pdifferential x VTotal Tank (Ptotal +PAtmosphere)
Lower tank pressure rating
Sizing and Selecting Drawdown Tank : Sizing and Selecting Drawdown Tank All three of these factors must be considered in selecting the appropriate tank
Vstorage = Pdifferential x VTotal Tank (PTotal +PAtmosphere)
Where Should the Tank be Installed ? : Where Should the Tank be Installed ? Packaged Mounted
Tank water storage may be limited by tank size
Will require higher tank pressure rating
More Costly
Difficult to maneuver due to weight and may require building structural reinforcement.
Where Should the Tank be Installed ? : Where Should the Tank be Installed ? Adjacent Mounted
Tank is supplied as a loose component for connection on site
Tank is not mounted on skid with pumps
Contractor has freedom to locate tank in mechanical room
System is easier to maneuver
Where Should the Tank be Installed? : Where Should the Tank be Installed? Remote Mounted
Roof mounting - Lowers Tank Total Pressure and Tank Pressure Rating Required
Allows for the use of smaller tanks for desired water storage
Contractor has flexibility locating and installing tank
Questions & Answers : Questions & Answers
Thank You : Thank You
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