INTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTIONINTRODUCTION

Day OneDay One��Piping SystemsPiping Systems

��Friction LossesFriction Losses

��Flow Rate limitationFlow Rate limitation

��AshraeAshrae & Carrier Guide Line& Carrier Guide Line

��Acceptable PracticesAcceptable Practices

��Pipe SizingPipe Sizing

��Head Losses CalculationHead Losses Calculation

��Case PracticeCase Practice

Day 2Day 2

�� PumpsPumps

�� Performance CurvesPerformance Curves

�� Power consumption & Power consumption &

Efficiency CurveEfficiency Curve

�� Pump LawsPump Laws

�� Pumps & System Pumps & System

CurveCurve

�� NPSHR & NPSHANPSHR & NPSHA

�� Pump SelectionPump Selection

�� Pumps Arrangements Pumps Arrangements

& their performance & their performance

CurveCurve

�� Case StudiesCase Studies

WATER PIPING SYSTEMWATER PIPING SYSTEMWATER PIPING SYSTEMWATER PIPING SYSTEMWATER PIPING SYSTEMWATER PIPING SYSTEMWATER PIPING SYSTEMWATER PIPING SYSTEM

Open SystemOpen System

��In this system, the water flows thru heat exchanger In this system, the water flows thru heat exchanger and then exposed to atmosphere. and then exposed to atmosphere.

��such as in such as in Cooling tower and air washerCooling tower and air washer..

Closed systemClosed systemClosed systemClosed systemClosed systemClosed systemClosed systemClosed system

��In this system, the water flow is not exposed to the In this system, the water flow is not exposed to the atmosphere at any point.atmosphere at any point.

��But some times contains an expansion tank that is But some times contains an expansion tank that is open to the atmosphere but water area exposed is open to the atmosphere but water area exposed is insignificant. Such as insignificant. Such as Chilled water systemChilled water system

Closed Water Piping SystemClosed Water Piping System

��Parallel Piping System Parallel Piping System Parallel Piping System Parallel Piping System Parallel Piping System Parallel Piping System Parallel Piping System Parallel Piping System

�� Reverse return pipingReverse return pipingReverse return pipingReverse return pipingReverse return pipingReverse return pipingReverse return pipingReverse return piping

�� Reverse return header with direct Reverse return header with direct Reverse return header with direct Reverse return header with direct Reverse return header with direct Reverse return header with direct Reverse return header with direct Reverse return header with direct

return risersreturn risersreturn risersreturn risersreturn risersreturn risersreturn risersreturn risers

�� Direct return pipingDirect return pipingDirect return pipingDirect return pipingDirect return pipingDirect return pipingDirect return pipingDirect return piping

��Compound Piping system Compound Piping system Compound Piping system Compound Piping system Compound Piping system Compound Piping system Compound Piping system Compound Piping system

(Primary & Secondary System)(Primary & Secondary System)(Primary & Secondary System)(Primary & Secondary System)(Primary & Secondary System)(Primary & Secondary System)(Primary & Secondary System)(Primary & Secondary System)

Reverse Return PipingReverse Return Piping

Reverse Return Headers with Reverse Return Headers with

Direct Return RisersDirect Return Risers

Direct Return Water PipingDirect Return Water Piping

Primary & Secondary PipingPrimary & Secondary Piping

FRICTION LOSSESFRICTION LOSSES

When water flows in a pipe, friction is When water flows in a pipe, friction is

produced by the rubbing of water particles produced by the rubbing of water particles

against each other and against the wall of against each other and against the wall of

the pipe. This friction produced by the the pipe. This friction produced by the

flowing water causes a loss in pressure, flowing water causes a loss in pressure,

which is called Friction Loss.which is called Friction Loss.

The Friction losses depends uponThe Friction losses depends upon::::::::

��Water velocityWater velocity

��Interior surface roughnessInterior surface roughness

��Pipe lengthPipe length

��Pipe diameterPipe diameter

Flow Rate LimitationFlow Rate Limitation

��ServicesServices

��ErosionErosion

��NoiseNoise

��Installation CostInstallation Cost

��Operating CostOperating Cost

All above limit Maximum and All above limit Maximum and

minimum velocities in piping minimum velocities in piping

system.system.

Recommended Water Recommended Water

Velocities Velocities Based on ServicesBased on Services

��Pump DischargePump Discharge 88--12 FPS 12 FPS

��Pump SuctionPump Suction 44--7 FPS7 FPS

��HeaderHeader 44--15 FPS15 FPS

��RiserRiser 33--10 FPS10 FPS

��Drain LineDrain Line 44--7 FPS7 FPS

��General ServiceGeneral Service 55--10 FPS10 FPS

��City WaterCity Water 33--7 FPS7 FPS

ErosionErosionErosionErosionErosionErosionErosionErosion

��Erosion in water piping system is Erosion in water piping system is

the impingement on inside surface the impingement on inside surface

of pipe of rapidly moving water of pipe of rapidly moving water

containing air bubbles, sand and containing air bubbles, sand and

other solid matter.other solid matter.

��Due to this impingement, pipes Due to this impingement, pipes

gets eroded over a period of time gets eroded over a period of time if if

Recommended velocity not Recommended velocity not

maintained in piping systems.maintained in piping systems.

MAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TOMAXIMUM WATER VELOCITY TO

MINIMIZE EROSIONMINIMIZE EROSIONMINIMIZE EROSIONMINIMIZE EROSIONMINIMIZE EROSIONMINIMIZE EROSIONMINIMIZE EROSIONMINIMIZE EROSION

Normal OperationNormal Operation Velocity RangeVelocity Range

��1500 Hrs/Year1500 Hrs/Year 15 FPS15 FPS

��2000 2000 ““ 14 FPS14 FPS

��3000 3000 ““ 13 FPS13 FPS

��4000 4000 ““ 12 FPS12 FPS

��6000 6000 ““ 10 FPS10 FPS

��8000 8000 ““ 8 FPS8 FPS

Noise GenerationNoise Generation

Velocity-dependent noise in piping systems

results from any or all of four sources:

�Turbulence

�Cavitation

�Release of entrained air

�Water hammer

In investigations of flow-related Noise, Marseille,

Ball and Webster and Rogers reported that

velocities on the order of 10 to 1710 to 17 fps lie within the

range of allowable noise levels for residential and

commercial buildings.

AshraeAshraeAshraeAshraeAshraeAshraeAshraeAshrae Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations Recommendations For For

Hydronic SystemHydronic System

��Friction Loss Rate should be taken as Friction Loss Rate should be taken as 1 to 1 to

44 Feet/100 feet of Pipe Feet/100 feet of Pipe Eq.LengthEq.Length. .

��A Value of A Value of 2.5 Feet/1002.5 Feet/100 Feet is the mean Feet is the mean

to which most systems are designed.to which most systems are designed.

��For 2 Inch and below pipes, Velocity limit For 2 Inch and below pipes, Velocity limit

is is 4 FPS.4 FPS.

��For above pipes, For above pipes, FLR limit is FLR limit is 4 Feet/1004 Feet/100

Feet.Feet.

AndAnd

��As per Carrier Guide Line FLR is 8As per Carrier Guide Line FLR is 8--10 feet /100 10 feet /100

feet and velocity limit 10 FPS. feet and velocity limit 10 FPS.

PIPE SIZING CRITERIAPIPE SIZING CRITERIAPIPE SIZING CRITERIAPIPE SIZING CRITERIAPIPE SIZING CRITERIAPIPE SIZING CRITERIAPIPE SIZING CRITERIAPIPE SIZING CRITERIA

��Water Flow Water Flow

��Based on Cooling load on respective AHU Based on Cooling load on respective AHU

/FCU/BCU/FCU/BCU

��Can be calculated as:Can be calculated as:

Tonnage X 24Tonnage X 24

Flow In GPM= Flow In GPM= ------------------------------------------------------------------Temperature differenceTemperature difference

��Friction Loss Rate / Velocity LimitationFriction Loss Rate / Velocity Limitation

specified by consultant or ASHRAE.specified by consultant or ASHRAE.

Pipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing Method

Step Step --11

��Make a layout sketch showing individual Make a layout sketch showing individual AHU,FCU and BCU on Master layout plan.AHU,FCU and BCU on Master layout plan.

Step Step -- 22

��Mark selected /design flow on individual AHU, Mark selected /design flow on individual AHU, FCU and BCU.FCU and BCU.

Step Step -- 33

��Review layout sketch w.r.t. space available , Review layout sketch w.r.t. space available , other services,economy and consultant other services,economy and consultant concurrence.concurrence.

��Conclude layout.Conclude layout.

Pipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing MethodPipe Sizing Method…………………………………………................

Step Step --44

��Starting from most remote terminal working Starting from most remote terminal working towards the pump, Mark the Cumulative flow in towards the pump, Mark the Cumulative flow in mains and branch circuits.mains and branch circuits.

Step Step --66

��Select pipe size for required Flow and as per Select pipe size for required Flow and as per selected Friction Loss Rate from Friction chart for selected Friction Loss Rate from Friction chart for respective application.respective application.

��ReRe--check Chart water velocity with recommended check Chart water velocity with recommended velocity.velocity. If within limit.Selection is ok.If within limit.Selection is ok.

��Repeat for other flow requirements.Repeat for other flow requirements.

Friction Loss Rate Vs Flow Charts Friction Loss Rate Vs Flow Charts --SchSch. 40 pipes. 40 pipes

Head Loss & CalculationHead Loss & Calculation

It is the total loss of pressure energy due to It is the total loss of pressure energy due to

friction/resistance offered by Pipes & Fittings friction/resistance offered by Pipes & Fittings

in the piping systemin the piping system

TThe he Head LossHead Loss is equal to the is equal to the Total Total

Frictional LossesFrictional Losses in highest resistant in highest resistant

circuit of piping system.circuit of piping system.

�To Calculate Head Loss, Calculate the Total

Frictional Losses

�of pipes

�of fittings

�of equipments

Valve & Fitting LossesValve & Fitting Losses

��Valves & Fitting cause pressure losses greater Valves & Fitting cause pressure losses greater than those caused by the pipe alone.than those caused by the pipe alone.

��Fitting Losses are frequently expressed in Fitting Losses are frequently expressed in Equivalent length of pipe, Equivalent length of pipe,

��It can be expressed as per following equationIt can be expressed as per following equation

��������h = K x Vh = K x V22//2g2g����������hh-- Head/Pressure loss in FeetHead/Pressure loss in Feet��KK -- Geometry & Size dependent loss coefficientGeometry & Size dependent loss coefficient��VV -- Average velocity of waterAverage velocity of water��gg -- Gravitational force as 32.20Gravitational force as 32.20

K FactorsK Factors--Screwed FittingsScrewed Fittings

K FactorsK Factors--Flanged FittingsFlanged Fittings

Fitting Losses in Equivalent Length of Fitting Losses in Equivalent Length of

PipePipe

Valves Losses in Valves Losses in EqEq. Length of . Length of

PipesPipes

System Friction LossesSystem Friction LossesSystem Friction LossesSystem Friction LossesSystem Friction LossesSystem Friction LossesSystem Friction LossesSystem Friction Losses

Relation between Relation between Flow & Head Losses Flow & Head Losses for a systemfor a system: :

1.85 1.85 1.85 1.85 1.85 1.85 1.85 1.85 --------1.91.91.91.91.91.91.91.9

H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)H2/H1 = (Q2/Q1)

Q1& Q2 = FlowsQ1& Q2 = FlowsQ1& Q2 = FlowsQ1& Q2 = FlowsQ1& Q2 = FlowsQ1& Q2 = FlowsQ1& Q2 = FlowsQ1& Q2 = Flows

H1 & H2=Head LossesH1 & H2=Head LossesH1 & H2=Head LossesH1 & H2=Head LossesH1 & H2=Head LossesH1 & H2=Head LossesH1 & H2=Head LossesH1 & H2=Head Losses

Water Piping DiversityWater Piping Diversity

� When the air conditioning load is determined for each exposure of a building, it is assumed that the exposure is at peak load.

� Since the sun load is at a maximum on one exposure at a time, not all of the units on all the exposures require maximum water flow at the same time to handle the cooling load.

� Units on the same exposure normally require maximum flow at the same time; units on the adjoining or opposite exposures do not.

� Therefore, if the individual units are automatically controlled to vary the water quantity, the system water quantity actually required during normal operation is less than the total water quantity required for the peak design conditions for all the exposures.

Diversity ApplicationDiversity Application

�� The principle of diversity allows the The principle of diversity allows the

engineer to evaluate and calculate the engineer to evaluate and calculate the

reduced water quantity. reduced water quantity.

�� For applying diversity two conditions For applying diversity two conditions

must be satisfied:must be satisfied:

�� The water flow to the units must he The water flow to the units must he

automatically controlled to compensate for automatically controlled to compensate for

varying loads.varying loads.

�� Diversity may only be applied to piping that Diversity may only be applied to piping that

supplies units on more than one exposure.supplies units on more than one exposure.

Diversity ApplicationDiversity Application

•Calculate Accumulated Flow in

exposure.

•Find Out Ratio of Accumulated flow

to Total Pump Flow.

•Apply this ratio to diversity Charts

and obtain diversity factor for the

particular section.

Diversity ApplicationDiversity Application

A Sample ProjectA Sample ProjectA Sample ProjectA Sample ProjectA Sample ProjectA Sample ProjectA Sample ProjectA Sample Project

A schematic chilled water piping layout A schematic chilled water piping layout

is enclosed for a G+4 Building.is enclosed for a G+4 Building.

Please size the pipes for individual Please size the pipes for individual

branch and headers.branch and headers.

Calculate the total friction losses.Calculate the total friction losses.

Select the Pumps:Select the Pumps:

Option 1Option 1-- With single pumps operationWith single pumps operation

Option 2Option 2-- With two pumps in operationWith two pumps in operation