Pumps and Pumping Systems

1Training Session on Energy Equipment

Pumps & Pumping Systems

Presentation from the

Energy Efficiency Guide for Industry in Asia

www.energyefficiencyasia.org

UNEP 2006

ModeradorNotas de la presentacinTO THE TRAINERThis PowerPoint presentation can be used to train people about the basics of pumps and pumping systems. The information on the slides is the minimum information that should be explained. The trainer notes for each slide provide more detailed information, but it is up to the trainer to decide if and how much of this information is presented also.

Additional materials that can be used for the training session are available on www.energyefficiencyasia.org under Energy Equipment and include:Textbook chapter on this energy equipment that forms the basis of this PowerPoint presentation but has more detailed informationQuiz ten multiple choice questions that trainees can answer after the training sessionWorkshop exercise a practical calculation related to this equipmentOption checklist a list of the most important options to improve energy efficiency of this equipmentCompany case studies participants of past courses have given the feedback that they would like to hear about options implemented at companies for each energy equipment. More than 200 examples are available from 44 companies in the cement, steel, chemicals, ceramics and pulp & paper sectors

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Training Agenda: Pumps

Introduction

Type of pumps

Assessment of pumps

Energy efficiency opportunities

ModeradorNotas de la presentacin

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Introduction

20% of worlds electrical energy demand

25-50% of energy usage in some industries

Used for Domestic, commercial, industrial and

agricultural services

Municipal water and wastewater services

What are Pumping Systems

ModeradorNotas de la presentacinPumping systems account for nearly 20% of the worlds electrical energy demand. Furthermore, they range between 25-50% of the energy usage in certain industrial plant operations. The use of pumping systems is widespread. They provide domestic, commercial and agricultural services. In addition, they provide municipal water and wastewater services, and industrial services for food processing, chemical, petrochemical, pharmaceutical, and mechanical industries.

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Introduction

Objective of pumping system


(US DOE, 2001)

Transfer liquid from source to destination

Circulate liquid around a system

ModeradorNotas de la presentacinPumps have two main purposes:Transfer of liquid from one place to another place (e.g. water from an underground aquifer into a water storage tank)Circulate liquid around a system (e.g. cooling water or lubricants through machines and equipment)

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Introduction

Main pump components Pumps Prime movers: electric motors, diesel engines,

air system Piping to carry fluid Valves to control flow in system Other fittings, control, instrumentation

End-use equipment Heat exchangers, tanks, hydraulic machines


ModeradorNotas de la presentacinThe main components of a pumping system are:Pumps (different types of pumps are explained in section 2)Prime movers: electric motors, diesel engines or air system Piping, used to carry the fluidValves, used to control the flow in the systemOther fittings, controls and instrumentationEnd-use equipment, which have different requirements (e.g. pressure, flow) and therefore determine the pumping system components and configuration. Examples include heat exchangers, tanks and hydraulic machines

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Introduction

Head Resistance of the system Two types: static and friction

Static head Difference in height between

source and destination

Independent of flow

Pumping System Characteristics

destination

source

Static

head

Statichead

Flow

ModeradorNotas de la presentacinPressure is needed to pump the liquid through the system at a certain rate. This pressure has to be high enough to overcome the resistance of the system, which is also called head. The total head is the sum of static head and friction head.Static headStatic head is the difference in height between the source and destination of the pumped liquid (see top figure)Static head is independent of the flow (see bottom figure)

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Introduction

Static head consists of Static suction head (hS): lifting liquid relative to

pump center line Static discharge head (hD) vertical distance

between centerline and liquid surface in destination tank

Static head at certain pressure


Head (in feet) = Pressure (psi) X 2.31Specific gravity

ModeradorNotas de la presentacinStatic head consists of:Static suction head (hS): resulting from lifting the liquid relative to the pump center line. The hS is positive if the liquid level is above pump centerline, and negative if the liquid level is below pump centerline (also called suction lift)Static discharge head (hd): the vertical distance between the pump centerline and the surface of the liquid in the destination tank The static head at a certain pressure depends on the weight of the liquid and can be calculated with this equation: Head (in feet) = Pressure (psi) X 2.31 Specific gravity

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Introduction

Friction head Resistance to flow in pipe and fittings Depends on size, pipes, pipe fittings, flow

rate, nature of liquid Proportional to square of flow rate Closed loop system

only has friction head(no static head)


Frictionhead

Flow

ModeradorNotas de la presentacinFriction head: This is the loss needed to overcome that is caused by the resistance to flow in the pipe and fittings.It is dependent on size, condition and type of pipe, number and type of pipe fittings, flow rate, and nature of the liquid.The friction head is proportional to the square of the flow rate as shown in the figure. A closed loop circulating system only exhibits friction head (i.e. not static head).

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Introduction

In most cases:Total head = Static head + friction head


Systemhead

Flow

Static head

Frictionhead

Systemcurve

System head

Flow

Static head

Frictionhead

Systemcurve

ModeradorNotas de la presentacinIn most cases the total head of a system is a combination of static head and friction head as shown in the figuresLeft figure is system with a high static head (i.e. the destination reservoir is much higher than the source)Right figure is system with a low static head (i.e. the destination reservoir is not much higher than the source)

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Introduction

Pump performance curve Relationship between

head and flow Flow increase System resistance increases Head increases Flow decreases to zero

Zero flow rate: risk of pump burnout


Head

Flow

Performance curve for centrifugal pump

ModeradorNotas de la presentacinThe head and flow rate determine the performance of a pump, which is graphically shown in the Figure as the performance curve or pump characteristic curve. The figure shows a typical curve of a centrifugal pump where the head gradually decreases with increasing flow.As the resistance of a system increases, the head will also increase. This in turn causes the flow rate to decrease and will eventually reach zero. A zero flow rate is only acceptable for a short period without causing to the pump to burn out.

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Introduction

Pump operating point


Duty point: rate of flow at certain head

Pump operating point: intersection of pump curve and system curve

Flow

Head

Statichead

Pump performance curve

System curve

Pump operating point

ModeradorNotas de la presentacinThe rate of flow at a certain head is called the duty point. The pump performance curve is made up of many duty points. The pump operating point is determined by the intersection of the system curve and the pump curve as shown in the FigureThe Best Efficiency Point (BEP) is the pumping capacity at maximum impeller diameter, in other words, at which the efficiency of the pump is highest. All points to the right or left of the BEP have a lower efficiency.

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Introduction

Pump suction performance (NPSH) Cavitation or vaporization: bubbles inside pump

If vapor bubbles collapse Erosion of vane surfaces Increased noise and vibration Choking of impeller passages

Net Positive Suction Head NPSH Available: how much pump suction

exceeds liquid vapor pressure NPSH Required: pump suction needed to avoid

cavitation


ModeradorNotas de la presentacinCavitation or vaporization is the formation of bubbles inside the pump. This may occur when at the fluids local static pressure becomes lower than the liquids vapor pressure (at the actual temperature).A possible cause is when the fluid accelerates in a control valve or around a pump impeller.Vaporization itself does not cause any damage. However, when the velocity is decreased and pressure increased, the vapor will evaporate and collapse. This has three undesirable effects:Erosion of vane surfaces, especially when pumping water-based liquidsIncrease of noise and vibration, resulting in shorter seal and bearing lifePartially choking of the impeller passages, which reduces the pump performance and can lead to loss of total head in extreme cases. The Net Positive Suction Head Available (NPSHA) indicates how much the pump suction exceeds the liquid vapor pressure, and is a characteristic of the system design. The NPSH Required (NPSHR) is the pump suction needed to avoid cavitation, and is a characteristic of the pump design.

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Introduction

Type of pumps

Assessment of pumps


ModeradorNotas de la presentacinThis section include various types of pumps. Pumps come in a variety of sizes for a wide range of applications. They can be classified according to their basic operating principle as dynamic or displacement pumps. Dynamic pumps can be sub-classified as centrifugal and special effect pumps. Displacement pumps can be sub-classified as rotary or reciprocating pumps. In principle, any liquid can be handled by any of the pump designs. Where different pump designs could be used, the centrifugal pump is generally the most economical followed by rotary and reciprocating pumps. Although positive displacement pumps are generally more efficient than centrifugal pumps, the benefit of higher efficiency tends to be offset by increased maintenance costs.

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Type of Pumps

Classified by operating principle

Pump Classification

Dynamic Positive Displacement

Centrifugal Special effect Rotary Reciprocating

Internal gear

External gear Lobe

Slide vane

Others (e.g. Impulse, Buoyancy)

Pumps

Dynamic Positive Displacement

Centrifugal Special effect Rotary Reciprocating

Internal gear

External gear Lobe

Slide vane

Others (e.g. Impulse, Buoyancy)

Pumps

ModeradorNotas de la presentacinPumps come in a variety of sizes for a wide range of applications. They can be classified according to their basic operating principle as dynamic or positive displacement pumps In principle, any liquid can be handled by any of the pump designs. Centrifugal pump is generally the most economical but less efficient.Positive displacement pumps are generally more efficient than centrifugal pumps, but higher maintenance costs.

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Type of Pumps

Positive Displacement Pumps For each pump revolution

Fixed amount of liquid taken from one end Positively discharged at other end

If pipe blocked Pressure rises Can damage pump

Used for pumping fluids other than water

ModeradorNotas de la presentacinPositive displacement pumps are distinguished by the way they operate: liquid is taken from one end and positively discharged at the other end for every revolution. In all positive displacement type pumps, a fixed quantity of liquid is pumped after each revolution. So if the delivery pipe is blocked, the pressure rises to a very high value, which can damage the pump.Positive displacement pumps are widely used for pumping fluids other than water, mostly viscous fluids.

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Type of Pumps

Positive Displacement Pumps Reciprocating pump

Displacement by reciprocation of piston plunger

Used only for viscous fluids and oil wells

Rotary pump Displacement by rotary action of gear, cam

or vanes Several sub-types Used for special services in industry

ModeradorNotas de la presentacinPositive displacement pumps are further classified based upon the mode of displacement:Reciprocating pump if the displacement is by reciprocation of a piston plunger. Reciprocating pumps are used only for pumping viscous liquids and oil wells.Rotary pumps if the displacement is by rotary action of a gear, cam or vanes in a chamber of diaphragm in a fixed casing. Rotary pumps are further classified such as internal gear, external gear, lobe and slide vane etc. These pumps are used for special services with particular conditions existing in industrial sites.

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Type of Pumps

Dynamic pumps Mode of operation

Rotating impeller converts kinetic energy into pressure or velocity to pump the fluid

Two types Centrifugal pumps: pumping water in

industry 75% of pumps installed Special effect pumps: specialized conditions

ModeradorNotas de la presentacinDynamic pumps are also characterized by their mode of operation: a rotating impeller converts kinetic energy into pressure or velocity that is needed to pump the fluid. There are two types of dynamic pumps:Centrifugal pumps are the most common pumps used for pumping water in industrial applications. Typically, more than 75% of the pumps installed in an industry are centrifugal pumps. For this reason, this pump is further described on the next slides.Special effect pumps are particularly used for specialized conditions at an industrial site

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Type of Pumps

Centrifugal PumpsHow do they work?

(Sahdev M)

Liquid forced into impeller

Vanes pass kinetic energy to liquid: liquid rotates and leaves impeller

Volute casing converts kinetic energy into pressure energy

ModeradorNotas de la presentacinA centrifugal pump is one of the simplest pieces of equipment in any process plant. The figure shows how this type of pump operates:Liquid is forced into an impeller either by atmospheric pressure, or in case of a jet pump by artificial pressure.The vanes of impeller pass kinetic energy to the liquid, thereby causing the liquid to rotate. The liquid leaves the impeller at high velocity.The impeller is surrounded by a volute casing or in case of a turbine pump a stationary diffuser ring. The volute or stationary diffuser ring converts the kinetic energy into pressure energy.

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Type of Pumps

Centrifugal Pumps

Rotating and stationary components

(Sahdev)

ModeradorNotas de la presentacinA centrifugal pump has two main components. First, a rotating component comprised of an impeller and a shaft (click once and circles will appear). And secondly, a stationary component comprised of a casing, casing cover, and bearings (click once and circles will appear).

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Type of Pumps

Centrifugal Pumps

Impeller Sahdev) Main rotating part that provides centrifugal

acceleration to the fluid

Number of impellers = number of pump stages

Impeller classification: direction of flow, suction type and shape/mechanical construction

Shaft Transfers torque from motor to impeller during pump

start up and operation

ModeradorNotas de la presentacinImpellerAn impeller is a circular metallic disc with a built-in passage for the flow of fluid. Impellers are generally made of bronze, polycarbonate, cast iron or stainless steel, but other materials are also used. The number of impellers determines the number of stages of the pump. A single stage pump has one impeller and is best suited for low head (= pressure) Impellers can be classified on the basis of (which will determine their use): Major direction of flow from the rotation axisSuction type: single suction and double suctionShape or mechanical construction: Closed impellers have vanes enclosed by shrouds; Open and semi-open impellers; Vortex pump impellers. The figure shows an open type impeller and a closed type impellerShaftThe shaft transfers the torque from the motor to the impeller during the startup and operation of the pump.

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Type of Pumps

Centrifugal PumpsCasings

Volute Casing (Sahdev) Functions Enclose impeller as pressure vessel Support and bearing for shaft and impeller

Volute case Impellers inside casings Balances hydraulic pressure on pump shaft

Circular casing Vanes surrounds impeller Used for multi-stage pumps

ModeradorNotas de la presentacinCasings have two functionsThe main function of casing is to enclose the impeller at suction and delivery ends and thereby form a pressure vessel. A second function of casing is to provide a supporting and bearing medium for the shaft and impeller. (Click once) There are two types of casingsVolute casing (see figure) has impellers that are fitted inside the casings. One of the main purposes is to help balance the hydraulic pressure on the shaft of the pump. Circular casing has stationary diffusion vanes surrounding the impeller periphery that convert speed into pressure energy. These casings are mostly used for multi-stage pumps. The casings can be designed as solid casing (one fabricated piece) or split casing (two or more parts together)

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Introduction

Type of pumps

Assessment of pumps


ModeradorNotas de la presentacin

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Assessment of pumps

Pump shaft power (Ps) is actual horsepower delivered to the pump shaft

Pump output/Hydraulic/Water horsepower (Hp) is the liquid horsepower delivered by the pump

How to Calculate Pump Performance

Hydraulic power (Hp):Hp = Q (m3/s) x Total head, hd - hs (m) x (kg/m3) x g (m/s2) / 1000

Pump shaft power (Ps):Ps = Hydraulic power Hp / pump efficiency Pump

Pump Efficiency (Pump): Pump = Hydraulic Power / Pump Shaft Power

UNEP 2006

hd - discharge head hs suction head, - density of the fluid g acceleration due to gravity

ModeradorNotas de la presentacinThe work performed by a pump is a function of the total head and of the weight of the liquid pumped in a given time period. Pump shaft power (Ps) is the actual horsepower delivered to the pump shaft, and can be calculated as follows: Pump shaft power Ps = Hydraulic power hp / Pump efficiency pumpor Pump efficiency pump = Hydraulic power / Pump shaft powerPump output, water horsepower or hydraulic horsepower (hp) is the liquid horsepower delivered by the pump, and can be calculated as follows:Hydraulic power hp = Q (m3/s) x (hd - hs in m) x (kg/m3) x g (m/s2) / 1000 Where:Q = flow ratehd = discharge head hs = suction head = density of the fluidg = acceleration due to gravity

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Assessment of pumps

Absence of pump specification data to assess pump performance

Difficulties in flow measurement and flows are often estimated

Improper calibration of pressure gauges & measuring instruments Calibration not always carried out

Correction factors used

Difficulties in Pump Assessment

ModeradorNotas de la presentacinIn practice, it is more difficult to assess pump performance. Some important reasons are:Absence of pump specification data: Pump specification data (see Worksheet 1 in section 6) are required to assess the pump performance. Most companies do not keep original equipment manufacturer (OEM) documents that provide these data. In these cases, the percentage pump loading for a pump flow or head cannot be estimated satisfactorily.Difficulty in flow measurement: It is difficult to measure the actual flow. The methods are used to estimate the flow. In most cases the flow rate is calculated based on type of fluid, head and pipe size etc, but the calculated figure may not be accurate. Another method is to divide the tank volume by the time it takes for the pump to fill the tank. This method can, however, only be applied if one pump is in operation and if the discharge valve of the tank is closed. The most sophisticated, accurate and least time consuming way to measure the pump flow is by measurement with an ultrasonic flow meter.Improper calibration of pressure gauges and measuring instruments: Proper calibration of all pressure gauges at suction and discharge lines and other power measuring instruments is important to obtain accurate measurements. But calibration has not always been carried out. Sometimes correction factors are used when gauges and instruments are not properly calibrated. Both will lead to incorrect performance assessment of pumps.

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Introduction

Type of pumps

Assessment of pumps


ModeradorNotas de la presentacinThis section includes the factors affecting pump performance and areas of energy conservation.

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Energy Efficiency Opportunities

1. Selecting the right pump2. Controlling the flow rate by speed

variation3. Pumps in parallel to meet varying

demand4. Eliminating flow control valve5. Eliminating by-pass control6. Start/stop control of pump7. Impeller trimming

ModeradorNotas de la presentacinThis section includes the factors affecting pump performance and areas of energy conservation. The main areas for energy conservation include:Selecting the right pumpControlling the flow rate by speed variationPumps in parallel to meet varying demandEliminating flow control valveEliminating by-pass controlStart/stop control of pumpImpeller trimming

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1. Selecting the Right PumpPump performance curve for centrifugal pump

BEE India, 2004

ModeradorNotas de la presentacinThis figure shows a typical vendor-supplied pump performance curves for a centrifugal pump where clear water is the pumping liquid. In selecting the pump, suppliers try to match the system curve supplied by the user with a pump curve that satisfies these needs as closely as possible. The operating point is where the system curve and pump performance curve intersect (as explained in the introduction)The Best Efficiency Point (BEP) is the pumping capacity at maximum impeller diameter, in other words, at which the efficiency of the pump is highest. All points to the right or left of the BEP have a lower efficiency.

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1. Selecting the Right Pump Oversized pump

Requires flow control (throttle valve or by-pass line)

Provides additional head System curve shifts to left Pump efficiency is reduced

Solutions if pump already purchased VSDs or two-speed drives Lower RPM Smaller or trimmed impeller

ModeradorNotas de la presentacinThe BEP is affected when the selected pump is oversized. The reason is that the flow of oversized pumps must be controlled with different methods, such as a throttle valve or a by-pass line. These provide additional resistance by increasing the friction. As a result the system curve shifts to the left and intersects the pump curve at another point. The BEP is now also lower. In other words, the pump efficiency is reduced because the output flow is reduced but power consumption is not. Inefficiencies of oversized pumps can be overcome by, for example, the installation of VSDs, two-speed drives, lower rpm, smaller impeller or trimmed impeller

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2. Controlling Flow: speed variationExplaining the effect of speed

Affinity laws: relation speed N and Flow rate Q N

Head H N2

Power P N3

Small speed reduction (e.g. ) = large power reduction (e.g. 1/8)

ModeradorNotas de la presentacinA centrifugal pumps rotating impeller generates head. The impellers peripheral velocity is directly related to shaft rotational speed. Therefore varying the rotational speed has a direct effect on the performance of the pump. The pump performance parameters (flow rate, head, power) will change with varying rotating speeds. To safely control a pump at different speeds it is therefore important to understand the relationships between the two. The equations that explain these relationships are known as the Affinity Laws: Flow rate (Q) is proportional to the rotating speed (N)Head (H) is proportional to the square of the rotating speedPower (P) is proportional to the cube of the rotating speedAs can be seen from the above laws, doubling the rotating speed of the centrifugal pump will increase the power consumption by 8 times. Conversely a small reduction in speed will result in a very large reduction in power consumption. This forms the basis for energy conservation in centrifugal pumps with varying flow requirements.

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Variable Speed Drives (VSD) Speed adjustment over continuous

range Power consumption also reduced! Two types

Mechanical: hydraulic clutches, fluid couplings, adjustable belts and pulleys

Electrical: eddy current clutches, wound-rotor motor controllers, Variable Frequency Drives (VFDs)

2. Controlling Flow: speed variation

ModeradorNotas de la presentacinControlling the pump speed is the most efficient way to control the flow, because when the pumps speed is reduced, the power consumption is also reduced. The most commonly used method to reduce pump speed is Variable Speed Drive (VSD).VSDs allow pump speed adjustments over a continuous range, avoiding the need to jump from speed to speed as with multiple-speed pumps. VSDs control pump speeds use two types of systems:Mechanical VSDs include hydraulic clutches, fluid couplings, and adjustable belts and pulleys. Electrical VSDs include eddy current clutches, wound-rotor motor controllers, and variable frequency drives (VFDs). VFDs are the most popular and adjust the electrical frequency of the power supplied to a motor to change the motors rotational speed.

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Benefits of VSDs

Energy savings (not just reduced flow!)

Improved process control

Improved system reliability

Reduced capital and maintenance costs

Soft starter capability

2. Controlling Flow: speed variation

ModeradorNotas de la presentacinThe major advantages of VSD application in addition to energy saving are:Improved process control because VSDs can correct small variations in flow more quickly.Improved system reliability because wear of pumps, bearings and seals is reduced.Reduction of capital & maintenance cost because control valves, by-pass lines, and conventional starters are no longer needed.Soft starter capability: VSDs allow the motor the motor to have a lower startup current.

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3. Parallel Pumps for Varying Demand

Multiple pumps: some turned off during low demand

Used when static head is >50% of total head

System curvedoes not change

Flow rate lowerthan sum ofindividual flow rates

(BPMA)

ModeradorNotas de la presentacinOperating two or more pumps in parallel and turning some off when the demand is lower, can result in significant energy savings. Pumps providing different flow rates can be used.Parallel pumps are an option when the static head is more than fifty percent of the total head. (Click once) The figure shows the pump curve for a single pump, two pumps operating in parallel and three pumps operating in parallel. that the system curve normally does not change by running pumps in parallel. that flow rate is lower than the sum of the flow rates of the different pumps.

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4. Eliminating Flow Control Valve Closing/opening discharge valve (throttling)

to reduce flow

Head increases: does not reduce power use

Vibration and corrosion: high maintenance costs and reduced pump lifetime

(BPMA)

ModeradorNotas de la presentacinAnother method to control the flow by closing or opening the discharge valve (this is also known as throttling the valves). While this method reduces the flow, disadvantages areIt does not reduce the power consumed, as the total head (static head) increases. The figure shows how the system curve moves upwards and to the left when a discharge valve is half closed.increases vibration and corrosion and thereby increases maintenance costs of pumps and potentially reduces their lifetimesVSDs are a better solution from an energy efficiency perspective.

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5. Eliminating By-pass Control Pump discharge divided into two

flows One pipeline delivers fluid to destination

Second pipeline returns fluid to the source

Energy wastage because part of fluid pumped around for no reason

ModeradorNotas de la presentacinThe flow can also be reduced by installing a by-pass control system, in which the discharge of the pump is divided into two flows going into two separate pipelines. One of the pipelines delivers the fluid to the delivery point, while the second pipeline returns the fluid to the source. In other words, part of the fluid is pumped around for no reason, and thus is an energy wastage. This option should therefore be avoided.

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6. Start / Stop Control of Pump Stop the pump when not needed

Example: Filling of storage tank

Controllers in tank to start/stop

Suitable if not done too frequently

Method to lower the maximum demand (pumping at non-peak hours)

ModeradorNotas de la presentacinA simple and reasonable energy efficient way to reduce the flow rate is by starting and stopping the pump, provided that this does not happen to frequently. An example where this option can be applied, is when a pump is used to fill a storage tank from which the fluid flows to the process at a steady rate. In this system, controllers are installed at the minimum and maximum level inside the tank to start and stop the pump. Some companies use this method also to avoid lower the maximum demand (i.e. by pumping at non-peak hours).

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7. Impeller Trimming Changing diameter: change in

velocity

Considerations Cannot be used with varying flows

No trimming >25% of impeller size

Impeller trimming same on all sides

Changing impeller is better option but more expensive and not always possible

ModeradorNotas de la presentacinChanging the impeller diameter gives a proportional change in the impellers peripheral velocityChanging the impeller diameter is an energy efficient way to control the pump flow rate. However, for this option, the following should be considered:This option cannot be used where varying flow patterns exist. The impeller should not be trimmed more than 25% of the original impeller size, otherwise it leads to vibration due to cavitation and therefore decrease the pump efficiency. The balance of the pump has to been maintained, i.e. the impeller trimming should be the same on all sides.Changing the impeller itself is a better option than trimming the impeller, but is also more expensive and sometimes the smaller impeller is too small.Figure 17 illustrates the effect of impeller diameter reduction on centrifugal pump performance.

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7. Impeller TrimmingImpeller trimming and centrifugal pump performance

(BEE India, 2004)

ModeradorNotas de la presentacinThe figure illustrates the effect of impeller diameter reduction on centrifugal pump performance. (Click once) With the original impeller diameter the flow is higher(Click once) With the trimmer impeller the flow is lower

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Comparing Energy Efficiency Options

Parameter Change control valve

Trim impeller VFD

Impeller diameter

430 mm 375 mm 430 mm

Pump head 71.7 m 42 m 34.5 mPump efficiency 75.1% 72.1% 77%Rate of flow 80 m3/hr 80 m3/hr 80 m3/hrPower consumed

23.1 kW 14 kW 11.6 kW

ModeradorNotas de la presentacinThis table compares three options to improve energy efficiency in pumps: changing the control valve, trim the impeller and variable frequency drive.The VFD clearly reduces power most, but a disadvantage is the high costs of VFDs.Changing the control valves should at all times be avoided because it reduces the flow but not the power consumption and may increase pump maintenance costs.

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Training Session on Energy Equipment

Pumps & Pumping Systems

THANK YOU

FOR YOUR ATTENTION

UNEP 2006

ModeradorNotas de la presentacinHello.

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Disclaimer and References

This PowerPoint training session was prepared as part of the project Greenhouse Gas Emission Reduction from Industry in Asia and the Pacific (GERIAP). While reasonable efforts have been made to ensure that the contents of this publication are factually correct and properly referenced, UNEP does not accept responsibility for the accuracy or completeness of the contents, and shall not be liable for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the contents of this publication. UNEP, 2006.

The GERIAP project was funded by the Swedish International Development Cooperation Agency (Sida)

Full references are included in the textbook chapter that is available on www.energyefficiencyasia.org

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Pumps and Pumping Systems

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