1 Pumping 101

2 Learning Outcomes Upon completion of this training one should be able to: Know what are the key pump components and how they impact pump performance. Know what the impact of pump efficiency is on annual operating cost. Know what TDH is and how to calculate it. Define the three Pump Affinity Laws. Know the difference between NPSH R and NPSH A. Describe the difference between series and parallel pumping. Know what WWE is. Know the difference between a dry running and wet running pump.

3 Unit 1 Pump Mechanics

4 What is a pump?

5 What is a Pump? A pump is a machine which adds energy to a fluid for the purpose of increasing the pressure or moving it along a pipeline. Pumps don’t make water. Pumps don’t make pressure, it just operates against the pressure.

6 Basic Types of Pumps Positive displacement pumps, add energy directly to a movable boundary, which imparts the energy to the fluid. –Examples include screw pumps, piston pumps, gear pumps. Roto-dynamic pumps, add the energy indirectly through a rotating part in the form of velocity, and subsequently converts the velocity to pressure. –These pumps are commonly referred to as centrifugal pumps.

7 Basic Impeller Types OPENSEMI-OPENCLOSED

8 Impeller Discharge Configurations

9 Centrifugal Impellers A. Width = Flow B. Diameter = Head C. Vane Design = BEP / Efficiency B A C

10 Impeller Direction of Rotation

11 The fluid enters the pump through the inlet (suction eye) where the impeller adds energy (in the form of velocity) through centrifugal force. When the fluid leaves the impeller, there is a decrease in velocity. Velocity and pressure are inversely proportional. The decrease in velocity results in an increase in pressure as the fluid leaves the pump. Centrifugal Action

12 Other Pump Parts Coupling: Connects motor to shaft. Shaft: Mount for impeller. Bearings: Keeps shaft aligned. Mechanical Seal: No leak at shaft. Nameplate: Data about pump.

13 Dry Running (Three-Piece) Requires shaft seal. Can change the size of motors. Repairable. Shaft Seal

14 Dry Running (Three-Piece) Shaft Seal Requires shaft seal. Can change the size of motors. Repairable.

15 Wet Running (Wet Rotor) Does not require shaft seal. Cannot oversize motors. Not repairable.

16 Wet Running (Wet Rotor) Does not require shaft seal. Cannot oversize motors. Not repairable. Water Cooled Areas

17 Questions on Wet Runners Can you mount a wet running pump in a vertical position with the bearing facing up? –No, airlock can occur. Also, the bearings may not be lubricated which could cause bearing failure. Can you pump syrup with a wet running pump? –No, the “fluid” lubricates the pump and pumping syrup would generally gum up the pump.

18 Unit 2 Pump Curves, Affinity Laws, and System Curves

19 A Typical Pump Curve Format Performance Curve Efficiency (  or eta) Curve BHP Curve NPSHr Curve

20 A Typical Catalog Performance Curve

21 Head, H Centrifugal pump curves are generally not rated in psi. Rating is in feet of head. Total Dynamic Head (TDH) is found by adding: 1.Elevation (He) – rated in feet. 2.Pressure (Hp or ∆P) – rated in psi. 3.Friction loss (Hf) – usually rated in feet.

22 Determining Elevation Head (He) What is the total elevation head of the above system? 200 ft S D

psi = _______ Feet of Water* 2.31 feet Converting Between Head and Pressure 32°F ~ 60°F 1 psi

24 Converting between Hp & ∆P Pg. 8 HVAC Technical Guide

25 What is 2.31? Where: 62.4 = specific weight of 32°F ~ 60°F

ft 23 ft 80 ft psi34.6 psi psi Head and Pressure Based on Water

27 GasolineSalt WaterSugar Water 0.70 s.g.1.03 s.g.1.30 s.g. 165 ft 50 psi 93 psi74 psi50 psi Effect of s.g. on Pressure and Head

28 Determining Friction Head

29 Friction of Water Asphalt-dipped Cast Iron and New Steel Pipe (Based on Darcy’s Formula) 8 Inch Note: No allowance has been made for age, difference in diameter, or any abnormal condition of interior surface., Any factor of safety must be estimated from the local conditions and the requirement of each particular installation. It is recommended that for most commercial design purposes a safety factor of 15 to 20% be added to the values in the tables.

30 Friction in Fittings The friction loss through one 1¼ inch standard 90 ° elbow is equal to the friction loss through how many feet of straight 1¼ inch pipe? 3.6 ft These are NOT friction values!!!

31 Friction Head 10 gpm thru 250 ft – 1” Sched. 40 steel pipe 1. What is the friction head in feet? _______________ 2. What is the pressure head in feet? _______________ 3. What is the elevation head in feet? _______________ 4. What is the total head? (4 = 1+2+3) _______________ 0 ft 17 ft SD Total LengthPer100’Friction FactorTotal Friction Loss 250÷100X6.81=17

32 Calculating Horsepower

33 Where do we get “3960” ? 1HP = 550 Foot Pounds per Second X 60 Seconds per Minute 33,000 Foot Pounds per Minute ÷ Pounds per Gallon of Water 3960

34 Practice Problems What is WHP(P3) for a pump moving 200 gpm of 60°F water against a TDH of 500’? (200 gpm X 500 feet) ÷ 3960 = WHP

35 Practice Problems What is BHP(P2) if the efficiency of the pump is 83%? WHP ÷ 0.83 = BHP

36 Practice Problems What is EHP(P1) if the efficiency of the motor is 90%? BHP ÷ 0.90 = EHP

37 Convert EHP to Kilowatts EHP X = kW What is kW value if the EHP of the pump is 33.81?

38 Calculate Energy Cost kW X 1000 hours per year 25,210 kW/hrs per year X $0.10 per kWh $2, cost per year

39 An Important Point!!!!! At a given speed, with a given impeller diameter: the pump will perform along its characteristic curve, from run out to shut off.

40 Pump Affinity Laws

41  FLOW changes DIRECTLY as a change in speed or diameter*  HEAD changes as the SQUARE of a change in speed or diameter*  HORSEPOWER changes as the CUBE of a change in speed or diameter*  FLOW changes DIRECTLY as a change in speed or diameter*  HEAD changes as the SQUARE of a change in speed or diameter*  HORSEPOWER changes as the CUBE of a change in speed or diameter* Pump Affinity Laws * May not be true for higher specific speeds

42 Important...Remember these: Pump Affinity Laws Pg. 14 HVAC Technical Guide

43 What are the affects of the Affinity Laws? %SPEED POWER PG: 113 HEAD FLOW

44 As we trim, we would expect the efficiency to stay the same, but remember the internal losses! What are the affects of the Affinity Laws? ACTUAL PUMP CURVE H Q THEORETICAL PUMP CURVE LOSSES DUE TO SHOCK, TURBULENCE, RECIRCULATION AND FRICTION

45 Catalog Pump Curve

46 System Curves

47 Creating a System Curve

48 Graph the head required through point for 100’ Equivalent Length of 2” Type L Copper Tubing for the following flows: GPM TDH Creating a System Curve

49 Graph the head required through point for 200’ Equivalent Length of 2” Type L Copper Tubing for the following flows: GPM TDH Creating a System Curve

50 System Curve

51 Operating Point Duty Point System and Pump Curves

52 System Curves Open System w/ Static Head

53 System Curves Open System w/ Static Head

54 Overlaying the pump curve and the system curve for systems with static head Operating Point Duty Point System Curves

55 Unit 3 NPSH & Multiple Pump Operation

56 NPSH Net Positive Suction Head

57 Why Worry About NPSH ? Pumps Don’t Suck.

58 The fluid needs to enter the impeller before the impeller can begin adding energy. NPSH defines the energy available to the fluid above it’s vapor pressure. Remember Pump Basics

59 Two “Types” of NPSH NPSH R is the NPSH required by the pump. –It is a function of the pump design. (This is the NPSH shown on the pump curve.) NPSH A is the NPSH available to the pump. –It is a function of the system design.

60 NPSH is Like a Checkbook NPSH R is like the money needed to pay your bills NPSH A is income. You need much more income than bills!

61 The “Rule”: For practical purposes, forget the equal sign: NPSH Available must be GREATER than the NPSH Required. NPSH A NPSH R 

62 Take This Note!!!! Add minimum 2 foot safety factor to NPSH R !

63 NPSH R Chief factors influencing NPSH R include: –impeller eye area –vane inlet design –the relationship with the casing. NPSH R is determined by factory testing.

64 NPSH A The NPSH A is influenced by several factors, many of which are controllable or modifiable. These factors include: –Absolute pressure –Vapor pressure –Suction pressure –Friction loses –Highly aerated water (as seen in cooling towers)

65 NPSH A Formula NPSH A = H A + H S - H VPA - H F Where: H A = Absolute pressure H S = Suction pressure (head) H VPA = Vapor pressure H F = suction piping Friction head

66 In Suction Lift Example B, H S will be a Negative Number

67 Question: What is difference between PSI, PSIA and PSIG? –PSI is a unit of measurement. –PSIG is Gauge pressure, and is relative to atmospheric pressure (reads 0 psi on the bench). –PSIA is Absolute pressure, and includes atmospheric pressure (reads about 14.7 psi on the bench at sea level).

68 Absolute Pressure The absolute pressure is the pressure (energy) added to the fluid by an outside source. In an open system, this is the atmospheric pressure.

69 Atmospheric Pressure 1 PSI = 2.31 ft H 2 70 O F = inches of mercury (hg) PSI = 33.9 ft = 30 inches of mercury (hg). (Watch the weather report!)

70 Atmospheric Pressure vs. Altitude Atmospheric Pressure Pg. 31 HVAC Technical Guide

71 Vapor Pressure of Water Pg. 30 HVAC Technical Guide

72 Vapor Pressure Curve

73 Multiple Pump Operation

74 Pumping in Series

75 Pumping in Parallel

76 Unit 4 The Cost of Pumping

77 Cost Per Hour of Pumping WWE = Wire To Water Efficiency Fixed Speed WWE = (PE) (ME) Variable speed WWE = (PE) (ME) (DE) OR

78 Calculating Operating Costs DESIGN POINT: 160’TDH (PUMP “A”)

79 Calculating Operating Costs  Assume $0.10 /kWH  Assume 92% Motor Efficiency  Assume 84.5% Pump Efficiency  Assume 1 Pump  Assume 24 Hrs / Day  Assume 365 Days / Yr  Assume 60°F Water (s.g. = 1)

80 Calculating Operating Costs ≈ $108,711 / YEAR

81 Calculating Operating Costs  Assume $0.10 /kWH  Assume 92% Motor Efficiency  Assume 90.5% Pump Efficiency  Assume 1 Pump  Assume 24 Hrs / Day  Assume 365 Days / Yr  Assume 60°F Water (s.g. = 1)

82 Calculating Operating Costs DESIGN POINT: 160’TDH (PUMP “B”)

83 Calculating Operating Costs ≈ $102,054 / YEAR

84 The Difference is Savings  The difference in PUMP EFFICIENCY between the 84.5% Efficient Pump “A” and the 90% Efficient Pump “B” Results in Real Operating Cost Savings  Pump “A” Operating Cost ≈ $108,711 / Year  Pump “B” Operating Cost ≈ $102,054 / Year $ Operating Cost Savings = $6,657 / Year

85 What Questions Do you Have?