5.energy audit of pumps
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5.energy audit of pumps

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5.energy audit of pumps 5.energy audit of pumps Presentation Transcript

  • Submitted By : Padma Dhar Garg 2011PME5258 ENERGY AUDIT OF PUMP
  • INTRODUCTION What is a Pump?  A pump is a device used to convert mechanical energy to pressure energy for the movement of fluids, such as liquids, gases or slurries. Objective • Transfer fluid from source to destination • Circulate fluid around a system
  • MAIN PUMP COMPONENTS  Pumps  Prime movers: electric motor  Piping to carry fluid  Valves to control flow in system
  • PUMP LAYOUT
  • PUMP CURVES Pump Operating Point System head curve Pump Head – Flow curve
  • PUMP TERMINOLOGY  Friction Head :- Friction head is the measure of resistance to flow provided by the pipe , valve etc.  Static Head:-The static head is the amount of feet of elevation the pump must lift the water regardless of flow.  Operating Point:- It is a point where system curve and pump curve intersect .  Static Suction Lift :- The vertical distance from the water line to the centerline of the impeller.  Static Discharge Head :- The vertical distance from the discharge outlet to the point of discharge or liquid level when discharging into the bottom of a water tank
  • DATA COLLECTION Specifications and design details
  • DATA COLLECTION Specifications and design details contd…
  • INSTRUMENTS REQUIRED • Power Analyzer: Used for measuring electrical parameters such as kW, kVA, pf, V, A and Hz •Stroboscope: To measure the speed of the driven equipment and motor • Ultra sonic flow meter or online flow meter •The above instruments can be used in addition to the calibrated online / plant instruments
  • PARAMETERS TO BE MEASURED • Energy consumption pattern of pumps (daily / monthly /yearly consumption) • Motor electrical parameters (kW, kVA, pf, A, V, Hz) for individual pumps
  • Contd..  Pump operating parameters to be monitored for each pump  Discharge Flow,  Head (suction & discharge),  Load variation,  Pumps operating hours and operating schedule,  Pump /Motor speed,
  • EFFICIENCY AND PERFORMANCE EVALUATION OF THE PUMPS Performance parameters for water pumps
  • EFFICIENCY AND PERFORMANCE EVALUATION OF THE PUMPS Performance parameters for water pumps contd..
  • EFFICIENCYAND PERFORMANCE EVALUATION OF THE PUMPS Pump hydraulic power can be calculated by the formula: Hydraulic kW = Q x Total Head, (hd – hs) x x g 1000 Parameter Details Unit Q Water flow rate m3/s Total head Difference between discharge head, hd & suction head, hs m Density of water or fluid being pumped Kg/m3 g Acceleration due to gravity m2/s Pump efficiency, Pump = Hydraulic power Pump shaft power Pump shaft power = Hydraulic power x Motor
  • FLOW MEASUREMENT, Q  The following are the methods for flow measurements: • Ultrasonic flow measurement • Tank filling method • Installation of an on-line flow meter
  • RATING OF MOTOR
  • DATA TABLE Sr. No. Description UOM Present Pump Proposed Pump 1 Name 2 Head Mtrs. 6.70 3 Discharge m3/S 0.013 4 Input Power motor KW 3.89 4 Power consumption daily kWh 11.67 5 Efficiency % 92 6 Specific Power Consumption kWh/m3 7 Running Hrs/day Hrs. 3 8 Running Hrs./ Annum Hrs. 330 9 Power consumption/Annum kWh 1283.70 10 Unit Rate Rs 8.00 11 Total expenditure/Annum Rs. 10269.60 13 Estimated Saving Rs. 4519.00 14 Cost of proposed VFD Rs. 15 Simple Pay Back Period (year) 2.27
  • MEASURED DATA Flow rate (m3/s) 0.013 HD (mtrs.) 9.14 HS (mtrs.) 2.44 HD - HS (mtrs.) 6.7 Motor voltage (V) 393 Motor current (A) 10 Motor input power (kW) 3.89
  • CALCULATION  Hydraulic power = (0.013 × 6.7 × 1000 × 9.8)/1000 = 0.8754 kW Motor air gap power PG = 3.89 kW Motor shaft power = Pump shaft power Motor shaft power = PG - s PG Motor slip ‘s’ = (NS – NR)/ NS NS = 120 f / P = (120×50) /4 = 1500 s = (1500 – 1440)/1500 = 0.04 Pump shaft power = 3.89 – (0.04 × 3.89) = 3.73
  • CONTD.. Pump efficiency, Pump = Hydraulic power / Pump shaft power = 0.8754 / 3.73 = 0.24 = 24%
  • CALCULATION Running Hrs/day = 3 Hrs Working days = 110 days/sem Running Hrs./ Annum = 330 Hrs Power consumption daily = 3.00 3.89 = 11.67kWh Power consumption/Annum = 330 3.89 = 1283.7 kWh Unit Rate = 8 Rs. Total expenditure/Annum = 8 1283.7 = 10269.6 Rs.
  • Affinity Laws of Centrifugal Loads  ƒ FLOW is proportional to motor speed.  ƒ PRESSURE is proportional to the motor speed squared.  ƒ POWER is proportional to the motor speed cubed.
  • A VFD IN A BLOCK DIAGRAM
  • AFFINITY LAWS FOR PUMP
  • CONTD..  Assuming the Pump does not need to run at full speed all of the day, we will use an example of:  Running full speed (100%) for 25% of the day  80% speed for 50% of the day  60% speed for the remaining 25% of the day  Cost of running with an AC drive controlling the motor: • 5.2 hp x (1)3 x 0.746 kW/hp x 82.5 hours x 8/kWh = 2567.40 • 5.2 hp x (0.8)3 x 0.746 kW/hp x 165 hours 8/kWh=2629.00 • 5.2hp x (0.6)3 x 0.746 kW/hp x 82.5 hours x 8/kWh =554.50
  • CONTD..  Total =5750.9 Rs.  Annual saving = 10269.60 – 5750.90 =4519Rs.  Pay back period = 2.27yr
  • EFFECT OF VFD ON FLOW RATE  F N F =k N At 100% speed ie. 1440 rpm 0.013= k 1440 K = 9.03 10-6 • At 80% speed ie. 1152 F= 9.03 10-6 1152 = 0.014m3/s • At 60% speed ie. 864 F= 9.03 10-6 1864 = 0.0071m3/s 864 1152 1440 0 200 400 600 800 1000 1200 1400 1600 0.007 0.01 0.013 speed flow rate
  • ENERGY CONSERVATION OPPORTUNITIES • Compare the actual values with the design / performance test values if any deviation is found, list the factors with the details and suggestions to over come. • Compare the specific energy consumption with the best achievable value (considering the different alternatives). Investigations to be carried out for problematic areas.. • Enlist scope of improvement with extensive physical checks / observations. Based on the actual operating parameters, enlist recommendations for action to be taken for improvement, if applicable such as: • Replacement of pumps • Impeller replacement • Impeller trimming • Variable speed drive application, etc
  • Avoiding over sizing of pump ENERGY CONSERVATION OPPORTUNITIES Head Head Partially closed valve Const. Speed A B C Meters Pump Efficiency 24% Pump Curve at Full open valve System Curves Operating Points 14401152 7.14 m 9.14 m Static 5.14 m Flow (m3/s) Oversize Pump Required Pump
  • ENERGY CONSERVATION POSSIBILITIES- SUMMARY • Improvement of systems and drives. • Use of energy efficient pumps • Replacement of inefficient pumps • Trimming of impellers • Correcting inaccuracies of the Pump sizing • Use of high efficiency motors • Integration of variable speed drives into pumps: The integration of adjustable speed drives (ASD) into compressors could lead to energy efficiency improvements, depending on load characteristics. • High Performance Lubricants: The low temperature fluidity and high temperature stability of high performance lubricants can increase energy efficiency by reducing frictional losses.