Condenser specifications

Collect the condenser design specifications in respect of the following key parameters

• Heat load considered for design

• Design inlet cooling water temperature

• Design TTD

• Cleanliness factor

• Cooling water temperature raise

• Condenser back pressure

• Cooling water flow

• Cooling water side pressure drop

• No of cooling water pass

• Total heat transfer area

• Condenser no of tubes:

• Water box design pressure

9.4 Instruments Required

The following instruments are required for conducting the water pumping energy audit:

• Power Analyzer: Used for measuring electrical parameters of motors such as kW, kVA, pf, V, A and Hz

• Temperature Indicator & Probe

• Pressure Gauge: To measure operating pressure and pressure drop in the system

• Stroboscope: To measure the speed of the driven equipment and motor

• Ultra sonic flow meter or online flow meter

• Sling hygrometer or digital hygrometer

• Anemometer

• In addition to the above calibrated online instruments can be used

• PH meter

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PUSAT PENDIDIKAN DAN PELATIHAN CONDENSOR COOLING

9.5 Measurements & Observation to Be Made

While conducting the audit, the following measurements and observations are necessary

• Energy consumption pattern of pumps and cooling tower fans

• Motor electrical parameters (kW, kVA, Pf, A, V, Hz, THD) for pumps and cooling tower fans

• Pump operating parameters to be measured/monitored for each pump are:

 Discharge

 Head (suction & discharge)

 Valve position (observation)

 Temperature

 Load variation

 Power parameters of pumps

 Pumps operating hours and operating schedule

 Pressure drop in the system (between discharge and user point)

 Pressure drop and temperatures across the users (heat

 exchangers, condensers, etc)

 Cooling water flow rate to users

 Pump /Motor speed

 Actual pressure at the user end

 User area pressure of operation and requirement

• Cooling tower parameters to be monitored

 Inlet temperature

 Outlet temperature

 Dry bulb temperature

 Wet bulb temperature or relative humidity

 Water flow to cooling tower

 Fan power consumption (kW/cell)

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• While conducting the measurement or performance evaluation any system simultaneously the following need to be noted

 Unit load of the plant

 Date & time of measurement

 Instruments used of measurement

 Frequency of the measurement 9.6 Observations and Analysis

9.6.1 System familiarization and operational details

Detailed interactions with the plant personnel have to be carried out to get familiarization for system detail and operational details. The brief details of the entire system have to be given in the report

9.6.2 Energy consumption Pattern

If the plant is monitoring the energy consumption, it is suggested to record the data and monitor the daily and monthly consumption pattern. Collect the past energy consumption data (month wise for at least 12 months, daily consumption for about a week for different seasons, daily consumption during the audit period). Work out the total consumption of cooling water and cooling tower system to arrive at percentage to the total consumption of the auxiliary consumption. If the energy meters are not installed to water pumps and cooling tower fans & its auxiliary units of, instantaneous measurements can be carried out, based on the loading pattern the daily consumption can be worked out (as shown in Table 9-6).

Table 9-6: Energy consumption pattern

Equipment Instantaneous kW Daily consumption, kWh Cooling water pumps

Make up water pumps Cooling tower fans Others

Total

The energy consumption of cooling water and associated system: kWh/day Total auxiliary power consumption: kWh/Day

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9.6.3 Operating efficiency and performance evaluation of the pumps

All operating pumps in cooling water circuit needs to be studied for its operating efficiency (As run performance test) with the aid of sophisticated energy audit instruments. In addition to these portable instruments online valid calibrated instruments can also be used during the energy audits. The parameters to be studied in detailed are:

 Water flow rate and pressure of pumps/headers

 Velocity in the main headers and pumps and major lines (to verify adequacy of line sizes)

 Power consumption of pumps (for estimating the operating efficiency of the pumps)

 Monitor present flow control system and frequency of control valve variation if any (for application of variable speed drives)

 Fill up the following data sheet for every pump for comparison with the design/PG test values

The following Table 9-7 gives the list of parameters to be considered for performance evaluation.

Table 9-7: Performance parameters for water pumps

Particulars Unit Design/PG

test value Actual Remarks Pump ID code

Total head developed by pump Water flow

Speed of the pump/ motor Hydraulic kW

Input kW to the motor Combined efficiency

Motor efficiency (Refer to motor performance curve)

Pump efficiency

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Type of discharge flow control mechanism

Discharge throttle valve position (%

open)

Flow control frequency and duration if any

Hydraulic power can be calculated by using the following:

Q(m³/s) x Total head.(hd - hs)m x ρ.(kg/m³) x g.(m/s² ) Hydraulic kW =

1000

Where:

If the pumps are operating in parallel, it is advised to measure all above parameter for every pump separately to evaluate the individual pump performance. However combined parameters of flow and head need to be verified with Performance curve for parallel operation.

Compare the actual values with the design/performance test values if any deviation is found, investigate for the contributing factors and arrive at appropriate suggestions.

• The investigations for abnormality are to be carried out for problems.

• Enlist scope of improvement with extensive physical checks/observations.

Q Water flow rate m³/s

Total head

Difference between discharge head (hd)

and suction head (hs ) m

ρ Density of the water or fluid being pumped kg/m³ g Acceleration due to gravity m/s²

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• 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

• Compare the specific energy consumption with similar type of pumps and latest energy efficient pumps

• Cost analysis with savings potential for taking improvement measures.

In document Energy Audit (Page 110-115)