ENERGY EFFICIENCY BENCHMARKING STUDY OF FOOD …

Methodology| Findings | Savings Opportunities | Recommendations

ENERGY EFFICIENCY BENCHMARKING STUDY OF FOOD MANUFACTURING PLANTS IN SINGAPORE

Objectives of Workshop

To provide an overview of the energy efficiency benchmarking study of food

manufacturing plants in Singapore

Share the findings of the study:

Aggregate results of the energy efficiency of major systems and equipment

Energy saving opportunities

Energy saving potential

Other recommendations

Best practices to be adopted to improve energy efficiency of food manufacturing

plants

1

Introduction

LJ Energy Pte Ltd was appointed by National Environment Agency (NEA) to conduct

an Energy Efficiency Benchmarking Study of Food Manufacturing Plants in Singapore

The benchmarking study involved ten food manufacturing plants, out of which,

nine of the Plants have a minimum energy consumption of 30 TJ per year while the

remaining Plant has a minimum energy consumption of 15 TJ per year

The main objectives of the Study were to:

Develop an energy consumption profile of the food manufacturing industry by studying

the major systems and equipment of each participating Plant;

Identify suitable metrics to assess and benchmark the energy efficiency of major systems

and equipment;

Assess and benchmark the energy efficiency of major systems and equipment of

participating Plants; and

Identify effective measures to improve the energy efficiency of major systems and

equipment.

2

Overview

Methodology

Types of selected plants

Main energy consuming systems

Assessment Framework

Energy usage profiles

Main findings

Typical energy saving opportunities

Overall savings potential

Other findings and recommendations

3

Methodology

4

Identify types of food

manufacturing plants

Identify main energy consuming

equipment & systems

Identify suitable Energy

Performance Indicators

EnPIs

Determine data required to

compute each EnPIs

Prepare methodology for data

collection

Compare with benchmarks

Collect data Compute EnPIs

Identify potential improvement

measures

Estimate savings and cost for

improvement measures

Identify ten suitable plants

Establish total energy usage

Methodology

5

Types of Selected Plants

6

Types of Selected Plants

Beverage

Dairy

Food ingredients

Frozen and cooked food

Noodle manufacturing

7

Main Energy Consuming Systems

8

Main Energy Consuming Systems

Boiler systems

Chiller systems

Refrigeration systems

Compressed air systems

Process cooling systems

Ovens and heaters

Production systems & motors

Lighting systems

9

Boiler Systems

All use fire tube boilers except for one with a water tube boiler

Natural gas, diesel, town gas, biomass or electricity is used as the input energy

source

Steam and hot water boilers

Operating pressure ranges from 7 to 16 bar

Steam used for heating and process applications

like drying & frying

10

Chiller Systems

Mixture of water cooled and air cooled chillers are used

Operate 24 hours a day

All systems use chilled water except for two that use glycol

Operating temperatures vary from 6/7 oC (CHW) to 2/3 oC (glycol)

Operating cooling load for chillers between 20 and 500 RT

Chillers are more than 10 years old

VRV, split units and package units are also used for space cooling

11

Refrigeration Systems

Used for low temperature process cooling and cold rooms

Ammonia is used as the refrigerant for the main system except in two plants which

use R507 and 404a

A mixture of evaporative condensers, water cooled condensers and air cooled

condensers are used

Operating temperatures range from about -30 to +2 oC

12

Compressed Air Systems

Compressed air is used for operations and control of pneumatic equipment,

machines and processes

Operating pressure ranges from 5.5 to 7.5 bar (except bottle blowing which

requires 39 bar)

Mix of fixed speed and VSD compressors are used

All use refrigerant type dryers

13

Process Cooling Systems

Cooling towers and pumps are used to circulate water for process cooling

applications

Operate 24 hours a day

Supply temperature ranges from 26 to 37 oC

Pumps and fans operate at constant speed

14

Ovens and Heaters

Used for cooking as well as process applications

Use natural gas, electricity or steam as the input energy source

15

Production Systems and Motors

Equipment such as mills, rollers, grinders, pulverizers and refiners are used in

various production processes

Companies feedback that majority of motors used have IE2 efficiency rating

Loading of some motors below 40%

Packing machines are used for bottling and packing of finished products

16

Lighting Systems

Lighting is provided for production areas, warehouses, offices, common areas

Most commonly used type of lighting is T8 fluorescent lamps with magnetic ballast

17


18


The main objectives of the assessment framework were to:

Identify major energy consuming systems and equipment that account for at least

80% of the total primary energy consumption of each participating Plant;

Identify suitable Energy Performance Indicators (“EnPIs”) for assessing the energy

efficiency of the major energy consuming systems and equipment;

Develop suitable methodologies for measuring the identified EnPIs for the various

equipment and systems; and

Benchmark the performance of the equipment and systems using the measured

EnPIs with industry established values or standards.

19


Main Features of the Assessment Framework:

Identification of EnPIs

Methodology for computing EnPIs

Methodology for measurements

Instruments to be used

Accuracy of instruments

Duration of measurements

20

Assessment Framework – Boiler Systems

Boiler Thermal Efficiency,

Energy output to steam = msteam x hsteam – mfeed x hfeed

hfeed = Enthalpy of feed water at Tfeed, kJ/kg

mfeed = Mass flow rate of feed water to boiler, kg/s

msteam = Mass flow rate of steam, kg/s = mfeed - mbd

hsteam = Enthalpy of steam at the outlet of boiler, kJ/kg

Energy input of fuel = Vfuel x fuel x CV

Vfuel = Fuel consumption rate, m3/s

fuel = Density of fuel, kg/m3

CV = Gross calorific value of fuel, kJ/kg

Parameter Sensor type Accuracy Measurement type

Measurement Duration

mfeed Ultrasonic flow meter

2% Trend log 1 minute interval for 3 days

Tfeed Thermistor 0.04oC Trend log 1 minute interval for 3 days

Tsteam RTD Based on

installed sensor

Spot

measurement/Trend log

1 minute interval for 3

days (Depending on installed system)

Psteam Pressure gauge Based on

installed sensor

Spot

measurement/Trend log

1 minute interval for 3

days (Depending on installed system)

Vfuel Plant flow meter or tank measurements

Based on

installed sensor

Cumulative Daily readings

TDS Measured by

permanent sensor

or periodic

sampling as part of

boiler O&M procedure

Based on

current sensor

/ measurement methodology

Periodic sampling -

21

fuel of inputEnergy

steamto outputEnergy boiler

Assessment Framework – Chillers

Chiller COP

kWcompressor = Chiller compressor power consumption, kW

Qcooling = Cooling load of the chiller, kW

Qcooling = mchw x Cp x (Tchwr – Tchws), kW

mchw = Mass flow rate of cooling liquid, kg/s

Cp = Specific heat capacity of liquid, kJ/kg.K

Tchwr = Cooling liquid return temperature, oC

Tchws = Cooling liquid supply temperature, oC

Parameter Sensor type

Accuracy Measurement type

Measurement Duration

mchw Ultrasonic Flow meter


Tchwr Thermistor 0.04oC Trend log 1 minute interval for 7 days

Tchws Thermistor 0.04oC Trend log 1 minute interval for 7 days

mcw Ultrasonic flow meter


Tcwr Thermistor 0.04oC Trend log 1 minute interval for 7 days

Tcws Thermistor 0.04oC Trend log 1 minute interval for 7 days

kWcompressor Power transducer


22

compressor

cooling

kW

Q

mchw, Tchwr

Tchws

Assessment Framework – Pumps

Specific power of pumps

Efficiency of pumping system, x 100%

kW = Power consumed by pump, kW

Q = Cooling or heat rejection load, kW

Q = m x Cp x (Tr – Ts), kW

m = Mass flow rate of chilled water, kg/s

Cp = Specific heat capacity of pumped liquid

Tr = Liquid return temperature, oC

Ts = Liquid supply temperature, oC

V = Volume flow rate of liquid, m3/s

p = Pressure difference, Pa

= (Pd - Ps), Pa

Pd = Pump discharge pressure, Pa

Ps = Pump suction pressure, Pa

23

Q

kW

1000x

Px

kW

Vchwp

Parameter Sensor type Accuracy Measurement type Measurement Duration mchw Ultrasonic flow

meter 2% Trend log 1 minute interval for 7

days

Tchwr Thermistor 0.04oC Trend log 1 minute interval for 7

days

Tchws Thermistor 0.04oC Trend log 1 minute interval for 7

days

kWchwp Power meter 1% Trend log 1 minute interval for 7

days

Vchw Ultrasonic flow

meter 2% Spot measurement -

Pd Pressure gauge ±0.5% Spot measurement -

Ps Pressure gauge ±0.5% Spot measurement -

Assessment Framework – Chiller Systems

COPchiller system = Qcooling/kWcompressor + Qcooling/kWchwp + Qcooling/kWcwp + Qcooling/kWct

Qcooling = Cooling load of the chiller, kW

kWcompressor = chiller compressor power, kW

kWchwp = chilled water pump power, kW

kWcwp = condenser water pump power, kW

kWct = cooling tower fan power, kW

24

By-p

assCondenser

Evaporator

Cooling tower A

HU

kWct

Chilled water pump

Condenser water pump Vch,

Tch,return

Tch,supplyTchws

mchw,

Tchwr

Assessment Framework – Refrigeration Systems

Refrigeration system COP =

kWcompressor = Refrigeration system compressor power, kW

Qcooling = Refrigeration load , kW

= (Qheat - kWcompressor x F)

Qheat = heat rejection rate of refrigeration system

= mcw x Cp x (Tcwr – Tcws), kW

mcw = Mass flow rate of condenser water, kg/s

Cp = Specific heat capacity of water, kJ/kg.K

Tcwr = Condenser water return temperature, oC

Tcws = Condenser water supply temperature, oC

F = 1.0 for hermetically sealed systems

= motor efficiency /100 for open drive

Parameter Sensor type Accuracy Measurement type Measurement Duration


2% Trend log 1 minute interval for 7

days s

Tcwr Thermistor 0.04oC Trend log 1 minute interval for 7

days

Tcws Thermistor 0.04oC Trend log 1 minute interval for 7

days

kWcompressor Power transducer

1% Trend log 1 minute interval for 7

days

kWfan Power meter 1% Spot measurement -

kWpump Power meter 1% Spot measurement -

25

kW *,compressor ionrefrigerat of nconsumptio Power

kW system,ionrefrigerat theby produced Cooling

Assessment Framework – Compressed Air Systems

Specific power =

Free air delivery rate FAD = Average air intake rate into compressor, m3/s

FADactual = (P x V x Tatm) / (Patm x T)

V = Volume flow rate at the measured point, m3/s

P = Pressure at the measurement point, kPa

Patm = Atmospheric pressure, kPa

T = Temperature at the measurement point, K

Tatm = Temperature of ambient air, K


V Ultrasonic flow meter


P Pressure transmitter

0.5% Trend log (where port available)

1 minute interval for 3 days

T Surface

temperature sensor

0.5oC Spot

measurement/Trend

log (if sensor is available)

-

Tatm RTD 0.5oC Spot measurement -

kWcompressor Power transducer 1% Trend log 1 minute interval for 3 days

26

/sNm ,conditions actualat ratedelivery air free Average

kW system, cooling & dryers s,compressor ofn consumptiopower Average3

Assessment Framework – Process Cooling Systems

Specific heat rejection rate =

kWct = Power consumed by fan of cooling tower, kW

Qheat = Heat rejection rate, kW

Qheat = mcw x Cp x (Tcwr – Tcws)

mcw = Mass flow rate of cooling tower water, kg/s

Cp = Specific heat capacity of water, kJ/kg.K

Tcwr = Cooling tower water return temperature, oC

Tcws = Cooling tower water supply temperature, oC



2% Trend log Logging at 1 minute

interval for 1 to 2 days

Tcwr Thermistor 0.04oC Trend log Logging at 1 minute


Tcws Thermistor 0.04oC Trend log Logging at 1 minute


Twb Ambient

temperature & RH sensor

0.5oC and 3% RH

Trend log 1 minute interval for 2

days

kWct Power meter 1% Spot measurement for

constant speed or logging for variable speed

Spot measurement for

constant speed or

logging at 1 minute


for variable speed

27

ct

heat

kW

Q

Suitable Energy Performance Indicators

Boilers

Thermal efficiency (%)

Combustion efficiency (%)

Condensate recovery rate (%)

Chillers

COP (kWc/kWe)

kW/RT

Pumps

Efficiency

Specific power (kWe/kWc)

Cooling towers

COP (kWc/kWe)

28


Chiller Systems

COP

kW/RT

Process cooling systems

Pump efficiency

Pump specific power (kWe/kWc)

Cooling tower COP (kWh/kWe)

Refrigeration systems

COP (kWc/kWe)

29


Compressed air systems

Specific power (kW/Nm3/s)

Leakage rate (%)

Compressor loading

Motors

Rated efficiency

Loading (%)

Ovens / Heaters / Heat Exchangers

Thermal efficiency (%)

Lighting

Power density (W/m2)

Illuminance level (lux)

30

Data Collection – Typical Instruments

Liquid flowmeters Compressed air flowmeter Lux meter Anemometer Flue gas analyser

Power meters Split core CTs T/RH loggers Temperature sensors 31

Energy Usage Profiles

32

Overall Energy Usage by Fuel Type

All plants All excluding one plant

Total consumption 350 million kWh/year =1,260 TJ/year

33

Overall Energy Usage by Fuel Type

34

Overall Energy Usage by System

All plants

35

Electrical Energy Usage Profile

36 Production equipment (energy intensive) includes: mills, rollers, grinders etc.

Main Findings

37

Boiler Steam Pressure

• Operating steam

pressure ranges from

7 to 16 bar

38

Boiler Thermal Efficiency

Benchmark

(SS 530:2014)

Efficiency 77 to 82%

• Boiler thermal

efficiency within

benchmark values

except for plants with

boilers operating at

relatively low loading

39

94

Boiler Net Combustion Efficiency

Benchmark

(SS 530:2014)

Efficiency 77 to 84%

• Net combustion

efficiency ranges from

83 to 92% for steam

boilers

40

Boiler Flue Gas

• Flue gas temperature

ranges between 118oC

(hot water boiler)

and 243oC

• O2 level varies

between 5 and 11.6%

Hot

water

boiler

41

• Ideal value is 2%

Condensate Recovery Rate

• Condensate recovery

rate varies from 23 to

88%

Not recovered

to prevent

contamination

Condensate

used as hot

water for

process

Steam

used for

process

42

Boiler Blowdown and Economiser

43

Chiller COP

Industry Benchmark

COP 6.9

Water cooled > 300RT

• All water cooled

chillers except for 3

plants

• Chiller capacity ranges

from 45 to 750 RT

• Supply temperature

ranges from 2 to 10oC

• Average COP is

between 2.61 to 5.27

44

Chiller Cooling Load

• Average load ranges

from 95 to 500 RT

45

Average Chilled Water Supply Temperature

• Average supply

temperature ranges

from 3.6 to 16oC

46

Average Condenser Water Supply Temperature

• Average supply

temperature ranges

from 27.5 to 30oC

47

Chilled Water Pump Specific Power

Consumption

Pump efficiency

ranges from as low

as 30% to 64%

Industry Benchmark

Efficiency 72%

Specific power consumption

ranges from 0.02 to 0.07

Benchmark (SS 553)

Sp. power 0.02

Target for specific power

consumption for industrial

systems:

Normal pressure drop 0.02

High pressure drop 0.03

48

With

VSD

Condenser Water Pump Specific Power

Consumption

• Specific power

consumption ranges

from 0.02 to 0.12

• Benchmark (SS 553)

Sp. power 0.02

• Pump efficiency

ranges from as low as

33% to 70%

• Industry Benchmark

Efficiency 72%

49

Cooling Tower COP

Industry Benchmark

COP 117

• COP ranges from 29 to

117

50

Chiller Systems Efficiency Industry Benchmark

COP 5.85

CHWS = 7oC

Cooling Load >300

RT

• COP for low capacity

chiller systems range

from 1.3 to 2 (1.8 to 2.7

kW/RT)

• COP for air cooled chiller

systems range from 1.3

to 2.9 (1.2 to 2.7 kW/RT)

• COP for higher capacity

(above 120 RT) water

cooled chiller systems

range from 2.9 to 4.0

(0.9 to 1.2 kW/RT)

51

Refrigeration Systems

Industry Benchmark

With evaporative

condenser

Temperature COP

-35/+35 1.8

-20/+35 2.9

-5/+35 4.3

52

Evaporative

condenser

Water cooled

condenser

Air cooled

condenser

Compressed Air System Pressure

• Operating pressure

ranges from 5.5 to 7.5

bar (except for 39 bar

used for special

application)

53

Compressed Air Pressure and Specific Power

Consumption

54

• Specific power ranges

from 0.07 to 0.1

kWh/Nm3 (4.2 TO 6

kW/CMM) except for

oil free and high

pressure compressors

Compressed Air Specific Power Consumption

Benchmark (German Energy

Agency - dena)

Pressure kWh/Nm3

4 0.050 – 0.073

5 0.058 – 0.083

6 0.067 – 0.097

7 0.073 – 0.107

8 0.080 – 0.117

9 0.087 – 0.127

10 0.092 – 0.135

20 0.133 – 0.192

55

Compressed Air Leakage Rate

Industry target

< 2%

• Leakage rate varies

from 6% to 44%

56

Process Cooling Pump Specific Power

Consumption

• Specific power

consumption ranges

from 0.02 to 0.031

• Benchmark (SS 553)

Sp. power 0.02

• Pump efficiency

ranges from as low as

45% to 60%

• Industry benchmark

Efficiency 72%

57

Process Cooling Systems Specific Heat

Rejection Rate

Industry Benchmark

Heat rejection rate

117

(based on 0.03

kW/RT)

• Cooling water supply

temperature ranges

from 26.8 to 37oC

• Specific heat

rejection rate ranges

from 20 to 270

58

Lighting Illuminance Levels (warehouse areas)

Benchmark (SS531 Part 1)

100 to 200 lux

59

Lighting Illuminance Levels (production areas)


200 – 500 lux

60

Lighting Illuminance Levels (office areas)


300 to 500 lux

61

Lighting Power Density (warehouse areas)

Benchmark (SS530)

7 W/m2

62

Lighting Power Density (production areas)

Benchmark (SS530)

13 W/m2

63

Lighting Power Density (office areas)

Benchmark (SS530)

12 W/m2

64

Typical Energy Saving Opportunities

65

Energy Saving Opportunities – Boiler Systems

Improve combustion efficiency

Adjust air to fuel ratio to minimize oxygen level in the flue gas.

Heat recovery from flue gas

Since a considerable amount of heat energy is lost through flue gas, economizers

can be installed to recover heat from flue gas to pre-heat feed water.

Reduce operating pressure

Lower the operating pressure, increases the latent heat resulting in less steam

required to provide a particular heating load.

Less heat required to raise feedwater to saturation point.

66


Condensate recovery

Recover as much condensate as possible.

Where condensate cannot be recovered because of potential contamination, to

recover heat from the condensate.

Automatic blowdown control

TDS control is done manually in most plants based on a set schedule. Auto

blowdown control systems can be installed to maintain the required TDS level while

reducing heat losses from blowdown.

Heat recovery system can be installed with the auto blowdown system to pre-heat

make-up water.

67


Reducing losses from boiler

The outer surface temperature of boilers at 6 plants range from 50 to 70oC.

Additional insulation can be used to reduce radiation and convection losses from

boilers.

Reducing losses from steam heated equipment

The outer surface temperature of some equipment such as heat exchangers using

steam are relatively high and additional insulation can be installed to reduce heat

losses.

Improving boiler loading

Some boilers operate at low loading. Operating efficiency can be improved by

operating less number of boilers or installing a lower capacity boiler.

68


Using natural gas for boilers

Where available, use natural gas instead of diesel

Use heat pumps

Use heat pumps to generate hot water

Solar heaters for make-up water

Where space is available, use solar hot water systems to generate hot water or to

supplement heat pumps / boilers

69

Energy Saving Opportunities – Chiller Systems

Increasing supply temperature

Typically, 1oC increase in set-point will result in 3% improvement in chiller

efficiency.

In majority of systems, set-point is about 7oC. However, the actual operating supply

temperature in some cases is about 6oC (possibly due to inaccurate temperature

sensors).

The sensor can be calibrated or replaced to increase the supply temperature.

In some cases, the actual supply temperature is different during day and night time

operation (due to insufficient chiller capacity).

If the higher supply temperature at certain times is acceptable, then the set-point

can be set at the higher value throughout the day.

70


Increasing supply temperature (contd.)

The set-point is maintained at 2 to 4.5oC in system which require low RH.

However, the low RH is required only in specific areas.

If alternative dehumidification systems are installed in such areas, the overall

supply temperature can be increased for the entire system.

Once the operating set-point is increased, glycol can be replaced with chilled

water, which will further improve the performance of the chillers and AHUs.

71


Use of water cooled chillers

Some plants use air cooled chillers. The operating efficiency of water cooled

chillers is almost double that of air cooled chillers. Since most cooling systems

operate 24 hours a day, significant energy savings can be achieved by replacing the

air cooled chillers with water cooled chillers.

Sizing of chillers

In many plants, multiple chillers of relatively low cooling capacity are operated

simultaneously to provide the cooling requirements of various systems.

This results in lower loading of the chillers which results in poor efficiency.

Also, low capacity chillers have relatively lower rated efficiency.

Therefore, such multiple chillers can be replaced with centralized common system

with relatively higher capacity chillers with higher rated efficiency.

Common chiller systems will also operate at higher efficiency due to better loading

(due to load diversity).

72


Chiller replacement

Chillers are old and have relatively poor rated efficiency of about 0.7 to 0.9 kW/RT

(water cooled chillers).

When replacing these chillers, they can be replaced with new high efficiency

chillers.

Chillers with VSD compressors can be considered for applications with highly

variable loads.

73

Energy Saving Opportunities – Pumps

Replacement of inefficient pumps

The combined operating efficiency of pump + motor generally ranges from 40 to

50%.

Such pumps can be replaced with new ones suitable selected to have a combined

efficiency of at least 73% (80% x 92%).

Reducing capacity of pumps

Pumps that are over capacity result in higher flow rate or throttling of flow, both of

which result in energy wastage.

Capacity of pumps can be reduced to match demand by replacing pumps, reducing

speed (using VSD) or trimming impellers.

Throttling devices should be removed or fully open.

In variable load applications, variable flow systems can be considered using VSD

pumps and suitable controls.

74

Energy Saving Opportunities – Cooling Towers

In all the plants, the installed capacity of cooling towers is higher than the heat

rejection load.

The cooling tower fans generally operate at fixed speed.

VSDs can be installed to vary the fan speed to better match cooling tower capacity

to the load.

Where standby towers are available, they can be operated in parallel to increase

the available heat rejection capacity which would further reduce the operating

speed of the fans.

In cases where, a number of individual cooling tower systems are used, they can be

consolidated so that the load diversity will result in lower cooling tower fan and

pump power.

Cooling tower in-fill should be cleaned or replaced to ensure good water circulation

in cooling towers.

75

Energy Saving Opportunities – Refrigeration Systems

Increase the compressor suction pressure

The saturation temperature of the suction pressure should not be more than 10 oC

lower than the refrigerated space temperature. Therefore, the suction pressure

can be raised to suit the required temperature set-point.

Reducing condensing pressure

Using evaporative condensers instead of air cooled condensers which can reduce

the condensing temperature by about 5oC.

If capacity of evaporative condenser is not sufficient (high condensing pressure),

additional (standby) condenser can be operated in parallel.

Repair / replace defective controls

Where more compressors than necessary are operated leading to inefficient

operation.

76


New systems

Older inefficient systems should be replaced with new systems with higher COP

(-5/+35oC can achieve COP of 4.3).

VSD for compressors

Where load varies significantly, VSDs can be considered for reducing compressor

capacity rather than using sliding valves or other means of capacity control.

Alternative systems

Where sub-zero operating temperatures are not required (2 to 4oC), glycol or

chilled water systems can be considered.

77


Vary speed of evaporator fans

Once the refrigerated space temperature is reached, it is not necessary to operate

the evaporator fan at full speed. A suitable control system and a VSD can be used

to reduce the fan speed when a set-temperature is achieved and maintained.

Minimizing load

Once the product stored in the refrigerated space reaches the set-temperature,

the main contributors of cooling load for the refrigeration system are the lights,

heat emitted by occupants and infiltration.

Therefore, lights should be switched-off when not necessary and inefficient lamps

should be replaced with more efficient lamps.

Doors should be kept closed or automatic doors should be installed to minimize

infiltration of air.

78

Energy Saving Opportunities – Compressed Air Systems

Reducing compressed air demand

Identify and rectify leaks

Corroded piping

Damaged fittings like pressure regulators

Loose hoses

Use alternative sources where possible

Cleaning

Conveying

Agitation

79

Energy Saving Opportunities – Compressed Air Systems

Use more efficient compressors

Replace multiple low capacity compressors with single compressor

Install VSD compressors for variable loads

Compressed air recovery

Recover high pressure air after blowing for low pressure applications

Reducing compressor pressure ratio

Reducing discharge pressure

Reducing inlet temperature

80

Energy Saving Opportunities – Motors

Replace old IE1 and IE2 motors with high efficiency IE3 and IE 4 motors.

Where motors are operating at low loading, to replace them with lower capacity

motors to improve the operating efficiency.

81

Energy Saving Opportunities – Lighting Systems

Replace older T8 lamps with more efficient LED lamps

Replace inefficient high bay lamps with LED lamps

Reduce illuminance levels by reducing the number of lamps

Install occupancy sensors where applicable to switch-off lighting

82

Overall Savings Potential

83

Savings Potential –Electricity

84

Savings Potential – Fuel

85

Savings Potential – By System

86

Savings Potential – Cost Savings

87

Other Findings and Recommendations

88

Assessment of Energy Management Systems

No certified Energy Management System (EMS)

Energy Management is generally the responsibility of the Energy Manager (no

formal Energy Management Team)

Energy Managers role in Energy Management is mainly part-time

Stakeholders are not aware of energy management goals

Only the total energy consumption is tracked with no key Energy Accounting

Centres

No specific EnPIs for key systems and permanent monitoring systems

89

Assessment of Maintenance Practices

Mainly preventive maintenance

Regular checking of filters and strainers

Steam leaks are generally rectified (no significant steam leaks were observed)

Regular checking and replacement of steam traps

Relatively high compressed air leakage indicates no regular leak rectification

programs are in place

No regular fine-tuning boiler burners to adjust air to fuel ratio

No regular checking and calibration of sensors and instruments

90

Recommendations for Energy Management System

Have clear Energy Policy with targets

Establish a formal Energy Management Team with representation from all

stakeholders

To appoint a dedicated Energy Manager

Identify main Energy Accounting Centres (EACs)

Install monitoring systems for the EACs and energy sub-meters

Set EnPIs for the EACs and regularly track performance

Recognise and reward staff based on achieving targets

Implement ISO 50001 compliant EMS

91

Recommendations for Maintenance Practices

Regularly check and calibrate instruments

Supplement the current preventive maintenance programs with predictive

maintenance strategies such as ultrasonic leak testing for compressed air and

steam traps

Regularly conduct compressed air leak tests

Install permanent systems to monitor boiler flue gas and adjust air to fuel ratio

92

Other Recommendations

To have interaction and sharing of best practices within sector

Give priority to Energy Management and improve motivation

Develop ability to convince top management and secure commitment for energy

management

Consider newer technology and more efficient designs when replacing old

equipment

Invest resources to identify energy savings from process systems

93

Summary

Ten plants participated in the energy efficiency benchmarking study of food

manufacturing plants

The main energy consuming systems were identified and a suitable assessment

framework was developed

Comparison of the performance of individual systems with benchmark values

indicate significant potential for improvement

Many energy saving opportunities have been identified and savings have been

quantified

Total savings of 103.1TJ/year have been identified for the participating plants

which is 8% of the total annual energy consumption

Other measures were identified to improve energy management and maintenance

practices

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ENERGY EFFICIENCY BENCHMARKING STUDY OF FOOD …