Tetra Pak Jeddah Report

Introduction

The cooling system installed at Tetra Pak has gotten obsolete and has suffered

from several breakdowns in the past. In order to control, monitor and optimize

the cooling system, a building management system was installed at the facility on

22nd of September 2014.

A BMS or Building Management System is a computer-based system that is

installed in the building for controlling, monitoring and optimizing the building’s

mechanical as well as electrical equipment such as HVAC systems, lighting,

security system, etc. Building Management Systems are critical components to

managing energy demand. Improperly installed BMS can cost up to 20% of energy

usage.

The building management system has a coverage of the following areas:

Carton Factory

1. Printer Zone HVAC Systems (MCC1)

2. Laminator Zone HVAC Systems (MCC2)

3. Slitting and Palletizing Zone HVAC Systems (MCC2 Slave)

Straw Factory

1. Straw Factory HVAC System (MCC4)

The BMS grants us the ability to control and monitor all of the Chillers and the Air

Handling Units of the entire Production Building. Currently it monitors:

Chillers Inlet and Outlet Temperatures

Cooling Tank Temperatures

Outside Temperature and Humidity

Zones Temperature and Humidity

AHU return and supply Temperatures and Humidity

Air flow monitoring of AHUs

Control of AHU fan speed

Dampers Controls

CW Control Valves

This illustration shows an example of a Building Management System installed

in the Straw Factory at Tetra Pak Jeddah.

AHU1-DA1: Sensor controlling the damper that draws in fresh outside air.

AHU1-CV1: Sensor controlling the CW Valve that regulates the flow of

chilled water to enter the AHU.

AHU1: Sensor that controls the AHU’s fan speed.

AHU1-ST2: Sensor that shows the temperature of air that is being supplied.

AHU1-ST1: Sensor that shows the room temperature of the factory.

AHU1-SH1: Sensor that shows the humidity that is being drawn out from

the room.

AHU1-ST3: Sensor that shows the temperature of the air that is being

drawn out of the room.

AHU1-DA2: Sensor controlling the 2nd damper that allows the exhaust air to

circulate by mixing with the supply air.

Out-ST10: Sensor that shows outside temperature.

Out-SH10: Sensor that shows outside humidity.

Chiller Tank: Acts as a reservoir of water for the chiller to draw and release water.

CT-ST2: Sensor that shows the temperature of the hot water from where the chiller

draws in water.

CT-ST1: Sensor that shows the temperature of the cold water where the chiller

releases its chilled water.

CH7-P1A / CH7-P1B / CH-20(A – D): These sensors are installed on the pumps that

pump water from the tank towards the chiller.

CH (3 – 7)-ST1: Sensor that shows entering water temperature to the chiller.

CH-ST2 / CH7-ST2: Sensor that shows the leaving water temperature, once it has

been chilled, towards the tank.

AHU-SP1: Sensor that shows the pressure of water that is being pumped towards the

AHUs from the chiller tank.

AHU-ST1: Sensor that shows the temperature of water being pumped towards the

AHUs from the chiller tank.

AHU-ST2: Sensor that shows the temperature of water returned back to the chiller

tank’s hot area from the AHUs.

Suggestions on expanding the Building Management System

The BMS could be expanded to cover the following areas:

Chillers

There are a total of 10 chillers installed at the facility and another chiller is

currently under installation and will be put into commission soon.

Carton Factory Chillers

There are 7 chillers installed for the carton factory among which chillers 1 and 2

are installed separately. The rest of the chillers 3-7 are installed adjacent to the

carton factory.

Chiller 1 and 2

These chillers only provide comfort cooling to the Printer Zone.

Chiller 3-7

Provide process cooling to the Printer Zone.

Provide comfort and process cooling to the Laminator Zone.

Straw Factory Chillers

There are 3 chillers installed for the Straw Factory. These chillers operate

independent of the carton factory’s chillers and are responsible for the comfort as

well as process cooling of the Straw Factory.

OBJECTIVE

ANALYZE AND REVIEW THE BUILDING MANAGEMENT SYSTEM AND SUGGEST

IMPROVEMENTS

LEARN AND UNDERSTAND THE OPERATION OF CHILLERS AND SUGGEST METHODS TO

IMPROVE THE COOLING SYSTEM.

LEARN AND UNDERSTAND THE OPERATION OF AHUS AND SUGGEST IMPROVEMENTS.

Description of chillers

The aforementioned Straw Factory chillers 1, 2&3 are operating independently

and pose no major breakdowns. The area which demands attention is the Carton

Factory.

Cooling Loads

The cooling loads where the chillers are providing their chilled water include:

AHUs (Air Handling Units)

FCUs (Fan Coil Units)

Cooling Units (CUs)

Chilled Rollers (Used in Laminator as well as Printer)

Heat Exchangers

Segregating Straw and the Carton Factory into different cooling

systems

Cooling System 1 (Carton Factory)

Consists of 2 York Chillers (1 & 2) with reciprocating compressors and R22

refrigerant.

This system supplies comfort cooling to the Printer Zone (AHU-101, AHU-

102).

Chillers were installed in 1995.

The total cooling capacity of this system is 800KW.

Cooling System 2 (Carton Factory)

Consists of 5 York Chillers (3 – 7).

The chillers 3-6 are equipped with 4 screw compressors and use R407c

refrigerant. ( Chiller No 3 has been upgraded and now uses refrigerant

R134a)

Chiller no 7 is a relatively contemporary chiller. It is equipped with 3

variable speed drives (VSD) screw compressors and R134a as a refrigerant.

Supplies process cooling to the Printer Zone and comfort + process cooling

to the Laminator Zone.

Chillers 3-6 were installed in 2003.

Chiller no 7 was installed in 2010.

The total cooling capacity of this system if working properly should be

5800KW.

Cooling System 3 (Straw Factory)

This system consists of 3 chillers.

Chillers are equipped with 6 scroll compressors and uses R407c as a

refrigerant.

The chillers supply comfort and process cooling to the Straw Factory.

Installed in 2001

Chiller Structure

Chiller 3-6 and chiller 7 consists

of 4 and 3 screw compressors

respectively.

The entering water

temperature (EWT) t1 is 12⁰C,

which comes from the AHUs

and the production building

processes after being

consumed and warmed. The

water that enters is cooled

down by the chiller and now

the leaving water temperature

has been reduced by 5⁰C (∆T =

5) and now has a value of 7⁰C. This water is again sent to the AHUs to

provide with comfort cooling and to the machines in the production

building (Printer, Laminator, Slitter and Straw) to provide process cooling

and the cycles goes on.

The chiller control panel operates independently. It monitors the ∆T (t1 -

t2) and off loads 2 out of 4 compressors if the value of ∆T is high or if there

is sufficient cooling in order to optimize energy consumption.

The building management system operates rather differently. It basically

acts like a switch to the entire chiller machine, switching it off entirely. With

respect to chiller 7, the BMS switches on or switches off the rest of the

chillers 3-6. If the value of ∆T is too low, that would mean chiller 7 isn’t

providing sufficient cooling and so the BMS switches on another chiller to

compensate for it. Similarly, if ∆T is too high, chillers except for chiller 7

would be switched off accordingly to save energy.

Ambient Temperature Cutoff

The obsolete Chillers 3 to 6 were installed 12 years ago which has caused its

condenser fins to deteriorate significantly and hence are not able to

dissipate heat efficiently. Due to the damaged fins the max ambient

temperature, after which the condenser is no longer able to dissipate

anymore heat due to the extreme pressure build up and thus causes the

compressor to shut down to prevent it from receiving damage, is 42⁰C

(107.6 F).

Chiller 3 Upgradation

Chiller 3 has been upgraded and now uses 134a as a refrigerant instead of

407e, which is still being used in chillers 4 to 6.

134a, which has an empirical formula 1,1,1,2 – Tetrafluoroethane, is a halo

alkane refrigerant. It is a low pressure inert gas used primarily as a ‘high

temperature refrigerant’ for domestic refrigeration and automobile air

conditioners. Due to its low pressure characteristic, the 134a refrigerant

prevents the extreme pressure build up and allows the condenser to

operate normally beyond the max ambient temperature, 42⁰C (107.6 F).

Chiller 7, that was installed in 2010, already uses 134a as a refrigerant and

hence is capable of running normally even beyond 42⁰C.

290

260

190

399

375

290

0

159

0

50

100

150

200

250

300

350

400

450

DSCH PRESS CUTOUT DSCH PRESS UNLOAD SYS DSCH PRESS

PR

ESSU

RE

IN P

SIG

Chiller 3 upgradation comparison

CH 3 CH 4 CH 7

This graph shows that Chiller 3’s discharge pressure has been significantly

reduced after the upgradation to 134a compared to the Chiller 4, which

still uses 407e.

DSCH PRESS CUTOUT – Discharge Pressure Cutout

DSCH PRESS UNLOAD – Discharge Pressure Unload

SYS DSCH PRESS – System Compressor Discharge Pressure

CH 3 – Chiller 3

CH 4 – Chiller 4

CH 7 – Chiller 7

Chiller Status

Carton Factory

Chiller # 1

Compressor 1

Condenser Fan Unbalance

High Superheat from evaporation giving low evaporation

Compressor 2

High superheat from evaporation

Chiller # 2

Compressor 1

Large sub cooling in condenser

Excess of refrigerant

Compressor 2

Performing good

Chiller # 3

Filter Dryer

The filter dryers of this chiller have

been reoriented to vertical, which

has now improved its filtration

process of particles and the

prevention of moisture to avoid any

damage to the refrigeration cycle.

The refrigerant has been upgraded

to 134A from the previous R407C.

134A is a low pressure gas, which

has reduced its discharge pressure

and in turn enabled the

compressors to operate beyond the

max ambient temperature.

Condenser Fins

Fins are not in good condition.

Cleaning the condenser fins every

month is an easy and inexpensive

to ensure an efficient chiller.

The fins can be cleaned with a

brush-tipped vacuum or with

clean, dry compressed air; a

condenser cleaning solution can

also be used.

Chiller Readings (5th July 2015)

Compressors Status

System 1 Compressor: Running

System 2 Compressor: Running

System 3 Compressor: Running

System 4 Compressor: No Cooling Load (Switched Off)

Refrigerant

Previous Type: R407C (High Pressure Gas)

Upgraded to: 134A (Low Pressure Gas)

Discharge Pressure

Pressure Cutout: 290 PSIG (Has been significantly reduced from approx.

400 PSIG after upgrading it to 134A)

Pressure Unload: 260 PSIG (Has been significantly reduced from approx. 400

PSIG after upgrading it to 134A)

Evaporator

The evaporator plays a major role

in the operation of the chiller. It’s

responsible for converting the

water into a gas by transferring

the heat to the refrigerant and

emitting that gas into the

compressor.

The illustration clearly depicts the

old age of the evaporator, which

could be affecting its efficiency.

Temperatures

Leaving Liquid Temp: 42.4 DEGF (5.7⁰C)

Return Liquid Temp: 51.1 DEGF (10.6⁰C)

∆T = 4.9⁰C

Ambient Temp: 90.5 DEGF (32.5⁰C)

Chiller # 4

Condenser Fins

Chiller’s condenser fins are in poor

condition.

A dirty condenser prevents air from

flowing through the system and

keeps heat trapped within the

cooling system.

Clean the fins with a brush-tipped

vacuum or with clean, dry

compressed air; a condenser

cleaning solution can also be used.

Filter Dryer

Filter Drier is responsible for the

filtration of particles and the

prevention of the moisture to

circulate through the system to avoid

damage to the refrigerant cycle.

The filter drier operates more

efficiently in vertical orientation, as

observed in chiller 3.

Chiller Readings (5th July 2015)

Compressor Status

System 1 Compressor: Running

Evaporator

The evaporator of the chiller cools

the water by transferring the heat to

its refrigerant and then converting it

into a gas which is then transferred

to the compressor.

The illustration clearly shows that the

condition of the evaporator has

deteriorated significantly, which

could be seriously affecting the

chiller’s efficiency.

System 4 Compressor

The illustration shows the area which

was supposed to be occupied by

System 4 Compressor to be vacant.

This compressor of chiller 4 has been

removed for maintenance purposes.

System 2 Compressor: Running

System 3 Compressor: Switched Off

System 4 Compressor: Switched Off

Refrigerant

Type: R407C

Discharge Pressure

Pressure Cutout: 399 PSIG

Pressure Unload: 375 PSIG

Temperatures

Leaving Liquid Temp: 44.9 DEGF (7.16⁰C)

Return Liquid Temp: 51.2 DEGF (10.67⁰C)

∆T = 3.51⁰C

Ambient Temperature: 90.9 DEGF (32.22⁰C)

Chiller # 5

Condenser Fins

The fins are in poor condition.

Obsolete and damaged fins of the

condenser can cause the heat to

be trapped inside and prevent the

movement of air throughout the

system.

Clean the fins with a brush-tipped

vacuum or with clean, dry

compressed air.

Filter Dryer

Filter Driers, responsible for the

absorption of moisture to prevent

it from entering the refrigeration

cycle and for providing physical

filtration of unwanted particles.

Again, the orientation of the filter

drier must be vertical for it to

perform more efficiently.

Evaporator

The evaporator responsible for

cooling the water by converting it

into gas and transferring its heat

to the refrigerant is not in a good

condition, as shown in the picture.

This illustration shows that chiller’s 5 compressor is under

maintenance due to high discharge temperature.

Chiller Readings (5th July 2015)

Compressor Status:

System 1 Compressor: Switched Off

System 2 Compressor: Running

System 3 Compressor: Switched Off

System 4 Compressor: Switched Off

Refrigerant

Type: R407C

Discharge Pressure

Pressure Cutout: 390 PSIG

Pressure Unload: 375 PSIG

Temperatures

Leaving Liquid Temp: 48.4 DEGF (9.11 ⁰C)

Return Liquid Temp: 49.5 DEGF (9.722 ⁰C)

∆T = 0.612⁰C

Ambient Temperature: 89.4 DEGF (31.8 ⁰C)

Chiller 6

Condenser Fins

This Chiller’s condenser fins are in

very poor condition.

Obstructed fins can lead to heat

being trapped inside and preventing

the circulation of air inside the

system.

Clean the fins with a brush-tipped

vacuum or with clean, dry

compressed air.

Filter Dryer

The orientation of the filter drier

is again horizontal. In order for it

to perform its function more

efficiently, which is preventing

moisture and particles from

entering the refrigeration cycle,

the filter drier must be kept in a

vertical orientation.

Evaporator

The evaporator cools the water by

transferring its heat to the

refrigerant and converting the

water into a gas.

This chiller’s seems to have a

reciprocating evaporator, implying

that its evaporator is not the cause

for its poor efficiency.

The illustration shows that the outer covering of this chiller has

been removed to allow air flow to minimize the effect of

ambient temperature.

Chiller Readings (5th July 2015)

Compressor Status:

System 1 Compressor: Switched Off

System 2 Compressor: Running

System 3 Compressor: Running

System 4 Compressor: Switched Off

Refrigerant:

Type: R407C

Discharge Pressure

Pressure Cutout: 390 PSIG

Pressure Unload: 375 PSIG

Temperatures

Leaving Liquid Temp: 47.6 DEGF (8.667 ⁰C)

Return Liquid Temp: 49.7 DEGF (9.833 ⁰C)

∆T = 1.156 ⁰C

Ambient Temp: 92.2 DEGF (33.44 ⁰C)

System 4 Compressor

The illustration shows that

system 4 compressor of chiller 6

has been removed for

maintenance purposes.

Chiller 7

Condenser Fins

This chiller’s condenser fins are in

good condition.

Well maintained condenser fins

dissipate heat efficiently and

prevent the heat from being

trapped inside and in turn causes

the condenser to operate

efficiently.

Evaporator

The evaporator of this chiller is in

good condition.

A well maintained and a reciprocating

evaporator cools the water by

transferring its heat to the cooled

refrigerant and converting it into

vapors more efficiently than a

damaged evaporator would by

maintaining its discharge pressure

under adequate limits for the

compressor.

Filter Dryer

The filter drier removes the

moisture and prevents any

anomalous particle from entering

the refrigeration cycle.

This device must be in a vertical

orientation for better

performance.

Oil Separator

This is a centrifugal water-oil

separator designed to separate oil

and water.

It contains a cylinder that rotates

inside a larger stationary

container. Water being the denser

liquid accumulates outside and is

collected from the side, whereas

the oil being the less dense

accumulates inside and is

collected from the center.

Chiller Readings (5th July 2015)

Compressor Status

System 1 Compressor: Running

System 2 Compressor: Running

System 3 Compressor: Running

Virtual Speed Drives

These equipment are used to control

the speed of the machine where the

output speed can vary without steps

over a range of different speeds.

The speed control allow for a much

smoother operation by gradually

increasing and decreasing the

compressor system’s current, thus

preventing high surges of electric

current to start the motors resulting in

electromagnetic and thermal stresses.

Refrigerant

Type: 134A (Low Pressure)

Temperatures

Leaving Liquid Temperature: 42.1 DEGF (5.611 ⁰C)

Return Liquid Temperature: 48.6 DEGF (9.22 ⁰C)

∆T = 3.6 ⁰C

Ambient Temperature: 88.6 DEGF (31.4 ⁰C)

5.7

7.16

9.118.667

5.611

10.6 10.67

9.722 9.833

9.22

0

2

4

6

8

10

12

CH 3 CH 4 CH 5 CH 6 CH 7

TEM

PER

ATU

RE

IN ⁰

C

CHILLERS

Leaving and Return Water Temperatures

Leaving Water Temperature Return Water Temperature

Air Handling Units (AHUs)

Printer Zone

The Printer Zone is provided with comfort cooling by the following AHUs:

101-AHU

102-AHU

The following exhaust fans are installed for the circulation of air:

101-EF

102-EF

4.9

3.51

0.612

1.156

3.6

0

1

2

3

4

5

6

CH 3 CH 4 CH 5 CH 6 CH 7

TEM

PER

ATU

RE

⁰C

CHILLERS

∆T Readings of different Chillers

∆ T

Laminator Zone

The Laminator Zone is provided with comfort cooling by the following AHUs:

201-AHU

202-AHU

Exhaust Fans installed for air circulation:

201-EF

Straw Factory

The Straw Factory is provided with comfort and process cooling by the following

AHUs:

AHU1

Exhaust Fans installed for the air circulation:

EF1