Investigation of the COOLNOMIX control system under Western Australia climatic conditions

A report submitted to the School of Engineering and Information Technology at Murdoch University, in partial fulfillment of the requirements for a

Bachelor of Engineering with Honours

Jovi Yu Xuan OH

SUPERVISOR

Dr. Jonathan Whale

Date: 18/11/2016

Declaration

I declare that this thesis is my own account of my research and contains as its main content work

which has not previously been submitted for a degree at any tertiary education institution

Signed: ________________________

iii

Abstract

COOLNOMIX is an intelligent control system which improves energy efficiency in refrigeration and air

conditioning systems by replacing the thermostat in a compressor driven cooling system. In the

traditional cooling system, most of the manufacturers do not take into account the hydraulic work of

the compressor. The compressor of a traditional cooling system continues running even if the

hydraulic work is done and space is already at its desired temperature. This wastes energy as 95% of

the costs of operating air conditioning and refrigeration systems come from the compressor itself.

This thesis aims to study the effectiveness of COOLNOMIX by doing some practical experiments to

investigate the amount of energy saved by COOLNOMIX and how COOLNOMIX is being affected by

Western Australia climatic conditions. Three different experiments have been investigated in this

thesis, which are practical experiment for air conditioning, practical experiment for refrigeration

system and existing experiment of a cooling system. Practical experiments were designed and

researched by installing COOLNOMIX product in air conditioners and a cool room at Murdoch

University and let it run for a period of time to investigate the energy saved and the system

performance under different climatic condition. The existing experiment of a cooling system is to

analyze the data of a cool room which already having installed COOLNOMIX product in real life.

The results of the air conditioning system experiment showed that the COOLNOMIX is saving 14% of

energy during hot weather and 20% of energy during cold weather. For the refrigeration system,

COOLNOMIX saves up to 53.5% of its original energy consumption.

iv

Acknowledgments

I would first like to acknowledge my thesis supervisor Dr. Jonathan Whale the senior lecturer in

Energy Studies and Renewable Energy Engineering at Murdoch University for all the supports and

help You were always there when I was lost and put me on the right track. Thank you for helping me

to go through all the problems I have faced.

I would also like to thank Mr. Jagpreet Walia the Industry supervisor of my thesis for his time and

guidance. Thank you for all the technical advice and knowledge you have given to me.

I am also grateful to Mr. Gary Higgins the General Manager of Assets and Maintenance at Murdoch

University for all the help for my project, this project would not have been done without your help.

Thank you for spending so much time to help me in solving my problems, contacting relevant

department and all the permission, advises and suggestions given.

I also wish to express my sincere thanks to all the relevant technicians that make this project

happened, especially Mr. Vlad Ugrinov the site supervisor of air master, thank you for always be

there for me when I need help for my experiment.

I would also like to acknowledge Ms. Caitlin Sweeney the Laboratory Technician at Murdoch

University for assistance with the equipment and the experiment data.

And I would also like to thank Professor Parisa Arabzadeh Bahri the unit coordinator of ENG470 for

all the reminders and supports you have given.

And also thanks to Murdoch University for the funding for this project.

I would also like to take this opportunity to express gratitude to one and all, who directly or

indirectly provide help to this project.

In particular, special thanks to Jose Loh for all the supports throughout the thesis.

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Table of contents

Declaration .............................................................................................................................................. ii

Abstract .................................................................................................................................................. iii

Acknowledgments .................................................................................................................................. iv

Table of contents .................................................................................................................................... v

List of Figures ........................................................................................................................................ vii

List of Tables ......................................................................................................................................... vii

Table of Abbreviations ......................................................................................................................... viii

1 Introduction .................................................................................................................................... 1

2 Objective ......................................................................................................................................... 2

3 Literature review ............................................................................................................................. 3

3.1 Refrigeration ........................................................................................................................... 3

3.1.1 Vapour Compression Refrigeration System .................................................................... 3

3.2 Reversed Carnot cycle ............................................................................................................. 4

3.3 3.3 COOLNOMIX ...................................................................................................................... 6

3.3.1 COOLNOMIX components ............................................................................................... 7

3.3.2 Differences between Optimized Refrigerant Supply and Original Temperature Control

System 8

3.3.3 Pros and Cons ................................................................................................................ 10

3.4 Weather ................................................................................................................................ 10

3.4.1 Effects of weather on cooling system ........................................................................... 11

3.5 Cooling Load .......................................................................................................................... 12

3.6 Thermal comfort ................................................................................................................... 12

4 Practical Experiments & Existing Experiment ............................................................................... 13

4.1 Design .................................................................................................................................... 13

4.1.1 Consideration ................................................................................................................ 13

4.1.2 Air conditioning system ................................................................................................ 14

4.1.3 Refrigeration system ..................................................................................................... 18

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4.2 Pros and Cons of Linear test and Parallel test ...................................................................... 19

4.3 Methodology ......................................................................................................................... 20

4.4 Existing Experiment ............................................................................................................... 21

5 Results and Discussion .................................................................................................................. 22

5.1 Air Conditioning System ........................................................................................................ 22

5.1.1 Climate condition .......................................................................................................... 22

5.1.2 Cold Weather ................................................................................................................ 23

5.1.3 Hot Weather ................................................................................................................. 25

5.2 Refrigeration System ............................................................................................................. 27

5.3 Existing Experiment ............................................................................................................... 29

6 Economic Analysis ......................................................................................................................... 30

7 Conclusion ..................................................................................................................................... 31

8 Future Work .................................................................................................................................. 32

8.1 Reversed Carnot Cycle .......................................................................................................... 32

8.2 Thermal Comfort Test ........................................................................................................... 33

8.3 Experiment Period ................................................................................................................ 33

9 References .................................................................................................................................... 34

10 APPENDIX .................................................................................................................................. 35

10.1 Appendix A ............................................................................................................................ 35

10.1.1 COOLNOMIX installation (AC-01) .................................................................................. 35

10.1.2 COOLNOMIX installation (AR-01) .................................................................................. 37

10.1.3 COOLNOMIX LED Indicator Description ........................................................................ 41

10.2 APPENDIX B calculation ........................................................................................................ 41

10.2.1 Payback Period (AC-01) ................................................................................................. 41

10.2.2 Payback Period (AR-01) ................................................................................................. 42

10.2.3 Appendix C .................................................................................................................... 43

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List of Figures

Figure 1 Vapor Compression Refrigeration Cycle ................................................................................... 3

Figure 2 P-V diagram of Reversed Carnot cycle ...................................................................................... 5

Figure 3 Model of Reversed Carnot Cycle ............................................................................................... 6

Figure 4 COOLNOMIX Components ........................................................................................................ 7

Figure 5 Building 126 Location .............................................................................................................. 15

Figure 6 Building 124 Location .............................................................................................................. 18

Figure 7 Ambient Temperature ............................................................................................................ 22

Figure 8 Results of Air Conditioning Systems (Cold Weather) .............................................................. 23

Figure 9 Results of Air Conditioning Systems (Hot Weather) ............................................................... 25

Figure 10 Results of Cool Room ............................................................................................................ 27

Figure 11 Results of Existing Experiment .............................................................................................. 29

Figure 12 COOLNOMIX AC-01 wiring .................................................................................................... 35

Figure 13 COOLNOMIX AC-01 Sensors Locations ................................................................................. 36

Figure 14 COOLNOMIX AC-01 Set Point Orientations........................................................................... 37

Figure 15 COOLNOMIX AR-01 Wiring ................................................................................................... 38

Figure 16 COOLNOMIX AR-01 Sensor Location..................................................................................... 39

Figure 17 COOLNOMIX AR-01 Set Point Orientation ............................................................................ 40

Figure 18 Model of Air conditioner for Practical Experiment ............................................................... 43

Figure 19 Model of Cool Room for Practical Experiment ..................................................................... 43

List of Tables

Table 1 Ambient Temperature in Western Australia [9] ...................................................................... 11

Table 2 Monitoring Equipment for Air Conditioners ............................................................................ 16

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Table 3 Monitoring Equipment for Cool Room ..................................................................................... 19

Table 4 Advantages and Disadvantages of Linear Test and Parallel Test ............................................. 20

Table 5 COOLNOMIX LED Flashing Sequence and Indication ............................................................... 41

Table of Abbreviations

kWh: Kilo Watt Hour

HVAC: Heating, Ventilation, and Air conditioning

LED: Light Emitting Diode

ORS: Optimized Refrigerant Supply

1

1 Introduction

In Australia, almost every single (99.8%) household has at least one refrigerator and also 41% of

the households in Western Australia were even having two or more refrigerators [3].

Furthermore, the research [3] also showed that over two-thirds (67%) of the households in

Australia had at least one air conditioner or cooler. This research proved that a big portion of

Australian households rely on cooling systems. However, both air conditioning systems and

refrigeration systems are electrical appliances that require electricity to run. A recent survey

found that estimated 24% of the Australian households’ electricity bills actually come from air

conditioner operation [1] and another 15% comes from refrigeration [2]. It means that the

electricity costs of these two cooling appliances are worth up to more than one-third (39%) of the

electricity bills. This is considered as an important area that needs to be focused on to reduce the

cost of electricity bills.

However, the best way to reduce the energy consumption of a cooling system is to focus on the

compressor in the refrigeration cycle because 95% of the energy consumption is actually from the

compressor. In this thesis, COOLNOMIX, an intelligent control system that focuses on improving

energy efficiency in air-conditioning and refrigeration systems by operating the compressor inside

a cooling system, is investigated to determine how this product saves energy under Western

Australia climatic conditions.

2

2 Objective

The main objective of this thesis is to investigate COOLNOMIX product under Western Australia

climatic conditions. As a build-up to achieve the main objective, the main objective was divided

into several smaller objectives listed below:

1. To investigate and compare the energy consumptions of both air conditioning and

refrigeration system, with and without the addition of COOLNOMIX product;

2. To investigate the room temperature of the researched rooms, with and without the

addition of COOLNOMIX product;

3. To investigate how the Western Australia climate affects the performances of the air

conditioning system, with and without the addition of COOLNOMIX product;

4. To investigate the economic savings of installing COOLNOMIX product.

3

3 Literature review

This chapter reviews the background of a cooling system and the technical information of

COOLNOMIX. This chapter also shows some research on the Western Australia climate.

3.1 Refrigeration

Refrigeration is known as a process that moves heat from one to another in controlled conditions.

However, according to the second law of thermodynamics, work is required in order to transfer

heat from a colder location to a hotter area. There are several systems that are able to do this,

but the Vapor Compression Refrigeration System is the system that is focused on in this thesis.

3.1.1 Vapour Compression Refrigeration System

Vapour compression refrigeration method, is the system that used most widely for air

conditioners and refrigerators, and the system is shown in figure 1:

Figure 1 Vapor Compression Refrigeration Cycle

A typical Vapour Compression Refrigeration cycle contains four different components: an

evaporator, a compressor, a condenser and an expansion valve. The evaporator is normally

placed inside the room and the condenser is placed outside the room.

Evaporator

Expansion

Valve

Condenser

Compressor

1 2

4 3

Vapor Vapor

Liquid Vapor + Liquid

Warm air Cold air

4

A Vapour Compression Refrigeration System can be considered as a flowing liquid cycle, where

liquid refrigerant is used as a medium that is able to absorb or remove heat and flows in the

system. A cooling cycle of this system works as following steps:

1. Heat is first absorbed by the refrigerant and the refrigerant turns into a thermodynamic

state known as saturated vapor at evaporator (4 - 1);

2. The saturated vapor enters the compressor and is compressed to a higher pressure state

known as superheated vapor (1 - 2);

3. The superheated vapor is then being cooled in the condenser and the heat is transferred

to the outside. The condensed refrigerant is now at the state known as saturated liquid

after cooling. (2 – 3);

4. The saturated liquid flows into expansion valve and the valve lowers the pressure of the

refrigerant. The refrigerant now becomes a cold mixture that contains both liquid and

vapor. (3 – 4);

5. The cold mixture is now entering the evaporator with low temperature (4 – 1).

A refrigeration cycle is now completed and the refrigerant repeats the cycle from step 1 to

step 5.

3.2 Reversed Carnot cycle

The Carnot cycle is a theoretical thermodynamic cycle which first purposed by Nicolas Leonard

Sadi Carnot in 1824 [4]. Carnot cycle shows the thermodynamic cycle inside a heat pump and the

relationship between the conversion of heat and work. However, this thesis focuses on a cooling

system not a heat pump, so a Reversed Carnot Cycle is used instead. The reversed Carnot cycle is

similar to the Carnot Cycle but operated in different direction which shown in figure 2:

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Figure 2 P-V diagram of Reversed Carnot cycle

Figure 2 shows a typical P-V graph of Reversed Carnot Cycle, where the points 1 -4 are referred to

figure 1 (Vapour Compression Refrigeration) in chapter 3.1.1. Similar to the steps discussed in

chapter 3.1.1, but a P-V graph of Reversed Carnot Cycle focuses on the pressure and volume of

refrigerant inside the cooling cycle at each stage. The P-V diagram can be understood as following

steps:

1 – 2: The vapor enters the compressor and is compressed isentropically, there is no heat

flow in or out the cooling system. In this stage the volume of the refrigerant is slightly

decreased and the pressure is increased significantly (T1);

2 – 3: Heat is expelled to the outside air isothermally at the condenser. In this stage the

volume of the refrigerant is decreased significantly and the pressure is slightly increased

(T2 = T3);

3 – 4: The vapor is now entering the expansion valve and expanded isentropically, no heat

exchange between the system and surrounding area. In this stage the volume of the

refrigerant is slightly increased and the pressure is decreased significantly (T3);

4 – 1: The heat is extracted from the room and the gas expands isothermally at the

evaporator, this is where the cooling takes place. In this stage, the volume of the

refrigerant is increased significantly and the pressure is slightly decreased. (T4 = T1). [5]

2

3

4

1

Volume

Pressure

6

Where:

T1 equals to the temperature at point 1, T2 equals to the temperature at point 2, etc.;

And also and ;

refers to the cool temperature and refers to the relatively hot temperature.

The steps of the P-V diagram can also be understood more easily as figure 3 below:

Figure 3 above shows the status of the refrigerant at each stage, where Q is the amount of

heat.

3.3 3.3 COOLNOMIX

COOLNOMIX is an intelligent control system designed to improve energy efficiency in both air

conditioning and refrigeration systems by using a unique control technology called Optimized

Refrigerant Supply (ORS). COOLNOMIX is having customers all around the world which having an

average 40% savings on air conditioners and an average 30% savings on refrigeration system from

the customers’ feedback [6].

Figure 3 Model of Reversed Carnot Cycle

1 2 3 4

Qin Qout

7

3.3.1 COOLNOMIX components

Figure 4 [12] below shows the components inside a COOLNOMIX product:

Figure 4 COOLNOMIX Components

These include:

AC power supply terminal - Connects to power supply

Set-point setting - Users are able to adjust the desired room temperature from here

Control relay terminal – This terminal is connected to the refrigeration unit and the

compressor operating signal is sent from here to the refrigeration unit

Supply air sensor – Installed at the evaporator fin to determine whether the unit has done

its hydraulic work (explanation refers to chapter 3 for hydraulic work)

Room temperature sensor – installed at the return air fin to measure the room

temperature

Diagnostics LED – Inform the COOLNOMIX conditions to users by flashing different lights

with different orders

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Reset button – Reset the COOLNOMIX

Alarm switch – Alerts users if COOLNOMIX fails (can be silenced).

Note that there are two models of COOLNOMIX, which are the AC-01 (for air conditioning

systems) and AR-01 (for refrigeration systems). The main difference between the models is the

temperature set point.

The specific setting of a set point, connection of the control relay terminals, location of sensors

and LED signals are shown in Appendix A. [12]

3.3.2 Differences between Optimized Refrigerant Supply and Original Temperature

Control System

3.3.2.1 Original Temperature Control System

Over the past few decades, there was a lot of technology that significantly improved the cooling

system’s efficiency such as inverters, digital scroll etc. However, there is one thing that remains

unchanged, which is most of the cooling systems at the moment are using the thermostat as their

control system. In thermostat a control system, the operation of the compressor is normally

controlled by the thermostat using a crude logic: the compressor is turned ON if the sensor

detects that the room temperature is 1 °C higher than the set point, turned OFF if the sensor

detects that the room temperature is 1 °C lower than the set point. Depending on the load, the

location of sensor etc., the unit takes a certain amount of time to cool down the room

temperature by 2°C (from 1°C higher to 1°C lower than the set point).However, the compressor

will keep running during this period of time, the thermostat ignores what is actually happening

inside the unit, and this may cause the compressor run for a longer period of time, which is

unnecessary. [8]

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3.3.2.2 Background - Air conditioner’s excess capacity

For a better understanding of how ORS works, the background of an air conditioner’s excess

capacity has to be understood. An air conditioner’s capacity is normally chosen to ensure it can

handle satisfactorily under different loads, which means that the air conditioner can run

continuously on the hottest day. At that situation, the refrigerant is boiling quickly in the

evaporator and the compressor manages to keep up with demand. However, in a cooler situation,

there is spare capacity in the unit and the compressor supplies the refrigerant at a faster rate

than the evaporator can boil. This is the situation where ORS can save energy, which will be

discussed in the chapter 3.3.2.3 below. [7]

3.3.2.3 Optimized Refrigerant Supply (ORS)

Optimized Refrigerant Supply is an advanced control system, which using two additional

temperature sensors shown in chapter 3.3.1 and a complex algorithm technology to monitor the

room temperature (thermodynamic) and refrigerant supply (hydraulic) performance of the

cooling system to improve compressor efficiency. Firstly, the ORS uses room temperature sensor

to evaluate the room temperature to ensure the temperature achieved the chosen set point. If

the sensor show that the room temperature is within +/- 0.5 °C of the setpoint, the supply air

sensor then allows the ORS to determine and predict whether the spare cooling capacity in the

evaporator is available and stops the compressor. On the other hand, when the compressor stops

working for a period of time, the condenser is relatively cooler and having lower pressure, while

the evaporator is relatively warmer and having higher pressure. Furthermore, when the

compressor starts, ORS always let it run at full rated so the compressor is possible to finish its

hydraulic work in less time. This technique uses the spare capacity to achieve the same

thermodynamic work by using less mechanical work, gives the compressor the most ideal

conditions to make the whole process more efficient. [7]

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3.3.3 Pros and Cons

There are some pros and cons by installed COOLNOMIX such as:

Pros:

Saves energy – COOLNOMIX reduces unnecessary energy waste and increases system

efficiency by using ORS;

Easy to be installed – COOLNOMIX can be installed easily, normally within an hour

Improved stability of temperature – ORS is designed to control the room temperature

variation to be less than 0.5°C;

No other maintenance fees and operating costs – COOLNOMIX needs no other

maintenance fees and operating costs while running, but only electricity;

Immediate savings – COOLNOMIX starts to save energy once it is installed and runs

successfully;

Low risks – COOLNOMIX has a secure design to make sure the system is able to run as

usual if COOLNOMIX product fails.

Cons:

Fixed temperature set point – COOLNOMIX has its own set point setting component

which shown in chapter 3.3.1. Users can only change the desired temperature from there,

which might be inconvenient for some users;

System limitations – COOLNOMIX only works on cooling only system, which is not be

suitable for reversed cycle units (the unit that can be changed between heating or

cooling).

3.4 Weather

Western Australia is a state, which has a most diverse climate in the country due to its huge size.

Western Australia’s climate can be separated by regional and seasonal (only extreme weather,

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summer and winter is focused in this thesis in order to get the maximum and minimum

temperature throughout the year) as follows:

Region Season Average daily

Maximum

Temperature (°C)

Average daily

Minimum

Temperature (°C)

Perth weather Summer 30 18

Winter 18 6

South West and

Margaret River

weather

Summer 27 15

Winter 12 3

North West and

Broome weather

Summer 39 24

Winter 27 12

Table 1 Ambient Temperature in Western Australia [9]

From the data shows from table 1 above, Western Australia’s average daily temperature changes

between 3 °C and 39 °C (extreme weather can be lower than 3 °C or higher than 39°C).

3.4.1 Effects of weather on cooling system

As mentioned in chapter 3 before, a compressor of a cooling system will start running if the

thermostat detected the space temperature is higher than the set point limit and needs cooling.

On the other hand, if the ambient temperature (temperature of the surrounding/outside the

room) is actually way lower than the set point limit, the compressor will not work and the air

conditioner (cooling only) will be blowing the cold air only.

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3.5 Cooling Load

A load of a cooling system can be defined as the heat that needs to be removed from the area to

maintain a constant area temperature and humidity. The ASHRAE handbook of fundamentals [10]

shows that heat gains for a space affected by the following six components:

Solar radiation through transparent surfaces;

Heat conduction through exterior roofs and walls;

Heat conduction through floors, ceilings, and interior partitions;

Heat generated in the room by appliances, such as lights, occupants etc.;

Energy transfer through ventilation and infiltration of outdoor air;

External Interruption.

3.6 Thermal comfort

Thermal comfort is defined as “a condition of mind which expresses satisfaction with the thermal

environment” [11], which can be understood as the occupants’ satisfaction with the surrounding

thermal conditions. Thermal comfort is always the first priority to be considered in an air

conditioning system. However, there are six important factors contributing to thermal comfort,

which are:

Air temperature – Temperature of air surrounding the occupant;

Metabolic rate – Energy generated from the human body;

Clothing insulation – the amount of thermal insulation an occupant wears;

Radiant temperature – Weighted average of all the temperatures of surfaces surrounding

the occupant;

Relative humidity – percentage of water vapor in the air;

Air velocity – Air moment rate in the space. [11]

13

4 Practical Experiments & Existing Experiment

In this chapter, three experiments are discussed to investigate the COOLNOMIX’s performances

on each system, which is practical experiment for air conditioning system, practical experiment

for refrigeration system and existing experiment for refrigeration system. COOLNOMIX products

are installed in chosen sites and run for a certain period of time to determine:

How does a COOOLNOMIX product affect a cooling system’s performance;

How does a COOOLNOMIX product affect the room temperature;

How does Western Australia ‘s climate affect the COOLNOMIX ORS’ operations;

How much energy does COOLNOMIX save in the practical experiments.

4.1 Design

Selecting a suitable site and design the experiments were the most time-consuming tasks to be

accomplished throughout this thesis. However, before selecting a suitable site for both the

experiments, several considerations were discussed in the following parts.

4.1.1 Consideration

4.1.1.1 Load management

In each experiment, the methods of motoring were separated into two periods, which were test

period and control period. Test period refers to the period without the addition of COOLNOMIX

and the control period refers to the period where COOLNOMIX has been installed in the system.

Therefore, load management for both periods must be able to be controlled to be as similar as

possible in order to get more reliable results.

4.1.1.2 Thermal comfort

For the air conditioning experiment, thermal comfort of the occupants is considered before

choosing an experiment site. Facilities Management at Murdoch University is more concerned

with the thermal comfort level of the air conditioners’ users.

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4.1.2 Air conditioning system

4.1.2.1 Site Selection

After several discussions with the Facilities Management Office at Murdoch University, two

empty classrooms in old Murdoch College (building 126, which is shown in Figure 5 below) were

used for this experiment. There are some reasons why these rooms were chosen as below:

Air conditioners – Both rooms have identical air conditioners with the same model, size

and similar performance (refer to APPENDIX C for specifications);

Room sizes – Both rooms have a very similar room size, so the cooling loads of the rooms

are similar to each other;

Room design – Both rooms are empty classrooms with exactly the same interior design,

so the heat conducted through the floors, ceilings, and interior partitions are similar with

each other;

Room location – The rooms are located next to each other, so the heat conducted

through roofs or walls is expected to be similar;

Ethical issues – Both rooms are empty classrooms that are not in-use. Therefore, ethical

issues such as thermal comfort are not considered.

15

Figure 5 Building 126 Location

A COOLNOMIX unit is then installed in one of the air conditioners by following the installation

manual (refer to APPENDIX A) and both air conditioners are running for a period of time.

However, the experiment is running under some other conditions as follows:

All windows are closed to prevent ventilation;

Only one curtain of each room is open to ensure similar amount of solar radiation

passed through the transparent surfaces;

Air conditioners of both rooms are set as COOLING ONLY and running 24 hours per

day;

No one entered or used the rooms during the experiment to prevent any other

external interruption.

16

From all the load controls shown above, it can be said that both rooms have been running under

similar conditions.

4.1.2.2 Monitoring Equipment

After the suitable site and air conditioners were selected, the next step of the experiment was

monitoring. The monitoring equipment used is shown in table 2 below:

Equipment Quantity

Temperature data logger 1 for each room, 2 in total

Power meter clamp 1 for each air conditioner, 2 in total

Transmitter 1 for each air conditioner, 2 in total

Engage Hub 1 in total

Table 2 Monitoring Equipment for Air Conditioners

Table 2 shows the monitoring equipment used in this experiment, where one temperature data

logger is placed in each room (at the place where student normally sit) to monitor the room

temperature of the space.

However, the power meter clamp, transmitter and engage hub are the components of a

monitoring device named Efergy Engage Hub Kit and it works as below:

1. The power clamp is first installed at the air conditioner power supply and connected to a

transmitter;

2. The engage hub is connected to internet and pairs the transmitters nearby;

3. The transmitters read the connected clamps’ data and send the data to the paired engage

hub;

4. The engage Hub uploads the data to a database where users are able to monitor the data

in real time by using Internet access devices such as a phone, laptop, etc.

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4.1.2.3 Monitoring Method

In this part of the experiment, since there are two air conditioners running under very similar

conditions, the parallel test is the better method to monitor the systems. The parallel test is a

monitoring method, which is normally used in COOLNOMIX testing while the customer has

multiple refrigerators or air conditioners of the same type, size and similar cooling loads. Parallel

test runs either air conditioners or refrigeration systems, with (control period) and without the

(test period) addition of COOLNOMIX together for a certain period of time. Users are able to

compare the differences between the two systems and calculate the energy saved by the addition

of COOLNOMIX product.

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4.1.3 Refrigeration system

4.1.3.1 Site Selection

In this part of experiment for the refrigeration system, only one cool room (refer to appendix C

for the model) in Murdoch University is currently empty and free to do the experiment. This cool

room is located in old Murdoch College (building 124,which shown in Figure 6 below) and has not

been used for quite some time.

Figure 6 Building 124 Location

A COOLNOMIX unit was installed in the cool room by following the installation manual (refers to

Appendix A). And also the experiment is running under some other conditions as follows:

The cool room is running 24 hours per day;

No one entered or used the room to prevent any other external interruption.

19

4.1.3.2 Monitoring Equipment

Monitoring equipment used in this part of experiment is shown in table 3 below:

Equipment Quantity

Temperature data logger 1

Power meter clamp 1

Transmitter 1

Engage Hub 1

Table 3 Monitoring Equipment for Cool Room

The installation of the monitoring devices is same as steps mentioned in chapter 4.1.2.2.

4.1.3.3 Monitoring Method

Different from the air-conditioning system in chapter 4.1.2.3, the refrigeration system in this

chapter is run under linear test because there is only one cool room in this situation. The Linear

test is another monitoring method, which normally used in COOLNOMIX testing while the

customer has only one unit. Linear test first runs the system for a certain period of time (test

period) before installing COOLNOMIX, and then it runs the system for a same period of time with

the addition of COOLNOMIX (control period). Users are able to determine the energy savings by

comparing the energy consumption of the two different periods.

4.2 Pros and Cons of Linear test and Parallel test

The previous chapters show that different methods are used in different systems depend on the

conditions. However, there are some advantages and disadvantages of both methods showed in

table 4 below:

20

Linear test Parallel Test

Advantages Only one unit and one

measuring device are needed

Takes less period of time to

see the energy saving

potential

Loads and environmental

conditions are more likely

similar to both units

Disadvantages Takes longer period of time to

see the energy saving

potential

More than one unit and

measuring devices are needed

Loads and environmental

conditions may vary over time

Table 4 Advantages and Disadvantages of Linear Test and Parallel Test

Users are able to monitor the energy-saving potential of COOLNOMIX more effectively by using a

suitable monitoring method.

4.3 Methodology

In order to get the data for results analysis, the methods are shown as follows:

1. Collect the temperature of the rooms;

2. Collect the ambient temperature during the experiment period from Murdoch University

Weather Station;

3. Collect the energy consumptions of the systems for both the control period and test

period from the database;

4. Investigate the differences between control period and test period;

5. Match the energy consumptions of the control period and test period with the room

temperature and ambient temperature;

21

6. Investigate how the systems’ performance affects the room temperature;

7. Compare control period and test period to determine how much energy is saved.

4.4 Existing Experiment

In this experiment, an existing cool room with installed COOLNOMIX is used to investigate how

the product affects a cool room’s performance. This cool room is located in a restaurant named

Copper Chimney in Fremantle, where a COOLNOMIX is installed on 31st of August. However, all

the data of this cool room is provided from the industry supervisor, therefore only energy

consumption is recorded in this experiment.

22

5 Results and Discussion

5.1 Air Conditioning System

In this part of the experiment, both air conditioners (with and without the addition of

COOLNOMIX) are run and monitored from 26th of October to 6th of November.

5.1.1 Climate condition

Figure 7 Ambient Temperature

Figure 7 above shows the ambient temperature during the experiment period and also the set

points of both air conditioners were set at 23 °C. As mentioned in chapter 3.4.1, the compressor

of a cooling only air conditioner will stop running while the ambient temperature is lower than

the set point, unfortunately during the experiment period, most of the time the ambient

temperature were lower than the set point or very near to the set point due to the cold weather

0

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25/10 27/10 29/10 31/10 02/11 04/11 06/11 08/11

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pe

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Ambient Temperature Ambient Temperature

Air conditioning setpoint

23

in Perth. On the other hand, Figure 7 shows that there was a day the ambient temperature is

significantly higher than the set point, which is 5th of November.

Therefore, the results were separated into two parts, cold weather (26th of October to 1st of

November) and hot weather (on 5th of November) which reflects winter period and summer

period in Western Australia respectively.

5.1.2 Cold Weather

Figure 8 Results of Air Conditioning Systems (Cold Weather)

Figure 8 shows the results of energy consumption of the air conditioners and the corresponding

room temperature in cold weather over time, where lines in blue color refer to the system with

installed COOLNOMIX and the lines in red color refer to the system without the addition of

0

50

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350

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Energy consumptions and room temperatures of air conditioning systems with/without addition of COOLNOMIX

Temperature (with)

Temperature (without)

set point

Energy consumption (with)

Energy consumption (without)

24

COOLNOMIX. Furthermore, the two curve lines on the top of the graph show the temperature of

the room and the two straight lines on the middle show the energy consumption of the air

conditioner.

The results in Figure 8 show that both room temperatures are always lower than the set point

during this period, which means the compressors in air conditioners are more likely not working

but still consuming some tiny amount of energy to keep the air flowing. However, the results also

show that there is always 1 °C difference between each room. The results show that there is a

significant difference between both air conditioners which is the air conditioner with installed

COOLNOMIX is always consuming less energy than another air conditioner. It is believed that

while the COOLNOMIX sensors detected the room temperature is lower than the set point limit,

COOLNOMIX ORS fully shut down the compressor. Conversely, the original air conditioner is still

consuming some energy to keep the compressor running at a very low rated power. This tiny

difference of operation of the compressor is suspected to be the reason that why the air

conditioner without the addition of COOLNOMIX is consuming more energy and the

corresponding room temperature is always slightly higher than another room’s temperature.

After calculating the results, the air conditioner without the addition of COOLNOMIX consumed

5.82 kWh of energy per day and the air conditioner with installed COOLNOMIX consumed 4.65

kWh of energy per day in this experiment. The calculated results show that the COOLNOMIX

technology saved around 1.17kWh of energy per day, which is about 20% of its original energy

consumption.

25

5.1.3 Hot Weather

Figure 9 Results of Air Conditioning Systems (Hot Weather)

Similar to chapter 5.1.2, Figure 9 shows the results of energy consumption of the air conditioners

and the corresponding room temperature in hot weather on 5th of November, where lines in blue

color refer to the system with installed COOLNOMIX and the lines in red color refer to the system

without the addition of COOLNOMIX. Furthermore, the two lines on the top of the graph show

the temperature of the room and the other two lines on the bottom show the energy

consumption of the air conditioner.

The result shows the performance differences between the two air conditioners can be clearly

seen. On this day, the energy consumptions and room temperature of the spaces are similar to

the results shown in Figure 9 before 09:00. However, at around 09:00 (green line), both air

0

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Energy consumptions and room temperatures of air conditioning systems with/without addition of COOLNOMIX

Average energyconsumption(without)

Average energy consumption(with)

9:00:00

26

conditioners’ sensors detected that the room temperature has met the set point and the room

needs cooling. At this stage, the compressors inside both air conditioners started working in order

to cool down the room, but Figure 9 shows that the patterns of energy consumptions in both air

conditioners are totally different, which can be explained as follows:

The air conditioner without addition of COOLNOMIX (Red line) – In this air conditioner,

when the temperature met the set point limit, the compressor started working for a

period of time in order to cool down the room temperature, however the results show

that the room temperature of the room after cooling is not the desired set point that the

users looking for, the room temperature changing around +2°C of the desired set point;

Air conditioner with addition of COOLNOMIX (Blue line) – In this air conditioner, when the

temperature met the set point limit, the compressor which is controlled by ORS started

running at full load for a small amount of time and the compressor stopped when the

COOLNOMIX supply air sensor detected that the compressor had done its hydraulic work.

The cold and sufficient refrigerant inside the cooling cycle has then absorbed the heat

from the room slowly to control the room temperature as stable as possible until the ORS

detected that the compressor needs to be started again in order to stabilize the room

temperature, this is what happened at 20:00 in Figure 9. Comparing the room

temperature of this room with the room without the addition of COOLNOMIX, this

temperature of this room are more stable and always within +/-1°C of the desired set

point.

By using the different operation methods of compressors, the energy consumptions of these two

air conditioners are found to be different. On this day, the air conditioner without the addition of

COOLNOMIX consumed 16.3 kWh of energy in total but the air conditioner with installed

COOLNOMIX consumed 14kWh of energy, which means the COOLNOMIX product saved 2.3 kWh

on that day which is about 14% of the original energy consumption.

27

5.2 Refrigeration System

Figure 10 Results of Cool Room

Figure 11 above shows the results energy consumption and its corresponding room temperature

of the cool room. Different from the air conditioners, climatic conditions of Western Australia are

not considered for a refrigeration system because as mentioned in chapter 3.4, most of the time

the ambient temperature of Western Australia will not get lower than a refrigeration system’s set

point. The results in Figure 10 can be separated into two parts: the data in blue color on the left

refers to the cool room with the addition of COOLNOMIX and the data in red color on the right

refers to the cool room without the addition of COOLNOMIX. For both parts, the data on the top

refers to the room temperature of cool rooms and the data on the bottom refers to the energy

-10

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Date

Power consumption / Room temperature of Cool room with COOLNOMIX ON/OFF

Power consumption (with)

Power consumption (without)

Max.Tempreature (with)

Max.Tempreature (without)

set point

28

consumptions of cool rooms. This experiment of the cool room had been running for 8 days, 4

days with COOLNOMIX and 4 days without COOLNOMIX product.

In this result, the differences between energy consumptions of the cool rooms are found difficult

to be investigated from the trends. However, Figure 10 shows there is a significant difference in

room temperature between the systems: the room temperature of the original cool room

(without COOLNOMIX) is always higher than the set point, which it can be defined as this is a bad

performing cool room that can’t meet the desired set point. Surprisingly, when a COOLNOMIX is

installed and run with the cool room successfully, the room temperature of the cool room is more

stable and is controlled within -2°C of the desired set point. It is suspected that the COOLNOMIX

sensors detected that the cool room was always above the set point limit, it ran the compressor

at full load for the most of the time to make sure the room temperature is at the preferable

temperature (3°C).

In this linear test experiment, the energy saved by COOLNOMIX product can be calculated by

comparing the total energy consumptions of the test period and control period with the same

amount of time. In this experiment, the test period consumed an average of 11 kWh of energy

per day and the control period consumed an average of 12kWh of energy per day. The

COOLNOMIX in this experiment made the cool room consumed an extra 1kWh per day, which is

about 8.1% of its original energy consumption.

Note that the reasons explained in this experiment of the cool room are just possible reasons and

that is not clearly understood why it consumed more energy instead of saving. The data did not

meet the expected results of using this setup, but this might contribute to future researchers who

will do this experiment with this cool room.

29

5.3 Existing Experiment

Figure 11 Results of Existing Experiment

Figure 11 above shows the daily energy consumption of another cool room in Copper Chimney

from 10th of July to 24th of September. In this experiment, COOLNOMIX was installed on 1st of

August until 8th of August and the cool room continue running on 9th of August after the

installation. The results show that the daily energy consumption during the test period (before

COOLNOMIX installation) is significantly higher than the daily energy consumption during the

control period (after COOLNOMIX installation).

The test period was assumed to be 22 days, from the 10th of July to 31st of July, the total energy

consumption during the test period is 895 kWh after calculated. In the other hand, the control

period is assumed to be 22 days also, which is 9th of August to 30th of August, the total energy

consumption during this period is calculated as 416 kWh. The results show that the cool room

saved 478 kWh of energy in total, 21.7 kWh per day during this experiment, which is around

53.5% of his original energy consumption, after installing COOLNOMIX unit.

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Energy consumption of Cool room Energy consumption

30

6 Economic Analysis

From all the results got in chapter 5, the payback period of a COOLNOMIX unit can be estimated

by using assumptions as follows:

Tariff – Assume Synergy Home Plan (A1) tariff is used for a typical household, and the

charges of electricity are AUD 26.4740 cents per unit (kWh); [12]

Operating hours – Assume air conditioner operates 7 days a week and 9 hours per day

(9am – 6pm). Assume refrigerator or cool room operates 7 days a week and 24 hours per

day;

Operating months – Assume air conditioner is only needed for 6 months (summer and

spring). Assume refrigerator or cool room is needed in every season;

COOLNOMIX unit price – A single COOLNOMIX unit costs around AUD 500.

Note that the assumptions made by considering cooling only air conditioners, normally cooling

only air conditioners are not used during cold weather (or switched to heating).

By using the same devices and results in chapter 5, the payback period for an AC-01 unit is 12

years, and the payback period for an AR-01 unit is 2.86 months (calculations shown in APPENDIX

B)

31

7 Conclusion

In conclusion, it can be said that the experiments achieved the project objectives. COOLNOMIX

product does save energy consumption and control the stability of the temperature by using its

ORS technology. This experiment is designed specifically with some considerations taken into

account. The experiment covers implementation in the refrigeration unit as well as air

conditioning units. Specific methodology steps were laid out and implemented to produce

reliable experimental results. The results of the experiments show that in air conditioning system,

COOLNOMIX saved 20% of the energy during cold weather and 14% of the energy during hot

weather without sacrificing the room temperature. In addition, in the existing experiment for a

cool room at the restaurant, the COOLNOMIX saved up to 53.5% of the energy and even have a

payback period of 2.86 months, which is considered as a huge success. From the result in this

thesis, it shows that COOLNOMIX is a potential energy saving product that worth investigating.

However, there are some limitations and conditions that caused these results not reliable during

the experiment such as:

No ambient temperature for the Copper Chimney experiment;

No details of cooling load for the Copper Chimney experiment;

No details of the Copper Chimney’s cool room;

The data of air conditioning system practical experiment during hot period is from a

single day.

32

8 Future Work

This chapter shows some future works that can be done to improve the depth of this project,

along with some suggestions and recommendations

8.1 Reversed Carnot Cycle

Draw a P-V diagram of Reversed Carnot Cycle is the best way to understand how a COOLNOMIX

affects the operation of the compressor and also the whole cooling system. However, in order to

draw the cycle, several monitoring devices have to be installed inside the cooling system. The

recommended method and equipment is shown as follows:

Pressure Meter – Pressure meters must be able to read the pressure of the refrigerant

(fluids/gas) inside the cooling system. Install the pressure meters at the four points of the

cooling systems, which mentioned in chapter 3.2 above. This monitoring method helps

the users to investigate what is happening with the refrigerant inside the cooling system,

and also how does the performance change with the addition of COOLNOMIX unit;

Temperature meter – Similar to the pressure meter, the temperature meters should be

installed at those four points and must be able to read the temperature of the

refrigerant.

Using the data above, the P-V diagram of Reversed Carnot Cycle can be drawn, where the volume

of refrigerant can be calculated by using ideal gas law. Meters with built-in batteries and data

loggers are recommended in this experiment to prevent wiring mess. If the next user is planning

to do this experiment in Murdoch University, it is recommended to discuss with Facilities

Management at Murdoch University to get the approval for this installation as early as possible,

because safety and ethical issues have to be considered before installing external product into

university’s property.

33

8.2 Thermal Comfort Test

In an air conditioning system, thermal comfort is always the first priority to be considered.

However, in this thesis, the experiment is prevented from dealing with the thermal comfort issues

because this is the first time Murdoch University doing the experiment with COOLNOMIX product,

Facilities Management at Murdoch University is unsure if the COOLNOMIX unit reduces the

thermal comfort of the room users. However, the next student who continues this experiment is

recommended to do the experiment in some in use classrooms or lecture theaters to test the

thermal comfort level of the air conditioner with and without the addition of COOLNOMIX.

8.3 Experiment Period

As mentioned before, Australia weather, climate and ambient temperature keep changing all over

the year, and also an air conditioner is not running if the temperature is lower than the set point

limit. It is recommended to run this project for a longer period of time (the best is over a year) to

investigate how a COOLNOMIX unit affects the performance of the air conditioners more reliably

under different types of climate in Western Australia.

34

9 References

[1]"How Much Electricity Does My Air Conditioner Use?", Canstar Blue, 2016. [Online]. Available:

http://www.canstarblue.com.au/appliances/cooling-heating/air-conditioners/how-much-electricity-does-

aircon-use/. [Accessed: 17- Nov- 2016].

[2]"Energy saving tips", Synergy, 2016. [Online]. Available: https://www.synergy.net.au/Your-home/Save-

energy/Energy-saving-tips. [Accessed: 17- Nov- 2016].

[3]"4602.0.55.001 - Environmental Issues: Energy Use and Conservation, Mar 2008", Abs.gov.au, 2008.

[Online]. Available:

http://www.abs.gov.au/AUSSTATS/abs@.nsf/39433889d406eeb9ca2570610019e9a5/0E43C98B32A7FE85

CA25750E00109A1D. [Accessed: 17- Nov- 2016].

[4]"Vapor-compression refrigeration", En.wikipedia.org. [Online]. Available:

https://en.wikipedia.org/wiki/Vapor-compression_refrigeration. [Accessed: 17- Nov- 2016].

[5]"Reverse Carnot Cycle Efficiency | Matt Evans", Mtdevans.com. [Online]. Available:

http://mtdevans.com/projects/physics-problems/reverse-carnot-cycle-efficiency/. [Accessed: 17- Nov- 2016].

[6]P. Michel, "Cool News", Watt Solutions, 2016. [Online]. Available:

http://www.wattsolutions.com.au/news/. [Accessed: 17- Nov- 2016].

[7]"How Coolnomix Works | OZWIDE POWER", Ozwidepower.com.au. [Online]. Available:

http://www.ozwidepower.com.au/how-coolnomix-works/. [Accessed: 17- Nov- 2016].

[8]"How COOLNOMIX® Works", Watt Solutions, 2016. [Online]. Available:

http://www.wattsolutions.com.au/how-coolnomix-works/. [Accessed: 17- Nov- 2016].

[9]"Australian Climate Averages - Maximum, Minimum & Mean Temperature maps", Bom.gov.au, 2016.

[Online]. Available:

http://www.bom.gov.au/jsp/ncc/climate_averages/temperature/index.jsp?maptype=1&period=win#maps.

[Accessed: 17- Nov- 2016].

[10]2009 ASHRAE handbook, 1st ed. Atlanta, GA.: ASHRAE, 2009.

[11]Developing an adaptive model of thermal comfort and preference, 1st ed. 1998.

[12]Maximizing sales, performance and installation instructions, 5th ed. COOLNOMIX General Guide AC-

01/AR-01, 2014.

[13]"Synergy Home Plan® (A1) tariff", Synergy, 2016. [Online]. Available:

https://www.synergy.net.au/Your-home/Energy-plans/Home-Plan-A1. [Accessed: 17- Nov- 2016].

35

10 APPENDIX

10.1 Appendix A

10.1.1 COOLNOMIX installation (AC-01)

1. The COOLNOMIX AC-01 power supply terminal is connected to the same mains source

with the air conditioner;

2. The air conditioners used in the practical experiment are controlled directly by a

mechanical thermostat, so the wiring method of the COOLNOMIX AC-01 is called Direct

Control Method, where the COOLNOMIX AC-01 control relay terminals are connected in

SERIES with the thermostat wire which control the compressor shown in Figure 12 [12]

below:

Figure 12 COOLNOMIX AC-01 wiring

36

3. The COOLNOMIX AC-01 supply air sensor is installed in the air supply outlet as close as

possible to the evaporator fin without touching it as the blue arrow shown in Figure 13;

4. The COOLNOMIX AC-01 room temperature sensor is installed in the air supply outlet as

close as possible to the evaporator fin without touching it as the red arrow shown in

Figure 13; [12]

Figure 13 COOLNOMIX AC-01 Sensors Locations

5. The COOLNOMIX AC-01 unit set point can be adjusted by following the orientation shown

in Figure 14. [12]

37

Figure 14 COOLNOMIX AC-01 Set Point Orientations

10.1.2 COOLNOMIX installation (AR-01)

1. The COOLNOMIX AR-01 power supply terminal is connected to the same mains source

with the cool room;

2. The COOLNOMIX AR-01 control relay terminals are connected as shown in Figure 15 [12]

below:

38

Figure 15 COOLNOMIX AR-01 Wiring

3. The COOLNOMIX AR-01 supply air sensor is installed inside the fins of the return air side

(usually near the bottom of the evaporator), but not touching the copper fluid pipes, only

aluminum fins, as shown in Figure 16 [12]:

39

Figure 16 COOLNOMIX AR-01 Sensor Location

4. The COOLNOMIX AR-01 room temperature sensor is placed a few inches away from the

return air side of evaporator and stay up high;

40

5. The COOLNOMIX AR-01 unit set point can be adjusted by following the orientation shown

in Figure 17; [12]

Figure 17 COOLNOMIX AR-01 Set Point Orientation

6. Note that for the COOLNOMIX AR-01:

Automatically timed defrost devices must be disabled

Timer that controls a heating coil for evaporator ice melting must be bypassed

Timer that turns off air circulation fans must be bypassed

If the existing temperature controller has a thermistor sensor for detecting ice build-

up, it can generally be left untouched, as a properly functioning AR-01 will prevent

any ice build-up, only auxiliary timers must be bypassed [12]

41

10.1.3 COOLNOMIX LED Indicator Description

COOLNOMIX LED flashing sequence and their indication is shown in table 5 [12] below:

LED flashing Sequence Phase Indication

Flashing GREEN Starting up, or Wait a minimum of 3 minutes to

gather data for start up

Gathering room

temperature and supply air

temperature data

Waiting for room temperature

and supply air temperature to

turn on the compressor

Steady GREEN with Flashing red Compressor started Waiting for the room

temperature and supply air

temperature data to be met to

turn off the compressor

Continuous RED Fault Failure detected, audible alarm

will work if activated

No LED ON Power Failure Check circuit breaker or fuse. If

air conditioner continues

running and no LED is working,

there may be a fault with

COOLNOMIX

Table 5 COOLNOMIX LED Flashing Sequence and Indication

10.2 APPENDIX B calculation

10.2.1 Payback Period (AC-01)

From the results, AC-01 saved 2.3 kWh a day and the annual saving can be calculated as:

42

And the pay pack period can be calculated as:

10.2.2 Payback Period (AR-01)

From the results, AR-01 saved 21.7 kWh a day and the annual saving can be calculated as:

And the pay pack period can be calculated as:

43

10.2.3 Appendix C

Figure 18 Model of Air conditioner for Practical Experiment

Figure 19 Model of Cool Room for Practical Experiment