Study On Predictive Maintenance Of HVAC System.
‘I admit that I have read this report and in my opinion this report is fulfilled the scope and quality for award condition of Bachelor of Mechanical Engineering (Thermal-Fluids)’
Signature : ... Supervisor’s Name : ... Date : ...
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STUDY ON PREDICTIVE MAINTENANCE OF HVAC SYSTEM
AHMAD BIN ISMAIL
This report was adduced in partial fulfillment for award condition of Bachelor of Mechanical Engineering (Thermal-Fluids)
Faculty of Mechanical Engineering Universiti Teknikal Malaysia Melaka
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“I hereby, declare this report is the result of my own research except as cited in the references”
Signatures :……….
Author ‘s Name:……….
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Special Thanks To My Beloved Parents, Ismail and Zainab… My Whole Family,
Abang Ki, Kak Na and Family Kak Yah, Abang Yie and Family
Abang Wi Abang Ha Adik Mil
And All My Beloved Friends and Lecturers at UTeM For All Your Commitments and Supports
Thank You Very Much… Love All of You Always….
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ACKNOWLEDGEMENT
Alhamdulillah, after all the effort of work and studies, this report of Projek Sarjana Muda (PSM) has finally completed. This one year of the PSM is able to complete within the time frame with the help of some of the people who have willingly to shared knowledge, ideas and lend their hand to me while completing this research. Therefore, I would like to take this opportunity to express my token of appreciation to those who have directly or indirectly involved in this project.
Firstly, I would like to thank both of my parents for their support upon completing this project. My deepest thank goes to my supervisor, Mr. Ahmad Fuad. Thank you very much for sharing his expertise knowledge, thoughts and ideas with me. Thanks for all the guidance he have given to me. Without his guidance and advice, I would not be able to perform my research project.
A token of appreciation also goes to all JKR staffs at Mechanical Department especially to Mr. Zainal as Head of Maintenance Unit (Building Services) and also Mr. Masri as JKR Technician at Seri Negeri. Not forgotten also to all my friends and all my fellow course mates in making this PSM a success. Thank you for their time, knowledge and skill for helping me in terms of ideas, transportation, facilities, financial, etc.
Hopefully my PSM will be helpful and beneficial to people who are interested to make further study in this field. Lastly, thank you very much again and certainly, it would be impossible to complete the PSM without helps from all of them.
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ABSTRACT
Heating, Ventilating and Air Conditioning (HVAC) is humidity equipment that comes in one package to provide comfort ability to people. Commercial HVAC systems provide the people working inside buildings with conditioned air so that they will have a comfortable and safe work environment. There are three main systems in HVAC system, which are heating, ventilating and air conditioning. For each main system, there are many others equipment or components in it. The maintenance of HVAC system is very important in order to maintain humidity services to people. So, many academics and researchers make a study about HVAC maintenance to always propose new method which is better than conventional maintenance method and replace it. In this paper or report, it is also mentioned about the methodology in order to do research about the HVAC maintenance which is focused on chillers and AHU only. The best method in HVAC maintenance is by predictive maintenance. Actually, there are many types of technologies used in predictive maintenance like, vibration analysis, oil analysis, eddy current testing, IR thermography and also ultrasonic testing. This type of maintenance has more advantages than disadvantages.
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ABSTRAK
Pemanasan, pengalihudaraan dan penyaman udara merupakan alat pelempap udara yang digabung menjadi satu sistem dan dipanggil sebagai sistem HVAC. Sistem ini berupaya untuk memberi keselesaan kepada manusia dengan terhasilnya udara yang lembap di dalam bangunan yang asalnya bersuhu tinggi. Ini membolehkan manusia melakukan aktiviti mereka dengan selesa dan dalam keadaan yang selamat. Terdapat tiga sistem yang utama dalam sistem HVAC ini iaitu pemanasan, pengalihudaraan dan penyaman udara. Setiap sistem ini pula mengandungi pelbagai alat kelengkapannya yang tersendiri. Penyelenggaraan sistem HVAC ini amat penting untuk menjamin dan mengekalkan kebolehfungsiannya dalam memberi keselesaan kepada manusia. Oleh itu, ramai antara ahli akademik dan pengkaji yang melibatkan diri dalam kajian ini untuk mencari satu kaedah penyelenggaraan yang baru dan lebih baik daripada yang sedia ada dan menggantikannya. Kertas kajian ini ataupun laporan ini turut mengandungi metodologi untuk menjalankan kajian tentang penyelenggaraan sistem HVAC ini dan menumpukan kepada dua komponen iaitu alat pendingin air dan unit pengelola udara (AHU). Penyelenggaraan jangkaan adalah kaedah yang paling sesuai dan tepat dalam proses menyelenggara system HVAC ini. Sebenarnya terdapat pelbagai teknologi yang digunakan dalam kaedah penyelenggaraan jangkaan ini antaranya ialah analisis getaran, analisis minyak, ujian arus pusar, thermografi inframerah dan juga ujian ultrasonik. Kaedah penyelenggaraan ini mempunyai banyak kelebihan daripada kelemahan.
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TABLE OF CONTENTS
CHAPTER ITEMS PAGES
CONFESSION ii
DEDICATION iii
ACKNOWLEDGEMENT iv
ABSTRACT v
ABSTRAK vi
TABLE OF CONTENTS vii
LIST OF TABLES xi
LIST OF FIGURES xii
LIST OF ABBREVIATIONS, SYMBOLS &
UNIT xv
LIST OF APPENDIXES xviii
CHAPTER 1 INTRODUCTION 1
1.1 Background 1
1.2 Objectives 2
1.3 Problem Statements 2
1.4 Scope 3
CHAPTER 2 THEORY 4
2.1 HVAC System 5
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CHAPTER ITEMS PAGES
2.2.1 Heating 6
2.2.2 Ventilating 9
2.2.3 Air Conditioning 10
2.3 Central HVAC System Components 11
2.4 How an HVAC Works 13
CHAPTER 3 LITERATURE REVIEW 16
3.1 Wireless Condition Monitoring and Maintenance for Rooftop Packaged Heating, Ventilating and Air-Conditioning by Katipamula, S. and Brambley, M. R 16
3.1.1 Monitoring Plan, Automated Fault Detection and Diagnostics 17
3.1.2 Costs of Package-Unit Monitoring Systems 22
3.2 Improved Thermal Building Management with the Aid of Integrated Dynamic HVAC Simulation by Mathews, E.H. and Botha, C.P. 26 3.2.1 Case Study 26
3.2.2 Improved Building Management Through Simulation 28
3.2.2.1 Cooling Coil Fouling 28
3.2.2.2 Chiller Degradation 30
3.2.2.3 Control Strategy Adjustment 32
3.3 Model-Based Fault Detection and Diagnosis of HVAC Systems Using Support Vector Machine Method by Liang, J. and Du, R 35
3.3.1 Design of MBFDD Scheme 35
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CHAPTER ITEMS PAGES
3.3.3 Fault Diagnosis Results 38
CHAPTER 4 METHODOLGY 40
4.1 Do Research By Articles, Journals,
Reference Books, Etc. 42 4.2 Identify Problems Statements 42 4.3 Identify Systems Used 42 4.4 Find the Place to Do Research 43 4.5 Make Observation Research and Interview 43 4.6 Make on Documentation Research 43 4.7 Make Analysis and Discussion 44
CHAPTER 5 RESULT 45
5.1 Common Problems Occurred 46 5.2 Predictive Maintenance (PdM) on Chiller 48 5.3 Predictive Maintenance (PdM) on Air
Handling Unit (AHU) 48
5.4 Vibration Analysis 48
5.5 Oil Analysis 51
5.6 Building Automation System (BAS) 52
CHAPTER 6 DISCUSSION 56
6.1 Advantages and Disadvantages of Predictive
Maintenance 56
6.2 Others Predictive Maintenance Technologies 59
6.2.1 Eddy Current Testing 59
6.2.2 IR Thermography 60
6.2.3 Ultrasonics Testing 62
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CHAPTER ITEMS PAGES
6.3 The Costs of Condition Monitoring
Technologies 64
CHAPTER 7 CONCLUSION 66
REFERENCES 68 BIBLIOGRAPHIES 69 APPENDIXES 70
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LIST OF TABLES
NO. TITLE PAGES
3.1 Costs for a Wired System for Monitoring Six HVAC Units
(Source: Katipamula and Brambley, 2004) 23 3.2 Costs for a Low-Cost Wireless System for
Monitoring HVAC Units
(Source: Katipamula and Brambley, 2004) 25 3.3 Simulated indoor (return) temperatures of
lecture rooms when heatingelements are disabled due to coil fouling. (The shaded area indicates the rooms that are unoccupied.)
(Source: Mathews and Botha, 2003) 34
6.1 Advantages and Disadvantages of Predictive Maintenance 58
6.2 Approximate Costs to Start CBM in Various Technologies
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LIST OF FIGURES
NO. TITLE PAGES
2.1 Boiler
(Source: Internet reference, 23/08/2008) 7
2.2 Furnaces
(Source: Internet reference, 23/08/2008) 8 2.3 Heating coils
(Source: Internet reference, 23/08/2008) 9 3.1 Schematic of Condition Monitoring System
for Rooftop Packaged Units with Wireless Sensors
(Source: Katipamula and Brambley, 2004) 18 3.2 Schematic Depiction of HVAC and Monitoring
Equipment Layout
(Source: Katipamula and Brambley, 2004) 22 3.3 Prototype Integrated Wireless Data Collection
and Transmission Unit
(Source: Katipamula and Brambley, 2004) 24
3.4 Schematic layout of the chilled water HVAC system
installed in the case study building
(Source: Mathews and Botha, 2003) 27
3.5 Simulated effect of reduced cooling coil efficiency
on indoor temperatures in the building
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NO. TITLE PAGES
3.6 Simulated effect of reduced cooling coil
efficiency on chiller power consumption
(Source: Mathews and Botha, 2003) 30
3.7 Simulated effect of reduced chiller efficiency
on indoor temperatures in the building
(Source: Mathews and Botha, 2003) 31
3.8 Simulated effect of reduced chiller efficiency
on chiller power consumption
(Source: Mathews and Botha, 2003) 32
3.9 Schematic layout of the air flow through the
reheating system currently used in the case study building
(Source: Mathews and Botha, 2003) 33 3.10 The block diagram of the MBFDD method
(Source: Liang and Du, 2006) 34 3.11 Illustration of a single zone HVAC system model
(Source: Liang and Du, 2006) 36 3.12 Design of the SVM classifier
(Source: Liang and Du, 2006) 38 3.13 Flow chart of the four-layer SVM classifier
(Source: Liang and Du, 2006) 39 4.1 Flow Chart of Research Procedure 41
5.1 Chiller 45
5.2 AHU 45
5.3 Typical Vibration Transducers
(Source: www.eere.energy.gov/femp, 27/03/2009) 49 5.4 Typical Hand-held Vibration Sensing Meters
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NO. TITLE PAGES
5.5 Typical Vibration Analyzer
(Source: www.eere.energy.gov/femp, 27/03/2009) 50 5.6 Oil Analysis Work and Typical Oil Analysis Equipment
(Source: Carrier Corp., 2002) 52 5.7 Chiller Plant Diagram
(Source: JKR, 2009) 54
5.8 DDC Controller Panel 55
6.1 Doing Eddy Current Testing
(Source: Carrier Corp., 2002) 59 6.2 Example Thermogram Showing Misalignment
(Source: www.eere.energy.gov/femp, 27/03/2009) 61 6.3 Typical IR Spot Thermometer
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LIST OF ABBREVIATIONS, SYMBOLS & UNIT
HVAC Heating, Ventilating and Air Conditioning IAQ Indoor Air Quality
ASHRAE American Society of Heating, Refrigerating and Air Conditioning Engineers
% Percentage
°F Fahrenheit Degree LPG Liquid Petroleum Gas cfm cubic feet per minute OA Outside Air
MUA Make-up air fpm feet per minute CT Cooling Tower
CWP Condenser Water Pump CWS Condenser Water Supply CWR Condenser Water Return CH Chiller
CHWP Chilled Water Pump CHWS Chilled Water Supply CHWR Chilled Water Return CC Cooling Coil
HC Heating Coil
HWS Heating Water Supply HWR Heating Water Return HWP Heating Water Pump
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HHWS Heating Hot Water Supply B Boiler
SAF Supply Air Fan
SAD Supply Air Duct
MVD Manual Volume Damper
CD Ceiling Diffuser
RA Return Air Inlet
RAF Return Air Fan
RA Return Air Dampers
ATC Automatic Temperature Control Damper
EA Exhaust Air (Dampers)
F Filters
ATC Automatic Temperature Control Valve
MBV Manual Balancing Valve
AHU Air Handling Unit
RTU Roof Top Unit
Btu/hr British thermal unit per Hour
MVD Manual Volume Dampers
TR Ton of Refrigeration
FDD Fault Detection and Diagnostic
m2 meter square
mm milimeter
FCU Fan Coil Units
COP Coefficient of Performance
MBFDD Model-Based Fault Detection and Diagnosis
SVM Support Vector Machine
SMO Sequential Minimal Optimization
Hz Hertz
AC Alternating Current
DC Direct Current
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PM Preventive Maintenance
PdM Predictive Maintenance
PaM Proactive Maintenance
FBM Failure Based Maintenance BAS Building Automation System DDC Direct Digital Control
CBM Condition Based Monitoring MCSA Motor Current Signature Analysis
IR Infrared
FAM Facilities and Asset Management
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LIST OF APPENDIXES
NUM. TITLE PAGES
A Gantt Chart 70
B Carrier Hermetic Screw Liquid Chiller 71
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CHAPTER 1
INTRODUCTION
1.1 Background
Heating, ventilating and air conditioning (HVAC) system is very useful to people especially those live in the working building that need comfortable and safe work environment. Many large buildings and campuses have HVAC system. Maintaining and optimizing the performance of HVAC equipments like pumps, chillers and motors can be challenging. These systems often have hidden performance problems that waste energy and cause excessive wear on equipment. A preventive and predictive maintenance plan is an excellent way to maintain an efficient system, save energy dollars, prevent costly breakdowns, and extend equipment life. Today, the HVAC system is one of the main necessities in the working building but to maintain it works smoothly and can provide good environment, it needs a good maintenance. Building systems are the lifeblood of any facility. Without lighting, water, or heating and cooling, a building would be uninhabitable. That is why a strong preventive and predictive HVAC maintenance program is not an option but it is the thing that we should do. So, with the blooming of technologies nowadays it should have the alternative way in HVAC maintenance to replace the old ones.
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1.2 Objectives
While doing this study or research, they are some objectives that should be achieved based on problems that we want to encounter. The objectives are to:
i. Identify the problems that commonly occurred on the HVAC system.
ii. Study the predictive maintenance or condition monitoring of the HVAC system iii. Analyze the advantages and disadvantages by using condition monitoring on
HVAC maintenance.
1.3 Problem Statements
Nowadays, HVAC system is very important to use and be a main necessity or requirement either to working building or living building like commercial buildings, offices, supermarkets and campuses building. To get good environments in the buildings, HVAC system should be monitored and controlled effectively, in other words the scheduled maintenance are required in order to maintain good working of HVAC systems. The cost of the maintenance is became the most factors to dispute and argue among engineers. So, they need to find a solution how to detect and identify developing problems before failure and extensive damage can occur. By this, they can make proper and suitable actions to avoid the HVAC equipments from breakdowns otherwise they will have problems to repair and maintenance. So, the best solution is by make a predictive maintenance on HVAC system based on condition monitoring methods and technologies.
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1.4 Scope
This research is about the study on the predictive maintenance on HVAC system. Means that, this research want to study what are the methods and technologies used in order to monitor the condition of the HVAC equipments in terms of problems occurred during the operation of these equipments. There are many types of HVAC equipments like boiler, chiller, cooling tower and air handling unit (AHU). But, in this research it will focus just on the chiller and AHU. In order to study about predictive maintenance, the basic information about the problems or failures that are commonly occurred on chiller and AHU need to be identified first. Then, how the predictive maintenance is going to overcome these problems need to study as a climax of the research.
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CHAPTER 2
THEORY
HVAC actually is an acronym for heating, ventilating and air conditioning. HVAC system is very important especially in working building or office building that involves many people in order to provide comfort ability to people. According to Samuel (2005), provide an acceptable level of occupancy comfort and process function is one of HVAC system objectives beside to maintain good indoor air quality (IAQ) and to keep system costs and energy requirements to a minimum. The three functions of heating, ventilating, and air-conditioning are closely interrelated. All seek to provide thermal comfort, acceptable indoor air quality, and reasonable installation, operation, and maintenance costs.
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2.1 HVAC System
Commercial heating, ventilating and air conditioning (HVAC) systems provide the people working inside buildings with conditioned air so that they will have a comfortable and safe work environment. People respond to their work environment in many ways and many factors affects their health, attitude and productivity. Air quality and the condition of the air are two very important factors. By conditioned air and good air quality, we mean that air should be clean and odor-free and the temperature, humidity and movement of the air will be within certain acceptable comfort ranges. ASHRAE, the American Society of Heating, Refrigerating and Air Conditioning Engineers, has established standards which outline indoor comfort conditions that are thermally acceptable to 80% or more of a commercial building’s occupants. Generally, these comfort conditions, sometimes called the “comfort zone”, are between 68°F and 75°F for winter and 73°F to 78°F during the summer. Both these ranges are for room air at approximately 50% relative humidity and moving at a slow speed (velocity) of 30 feet per minute or less.
An HVAC system is simply a group of components working together to move heat to where it is wanted (the conditioned space), or remove heat from where it is not wanted (the conditioned space) and put it where it is unobjectionable (the outside air).
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LIST OF APPENDIXES
NUM. TITLE PAGES
A Gantt Chart 70
B Carrier Hermetic Screw Liquid Chiller 71
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CHAPTER 1
INTRODUCTION
1.1 Background
Heating, ventilating and air conditioning (HVAC) system is very useful to people especially those live in the working building that need comfortable and safe work environment. Many large buildings and campuses have HVAC system. Maintaining and optimizing the performance of HVAC equipments like pumps, chillers and motors can be challenging. These systems often have hidden performance problems that waste energy and cause excessive wear on equipment. A preventive and predictive maintenance plan is an excellent way to maintain an efficient system, save energy dollars, prevent costly breakdowns, and extend equipment life. Today, the HVAC system is one of the main necessities in the working building but to maintain it works smoothly and can provide good environment, it needs a good maintenance. Building systems are the lifeblood of any facility. Without lighting, water, or heating and cooling, a building would be uninhabitable. That is why a strong preventive and predictive HVAC maintenance program is not an option but it is the thing that we should do. So, with the blooming of technologies nowadays it should have the alternative way in HVAC maintenance to replace the old ones.
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While doing this study or research, they are some objectives that should be achieved based on problems that we want to encounter. The objectives are to:
i. Identify the problems that commonly occurred on the HVAC system.
ii. Study the predictive maintenance or condition monitoring of the HVAC system iii. Analyze the advantages and disadvantages by using condition monitoring on
HVAC maintenance.
1.3 Problem Statements
Nowadays, HVAC system is very important to use and be a main necessity or requirement either to working building or living building like commercial buildings, offices, supermarkets and campuses building. To get good environments in the buildings, HVAC system should be monitored and controlled effectively, in other words the scheduled maintenance are required in order to maintain good working of HVAC systems. The cost of the maintenance is became the most factors to dispute and argue among engineers. So, they need to find a solution how to detect and identify developing problems before failure and extensive damage can occur. By this, they can make proper and suitable actions to avoid the HVAC equipments from breakdowns otherwise they will have problems to repair and maintenance. So, the best solution is by make a predictive maintenance on HVAC system based on condition monitoring methods and technologies.
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1.4 Scope
This research is about the study on the predictive maintenance on HVAC system. Means that, this research want to study what are the methods and technologies used in order to monitor the condition of the HVAC equipments in terms of problems occurred during the operation of these equipments. There are many types of HVAC equipments like boiler, chiller, cooling tower and air handling unit (AHU). But, in this research it will focus just on the chiller and AHU. In order to study about predictive maintenance, the basic information about the problems or failures that are commonly occurred on chiller and AHU need to be identified first. Then, how the predictive maintenance is going to overcome these problems need to study as a climax of the research.
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CHAPTER 2
THEORY
HVAC actually is an acronym for heating, ventilating and air conditioning. HVAC system is very important especially in working building or office building that involves many people in order to provide comfort ability to people. According to Samuel (2005), provide an acceptable level of occupancy comfort and process function is one of HVAC system objectives beside to maintain good indoor air quality (IAQ) and to keep system costs and energy requirements to a minimum. The three functions of heating, ventilating, and air-conditioning are closely interrelated. All seek to provide thermal comfort, acceptable indoor air quality, and reasonable installation, operation, and maintenance costs.
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2.1 HVAC System
Commercial heating, ventilating and air conditioning (HVAC) systems provide the people working inside buildings with conditioned air so that they will have a comfortable and safe work environment. People respond to their work environment in many ways and many factors affects their health, attitude and productivity. Air quality and the condition of the air are two very important factors. By conditioned air and good air quality, we mean that air should be clean and odor-free and the temperature, humidity and movement of the air will be within certain acceptable comfort ranges. ASHRAE, the American Society of Heating, Refrigerating and Air Conditioning Engineers, has established standards which outline indoor comfort conditions that are thermally acceptable to 80% or more of a commercial building’s occupants. Generally, these comfort conditions, sometimes called the “comfort zone”, are between 68°F and 75°F for winter and 73°F to 78°F during the summer. Both these ranges are for room air at approximately 50% relative humidity and moving at a slow speed (velocity) of 30 feet per minute or less.
An HVAC system is simply a group of components working together to move heat to where it is wanted (the conditioned space), or remove heat from where it is not wanted (the conditioned space) and put it where it is unobjectionable (the outside air).