Republic of Iraq Ministry of Higher Education & Scientific Research Northern Technical University Technical Institute /Kirkuk Equipments & Machineries Dep./ Branch of Ref. & Air Conditioning

A Research Submitted to

((Equipments & Machineries Dep./ Branch of Ref. & Air Conditioning))

Prepared by

Ibrahim Najmaldeen Mahmood Jalal Ali Asgher

Ahmed Bahir Mohammed Ibrahim Ahmed Mohammed

George Odisho Bawith

Supervised by

2018 1439

بِسْمِ ِهللا الرَّحْمهِ الرَّحٍِم ِ

﴿ رَبِّ أَوْزِعْىًِ أَنْ أَشْكُرَ وِعَْمتَكَ التًِ أَوعمت علً وعلى واِلدي َّ ََْْ َََّ َََ َ َ َّ وَأَنْ أَعَْملَ صَاِلحًا َترْضَاُي وَأَدْخِلْىًِ بِرَحَْمتِكَ فًِ عِبَادِك الصَّاِلحٍِه ﴾

صَدقَ هللا العظٍْم

(19)االٌت سورة الىمل

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اذا كان االىداء يعبر ولو بجزء من الوفاء فاالىداء إلى

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الى الوالدين الحبيبين الشموع التي تنير لنا دروب الحياة ..

الى اخواننا و اخواتنا الذين يؤازرونا ويدعموننا..

الى كل صديق اضاف لنا تقدما في الحياة ..

الى اساتذتنا و مربونا ..

الــــــى من ميدوا الطريق امامنا لموصول الى ىذه المرحمة

نيدي لكم ثمرة جيدنا واجتيادنا ..

الباحثون

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تستطع فال تبغضيم"

بعد رحمة بحث و جيد و اجتياد تكممت بإنجاز ىذا البحث ، نحمد اهلل عز وجل

عمى نعمو التي انعميا عمينا فيو العمي القدير ، كما ال يسعنا إال أن نخص بأسمى

عبارات الشكر و التقدير لألستاذة..

كما نتقدم بالشكر الجزيل لكل من أسيم في تقديم يد العون إلنجاز ىذا

البحث، و نخص بالذكر أستاذتنا الكرام الذين أشرفوا عمى تكوين دفعة..

نسال اهلل العمي القدير ان يجزي الجميع خير الجزاء

وان يوفقيم لما يحبو ويرضاه انو سميع مجيب ..

الباحثون

Symbols Description C.O.P Coefficient of Performance P h Enthalpy

Qc Heat of condenser

Qe Heat of T Temperature

Tsat Saturated temperature wt Percentage mixing ratio by weight

We Work of evaporator OD Ozone depletion

GW Global warming

Item Page Chapter One/Introduction 1-1 Introduction 1 1-2 Ozone layer 1 1-3 Global Warming 1 1-4 Phase Equilibrium Diagram of Binary Mixture 2 1-5 The Aim of This Work 3 Chapter Two/ Mixtures 2-1 Introduction 4 2-2 Background - Refrigerant Mixtures 4 2-3 Refrigerant Criteria 4 2-4 Alternative 5 2-5 Classification of Refrigerants 7 2-6 Azeotropic/Zeotropic Refrigerants 8 2-6-1 Azeotropic Mixtures 8 2-6-2 Non-Azeotropic/Zeotropic Mixtures 9 2-7 Oils 11 2-8 Refrigeration Oil 11 Chapter Three/Refrigerants Properties 3-1 Introduction 13 3-2 Azeotropic Refrigerants 13 3-3 Zeotropic Refrigerants 13 3-4 Saturated Properties Tables for Mixtures 13 3-4-1 For Azeotropic Refrigerants 14 3-4-2 For Zeotropic Refrigerants 17 3-5 Pressure – Enthalpy (P-h) Charts for Mixtures 21 3-5-1 For Azeotropic Refrigerants 21 3-5-2 For Zeotropic Refrigerants 24 Chapter Four/Conclusion and Recommendation 4-1 conclusion 28 4-2 Recommendation 29 References References 30

Chapter One Introduction 1-1 Introduction:-

Many of evolutions and modifications have been carried out compressive cooling systems since beginning until the present time. Most of studies focused on the mechanisms and methods of developing those systems, in terms of performance (C.O.P). And the key factor was energy consuming and their results, then the focus in researches and studies switched to other fields which was concentrated on two main hubs, which are, the first is to maintain a healthy environment by avoiding all harmful gasses accompanied from engine combustion and air- conditioning refrigerants which have a great impact on global warming and Ozone depletion, and second, is to accommodate a natural alternatives instead of classical energy for long term.

1-2 Ozone layer:-

The ozone layer or ozone shield is a region of Earth's stratosphere that absorbs most of the Sun ultraviolet radiation. It contains high concentrations of ozone (O3) in relation to other parts of the atmosphere, although still small in relation to other gases in the stratosphere. Where Refrigerants containing chlorine or bromine contribute to the breakdown of the ozone layer.

1-3 Global Warming:-

There is an average increase in earth surface temperature with the increase of the environmental harmful gases emission such as carbon dioxide ,Methane and other existed gases in the atmosphere . those gases called greenhouse gases because they contribute in increasing the earth temperature, this phenomenon is called the Global warming, and the average of increasing temperature in the air where noticed in the middle of 20th century as it continues to rise. Whereas the earth temperature was increased 0.74 ± 0.18° C over the last century. Where this increase in temperature negatively affect the industrial revolution and the advancement of technology which become one of the risks that surround the earth environment and must be taken into consideration [1].

1-4 Phase Equilibrium Diagram of Binary Mixture:-

Phase equilibriums of binary mixtures are represented on phase diagrams. Figure (1-1) depicts a for a binary mixture system at constant pressure. The dew point line represents the dew point temperatures of all the possible mixture compositions, where Tdew is defined as the temperature at which a superheated mixture will first begin to condense upon cooling. The bubble point line represents the bubble point temperatures of all the possible mixture compositions, where Tbub is defined as the temperature at which a sub-cooled mixture will first begin to evaporate upon heating. The composition of one of the components, in this case the component with the lowest , is depicted on the lower axis, where the equilibrium vapor composition Y is that which corresponds to the liquid composition X at the same temperature. It can be seen from the figure mentioned above that the saturation temperature of one pure component is on the left vertical axis while that of the other component is on the right vertical axis [2].

Figure (1-1) Phase equilibrium diagram at constant pressure for a binary mixture [2].

1-5 The Aim of This Work:-

The aim of this work is, to identify the blend refrigerant compression cooling system, which is consists of two or more refrigerant gases and knowing the proportion of each gas exist in the mixture and studying the differences in their properties and behavior, as well as comparing them with compression refrigeration pure gases which consist of one pure refrigerant gas.

Chapter Two Refrigerant Mixtures

2-1 Introduction:-

This chapter studies the properties of substances used as working fluids in compression cycles, and discusses the classification of refrigerants. Some of the most common refrigerants are presented, as well as the special phenomena occurring with the use of zeotropic refrigerant mixtures. Finally, the use of secondary refrigerants and oil in refrigerant are discussed.

2-2 Background - Refrigerant Mixtures:-

Evaporation or of a pure fluid is isothermal. However, a mixture with two or more components exhibits non-isothermal phase change behavior. For example, start and finish of evaporation of a mixture occur at bubble point and dew point temperature respectively [3].

2-3 Refrigerant Criteria:-

A working fluid in a compression refrigeration system must satisfy a number of requirements that can be divided into two groups:

1. The refrigerant should not cause any risk of injuries, fire or property damage in case of leakage. 2. The chemical, physical and thermodynamic properties of the refrigerant must suit the system and the working conditions at a reasonable cost. Table (2-1) show refrigerant criteria but at the same time it is not possible to fulfill all the requirements above at the same time. The most important criterion is chemical stability within the refrigeration system. All the other criteria are meaningless if the refrigerant decomposes or reacts with the materials used in the system.

Table(2-1) The criteria can be specified more precisely as follows [4]:

Chemical Stable and inert *Non-toxic Health & safety & *Non-flammable environmental *Benign to the atmosphere , etc

*Critical point and boiling point temperatures appropriate for the application *low vapor heat capacity Thermal *low viscosity *High thermal conductivity

*Satisfactory oil solubility \ miscibility *High dielectric strength of vapor Other *Low freezing point *Easy leak detection *Low cost

2-4 Alternative Refrigerants:-

The vast majority of refrigerating systems use the practical reversed Rankine cycle. Some alternative systems use the Rankine cycle with refrigerants which restrict their fields of application but many alternative systems are cycles or methods which are fundamentally different. Refrigerants are divided into groups according to their chemical composition. Following the discovery that some of these chemical compounds may be harmful to the environment, they are being replaced with more environmentally friendly alternatives (as show in figure 2-1). The process is not easy, and although there are alternatives to old refrigerants, the new ones are usually not flawless.

Alternative refrigerants

HCFC HFC Hologen free (with chlorine) (no chlorine)

mixtures pure mixtures pure pure mixtures e.g.R134a R407C e.g.R22 R410A e.g.Ammonia e.g.proanel iso-butane propane

Figure (2-1) Alternatives to the "old" refrigerants [4].

Table (2-2) Summary table of the different types of refrigerants.

Refrigerant Series Safety Glide R32 Methane series A1 R125 Ethane series A1 R134a Ethane series A1 R245ca Propane series A2 R245a Zeotropic mixture R404A A1\A1 1K (44%R125\52%R143a\4%R134a) Zeotropic mixture R407C A1\A1 7K (23%R32\25%R125\52%R134a) Azeotropic mixture R410A (50%R32\50%R125) Azeotropic mixture R507A (50%R125\50%R143a) Azeotropic mixture R508B (46%R23\54%R116A)

Table (2-3) Summary table of the different types of refrigerants. Prefix Meaning Atoms in the Molecule CFC Chlorofluorocarbn CL \ F \ C HCFC Hydrochlorofluorocarbon H \ CL \ F \ C HFC Hydrofluorocarbon H \ F \ C HC Hydrocarbon H \ C

Table (2-4) Health and safety classification.

CLASS/GROUP Description The toxicity of the refrigerant is not identified at A concentrations below 400 ppm volume.

Evidence of toxicity identified at concentrations below 400 B ppm by volume.

No flame propagation in air at 18*c and 101kpas> This group has the least severe restrictions, but the maximum amount of refrigerant in the system (g-room volume) is 1 limited. The purpose of this limitation is that if a pip fracture, the concentration of refrigerant in the room is kept below the hazardous level.

Lower flammability limit than group 1, but the toxicity is the largest hazard. These is also a limit on the amount of 2 refrigeration in the system, depending the category to which the room in question belongs.

Highly flammability. This group has the most severe restrictions. Depending on the filling licenses are needed in 3 some cases. If a refrigerant is not classified, it is considered as group 3 refrigerant until classification.

2-5 Classification of Refrigerants:- This section is focused only on the primary refrigerants which can be classified into thfollowing five main groups: • halocarbons. • hydrocarbons. • inorganic compounds. • azeotropic mixtures. • nonazeotropic mixtures.

Figure (2-2) refrigerant classification[1].

2-6 Azeotropic/Zeotropic Refrigerants:-

A refrigerant may be either a pure compound or a mixture (blend) of two or more refrigerants. Examples of pure refrigerants are R12, R22 and R134a. Examples of mixtures are R502, R404A and R407C. A mixture can behave either as a pure refrigerant (azeotropic mixtures), or differently (non- azeotropic, or zeotropic, mixtures). 2-6-1 Azeotropic Mixtures:-

Although it contains two or more refrigerants, at a certain pressure an azeotropic mixture evaporates and condenses at a constant temperature. Because of this, azeotropic mixtures behave like pure refrigerants in all practical aspects. Figure (2-3a) shows that the temperature is constant in the liquid-vapor mixture region for a given pressure. For example

1- R500 consist of (R12/R152)(73.8/26.2)wt% 2- R502 consist of (R22/R115)(8.8/51.2)wt% 3- R503 consist of (R23/R13)(40.1/59.9)wt%

2-6-2 Non-Azeotropic/Zeotropic Mixtures:-

Zeotropic mixtures have a gliding evaporation and condensing temperature [show Figures (2-4) and (2-5)]. When evaporating, the most volatile component will boil off first and the least volatile component will boil off last. The opposite happens when gas condenses into liquid. Figure (2- 3b) shows that for a given pressure, the temperature will change in the liquid-vapor mixture region. This results in a gliding evaporation and condensing temperature along the heat transfer surface. In practice, the saturation temperature at the inlet of the evaporator will be lower than at the outlet. In the condenser, the saturation temperature at the inlet will be higher than at the outlet.For example

1- R404a consist of (R122/R143/R134a)(44/52/4)wt% 2- R407c consist of (R32/R125/R134a)(23/25/52)wt% 3- R410a consist of (R32/R125)(50/50)wt% 4- R413a consist of (R600a/R218/R134a)(3/9/88)wt%

Figure (2-3)….(a): Pure refrigerant or azeotropic mixture (no glide). (b): Non-azeotropic (zeotropic) mixture (glide) [5].

Figure (2-4) Condenser and evaporator temperature program, counter- current flow [5].

Figure (2-5) Condenser and evaporator temperature program, co-current flow [5].

Zeotropic mixtures have a gliding evaporation and condensing temperature When evaporating, the most volatile component will boil off first and the least volatile component will boil off last. The opposite happens when gas condenses into liquid .change in the liquid-vapor mixture region. This results in a gliding evaporation and condensing temperature along the heat transfer surface. In practice, the saturation temperature at the inlet of the evaporator will be lower than at the outlet. In the condenser, the saturation temperature at the inlet will be higher than at the outlet [6]. 2-7 Oils:-

Oil is normally present in a refrigeration system, and the interaction between the oil and the refrigerant must be considered. High oil solubility is used in hermetic compressors, but immiscible oils are normally used when the working fluid is ammonia.

2-8 Refrigeration Oil:-

The moving parts of a compressor assembly must be lubricated for smooth operation and prevention of damage. Oil is also used at the seals and gaskets. In addition, a small amount of oil is added to the refrigerant in the system to maintain the thermostatic expansion valve in proper operating condition. The classification of refrigeration oil is based on three factors such as viscosity, compatibility with refrigerants, and pour point. R-12 requires oil with a viscosity rating of about 300 for air-conditioning service; however oil up to 1000 viscosity rating has been used in some systems. The refrigerant oil must be compatible with the refrigerant used in the system, and there must not be any change or separation by chemical interaction. The temperature at which oil just flows is its pour point. The properties of good refrigeration oil are low wax content, good thermal and chemical stability, low viscosity, and a low pour point.

Chapter Three Refrigerants Properties 3-1 Introduction:-

Refrigerants mixtures as a refrigerant has thermodynamic properties, in vapor compression refrigeration cycles design must know these properties to study refrigerant conditions and decide the acceptable design.

A program (REFPROP) were used to accomplished fluids mixing process (Zeotropic and Azeotropic) and getting properties table and (p-h) schemes and studying properties behaviour those mixtures [7].

In this work, seven refrigerants- as Examples for both Azeotropic and Zeotropic types - will be studded and comparing their properties:

3-2 Azeotropic Refrigerants:-

4- R500 consist of (R12/R152)(73.8/26.2)wt% 5- R502 consist of (R22/R115)(8.8/51.2)wt% 6- R503 consist of (R23/R13)(40.1/59.9)wt%

3-3 Zeotropic Refrigerants:-

5- R404a consist of (R122/R143/R134a)(44/52/4)wt% 6- R407c consist of (R32/R125/R134a)(23/25/52)wt% 7- R410a consist of (R32/R125)(50/50)wt% 8- R413a consist of (R600a/R218/R134a)(3/9/88)wt%

3-4 Saturated Properties Tables for Mixtures:-

For these tables the range of properties depending on pressure was (1 to 25) bar by (1 decrement) was shown in following tables (3-1 , 3-2,3-3,3-4,3-5,3- 6 and 3-7).

3-4-1 For Azeotropic Refrigerants:-

1- R500 consist of (R12/R152)(73.8/26.2)wt%

Tables (3-1) saturated properties for R500.

2- R502 consist of (R22/R115)(8.8/51.2)wt%

Tables (3-2) saturated properties for R502.

3- R503 consist of (R32/R125)(50/50)wt%

Tables (3-3) saturated properties for R503.

3-4-2 For Zeotropic Refrigerants:-

1- R404A consist of (R122/R143/R134a)(44/52/4)wt%

Tables (3-4) saturated properties for R404A.

2- R407C consist of (R32/R125)(50/50)wt%

Tables (3-5) saturated properties for R407C.

3- R410A consist of (R32/R125)(50/50)wt%

Tables (3-6) saturated properties for R410A.

4- R4013a consist of (R600a/R218/R134a)(3/9/88)wt%

Tables (3-7) saturated properties for R413a.

3-5 Pressure – Enthalpy (P-h) Charts for Mixtures:-

For these charts the range of pressure (Y axis) was (1 to 20) bar and of enthalpy ( X axis) was (100 -600) kJ/Kg shown in following figures [(3-1) , (3-2),(3-3),(3-4),(3-5),(3-6) and (3-7)].

3-5-1 For Azeotropic Refrigerants:-

1- R500 consist of (R12/R152)(73.8/26.2)wt%

Figure (3-1) saturated properties for R500.

2- R502 consist of (R22/R115)(8.8/51.2)wt%

Figure (3-2) saturated properties for R502.

3- R503 consist of (R23/R13)(40.1/59.9)wt%

Figure (3-3) saturated properties for R503.

3-5-2 For Zeotropic Refrigerants:-

1- R404A consist of (R122/R143/R134a)(44/52/4)wt%

Figure (3-4) saturated properties for R404A.

2- R407C consist of (R32/R125/R134a)(23/25/52)wt%

Figure (3-5) saturated properties for R407C.

3- R410A consist of (R32/R125)(50/50)wt%

Figure (3-6) saturated properties for R410.

4- R4013a consist of (R600a/R218/R134a)(3/9/88)wt%

Figure (3-7) saturated properties for R413.

Chapter Four Conclusion and Recommendation 4-1 Conclusion:-

1- Pure refrigerants which have low OD and GW are very limited and the number of diverse applications of refrigeration is ever increasing. If a pure refrigerant cannot meet the requirements. But mixture refrigerant offer the advantage of tailoring the composition to suit various temperature requirements. It is also possible to control the properties such as toxicity, flammability, oil miscibility by manipulating the composition. Hence, they are finding greater use. 2- A refrigerant may be either a pure compound or a mixture (blend) of two or more refrigerants. Examples of pure refrigerants are R12, R22 and R134a. Examples of mixtures are R502, R404A and R407C. A mixture can behave either as a pure refrigerant (azeotropic mixtures), or differently (non-azeotropic, or zeotropic, mixtures). 3- Zeotropic mixture is one whose composition in liquid face differs to that in vapour phase. Zeotropic refrigerants therefore do not boil at constant temperature unlike azeotropic refrigerants. For example

9- R404a consist of (R122/R143/R134a)(44/52/4)wt% 10- R407c consist of (R32/R125/R134a)(23/25/52)wt% 11- R410a consist of (R32/R125)(50/50)wt% 12- R413a consist of (R600a/R218/R134a)(3/9/88)wt%

4- Azeotropic mixture is a stable mixture of two or several refrigerants whose vapour and liquid phases retain identical compositions over a wide range of temperature. For example

7- R500 consist of (R12/R152)(73.8/26.2)wt% 8- R502 consist of (R22/R115)(8.8/51.2)wt% 9- R503 consist of (R23/R13)(40.1/59.9)wt%

5- Different zeotropic mixtures have different temperature glides. For Ex. zeotropic mixture R152a/R245fa has a higher temperature glide than R21/R245fa. A larger gap between the boiling points creates a larger temperature glide between the boiling curve and dew curve at a given mass fraction. However, with any zeotropic mixture, the temperature glide decreases when the mass fraction of a component approaches 1 or 0 (when the mixture is almost separated into its pure components) because the boiling and dew curves get closer near these mass fractions.

4-2 Recommendation:-

1- Drawing compression cycle for the fluids (R404a, R413a, R500, R502, ….) scheme for each fluid and conducting practical calculation,

such as (C.O.P , We , Qe , Qc). 2- Charging refrigeration system by two kinds of blends and study the differences between them practically.

References

[1] Thomas F. Stocker, Dahe Qin, Pauline M. Midgley, " 2013 The Physical Science Basis", Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, Printed in the United States of America, (2013). [2] Reinhard Radermacher and Yunho Hwang, "Vapor Compression Heat Pumps with Refrigerant Mixtures", by Taylor & Francis Group, LLCCRC Press is an imprint of Taylor & Francis Group, (2005).

[3] Leelananda Rajapaksha, "Zeotropic Refrigerant Mixtures in Vapour Compression Refrigeration Systems - Issues and Implications" ENGINEER - Vol. XXXVIII, No. 04, pp. 52-59, (2005). [4] Ibrahim Dincer, "Energy Solutions to Combat Global Warming", University of Ontario, Canada (2017).

[5] Xiayan Z., Changfa J., Xiuling Y., "Prediction Method for Evaporation Heat Transfer of Non-Azeotropic Refrigerant Mixtures Flowing Inside Internally Grooved Tubes", Applied Thermal Engineering, Vol. 28, Issues 14-15, pp. 1974-1983, (2007).

[6] Ibrahim D. "Refrigeration Systems and Application", John & Wiley,

England (2003).

[7] NIST Standard Reference Database 23, Version 9.0 E.W. Lemon, M.L. Huber and M.O. Mclinden , Copy right 2010 by U.S. Secretary of commerce on behalf of the United States of America.

جميورية العراق وزارة التعميم العالي والبحث العممي الجامعة التقنية الشمالية المعيد التقني/كركوك قسم المكائن والمعدات/فرع التبريد والتكييف

بحث مقدم الى

((قسم المكائن والمعدات / فرع التبريد والتكييف))

من اعداد

ابراهيم نجم الدين محمود جالل علي اصغر

ابراهيم احمد محمد احمد باهر محمد

جورج عوديشو باوث

باشراف

2018 1439