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2-6 Azeotropic/Zeotropic Refrigerants 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 ﴾ صدق هللا العظٍم ََ ْ (19) اﻻٌت سورة الىمل إليي ﻻ يطيب الميل إﻻ بشكرك وﻻ يطيب النيار إﻻ بطاعتك .. وﻻ تطيب المحظات إﻻ بذكرك .. وﻻ تطيب اﻵخرة إﻻ بعفوك .. وﻻ تطيب الجنة إﻻ برؤيتك .. اذا كان اﻻىداء يعبر ولو بجزء من الوفاء فاﻻىداء إلى من بمغ الرسالة وأدى اﻷمانة .. ونصح اﻷمة .. إلى نبي الرحمة ونور العالمين .. 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 "كن عالما .. فإن لم تستطع فكن متعمما ، فإن لم تستطع فأحب العمماء ،فإن لم تستطع فﻻ 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 ﻻ يسعنا إﻻ أن نخص بأسمى عبارات الشكر و التقدير لﻷستاذة.. كما نتقدم بالشكر الجزيل لكل من أسيم في تقديم يد العون ﻹنجاز 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 Pressure h Enthalpy Qc Heat of condenser Qe Heat of evaporator 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/Refrigerant Mixtures 2-1 Introduction 4 2-2 Background - Refrigerant Mixtures 4 2-3 Refrigerant Criteria 4 2-4 Alternative Refrigerants 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 phase diagram 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 vapor 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 boiling point, 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 condensation 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.
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