Lecture Chapter 2 : Refrigerant - ThS. Nguyễn Duy Tuệ

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Objectives lecture "Chapter 2 : Refrigerant" leaves: Understand the requirements of refrigerant and coolant, understand the thermodynamic and property of some refrigerants, use the refrigerant chart to display refrigeration cycle. Invite you to reference.

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Nội dung Text: Lecture Chapter 2 : Refrigerant - ThS. Nguyễn Duy Tuệ

CHAPTER 2: REFRIGERANT AND COOLANT 12/2015 Chapter 2 : Refrigerant 1
OBJECTIVES Student can: - Understand the requirements of refrigerant and coolant - Understand the thermodynamic and property of some refrigerants - Use the refrigerant chart to display refrigeration cycle 12/2015 Chapter 2 : Refrigerant 2
REFRERENCES [1]. Refrigerant and Air Contioning - A. [1] A R. R Trott and T. Welch [2] Danfoss document [2]. 12/2015 Chapter 2 : Refrigerant 3
CONTENTS REFRIGERANTS COOLANT REFRIGERANT CHART ANALYST 12/2015 Chapter 2 : Refrigerant 4
REFRIGERANT 1. Ideal properties for a refrigerant: (page28,[1]) It will ill be b usefulf l to t remindi d ourselvesl off the th requirements for a fluid used as a refrigerant. • A high hi h latent l t t heat h t off vaporization i ti • A high density of suction gas • Non-corrosive, N i non-toxic t i and d non-flammable fl bl • Critical temperature and triple point outside the working ki range • Compatibility with component materials and l b i ti oilil lubricating • Reasonable working pressures (not too high, or b l below 12/2015 Chapter 2 : Refrigerant 5
REFRIGERANT • Low cost • Ease E off leak l k detection d t ti • Environmentally friendly N single No i l fluid fl id has h allll these th properties, ti andd meets the new environmental requirements, but this chapter h t will ill show h th developments the d l t that th t are taking t ki place in influencing the selection and choice of a refrigerant. fi t 12/2015 Chapter 2 : Refrigerant 6
REFRIGERANT 2. Ozone depletion potential (ODP): Th ozone layer The l i our upper atmosphere in t h provides a filter for ultraviolet radiation, which can b harmful be h f l to t our health. h lth The Montreal Protocol in 1987 agreed that the production d ti off these th chemicals h i l would ld be b phased h d outt by 1995 and alternative fluids developed 12/2015 Chapter 2 : Refrigerant 7
REFRIGERANT R22 is an HCFC and now regarded as a t transitional iti l refrigerant, fi t in i that th t it will ill be b completely l t l phased out of production by 2030, as agreed under th Montreal the M t l Protocol. P t l 12/2015 Chapter 2 : Refrigerant 8
REFRIGERANT 12/2015 Chapter 2 : Refrigerant 9
REFRIGERANT 3. Global warming potential (GWP): - Global Gl b l warming i is i the th increasing i i off the th world’s ld’ temperatures, - It is i caused d by b the th release l i t the into th atmosphere t h of so-called ‘greenhouse’ gases, which form a bl k t and blanket d reflect fl t heat h t back b k to t the th earth’s th’ surface, f or hold heat in the atmosphere. - The Th mostt infamous i f greenhouse h gas isi carbon b dioxide (CO2), which once released remains in the atmosphere t h f 500 years, so there for th i a constant is t t build-up as time progresses. 12/2015 Chapter 2 : Refrigerant 10
REFRIGERANT Table 3.3 shows that the newly developed refrigerant fi t gases alsol h have a global l b l warming i potential if released into the atmosphere. F example, For l R134a R134 has h a GWP off 1300, 1300 which hi h means that the emission of 1 kg of R134a is equivalent i l t tot 1300 kg k off CO2. 12/2015 Chapter 2 : Refrigerant 11
REFRIGERANT 12/2015 Chapter 2 : Refrigerant 12
REFRIGERANT + Note : 12/2015 Chapter 2 : Refrigerant 13
REFRIGERANT 12/2015 Chapter 2 : Refrigerant 14
REFRIGERANT 4. Ammonia and the hydrocarbons: - These Th fl id have fluids h virtually i t ll zero ODP and d zero GWP when released into the atmosphere and th f therefore presentt a very friendlyf i dl environmental i t l picture. Ammonia has long been used as a refrigerant fi t for f industrial i d t i l applications. li ti - Ammonia cannot be used with copper or copper alloys, ll so refrigerant fi t piping i i and d components t have h t to be steel or aluminium. - Its It normall boiling b ili point i t is i –3333 °C. °C Ammonia A i has h a characteristic smell even in very small concentrations t ti i air. in i 12/2015 Chapter 2 : Refrigerant 15
REFRIGERANT - It cannot burn, but it is moderately explosive when h mixedi d with ith air i in i a volume l percentage t off 13 to t 28%. - Used U d ini industrial i d t i l system t 12/2015 Chapter 2 : Refrigerant 16
REFRIGERANT Fluorinated refrigerants always carry the d i designation ti “R” followed f ll d byb a number, b e.g. R22, R22 R134a, R404A and R407C. The fluorinated refrigerants fi t allll have h th following the f ll i features: f t - Vapour is smell-free and non-irritant. - Extensively E t i l non-poisonous. i I the In th presence off fire the vapour can give off fluoric acid and phosgene, h which hi h are very poisonous. i - Non-corrosive. - Non-flammable N fl bl and d non-explosive. l i 12/2015 Chapter 2 : Refrigerant 17
REFRIGERANT +The most common fluorinated refrigerants are: R134 which R134a, hi h is i a substance b t off the th ethane th group with the formula CH2FCF3 and has a normal b ili boiling point i t off –26.1°C. 26 1°C ItsIt th thermodynamic d i properties make it suitable as a refrigerant for medium di t temperature t applications li ti such h as domestic d ti refrigerators. 12/2015 Chapter 2 : Refrigerant 18
REFRIGERANT R22, which is a substance of the methane group withith the th formula f l CHF2CI and d has h a boiling b ili point of –40.8 °C. Its thermodynamic properties make k it suitable it bl as a refrigerant fi t for f a wide id range off applications in commercial refrigeration and air conditioning. diti i R22 is i being b i phased h d outt as refrigerant fi t in many countries due to its ozone depleting potential. t ti l 12/2015 Chapter 2 : Refrigerant 19
REFRIGERANT R32 is difluoromethane (methylene fluoride) and it is i an HFC type t refrigerant. fi t R32 has h been b used d for f many years as a component of both R407C and R410A It is R410A. i flammable fl bl on its it own, but b t nott when h mixed with the other components of these blends. 12/2015 Chapter 2 : Refrigerant 20