Refrigerant - Types, Properties, Designation, Examples

Table of Contents

Introduction to Refrigerants :

制冷剂是一种在周期中的热携带介质（即比较，冷藏，蒸发）在制冷系统中吸收允许温度的热量系统并将其吸收到更高温度系统中。
The natural ice and mixture of ice and salt were the first refrigerants. In 1834, edger氨，二氧化硫，氯化甲基和二氧化碳用作制冷剂compression cycle refrigeration machines. Most of the early refrigerant materials have been由于安全原因或缺乏化学或热稳定性而被丢弃。现在，许多新的制冷剂在内和制冷应用。
The suitability of a refrigerant for a certain application is determined by its physicalthermodynamic, chemical properties, and by various practical factors. There is no one refrigerantthat can be used for all types of applications i.e there is no ideal refrigerant. It one refrigeranthas certain good advantages, it will have some disadvantages also. Hence, a refrigerant is chosenwhich has greater advantages and fewer disadvantages.

Refrigerant Definition :

制冷剂是用于冷却机构的化学物质，例如空调或冰箱，从气体变为液体的热载体，然后在冷藏周期中返回气体。

Functions of Refrigerants:

(1) The main function of the refrigerant is to absorb the heat from the indoor air,它从低压气体转变为高压液体，然后将其转移到the atmosphere.

Desirable properties of an Ideal Refrigerant :

A refrigerant is said to be ideal if it has all of the following properties:

1. Low boiling and freezing point,
2.高临界压力和温度，
3. High latent heat of vaporization,
4. Low specific heat of the liquid, and high specific heat of vapor,
5.蒸气的特异性低，
6.高热电导率，
7. Non-corrosive to metal,
8.不易用和非爆炸性，
9. Non-toxic
10.低成本，
11. Easily and regularly available,
12.在中等压力和温度下易于液化，
13. Easy to locating leaks by our or suitable indicator,
14.与油充分混合
15.高表现系数，结束
16.臭氧友好。

Properties of refrigerant:

1) Thermodynamic Properties:-

（a）沸腾温度：The boiling temperature of the refrigerant should be low to reduce the capacity of the compressor.

(b) Freezing Temperature:冷冻温度应低于蒸发温度，以防止制冷剂在操作过程中冻结。

（c）蒸发器和冷凝器压力：Both Evaporator and Condenser pressure should be above slightly above the atmospheric level. Positive pressure required to prevent leakage of air and moisture into the refrigerant system.

（d）压缩比：It should be as small as possible.
e) It should have a high latent heat of vaporization.
f) It should be above the condensing temperature & pressure.

2) Chemical Properties:-

a）它不应有毒或有害。它不应对眼睛刺激。
b）它不应具有腐蚀性，也不应对设备中使用的材料产生任何影响。
c）它的泄漏趋势应该较少，如果泄漏，则应容易检测到它。
d) It should not be Inflammable.

3）其他属性： -

a) It should be easy & safe to handle.
b）应该容易以低成本提供。
c) It should have a high COP & low power requirements.

4) Physical properties:

1.它应该具有低粘度。
2.它应该具有高热电导率。

制冷剂的分类：

适合制冷目的的流体可以分为原始制冷剂和二级制冷剂。初级制冷剂是那些直接用作工作流体的流体，例如在蒸气压缩和蒸气吸收制冷系统中。

1）初级制冷剂

2）二级制冷剂

初级制冷剂： -

The refrigerant which takes part in the refrigeration cycle is known as the primary refrigerant. The refrigerants which directly take part in the refrigeration system are called primary refrigerant. Primary refrigerants are used in domestic refrigerator and Air conditioning system etc. Primary refrigerants are R-11, R-12, R-21, R-143a, etc.

他们被归类为

i) Halocarbon compounds
e.g R -11 – Trichloromonofluromethane
R – 12
R – 13
R -21等

ii）共解释： -Mixture of different refrigerant

iii）烃： -甲烷，乙烷，丙烷等

iv)Inorganic compounds:-氨，二氧化碳，二氧化硫，空气等。

v) Unsaturated organic compounds:– Refrigerant with ethylene and propylene base.

二级制冷剂

1.首先用原始制冷剂冷却并用于冷却目的的制冷剂称为二级制冷剂。
2. Secondary refrigerants allow the amounts of environmentally harmful primary refrigerants to be minimized and contained in a restricted area.
3. Examples of secondary refrigerants include water, air, hydrocarbons, ammonia, and carbon dioxide, which are more environmentally benign than traditional refrigerants such as HCFCs. They are safer and generally suitable for refrigeration systems.
4. Brines are often chosen as secondary refrigerants for large refrigeration systems, such as those supplying supermarkets, the most common brine being water-glycol solutions, water-ethanol solutions, and acetate solutions.
5. It is used in ice plant and in big installation.
6.二次制冷剂水、盐水、乙二醇, etc.

1.水：Used in Air conditioning systems for cooling, Dehumidification, etc.
2.盐水：Used in Ice plants to maintain temperatures lower than atmospheric temperatures.

制冷剂的名称系统：

The refrigerants are internationally designated as ‘R’ followed by certain numbers例如R-11，R-12，R-114等制冷剂源自甲烷碱，而三位数代表乙烷碱基。
The分配给水碳和光晕和制冷剂的数字具有特殊的含义。首先digest on the rightist the number of fluorine (F) atoms in the refrigerant. The second digit from the right is one more than the number of hydrogen (H) atoms present. The third digit from the right is one less than the number of carbon (C) atoms, but when this digit is zero, it is omitted.
用于甲烷或乙烷碱的制冷剂的一般化学公式，以n + p + q = 2m + 2的CMHNCLPFQ给出

其中m =碳原子数，
n =氢原子的数量，
p =氯原子的数量，以及
q = number of fluorine atoms.

As discussed above, the number of the refrigerants is given by R9m -1) (n + 1) (q). Let usconsider the following refrigerants to find its chemical formula and the number.

1. Dichloro-difluoro-methane

We see that in this refrigerant
Number of chlorine atoms, p = 2
Number of fluorine atoms q = 2
以及氢原子的数量，n = 0
我们知道N + P + Q = 2M +2
0 + 2 + 2 = 2m +2 or m = 1
即碳原子的数量= 1

Thus the chemical formula for discolor- difluoro-methane becomes CCl2F2 and the number of refrigerants becomes R (1-1) (0 +1)(2) or R-012 i.e R-12.

2. Dichloro-tetrafluoro-ethane

We see that in this refrigerant
Number of chlorine atoms, p = 2
氟原子的数量，Q = 4
And number of hydrogen atoms, n = 0
我们知道N + P + Q = 2M +2
0 + 2 + 4 = 2m + 2 or m=2
即碳原子的数量= 2

Thus the chemical formula for Dichloro-tetrafluoro-ethane becomes C2Cl2F4 and the numbers of Refrigerant becomes R(2-1) (0+1) (4) or R-114.

Refrigerants Example – Applications Of Refrigerants

i）空调 - R-22，R-114
ii）国内冰箱 - R-12，R-143A
iii) Ice Plant – In primary circuit Ammonia and secondary circuit Brine solution.
iv）水冷却器 - R-12，R-143A

汽车空调中使用的制冷剂：

1）Dichloro difluro-methane或Freon -12（R-12）
2) Tetra fluro- ethane or R-134a or HFC-134a
3) R-134a
4）R-22
5) R-410A
6) R-32

Refrigerants commonly used in practice-

1）NH3（氨）

特性 -Highly toxic, flammable, good thermal properties, highest refrigerating effect per kg of refrigerant.

Uses –It is widely used in large industrial and commercial refrigeration systems. It is mostly used with the Vapour absorption refrigeration cycle like ice plants, cold storage, packing plants, etc.

2) CO2 (Carbon dioxide)

特性 -Colorless, non-toxic, non-flammable, and non-corrosive gas. It gives a low refrigeration effect.

Uses –It is used in the marine refrigeration system.

3) Air

特性 -Easily available without cost, non-toxic, completely safe refrigerant, low COP.

Uses –It is used in an aircraft air-conditioning system.

4）R-11（Trichloro Mono Fluoro甲烷）或Freon-11

特性 -Non-toxic, Non-flammable, and Non-corrosive.

Uses –It is used in Small office buildings and factories for refrigeration.

5) R-12 (Dichlaro – difluro methane) or Freon -12

特性 -Non -toxic, Non-flammable, Non-explosive, high COP, and most suitable refrigerant.
Uses –It is used in domestic vapor compression refrigeration.

6）R -22（单氯 - Difluro甲烷）或Freon -22

特性 -Non-toxic, Non-flammable, Non-explosive Required less compressor displacement.
Uses –它用于商业和工业低温应用（空调）。

Advantages of R134a refrigerant over R-12.

– Refrigerant R134a is a hydro fluorocarbon (HFC) that has zero potential to cause the臭氧层的耗竭和几乎没有温室效应。
- R134a是易燃的和不爆炸性的，具有限制和良好的毒性chemical stability.
- 它对水分的亲和力高。
– The overall physical and thermodynamic properties of refrigerant R134a closelyresemble with that of refrigerant R12.
– Due to all the above factors, R134a is considered to be an excellent replacement forR12 refrigerant.

臭氧耗竭潜力（ODP）的概念

在地球大气周围连续破坏保护性臭氧气体层bychemical reaction of CFC refrigerants that are leaked from innumerable refrigeration systems on地球表面被称为“臭氧层耗竭”。
在平流层层中，臭氧气体浓度更多。该臭氧层周围形成一个保护层，该保护层在地球表面上，从太阳射线中吸收有害的紫外线（UV），并且只能使有益的光线和热射线到达地球表面。
预防到达地球表面的紫外线可保护人类，臭氧层的耗竭会导致臭氧层中的“臭氧孔”形成，并通过这些臭氧孔有害的超紫色射线进入大气中，危害了地球的生物生物。
Ozone depletion potentials (ODPs) were a very important measure in the formulation of the Montreal Protocol and its Amendments. ODP values are used to provide a simple way to compare the relative ability of various ODS to destroy stratospheric ozone. ODP is defined as “the integrated change in total ozone per unit mass emission of a specific ozone-depleting substance relative to the integrated change in total ozone per.
Harmful effects of UV rays on people: Skin cancer, Premature aging of the skin Cataracts and eye disorders, Immune system damage.

Concept of the greenhouse effect and ozone depletion

在地球大气周围连续破坏保护性臭氧气体层通过从无数的CFC制冷剂的化学反应refrigeration systems on earth’s surface is known as “Ozone Layer Depletion”.
In the outer atmosphere of earth up to 50 Km, there is a layer called Stratosphere.在此层中，臭氧气体浓度更多。这个臭氧层形成protective layer around the earth’s surface which absorbs the Harmful Ultraviolet rays(UV) from Sun’s rays and allows only beneficial light and heat rays to reach on地球表面。
Prevention of UV rays reaching to earth’s surface protects human and Depletion of Ozone layer leads to the formation of “Ozone Holes” in the Ozone layer andthrough these ozone holes Harmful Ultra Violet rays enter into the atmosphere
endangering the earth’s biolife.
由于“臭氧层耗竭”，大气使大部分射线很大一部分visible light from the sun to reach the earth surface and heat it. Out of the incident radiation由于碳分子，一些红外辐射被地球大气所困dioxide and water vapor in the atmosphere and causes the earth’s surface and loweratmospheric layer to warm to high temperature. This is called as global warming.