They space not in the stimulate of precedence together overtime priorities adjust when the influence on the Ozone great is thought about the many important.
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1. High latent heat of vaporization
High latent heat of vaporization is preferable in a refrigerant. It results in a high refrigerating effect and a low price of refrigerant in circulation.
More heat have the right to be took in and ejected in every cycle that refrigeration.
2. A High Suction gas density and also a short Compression ratio.
High suction gas density at the compressor suction way low size compressor and a lesser-powered compressor motor. ~ the refrigerant passes with the evaporator, the refrigerant gas growth is not very high, ie. Fluid to Gas expansion is low.
This home of refrigerant noted a short compression proportion for the compressor, the higher mass flow rate of the refrigerant resulting in a low price of circulation within the system.
3. Non-corrosive, non-toxic and non-flammable
Refrigerant must not be poisonous or lethal come air-conditioning, person health, and also foodstuff. As soon as coming in call with metal parts like piping and compressor must not cause any kind of sort of electrochemical corrosion.
Must it is in compatible with non-metallic parts such as nitrile rubber tubes, O-rings (used for sealing purpose).
As the refrigerant it s okay compressed under high pressure and also temperature inside the compressor, it need to not cause any type of explosion or catch fire in ~ the system and also continue that is non-flammable properties.
The presence of humidity in the system may reason the formation of very corrosive compounds (usual acids) which may react with compressor lubricating oil and with other products in the system consisting of metals.
Moisture may cause the failure of compressor valves in situation of hermetic compressor regularly causes break down of the engine winding insulation causing short-circuiting or grounding of the motor.
The visibility of moisture in lubricating oil might deteriorate properties of lubricating oil and formation of metallic or other sludge i m sorry may lead to clogging or chocking the valves, filters, and also other oil passages.
Moisture can get in into the mechanism while charging the refrigerant, while repair ie. Evacuation or vacuuming of the mechanism where moisture can enter through leaky joints, moisture deserve to exist as cost-free water although, a fully moisture cost-free refrigerating mechanism is no possible.
When moisture is current in the kind of water it may lead to icing in ~ the evaporator coil and choking the the thermostatic development valve.
Avoid moisture development by connecting a filter drier which absorbs humidity from the refrigerant.
4. High critical temperature
It is the temperature above which the vapour refrigerant continues to be in the vapour state and also cannot it is in liquefied ago into its fluid state even after passing v the condenser or any cooling medium at any kind of given pressure.
This happens only when the refrigerant temperature reaches past its critical temperature, ie. As soon as a refrigerant has actually a low an important temperature.
So, it’s much better to choose a refrigerant having a high an essential temperature, else the vapour refrigerant after obtaining compressed within the compressor right into a warm vapour will certainly not it is in condensed right into a liquid after passing inside condenser coil.
To have the ability to condense high-temperature vapour refrigerant right into a fluid refrigerant by passing outside hot wait in summer via a pan over condenser coils, the refrigerant must have actually high latent warm of vaporization.
5. Compatibility with the lubricating oil
The refrigerant used have to be compatible and miscible (means refrigerant have the right to be quickly separated) through the compressor oil as there are better chances of intermixing inside the compressor, wherein such condition following difficulties can occur:Acid or sludge formation.Acidic corrosion decreases alkalinity in oil.The to decrease in viscosity leading to poor lubrication.Oil carbonization with the increase in temperature.Compressor damages due to the ns of the lubricating oil properties and also load delivering property.
6. High latent heat
Latent heat means the quantity of heat forced by the refrigerant to readjust its state from liquid to vapour.
With a high implicitly heat, the refrigerant absorbs much more heat from the load; this increases the mechanism refrigeration efficiency. Also, the reduces the forced mass flow rate and the refrigerant quantity.
7. Low boiling point
The low boiling point allows the refrigerant to boil off right into vapor at a lower temperature. The refrigerant start the evaporator coils in liquid state and leaves as vapour.
As the refrigerant leaves the evaporator, the refrigerant has to be in 100 % vapour form, to protect against ingress of liquid refrigerant within compressor together the fluid is incompressible.
Also, through low boiling suggest refrigerant property, the low-temperature refrigerant can easily absorb the room heat and convert into vapour form.
Therefore through a low boiling point, we can maintain a short temperature favor at residence air-conditioner we can collection the temperature up to +16°C whereas for family members refrigerator we maintain lower temperatures of -5°C and also for the commercial mechanism we can maintain as low as -25°C.
The cooling procedure takes location by turn the same cold air in ~ the frozen fridge space, as the temperature that the re-circulated air drops down; the expansion valve throttles the flow of the refrigerant.
Now, the suggest here is the re-circulated cold air once passes through the evaporator; the refrigerant is able come extract the latent warm from the cold waiting to convert to 100% vapor as result of the property of low cook point.
8. Short condensing pressure
Lower condenser push reduces the power attracted by the compressor throughout compression thereby offering a smaller sized sized compressor.
The condenser tubes don’t have to handle high-pressure refrigerants; which reduces the overall architecture cost.
9. High dielectric strength (for compressors v integral motors)
Refrigerant with a high dielectric strength stays clear of short circuits as soon as refrigerant comes straight in contact with motor windings in a hermetically sealed compressor.
The dielectric strength of any type of material is a measure of the insulation property.
10. Need to be cheap and readily available
In case of a repair, maintenance or accidental leakage; refrigerant must be readily obtainable at a reasonable price.
11. Lull of leak detection
Leaks can be detected by smell, utilizing soap equipment over the connections, using press testing method by keeping the line under push for 20 to 30 minutes to inspect for a autumn in pressure.
U.V leak detection an approach where we inject a tiny amount the fluorescent dye into the to run refrigeration system and also later scan the system with a leak detection lamp. The dye escapes indigenous the leaky sites and also shows up together a environment-friendly or yellow solution.
Perform a halide leak test detection top top a refrigerant that space Halogenated Hydrocarbons (Freon compounds). It involves holding a torch or a flame close to the leak area. If over there is a refrigerant leak, the flame goes green. In every instance, the halide torch check are carried out in a well-ventilated room.
An digital detector for such refrigerant leaks is presently available. The detector provides off a chain of fast clicks if the refrigerant is present. The elevated the concentration the the refrigerant, the more rapid the clicks.
Refrigerant gas used in people War
In particular concentrations and the visibility of an open up flame such together a gas selection or a gas water heater, R-12 and also R-22 may break down and form a little amount that harmful phosgene gas. This gift gas was used in the people War.
– r12 refrigerant properties
It is completely a safe refrigerant non-toxic, non-flammable, and non-explosive, very stable compound under extreme operating conditions.
However, when brought in contact in an open flame or electrical heating facet R12 decomposes into products which are extremely toxic.
R12 condenses at a moderate push under normal atmospheric temperature, has actually a boiling allude of -29°C.
R12 is oil-miscible under all operating conditions, simple the difficulty of oil return thereby enhancing the mechanism efficiency.
The refrigerating result per lb for R12 is comparatively short as contrasted to various other refrigerants.
A Halide torch is used for leak detection.
R12 was fully phased out as result of its ozone exhausted potential (ODP) = 1 and an international Warming Potential (GWP) = 10000.
– r22 refrigerant properties
r22 has actually a boiling allude of -40.7°C, developed primarily for low-temperature systems.
r22 was used extensively in domestic, commercial and also industrial low-temperature equipment to evaporator temperatures as low together -87°C.
Both atmospheric pressure and also discharge temperature are greater compared come R12, but the power requirement is comparatively the same.
Evaporator temperature are in between -28 come -40°C.
The capability of r22 come absorb moisture is comparatively greater than r12, therefore, much less trouble as result of ice formation.
Fluorocarbon based refrigerants room safe.
Use a halide torch because that leak detection.
r22 was totally phased out because of its high ozone depleting potential (ODP) = 0.05 and an international Warming Potential (GWP) = 1100.How part refrigerants | HCFC’s and also CFC’s gained banned?
The ozone class in our atmosphere provides a filter because that ultraviolet radiation, which can be harmful come our health.
Research has uncovered that the ozone layer is thinning, because of emissions right into the setting by the substance like Chlorofluorocarbons (CFCs), HydroChloroFluoroCarbons (HCFC), halons and bromides.
Montreal and also Kyoto international protocols and also elimination that the chlorine-containing CFC and HCFCs in new equipment have effectively countered ozone depletion.
Some refrigerants provided in the previous are:Ammonia is very explosive and also toxic.Carbon dioxide requires high condensing press 72 bar in ~ 30°C and also the piping system is expensive.Methyl chloride is explosive and also toxic
CFC and HCFC refrigerants (Freon, Arcton, etc.) and given R numbers (R12, R22, R502) are replaced by HFCs like R134a.
Due to the chlorine molecules’ capacity to destroy the earth’s Ozone Layer by convert it to oxygen the international communities have agreed through a number of conventions come bring around its phase-out of together refrigerants.The Montreal protocol in 1985 i agree to mitigate production and usage that CFC is a chlorofluorocarbon.The Montreal protocol in 1992 i agreeed to alleviate production and also usage that HCFC is HydroChloroFluoroCarbons.The europe Union prohibition CFC’s in 1994 and HCFC.
The replace instead replace of the CFC and HCFC refrigerants room the HFC’s.
r134a is an HFC refrigerant.
– r11 refrigerant (CCl3F) properties
R-11 is a fluorocarbon of the methane series and has a boiling suggest of 23.7°C at atmospheric pressure.
Like other fluorocarbon compounds, the dissolves organic rubber.
It is non-corrosive, non-toxic, non-flammable.
Use halide torch for leak detection.
R11 was completely phased out because of its high ozone depleting potential (ODP) = 1 and worldwide Warming Potential (GWP) = 3300.
CCl2 ⇒ CCl2F + Cl (Presence that U.V rays and sunlight)
Cl + O3 ⇒ ClO + O2 ( O3 is stood for as Ozone)
ClO + O3 ⇒ Cl + 2O2 ( O2 is Oxygen)
Chlorine molecules have the capability to damage earth’s Ozone layer by convert it to oxygen.
One molecule of chlorine can ruin 1000 molecules of O3.What are ecological friendly | eco-friendly Refrigerants?ODP (ozone depleting potential) the the refrigerant should be zero as it destroys the ozone layer bring about ultravioletGWP (Global Warming Potential) that the refrigerant have to be low as it might cause an increase in worldwide warming.
a) r134a refrigerant properties
R134a is capable to be at temperature of -28°C in ~ room temperature of 38°C, its power being very comparable to that of one R12. However, the compressor must use a synthetic polyester lubricating oil.
Key properties of the main refrigerants are offered in in addition to their usual application ranges;
The crucial to a refrigeration device is to deliver heat power from the evaporator to the condenser.
In order to achieve this, the compressor circulates refrigerant about the system which changes state as it receives and rejects heat.
b) r134a and r407c refrigerant properties
These refrigerants are primarily used because that air conditioning and also heat pumps and have replaced R22 in countless applications. R134a has fairly low pressure and therefore around 50% larger compressor displacement is forced when compared to R22.
The combined refrigerant R-134a is a long-term, that is an HFC alternate with comparable properties to R-12.
R134a effectively works in screw chillers where short pipe lengths minimization costs associated with larger tubing. R134a likewise finds a place where high condensing temperatures are needed and in many transport applications
The HFO (hydro fluoro olefin) has actually zero ODP (ozone-depleting potential) and really low GWP (global warming potential) refrigerants R1234yf and also R1234ze run at comparable pressures come R134a and also are becoming accessible as irreversible alternatives.
However, castle are reasonably high in cost and also are flammable to a particular extent. R1234yf selected together a auto air air conditioning replacement.
R407C is a zeotropic mixture consisting of 23% R32, 25% R125 and 52% R134a. It has properties close come those of R22, and also for this reason, has been broadly used in Europe.
Due to a rapid R22 phase-out. Its glide and heat transport properties typically penalize the device performance, return counterflow warm exchange can deliver some benefit with plate form heat exchangers.
To discover longer-term alternatives, the is necessary to move to R32 HFO blends or R717, every one of which require far-reaching system re-design.
c) r410a refrigerant properties
R410a is a high-pressure refrigerant v a low vital temperature used largely in ac compressor. With proper system design, it has been displayed to give equivalent or much better performance 보다 R407C.
Many waiting conditioning carriers switched come R410a from R22, specifically for direct expansion-type equipment where an added advantage is the usage of smaller sized pipe sizes.
R32 is a possible longer-term alternative. That is already a 50% ingredient of R410A, yet alone the is flammable to a limited extent.
d) r404a refrigerant properties
R404A is an HFC blend designed excessively for commercial refrigeration. It has actually superior performance against many various other HFCs in low-temperature applications.
It likewise exhibits low compressor discharge temperature which renders it an ideal for single-stage compression, staying clear of the require for inter-stage cooling.
Its high GWP provides it unsuitable for future use, and it’s close come a fast phase-out. Medium-term replacements are R407A and also R407F.
HFO/HFC blends an alternate for the future. A big proportion the users room investing in R744 modern technology as a permanent solution.
R404a Ozone exhausted potential = 0 and global Warming Potential = 3260.
e) r717 ammonia properties
Ammonia is still, there is no a doubt, the most vital industrial refrigerant in the existing day since of its great thermodynamic properties and it’s cheap.
Ammonia is among the refrigerants most generally used in the absorption-type air-conditioning systems. Ammonia vapors are absorbed quickly by big amounts of cool water. In fact, it deserve to absorb vapor as quickly as a compressor.
Due come its high toxicity and flammability, an industrial application making use of ammonia requires strict regulations.
The extent of technical developments for ammonia are raising for e.g, low refrigerant charged packaged fluid chillers for usage in air conditioning.
Ammonia is not compatible v copper and also its alloys, therefore refrigerant piping and also components need to be do of steel or aluminum.
Ammonia has actually a lesser density contrasted to air, for this reason in situation of any leakage, ammonia mixes right into the atmosphere.
If the commercial plant is developed outside or top top the roof of a building, the escaping ammonia can easily drift far without harming the occupants.
Ammonia have the right to be detect by its odor at very low concentrations, and also this plot as very early warning signal.
The safety elements of ammonia plants room well known, and also there is a factor to expect a continued increase in the usage of ammonia as lengthy as refrigerant exists.
Ammonia has ozone-depleting potential = 0 and an international Warming Potential = 0.
f) r-401b Refrigerant properties
This blend refrigerant is similar to R-401A except, it is higher in R-22 content. This blend has actually a greater capacity at reduced temperatures and matches R-12 at –20°F. It likewise provides a closer complement to R-500 in ~ air-conditioning temperatures.
Applications for R-401B room in typically lower temperature R-12 refrigeration locations and in transport refrigeration, and also in R-500 together a direct expansion refrigerant in air-conditioning systems.
g) Carbon Dioxide refrigerant properties
Carbon dioxide is a colorless gas without any definite odor at ordinary temperature.
It calls for a high condensing press of 72 bar at 30°C come liquefy.
It needs an high value piping device to manage high condensing pressure.
Carbon dioxide is hazardous to person life with a concentration over 5 %. That is thermally stable and also does not decompose until the temperature is fine over 1000°C.
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A CO2 concentration higher than 2% reasons putrefaction of some fruits particularly apples and also pears into an interior brown color core.