Which one of the following refrigerants is an Azeotrope?
Azeotrope refrigerants are designated by R-500 series.
Hence, R-502 will be an Azeotrope.
The significant advantage of using Ammonia as a refrigerant is its.
Properties of Ammonia Refrigerant:
1. It is a chemical compound of Nitrogen and Hydrogen and under ordinary condition. It is a colourless gas.
2. High latent heat of vaporization at -15°C latent heat of vaporization is 131b kJ/kg.
3. It is poisonous if inhaled in large quantities.
4. It is some what flammable.
The recommended material for use with ammonia as a refrigerants is
Ammonia reacts with copper and hence when ammonia is used as a refrigerant copper material is not used.
Generally wrought iron and steel is used.
Which one eco-friendly refrigerant out of the following is used in many domestic and car air- conditioners now-a-days?
R-134a is known as eco-friendly refrigerant since it does not contain any Cl atom hence it does not lead to Ozone layer depletion.
What is an Azeotrope?
Azeotrope is a mixture of refrigerants without phase separation.
The use of refrigerant R-22 for temperatures below -30°C is not recommended due to its
Hydrogen is used in electrolux refrigeration system so that vapour pressure of ammonia in the evaporator should be
Which one of the following refrigerants has the highest critical temperature?
In an absorption type refrigerator, the heat is supplied to NH3 generator by condensing steam at 2 bar and 90% dry. The temperature in the refrigerator is to be maintained at - 5°C. If the refrigeration load is 20 tones and actual COP is 70% of the maximum then mass of steam required per hour is
(Take atmospheric temperature as 30°C saturation temperature of steam at pressure of 2 bar is 120.2°C, hfg at 2 bar is 2201.6 kJ/kg)
Given: TG = 393.2 k, Tc = 303 k,
TE = -5 + 273 = 268 k
actual COP = 0.7 x 1.756 = 1.229
actual heat supplied = Refrigeration load/Actual COP
Assuming that only latent heat of steam is used for heating
Match List-I (Refrigerant) with List-Il (Application) and select the correct answer using the codes given below the lists:
A. R-11 1. Window type air conditioning system
B. R-12 2. Central air-conditioning system
C. R-22 3. Domestic refrigerator
D. NH3 4. Cold storages, ice plants
A B C D
(a) 2 1 3 4
(b) 4 3 1 2
(c) 2 3 1 4
(d) 4 1 3 2
R - 11: It is used with centrifugal co m pressor in large capacity central air-conditioning plants.
R-12: It is used with reciprocating compressors in small units, specially domestic refrigerators, water coolers etc.
R-22: It is used with reciprocating compressors in window type air conditioners and large units such as package units and central air conditioning plants.
NH3: It is used with reciprocating and screw compressors, in cold storage, i.e., plants, food refrigeration, etc.
Match List-I (Property of refrigerant or absorbent) with List-II (Name of refrigerant) and select the correct answer using the code given below the lists
A. Used for very low temperature 1. CF4
B. Used with centrifugal compressors 2. CCI3F
C. Used in vortex tube 3. Air
Codes: A B C
(a) 1 2 3
(b) 3 1 2
(c) 1 3 2
(d) 3 2 1
When the mixture of refrigerant is used to replace a refrigerant, if the COP increase, the reason attributed is
i.e., cooling effect increases
Match List-l with List-ll and select the correct answer using the codes given below the lists:
A. Sulphur candle test 1. Propane
B. Halide torch test 2. Ammonia
C. Soap and water test 3. Halocarbon refrigerants
D. Ammonia Swab test 4. Sulphur dioxide
A B C D
(a) 2 3 1 4
(b) 4 1 3 2
(c) 2 1 3 4
(d) 4 3 1 2
Ideal refrigerant mixture is one which
Consider the following statements:
1. Azeotropes are the mixtures of refrigerants and behave like pure substances.
2. Isomers refrigerants are compounds with the same chemical formula but have different molecular structures.
3. The formula n + p + q = 2m is used for unsaturated chloro-fluorocarbon compounds (m, n, p and q are the number of atoms of carbon, hydrogen, fluorine and chlorine respectively.)
Q. Which of these statements are correct?
Azeotropes are non ideal mixture as they show deviation from Raoults law.