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Refrigeration: Definitions and Introduction to Its Fundamentals ​
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This lesson will help one gain comprehension on the concepts pertaining to refrigeration. Starting from the basic definition of refrigeration, one will come across and learn terms such as refrigerant, refrigeration effect, COP of the refrigerator, units of refrigeration and much more in this unit.

Harshit Aggarwal
Cleared UPSC ESE twice with Rank 63 and 90 in mechanical engg. Got 99 percentile in GATE. Cracked ONGC, BHEL,ISRO, SAIL, GAIL successfully

Unacademy user
Thanks mam.. Ithrayum Hardwork cheyyunna oru teacherine Njan kanditte illa.. Thanks a lot mam
Sir you made a mistake.. You double time divide with 60 ..
sir u have converted it in sec not min 8:43
1 TR= 2000 POUNDS X 144 BTU per pound / 24 hours = 12000 BTU'S per hour = 200 BTU/min = 3.517 kj/s = 3.517 kw = 3516 watts = 4.72 HP so, TR= 3.517 KW
Sahil Kumar Garg
2 years ago
you commit a mistake in pounds. 2205 punds x 144 BTU per pound/ (24 X 60) = 221 BTU'S per minute which is very close to (235.6÷1.055)=222 BTU'S PER MINUTE Because 1 BTU is equal to 1.055 kj
Sir , it confusing , why so much difference in the value of 1TR in SI and British Units.
Sahil Kumar Garg
2 years ago
Because 1 BTU is equal to 1055.055 joules
tr calculation shown wrong in kj/min .
Deepak L Gupta
2 years ago
correct harshal...

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  3. REFRIGERATION . It is a process of maintaining lower temperature compare to surroundings. In order to maintain lower temperature continuously, refrigeration system must run on a cycle. . Refrigerant: Refrigerant is a substance used for producing lower temperature. E.g NH3 , Water, Air, R-11,R-12, R-134.

  4. REFRIGERATION EFFECT (RE) . It is the amount of heat which is to be extracted from storage space in order to maintain lower temperature. It is the desired effect of refrigerator. SURROUNDIN Win COB= RE Nin NW In %-RE 2. STORAGE SPACE

  5. SIGNIFICANCE OF COP . COP (Coefficient of Performance): It represents running cost of the system for a given refrigeration capacity . Greater the COP lesser is the work input and hence lower is the running cost.

  6. COP OF REFRIGERATOR For ReFrigerator: Atm COP= Desired Effect-9 Work Input of] BODY A COP= Desired Effect / Work Input = Q2 /w [COP]ref =Q2 / (Q,-Q)

  7. COP OF HEAT PUMP For Hest ump umo. BODY AT 8, G1-81 Aim at COP= Desired Effect / Work Input =Q, /w

  8. UNITS OF REFRIGERATION Refrigeration is expressed in terms of" tonne of refrigeration" . A tonne of refrigeration is defined as amount of refrigeration effect produced by the uniformmelting of one tonne (1000 Kg) ofice from and at 0 C in 24 hours. . I TR = 1000 x 335 kJ in 24 hours 1 000 x 335/ 24 x 60 x 60 = 232.6 KJ/min In actual practice it is equivalent to 210 KJ/ min or 3.5 Kw