is .       Nomenclature of refrigerants        Gas Refrigeration-1       Q. Ans Air Refrigeration-2         Q. Ans Refrigeration         Off and On controls-Refrigeration         Q. Ans Air Refrigeration-3          Q Ans Super heating & sub-cooling          Thermostatic and automatic Expansion valves          Industrial refrigeration & air conditioning




Summary of air conditioning includes

comfort and industrial processes. It

increases the comfort to living beings and

improve the quality of industrial products.

Refrigeration is cooling. Air conditioning

is cooling in summer & heating in winter.

It also maintains moisture, purity &

velocity of air. Cryogenics deals

temperatures below -1500C.

 Air Conditioning

It controls simultaneously four parameters, temperature, humidity, purity and velocity of air in a closed space. Further, air conditioning is cooling in summer with ventilation and heating in winter with ventilation. It improves quality and quantity in industry under industrial air conditioning.

Practical Applications of summary of air conditioning

  1.  Comfort as well as food preservation need air conditioning

  2. Measuring instruments for more accuracy  and better quality require air conditioning.

  3. Comfort Air Conditioning is of three types, namely, summer air conditioning, winter air conditioning and year round air conditioning.

  4.  There is a requirement of human comfort in homes, offices and restaurants.

  5. All types of vehicles, namely, cars, buses, trucks, trains and airplanes use air conditioning..

  6. Printing, drugs, rubber and textile industries for controlling conditions to result in more production with better quality need air conditioning.

  7.  Shops, cinemas, hospitals, libraries, computer centers, beauty saloons, malls, telephone exchanges, data processing centers, mines and museums need air conditioning.

  8. Comfort Conditions for the human beings

Human comfort conditions are

temperatures between 22 to 270C

relative humidity between 35 to 60 %,

CO2 ≤ 600 ppm,

CO≤ 25 ppm,

odorless, virus free, fungus free and air velocity from 0.20 to 1.2 m/s. Air is purified with a filter.


It is a process of creating and maintaining lower temperatures as compared to the surrounding temperature.


(i)  Lower temperature inside a fridge

(ii) Lower temperature in a water cooler

(iii) Lower temperature inside an air conditioned room in summer


(i) Fridge

(ii)Air conditioner

(iii) Deep Freezer

(iv) Water cooler

(v) Display cabinets used in confectionery shops

(vi) Incubators

(vii) Cold storage

(viii) Ice plants

(ix)   Distilleries

(x)    Milk plants

(xi)   Dairy industry

(xii) Food processing, preservation and distribution

(xiii) Chemical and process industries

(xiv) Cold treatment of metals

(xv) Medical

(xvi) Construction,

(xvii) Ice skating 



1 TR = 1 ton of refrigeration= 211 k J/min

Like length is measured in meters, the refrigeration is measured in tons of refrigeration (TR).

1 TR means removal of heat at the rate of 211 k J/min from the products/space to be cooled.

This value of 211 has been achieved as follows:

 Convert 2000 pounds of water from 0C into ice at 0C in 24 hours.

Remove 144 BTU. It converts 1 pound of water at 0C into 1 pound of ice at 0C.

Heat removed from 2000 pounds in 24 hours= 2000 x 144.

Heat removed per minute  = 2000 x 144 / (24 x 60)                                                                       =200 BTU/min=211 k J/min

1 TR = = 211 k J/min=200 BTU/min

1 BTU=1.055 kJ 

12000 BTU =3025 kcal

1 kcal=4.187 k J