INTRODUCTION AIR CONDITIONING & FRIGERATION CLASS NOTES
INTRODUCTION AIR CONDITIONING &
REFRIGERATION CLASS NOTES
Air conditioning includes
comfort and industrial processes. It
increases the comfort to living beings
and improve the quality of industrial
products. Refrigeration is cooling only. Air
conditioning is cooling in summer and
heating in winter. It maintains
moisture and purity & velocity of air.
It controls four parameters. These are temperature, humidity, purity and velocity of air in a cooled space. Cooling with dehumification is summer air conditioning. It is heating & humidification in winter. Industrial air conditioning improves quality and quantity in industry.
Practical Applications of summary of air conditioning
Comfort and food preservation need air conditioning
Measuring instruments for more accuracy and better quality require air conditioning.
Comfort Air Conditioning is of three types, namely, summer air conditioning, winter air conditioning and year round air conditioning.
There is a requirement of human comfort in homes, offices and restaurants.
All types of vehicles, namely, cars, buses, trucks, trains and airplanes use air conditioning..
Printing, drugs, rubber and textile industries for controlling conditions to result in more production with better quality need air conditioning.
Shops, cinemas, hospitals, libraries, computer centers, beauty saloons, malls, telephone exchanges, data processing centers, mines and museums need air conditioning.
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 lowering of temperature by cooling.
(i) Lower temperature inside a fridge
(ii) Lower temperature in a water cooler
(iii) Lower temperature inside an air conditioned room in summer
APPLICATIONS OF REFRIGERATION
(iii) Deep Freezer
(iv) Water cooler
(v) Display cabinets used in confectionery shops
(vii) Cold storage
(viii) Ice plants
(x) Milk plants
(xi) Dairy industry
(xii) Food processing, preservation and distribution
(xiii) Chemical and process industries
(xiv) Cold treatment of metals
(xvii) Ice skating
UNIT OF REFRIGERATION (TON OF REFRIGERATION=TR
1 TR = 1 ton of refrigeration= 211 k J/min
Like measure length in meters, measure refrigeration in tons of refrigeration (TR).
Removal of heat for producing cooling
at the rate of 211 k J/min is 1 TR.
Achieve this value of 211 as follows:
Convert 2000 pounds of water from 00 C into ice at 00 C in 24 hours.
144 BTU converts 1 pound of water at 00 C into 1 pound of ice at 00 C.
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