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.

 Air Conditioning

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

1.  Comfort and 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.

 REFRIGERATION

It is lowering of temperature by cooling.

Examples

(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

(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 

(xviii

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

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