After discussing various types of insulating materials and their properties, it is now the turn of knowing about their application at the site and proper care and maintenance thereafter. One major threat to the insulating material is moisture. So, it should be applied and maintained in the way that it should always remain waterproof and air-proof. Other major consideration is for mechanical strength required at the place of application. It is more important in case of floor insulation when it has to bear load also. Now we will discuss one by one the insulation of different parts of a cold storage.
i. Insulation of Refrigeration Pipes
In a cold storage, the compressor sucks ‘low-pressure and low-temperature vapours’ from evaporator coil through the suction line. This suction line generally passes through normal temperature area outside the cold room. If it is not insulated, heat from surrounding area will pass naturally to low-temperature vapours and increase their temperature. The bad effect of this increase in suction temperature is the increase in compressor load. Hence, the suction line of compressor including pipe fitting must be insulated to retard the increase in suction temperature.
Before applying the insulating material pipes, & fittings must be cleaned and then painted with a heavy coat of waterproof asphalt paint. Then the pipes are covered with ready made cork or thermocole lengths which come in half hollow sections,matching with diameter of pipe as shown in Fig.7.7. The insulation covering should be securely wired with copper wire. The seams and any hollow space between the insulation packing should be filled with cork-dust. Then again the whole surface is coated with waterproof asphalt paint.
ii. Insulation of Cold Room
This is the main part of application of insulation. You already know the importance of effective insulation of a cold room. If properly applied and maintained, the insulation reduces the compressor running time to a great extent and saves the running cost of plant. No area of a cold room should be left without insulation. We will discuss here the insulation of different areas of a cold room.
a) Insulation of walls
Walls of a cold room are generally made of brick and cement. As shown in Fig.7.8 the inside surface of wall is first finished by applying water proof cement plaster or mastic. Then the corkboard or sheets of any other insulating material are fitted on the whole surface with nails. Care should be given on making of good tight joints. Thereafter a second layer of water proof cement plaster is applied by first fitting wire mash on the surface of corkboard. The wire mesh helps in applying and staying in place the layer of cement plaster.
b) Insulation of ceiling
It is based on the same general principle as that of wall insulation. If possible, the insulation is applied on the top of ceiling slab. In case if it is applied at the bottom of slab from inside the cold room, it is necessary to use more fastening nails or it may be hanged by a strong iron bar structure.
c) Insulation of floors
It is also based on same principle as in case of wall and ceiling but the difference is that the floors should be mechanically strong to bear the weight of storage material. Generally a thick concrete floor serves our purpose. However, when insulating material is applied, it should be mechanically strong and also it should be applied as air tight and water tight.
d) Insulation of doors
The double wall galvanized-sheet insulated doors are available as ready made and fitted on the site with strong hinges and other fittings. All the door fittings also must be galvanized i.e. of corrosion resistant material. The gasket or door seal is fitted on the circumference of door and it fills the annular space between door and doorframe. The door-seal forms the airtight joint between door and door frames and hence serves as an effective insulation against heat and moisture.
i. Insulation of Refrigeration Pipes
In a cold storage, the compressor sucks ‘low-pressure and low-temperature vapours’ from evaporator coil through the suction line. This suction line generally passes through normal temperature area outside the cold room. If it is not insulated, heat from surrounding area will pass naturally to low-temperature vapours and increase their temperature. The bad effect of this increase in suction temperature is the increase in compressor load. Hence, the suction line of compressor including pipe fitting must be insulated to retard the increase in suction temperature.
Before applying the insulating material pipes, & fittings must be cleaned and then painted with a heavy coat of waterproof asphalt paint. Then the pipes are covered with ready made cork or thermocole lengths which come in half hollow sections,matching with diameter of pipe as shown in Fig.7.7. The insulation covering should be securely wired with copper wire. The seams and any hollow space between the insulation packing should be filled with cork-dust. Then again the whole surface is coated with waterproof asphalt paint.
ii. Insulation of Cold Room
This is the main part of application of insulation. You already know the importance of effective insulation of a cold room. If properly applied and maintained, the insulation reduces the compressor running time to a great extent and saves the running cost of plant. No area of a cold room should be left without insulation. We will discuss here the insulation of different areas of a cold room.
a) Insulation of walls
Walls of a cold room are generally made of brick and cement. As shown in Fig.7.8 the inside surface of wall is first finished by applying water proof cement plaster or mastic. Then the corkboard or sheets of any other insulating material are fitted on the whole surface with nails. Care should be given on making of good tight joints. Thereafter a second layer of water proof cement plaster is applied by first fitting wire mash on the surface of corkboard. The wire mesh helps in applying and staying in place the layer of cement plaster.
b) Insulation of ceiling
It is based on the same general principle as that of wall insulation. If possible, the insulation is applied on the top of ceiling slab. In case if it is applied at the bottom of slab from inside the cold room, it is necessary to use more fastening nails or it may be hanged by a strong iron bar structure.
c) Insulation of floors
It is also based on same principle as in case of wall and ceiling but the difference is that the floors should be mechanically strong to bear the weight of storage material. Generally a thick concrete floor serves our purpose. However, when insulating material is applied, it should be mechanically strong and also it should be applied as air tight and water tight.
d) Insulation of doors
The double wall galvanized-sheet insulated doors are available as ready made and fitted on the site with strong hinges and other fittings. All the door fittings also must be galvanized i.e. of corrosion resistant material. The gasket or door seal is fitted on the circumference of door and it fills the annular space between door and doorframe. The door-seal forms the airtight joint between door and door frames and hence serves as an effective insulation against heat and moisture.
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