View
224
Download
0
Category
Preview:
Citation preview
8/4/2019 Study of Different Storage Structures
1/18
Study of different storagestructures
Presented by:Kavya shree M.GMK 815
8/4/2019 Study of Different Storage Structures
2/18
Storage structures:storage is one of the most important aspects of the postharvest handling of fruits and vegetables . The main objectof storage of fresh fruits and vegetables is to extend theirperiod of availability. A substantial quantity of thesecommodities go waste in our country due to lack of properstorage facilities. Orderly marketing of horticulturalproduce requires some storage facilities to balance betweenproduct harvest and sales as well as long term storage toextend marketing beyond the end of the harvest season.
8/4/2019 Study of Different Storage Structures
3/18
The objectives of storages :
1.To reduce physiological activity of
fruits and vegetables by maintainingthe lowest temperature that will notcause chilling injury and by controlling
atmospheric composition.2.Reduce the growth of microorganismsby maintaining low temperatures.
8/4/2019 Study of Different Storage Structures
4/18
3.Prevent drying of fruits and
vegetables by reducing the differencebetween fruits and air temperaturesand maintaining high humidity in the
storage room.
8/4/2019 Study of Different Storage Structures
5/18
cool store:
Here temperature is broughtdown by taking out the heatwith the help of mechanical
refrigeration.The expanded gas is then compressedThe heat is removed from theCompressed gas by means of running water.The ideal environmental condition for freshproduce in storage is the lowest temperature which doesnot cause chilling injury to the produce.A small temperature difference between the cooling coiland the stored fruits is required to maintain an adequate
control of relative humidity in a storage room.
8/4/2019 Study of Different Storage Structures
6/18
In order to increase relativehumidity, water may be sprayedInto the controlled storageChamber.
The storage life of fruits and
vegetables varies inversely withthe rate of respiration andevolution of heat.
8/4/2019 Study of Different Storage Structures
7/18
ice bank cooler:In this system, a bank of iceis built up with a relativelysmall refrigeration plant.The ice is accumulated on
extended surface plates,which are suspended in a tankof water.The water surrounding the ice is pumped to the top of a
cooling tower and falls through the tower passing overthe extended surface, giving a large surface area forheat exchange.The air leaving the tower maintains high humidity.
8/4/2019 Study of Different Storage Structures
8/18
Once the initial cooling is complete the store maintains atemperature of 0.5-0.8*c and relative humidity of98 per cent.
8/4/2019 Study of Different Storage Structures
9/18
low cost storage:
Low cost storage system has a great significancein India since other advanced storage systemswork out to be extremely expensive. Most of the
low cost storage structures are built by takingthe advantage of natural cooling.
There are two types of low cost storages:1) clamps and2) celler
8/4/2019 Study of Different Storage Structures
10/18
Clamps:
8/4/2019 Study of Different Storage Structures
11/18
Celler:
E l
8/4/2019 Study of Different Storage Structures
12/18
Evaporative cooling:Evaporative cooling occurs
when air, that is notsaturated with watervapour is blown across anywet surface.
The lowest temperature,that can be reached by theevaporation of water is called
the wet bulb temperature.It has considerable potentials for pre cooling and evenstorage of fruits.The principles of evaporative cooling can be gainfullyutilized for storage of fresh produce.
8/4/2019 Study of Different Storage Structures
13/18
Z l h b
8/4/2019 Study of Different Storage Structures
14/18
Zero energy cool chamber:This is based on the principles
of evaporative cooling.These structures have beenmade from cheap, locallyavailable raw materials, such as
brick, sand, bamboo, gunnycloth, etc., with a source ofwater supply. The floor ofstorage space is made with single layer bricks, the sidewalls with a double layer of bricks. The space (7.5 cm)between the bricks is filled with river bed sand.
The top of the storage space is covered with gunny clothin a bamboo structure.
8/4/2019 Study of Different Storage Structures
15/18
Refrigeration system :The refrigeration cycle in the
compression system is most widelyused system of refrigeration consistsessentially of:
1)The expansion device for thethrottling of pressurereduction effect.2)The cooler or the evaporator for thevapourisation and cooling
effect.3)The compressor in which thecompression of the vapour to the optimum pressure iseffected.
4)The condenser wherein the compressed vapour of therefri erant is li uified.
8/4/2019 Study of Different Storage Structures
16/18
Big size cool chamber :The low cost big size cool chamber has been
designed and constructed with a double brick wallhaving cavity filled with river bed sand.The bottom of the chamber is provided with fourDucts which are submerged in wet sand.
The floor the chamber is made of wooden plankswith provision of the entry of fresh air throughthe duct.An exhaust fan has been provided at the top ofventilation purpose.The trial with big size cool chamber showed thatIt could bring down the temperature by 8-10 c.
8/4/2019 Study of Different Storage Structures
17/18
Night time cooling :In some parts of the country there are
significant differences between night andday temperatures allowing night timeventilation to be a good sources of cold.
High altitude cooling :High altitude can also be a source of cold.air temperature decreases by 10 c (18 F)every 1km (0.62 miles) increase inaltitude. It is not possible to bring thisair down to ground level because itnaturally heats up as it drops in altitude.
8/4/2019 Study of Different Storage Structures
18/18
Thank you
Recommended