Expt: No 4 Visit to Cold Storage Plant. Place of Visit: M/s Deccancold cold storage, Pune Date of Visit : 26 July,2017 i.e Friday Div: A and B (BE Mech) Reporting time: 11 AM Venue : Gat No. 569/570, Kelavade, Tal. Bhor, Pune-Satara Road, Near Orchid Resorts, District : Pune 412 213 Cold Storages: Preservation of food by proper storage assumes greater importance in a country like India, where there is a substantial production of a variety of perishable foods like fruits and vegetables, milk products, fish, poultry and meat products. Amongst the various methods of preserving food products, refrigeration is the most important one. Cold storage conditions for food products differ from product to product, but certain basic facts are true for all fruits, vegetables and other fruit products. In the case of fruits and vegetables particularly, the problems faced in storage and handling are: 1. Desiccation or loss of moisture 2. Physical break-down of tissue 3. Chemical changes such as oxidation of certain matter in the product, hydrolysis of fats and esters, and changes in the food proteins. 4. Respiration changes in which the living cells take in oxygen and give up carbon dioxide (this action takes place along with the enzyme actions). 5. Bacterial, yeast and mold growth in or on the product. Such growth is very rapid at room temperatures, decreasing as the temperature is lowered and almost ceasing as the temperature drops to about ( )10 to ( )12 C. Cold stores can be classified, utility-wise, as follows: 1. Long term stores for fresh produce. 2. Long term stores for frozen products. 3. Short term or retail stores for fresh and frozen products. 4. Controlled atmosphere (CA) stores for fresh produce where oxygen and carbon dioxide levels are controlled in the chambers. Temperature wise, cold stores can be classified as: 1. Medium temperature cold stores - generally designed for storing a variety of products at 0 to 8 C. Commodities include various types of fresh fruits and vegetables, dry fruits, spices, pulses, milk products etc. The cold stores may be 1
designed for a single commodity such as potatoes, chillies, apples etc. or multipurpose type for storage of various commodities. The chambers in multicommodity stores have to be designed for maintaining different temperatures and sometimes different relative humidity s to suit various products. The bulk commodity stores have chambers of large sizes whereas the multi-purpose units have many chambers. This series of articles by Arvind Surange Sir covers the fundamentals of cold storage design. The articles will serve as a source of reference for newcomers joining the industry as well as for experienced engineers wishing to brush up on fundamentals. of smaller sizes to suit the customer needs. These medium temperature cold stores are, generally, constructed as single floor structures for small capacities and multi-floor structures for larger capacities. 2. Frozen food stores - designed for commodities which have to be processed and frozen for preservation over long periods of time. These include green peas, corn, okra, mixed vegetables, mango pulp and tomato puree. Other items are ice cream, butter, fish and meat products. Frozen food stores are designed for temperature of ( ) 18 to ( )22 C for most foods, but for items like ice cream, lower temperatures in the range of ( ) 25 to ( ) 30 C are specified. Frozen food stores are, normally, a part of food processing and freezing complex. However, they are also set up as a part of multi-purpose cold stores or as independent units to offer facilities for storage of Product Storage Temp0C Product Life Weeks Potato 2 to 4 32 36 Cauliflower 0 to 1.5 8-10 Cabbage 0 to 1.5 10-12 Tomatoes 7 4-5 Ginger 2 to 4 14 Lime 8 6 Orange 7 to 8 8 Sweet Lime (Mosambi) 6 to 8 8 Apples 0 to 15 16 20 Eggs 1 to 5 20 24 Mango 8 to 15 4-6 Frozen foods -18 to - 20 24 or more Table - 1. Cold Storage Data for some fruits & vegetables. R.H for most products is in the range of 85% to 95% Types of Cold Storages Cold stores may be identified by their size into the following categories: a) Small Cold Stores They are typically walk-in cold stores, working in different temperature ranges. They are generally used in hotels, super markets, food malls etc. for storage of 2
different items and are closest to the consumer, almost like window shops (for food items). b) Medium Sized Cold Stores Medium capacity cold stores range from 50 to 500 MT capacity with 1 or 2 chambers. They may be located at the farms (i.e producing area), market places (i.e consuming area), process / precooling plants, airports etc and may be used for storage of fresh foods as well as for processed foods. c) Large Sized Cold Stores These are bulk or multipurpose type and the capacities, generally, range from 1000 MT to 25000 MT. The bulk stores are, usually, located in the producing areas and also near market places and generally, have fewer chambers of large capacities. The multipurpose stores are mostly located near consuming centres. They have a number of chambers usually ranging from 4 to 50. Bulk cold stores generally store large quantities of fewer items whereas multipurpose cold stores are used for storing a variety of items requiring different storage conditions. Information on utilization of bulk and multipurpose units is shown in Table 2. Bulk Cold Stores at Producing & Consuming Centres Potatoes Apples Oranges Tamarind Raisin etc. Multipurpose Cold Stores at Consuming Centres Fruits & Vegetables Dry Fruits Spices Pulses Jaggery Milk Products etc. Specifications of Deccan Cold Storage: I. Deep Freeze located at Ground Floor Number of Deep Freeze 6 nos. Size 11.39 m length x 10.37 m width x 6.25 m ht. each Storage Capacity (approx.) 1104 MT Design condition (-) 20 +/- 2 deg C Daily loading approx. 3 to 5 % of the storage capacity 3
II. Ante room in Deep Freeze Section Number of Ante room 1 No. Size 34.17m Length x 3.89 m width x 6.25 m ht. clear Design condition 5ºC to 10ºC Refrigeration System actually used: The system has two stage Ammonia system with 1 No. Low stage compressor & 2 nos. High stage compressors (1 No stand by swing compressor) for deep freezers & cold stores. The system has 1 No evaporative condenser located on the terrace over the machine room; 2 Nos receivers to be located inside the machine room. The ACU s for deep freezer are ceiling suspended type. Specifications of few devices used in Cold Storage: Equipment Installed Low Stage Compressor 32 TR Kirloskar Pneumatic Co. Ltd. Pune Model KC - 3 Refrigerant Ammonia Refrigeration Capacity-KW 112 Condensing Temp. (deg.c) (-) 3 C Evaporating Temp. (deg. C) (-) 26 o C Speed ( RPM ) 800 Capacity control steps 3 Qty. 1 High Stage Compressor 87 TR Kirloskar Model KC - 4 Refrigerant Ammonia Refrigeration Capacity-KW 305 Condensing Temp. (deg.c) 38 C Evaporating Temp. (deg. C) (-) 3 o C 4
Speed ( RPM ) 800 Capacity control steps 4 Qty. 2 (1 working & 1 standby ) Electric motor to run the compressor (a) 30 KW TEFC squirrel cage Induction motor. 1 No. (b) 75 KW TEFC squirrel cage Induction motor. 2 (1 working & 1 standby ) EVAPORATIVE CONDENSER Qty: 1 Uma Industries Model UEC 110 Type Induced Draft Heat rejection Capacity kw 380 i.e 108 TR Condensing temp. (deg.c) 38 Ambient Wet bulb temp.(deg. C) 25 Total Estd. Airflow Rate CMH 36,000 At wg.sp. mm 10mm No. of Fans 2 Fan Motor - kw 1.5 Total Water flow Rate LPS 8 Head m 12 mts Water pump details Included MOC of sump tank/thickness SS 304 / min.2mm thck Coil MOC S.S./ M.S. SS 304 No of coils 2 Total estimated. Coil surface area --m 2 150 Coil test pressure kg/cm 2 ( pneumatic ) 30 Air Cooling Unit Specifications: Qty. 6 Nos. ( 1 no in each room ) Alfa Laval Model A-336-8/10-R Type of Unit Clg. Mtd. 5
Single / Twin Single Type of Refrigerant Ammonia Type of feed Gravity / Pump Circulation Gravity feed Capacity per unit in - KW 22 Evap. Temp. & TD C Coil / Fin MOC Fin spacing - mm Fin type (-) 26 0 / 6 0 C SS / Al 8 / 10 mm Plate Minimum heat transfer area in M 2 165 Air flow CMH CMH per unit 21500 sp. wg. (External) 6 mm No of Fans 3 Fan Motor - KW 0.55 Fan make Fan speed 1440 Air throw -m 11.0 Drain pan insulation Drain pan heating Type of Defrosting Water Fan peripheral heating Accumulator H.P.Receiver The receiver size shall be as follows : 2 (1 working & 1 standby ) Size-- 700 mm dia x 3600 mm long Test pressure -- 40 K.g/cm2 Shell thickness -- 12 mm (Hydraulic) Dished ends thickness -- 14 mm. Intercooler Qty:1 Vertical floor mounting type intercooler for interstage gas cooling and liquid sub-cooling. The intercooler shall be made from m.s. plate. The intercooler shall be complete with (i) interstage gas inlet & outlet connection (ii) liquid inlet, liquid and gas connection or float switch (iii) oil drain connection 6
(iv) liquid cooling coil of ASTM A106 Gr. B m.s. pipe - schedule 80 (v) supporting legs. Size -- 600 mm dia x 1250 mm high Shell thickness -- 10 mm Dished end thickness 12 mm Sub-cooling coil dia 20 NB x 6 m length AIR PURGER Automatic Air Purger suitable for the total capacity of the plant (approx 300 KW) Condenser Water Pumps (Qty: 2) Motor KW Approved make Monoblock pump set complete with TEFC squirrel cage induction motor Capacity -- 11 LPS at 15 m head each. of Condenser Water Pumps shall be -Beacon / Kirloskar / Jyoti / Grundfos / Eqvt. 7