Wednesday, December 15, 2010

【 Weak current College 】 combination cold storage basics 】

Introduction to the refrigerator cold storage refers to various equipment cooling, a human control and maintain a stable temperature of facilities. Refrigeration system, control equipment, insulation warehouse, subsidiary of buildings, etc. are an essential component of the cold store.
Cold storage and refrigeration system mainly includes cold storage unit, it is the core of the guarantee of cold storage, refrigeration storage storehouse supply of cold source. Control unit is the cold storage of the brain, it commands the refrigeration system guarantee cold energy supply.
Cold storage warehouse, is the place for fresh agricultural products, its role is to maintain the stability of low-temperature environment, usually heat insulation performance as insulation. Cold storage room sound insulation structure allows you to keep the freezer unit manufacture of cold in the refrigerator within less disclosure, on the contrary, is to reduce the heat to a cold cold storage-internal leakage, which is cold and general housing major differences.
Cold storage is mainly used for food, medicine, mechanical processing of frozen and refrigerated, it through artificial refrigeration to maintain a certain temperature indoors. Cold storage building of walls, floor and roof are laying a certain thickness of the insulation material to reduce cold heat from the outside world. To reduce the absorption of solar radiation energy cold facade surface, usually painted white or light color and cold storage building and general industry, civil construction, it has its own unique structure. Mechanical refrigeration storage works
Mechanical cold storage of fruits of this approach is in good thermal insulation of buildings, equipped with a mechanical cold storage units, and on the basis of the fruit on storage temperature, humidity and ventilation requirements for cold storage systems for regulation and control, so the storage time is longer, the better.
A, the principle of mechanical cold store refrigeration. Mechanical cold storage is using gasification temperature very low liquid (refrigerant) that would enable it in low pressure gas evaporation becomes so absorb heat, and cooling purposes.
Cold with the low refrigerant in addition to the boiling point, also called on the human organ sound, and will not corrode metals, non-combustion and explosion hazard, do not react with lubricant, should have good thermal performance, evaporation heat absorption in high pressure condensation system low pressure, low viscosity and low price, and so on. Cold store commonly used refrigerants type and nature of name boiling point (℃) the critical temperature (℃) 0 ° c time heat of vaporization (l/g) ammonia (NH3) 132.4-35.5 4.18 301.6 × CO2 (CO2) 31.1-78.2 55.0 × 4.18 sulphur dioxide (SO2) 157.2-10.0 91.3 × 4.18 chloromethanes (CH2CL) 143.1-23.7 98.8 × 4.18 freon (CCL2 F2) - 111.5 30.0 37.2 × 1.18 more freezer refrigerants, and ammonia, and freon refrigerating effect good application is most common. To heat absorption refrigerator refrigerant gasification and as principles of cold storage host — refrigeration machines, compression type, absorption. While the compression type application. Cold storage compression refrigeration machine main building; compressor, condenser, evaporator and cooler parts.
B, freezer storage management. Fruit frozen temperature varies by species, most of the late-maturing varieties to-1-0 ° c in the freezer. Cold storage humidity to 90%. Fruits harvested, must promptly cooling (cooling-0 ℃ or so), it is best to harvest after 1-2 days in the refrigerator. Because the mining of fruit in temperature 21 ° c 1 day delay, 0 ℃ down will be reduced by 10-20 days of longevity, therefore, selected postharvest after grading into cold storage of fruits, 3-5 days after should rapidly cooled to-1-0 ℃ storage.
Cold storage of fruits, mainly to control cold storage humidity and gas composition. Temperature adjustment is according to the different varieties at different times on the temperature requirements, control the speed of evaporation cold storage refrigerant to control the temperature of cold storage library. Cold store often cooling pipe system and hinder the Frost, heat conduction, the impact of cooling effect, and as a result of frost, cold storage warehouse in humidity is too low, there should be regular heating defrosting, and promptly got wet or cold spray regulation of humidity. Cold storage of ventilation to at night, if cold storage warehouse, excessive accumulation of carbon dioxide can plant air cleaner, or 7% caustic soda absorb.

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