Title: Commercial cooling of fruits and vegetables
Identifier: commercialcoolin43mitc (find matches)
Year: 1972 (1970s)
Authors: Mitchell, F. G. (F. Gordon)
Subjects: Fruit; Fruit; Vegetables
Publisher: (Berkeley)
Contributing Library: University of California, Davis Libraries
Digitizing Sponsor: University of California, Davis Libraries

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Text Appearing Before Image:
UNINSULATED HYDROCOOLER rr O30 x S20 UJ LU o 10 z o 8001-
Text Appearing After Image:
10 20 30 40 TONS PRODUCE COOLED PER HOUR Fig. 17. Estimated refrigeration requirement for hydrocooling. Here 30 tons of produce per hour, cooled at 40°F, requires approximately 360 tons of refrigeration, assuming a normal hydrocooling effi- ciency of 50 per cent. (Add two-thirds the weight of wood, one-fourth the weight of aluminum, or one- eighth the weight of steel if containers are run through hydrocooler; multiply refrigeration load by two-thirds for a well-insulated hydrocooler.) If H is greater than 4, ice contact is poor, possi- by because: • Ice is floating, allowing water to bypass the ice. • Water velocity over ice or cooling coils is too low—if so, propellers may be needed to increase water turbulence for better cooling. • Inadequate ice surface is available in too small an ice compartment, or cooling-coil surface is inadequate. If H is less than 4, ice contact is satisfactory and poor cooling of the produce is due to some other factor, such as: • Indequate refrigeration—figure 17 can be used to estimate the amount of refrigeration required to cool produce. • Inadequate water circulation—if water is cooled more than 2°F in passing over the cooling surface, water flow is inadequate (lor shower-type hydrocoolers, minimum water flows of 10 to 15 gallons per minute per square Eool 61 hydrocooler area are recommended) . • Conveyor speed is too last, so that produce docs noi remain in hydrocooler long enough. •Water channeling through the product— water must be moving over the surface of the produce lot efficient cooling; increasing water (low (or, in extreme (ases, redesign- ing the hydrocooler) may be necessary. • Excessive refrigeration loss caused by inad- equate insulation ol the hydiocooling unit. Fig. 18. Air flow in forced-air (pressure) cooling. Placement of containers and proper use of baffles blocks air return everywhere except through side vents in containers. Thus, air is forced to pass through con- tainers and around produce to return to exhaust fans. As air is exhausted from the center chamber, a slight pressure drop occurs across the produce. Forced-air (pressure) cooling Produce can be air-cooled rapidly by producing a difference in air pressure on opposite faces of stacks of vented containers (Guillou, 1963; Par- Fig. 19. A well-mounted, efficient single blower can be used to circulate air through both produce and cooling medium in forced-air cooling. Blower is mounted in wall, lined with foam plastic for a wall seal, and equipped with a permanently mounted fab- ric cover (shown at top of foam plastic wall seal).

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