5 Cooling Methods Flashcards

1
Q

what are 6 commercial cooling methods?

A
  • room cooling
  • forced air cooling
  • hydrocooling
  • package-icing
  • vacuum cooling
  • transit cooling
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2
Q

describe room cooling

A
  • simple
  • produce cooled in refrigerated room
  • cold air discharged from ceiling sweeps
  • heat from produce is brought to cooling coils
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3
Q

pros and cons of room cooling?

A

pros:

  • consolidated cooling and storage
  • decreased handling
  • simple design
  • suitable for moderate loads

cons:

  • slow cooling
  • desiccation when air speeds too high
  • slower air speeds prolong cooling
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4
Q

name some special considerations for room cooling (if you can name like 4 out 8 i’ll be happy)

A
  • need efficient storage maintainence
  • proper stacking to allow air to pass around the container
  • pallet frames for systematic loading
  • clear fork lift openings for air flow
  • container ventilation for air to contact the produce
  • good air speed to create turbulence
  • eliminate empty spaces in room
  • false walls can be used to divert air from empty spaces
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5
Q

you see a modified room cooling technique in which there are cones on the ceiling. what are those cones?

A

ceiling jets - they concentrate cool air into stack rather than over it

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6
Q

you see a modified room cooling technique in which the large room appears to be separated into several smaller sections. what are these sections called?

A

cooling bays - enables more specialized control for different varieties of produce

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7
Q

describe forced air cooling

A

high velocity air is forced through the container

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8
Q

what are the alternate names for forced air cooling?

A

pressure or suction cooling

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9
Q

compare forced air cooling to room cooling

A

forced air is more efficient - it removes heat faster.

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10
Q

describe the air flow in forced air cooling

A

negative pressure is created between the fan and container by appropriate stacking and blocking of open spaces. this causes suction of cold air from room through package vents.

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11
Q

describe hydrocooling

A

cold water is used to remove heat

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12
Q

what are the pros and cons of hydrocooling?

A

pros:

  • no moisture loss/desiccation
  • water is a more efficient medium than air

cons:

  • water must be cleaned
  • packages/produce must be water tolerant
  • cooled product must be moved quickly to a cold room
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13
Q

describe transit cooling

A

inside the truck: usually uses one of 4 methods: mechanical refrigeration, top icing, evaporation of liquid nitrogen (dry ice), or a combo of theesse

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14
Q

use of liquid nitrogen or solid CO2 is considered _____ cooling

A

cryogenic

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15
Q

what’s the incentive for using liquid nitrogen?

A
  • commercially available
  • environmentally friendly
  • minimal equipment required
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16
Q

what is the incentive for using solid CO2?

A
  • can desirably add CO2 to room
17
Q

what is the incentive for using package icing?

A
  • results in fast cooling

- provides high RH

18
Q

what are some cons to using package icing?

A
  • must accommodate for water from ice packs

- packages should be water tolerant

19
Q

describe vacuum cooling

A

decreasing pressure decreases the temperature at which water vaporizes; latent heat is removed faster

20
Q

what are the basic components of a vacuum cooler?

A
  • vacuum chamber: a cylindrical vessel. it’s leak-proof and can withstand at least 1 atm
  • vacuum device: mechanical or steam injection
  • condenser: water or refrigeration coils
21
Q

what factors influence vacuum cooling?

A
  • surface area
  • porosity
  • degree of vacuum
  • availability of water
22
Q

what factors influence your choice of cooling method?

A
  • nature of produce
  • compatibility with existing facilities
  • initial capital investment cost, operation, cost, labor cost & maintenance cost
  • harvesting in coolest part of the day
  • keeping delays short
  • parking in the shade