Refrigeration System for Food Preservation
Transcript of Refrigeration System for Food Preservation
Refrigeration System for Food Preservation
Dr. Apichit L. Pana (Ph.D.(Hon), ME) Managing Director – ITC Group
Fellow – ASHRAE Distinguish Lecturer (DL)
กรรมการบริหาร (BoD) ASHRAE-USA
Outlines
• Refrigeration System • Refrigeration Load Estimation • Freezing Technology • Product Weight Lost • Fruits & Vegetables : Control Parameters • Fruits & Vegetables : Pre-Cooling Method • Control atmosphere (CA) Control Parameters Type of C.A. System C.A. Equipment & Accessories
REFRIGERATION SYSTEM
Syst
em S
elec
tion
Single Stage With Economizer (Screw Comp)
Without Economizer (Piston, Screw)
Two Stage
Injection interstage gas cooling (system A)
Injection interstage gas and liquid cooling (system B)
Open flash interstage cooling (system C)
Closed flash interstage cooling (system D)
Cascade Ammonia – CO2
HFC - R23 Cryogenic
Application Temperature Range
High Temp.
Processing Line
Medium Temp.
Ante
Chill Room
Chill Water
Etc.
Low Temp.
Cold Storage
Freezer
Ultra Low Temp.
Cryogenic
Freezer
“Typical Temperature Range” In Food Processing Plant
Room Application Room Temp. (C)
Evaporating Temp. (C)
Ante, Loading, Boxing +5 ~ +15C +5 ~ -5C
Cut up, Processing Area +10 ~ +12C +5 ~ -5C
Chilled Room +5 ~ +0C -10C
Cold Storage -20 ~ -25C -30 ~ -35C
Freezing -35 ~ -40C -40 ~ -45C
Refrigeration System
• Typical using ammonia as an refrigerant • For worker congestion area using secondary refrigerant such as P.G. or E.G.
Flooded System for Falling Film Plate Chiller
Falling Film Plate Chiller
Compressor
Evap. Cond.
Receiver
Evap. Cond.
Plate in frame or shell & tube for glycol system
Plate Heat Exchanger
Receiver Compressor
REFRIGERATION LOAD
ESTIMATION
1
4
5
2
3 1. Transmission load 2. Product load 3. Internal load & Wet floor load 4. Infiltration air load 5. Equipment related load 6. Safety factor 7. Refrigeration system load
1. Transmission load
2. Product load
3. Internal load & Wet floor load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
q : heat gain; W A : outside area of section; m2 t : difference between outside air
temperature and air temperature of the refrigerated space; K
U : overall heat transfer coefficient; W/(m2∙K)
x : wall thickness; m k : thermal conductivity of wall
material; W/(m∙K) hi : inside surface conductance;
W/(m2∙K) ho : outside surface conductance;
W/(m2∙K)
Ref: Chapter 24 Refrigerated-Facility Loads, 2014 ASHRAE Handbook - Refrigeration
Ref: Chapter 24 Refrigerated-Facility Loads, 2014 ASHRAE Handbook - Refrigeration
Ref: Chapter 24 Refrigerated-Facility Loads, 2014 ASHRAE Handbook - Refrigeration
For general insulation panels
Note: Value in Table 3 apply over a 24 h period and are added to the ambient temp. when calculating wall heat gain.
Climate design information Bangkok Metropolis
Ref: Chapter 14 Climate Design Information, 2013 ASHRAE Handbook - Fundamental
Climate design information Bangkok Metropolis
Ref: Chapter 14 Climate Design Information, 2013 ASHRAE Handbook - Fundamental
Climate design information Bangkok Metropolis
Ref: Chapter 14 Climate Design Information, 2013 ASHRAE Handbook - Fundamental
Climate design information Bangkok Metropolis
Ref: Chapter 14 Climate Design Information, 2013 ASHRAE Handbook - Fundamental
Climate design information CDDn Cooling degree-days base n°F, °F-day Lat Latitude, °
CDHn Cooling degree-hours base n°F, °F-hour Long Longitude, °
DB Dry bulb temperature, °F MCDB Mean coincident dry bulb temperature, °F
DP Dew point temperature, °F MCDBR Mean coincident dry bulb temp. range, °F
Ebn,noon Edh,noon
Clear sky beam normal and diffuse horizontal irradiances at solar noon, Btu/h/ft2
MCDP Mean coincident dew point temperature, °F
MCWB Mean coincident wet bulb temperature, °F
Elev Elevation, ft MCWBR Mean coincident wet bulb temp. range, °F
Enth Enthalpy, Btu/lb MCWS Mean coincident wind speed, mph
HDDn Heating degree-days base n°F, °F-day MDBR Mean dry bulb temp. range, °F
PCWD Prevailing coincident wind direction, °, 0 = North, 90 = East
WS Wind speed, mph
Ref: Chapter 14 Climate Design Information, 2013 ASHRAE Handbook - Fundamental
Climate design information Period Years used to calculate the design conditions
Sd Standard deviation of daily average temperature, °F
StdP Standard pressure at station elevation, psi
taub Clear sky optical depth for beam irradiance
taud Clear sky optical depth for diffuse irradiance
Tavg Average temperature, °F
Time Zone Hours ahead or behind UTC
WB Wet bulb temperature, °F
Hours 8/4 & 55/69 Number of hours between 8 a.m. and 4 p.m. with DB between 55 and 69 °F
HR Humidity ratio, grains of moisture per lb of dry air
Ref: Chapter 14 Climate Design Information, 2013 ASHRAE Handbook - Fundamental
1. Transmission load
2. Product load
3. Internal load & Wet Floor Load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
Q1 = m ∙ c1 ∙ (t1 – tf) above freezing
Q2 = m ∙ hif latent heat Q3 = m ∙ c2 ∙ (tf – t3) below freezing
Q1,2,3 : heat remove; kJ m : mass of product; kg c1,c2 : specific heat of product; kJ/(kg∙K) t1 : initial temperature of product above freezing; oC tf : freezing temperature of product; oC t3 : initial temperature of product above freezing; oC hif : latent heat of fusion of product; kJ/kg
6
7
8
Ref: Chapter 13 Refrigeration Load, 2006 ASHRAE Handbook - Refrigeration
q4 = m ∙ heat of respiration
q4 : heat remove; W m : mass of product at full storage; kg heat of respiration : W/kg
5
Ref: Chapter 19 Thermal properties of foods, 2014 ASHRAE Handbook - Refrigeration
c1 c2 hif tf
Ref: Chapter 19 Thermal properties of foods, 2014 ASHRAE Handbook - Refrigeration
Ref: Chapter 19 Thermal properties of foods, 2014 ASHRAE Handbook - Refrigeration
• Total product load, kW
Cooling or Freezing = Pull Down Time for Walk-in Cooler and Freezer
= (𝑄1+𝑄2+𝑄3
Cooling or Freezing Time )+(𝑞4x10−3)
1. Transmission load
2. Product load
3. Internal load & Wet floor load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
• Electric equipment • Forklift • Processing equipment • People • Latent load
• Electric motor
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
• Lighting
• Chill & Cold Room : 200 Lux
• Fluorescent Fixtures room temp. ≥ -5 OC
• High Pressure Sodium Fixtures
• Metal Halide Fixtures
• Incandescent
• Lighting
• Packing Room : 300 Lux
• Fluorescent Fixtures room temp. ≥ -5OC
• Incandescent
• Forklift Forklift in some facilities can be a large and
variable contributor to the load. Although many
forklift in a space at one time, they do not all operate at the same energy level.
• Processing equipment • Grinding, mixing, or cooking equipment
• Packaging, glue melt, or shrink wrapping
• Makeup air replacing equipment exhausts air from refrigerated space.
• People
qp = 272 – 6t
t : the temperature of the refrigerated space (°C)
qp : Heat load from a person (Watts/person)
10
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
• Wet floor latent load
V = Air velocity across floor, assume 50 fpm
ew = vapor pressure of water temp. on wet floor, inHG. ( ex. 0.363 inHG at 50OF 100%RH )
ea = vapor pressure of water vapor in room air, inHG. ( ex. 0.225 inHG at 45OF 75%RH )
𝑏𝑡𝑢/ℎ𝑟/𝑓𝑡2 = 95 + 0.425𝑉 . 𝑒𝑤 − 𝑒𝑎
Ref: Carrier Product Refrigeration “Load Estimating Data”
1. Transmission load
2. Product load
3. Internal load & Wet floor load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
Fig.7 Flowing Cold and Warm Air Masses for Typical Open Freezer Doors
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
hi
hr
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
Fig.8 Psychrometric Depiction of Air Exchange for Typical Freezer Doorway
qt : average heat gain for the 24 hr period; kW q : sensible & latent refrigeration load for fully established
flow; kW
Dt : doorway open-time factor Df : doorway flow factor (0.85 – 1.1) E : effectiveness of doorway protective device
14 𝑞𝑡 = 𝑞.𝐷𝑡 . 𝐷𝑓. (1 − 𝐸)
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
When the door is open as need
E= 0.95 or higher for newly installed strip, fast-fold, and other non-tight-closing doors. Depending on the traffic level and door maintenance, E may quickly drop to 0.8 on freezer doorways and to about 0.85 for other doorways.
E = 0.85 - 0.95 for airlock vestibules with strip or push-through for freezers and between 0.95 and 0.90 for other doorways.
E = ranges from very poor to more than 0.7 for air curtains. E = 0 for a wide-open door with no devices
where Df , doorway flow factor is ratio of actual air exchange to fully established flow. Fully established flow occurs only in the unusual case of an unused doorway standing open to a large room or the outdoors, and where cold outflow is not impeded by obstructions. Under this condition, Df is 1. Recommend Value Df = 1.1 for temp. difference less than 11K (20F). Df = 0.8 for temp. difference higher than 11K (20F).
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
Dt : doorway open-time factor, decimal fraction P : number of doorway passages p : door open-close time, seconds per passage o : time door simply stands open, min d : daily (or other) time period, hour
𝐷𝑡 = 𝑃. 𝜃𝑝 + 60. 𝜃𝑜3600. 𝜃𝑑
17
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
Where the doorway open-time factor can be calculated as
q : sensible and latent refrigeration load; kW A : doorway area; m2
hi : enthalpy of infiltration air; kJ/kg hr : enthalpy of refrigerated air; kJ/kg i : density of infiltration air; kg/m3 r : density of refrigerated air; kg/m3 g : gravitational constant = 9.81 m2/s H : doorway height; m
Fm : density factor
𝑞 = 0.221𝐴 ℎ𝑖 − ℎ𝑟 . 𝜌𝑟 . (1 − 𝜌𝑖 𝜌𝑟 )0.5. (𝑔ℎ)0.5. 𝐹𝑚
developed by Gosney and Olama (1975)
15
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
When the door is open all the time
i : density of infiltration air; kg/m3
r : density of refrigerated air; kg/m3
𝐹𝑚 = 2
1 + (𝜌𝑟 𝜌𝑖 )1/3
1.5
Fm : density factor
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
qt : average refrigeration load; kW V : average air velocity; m/s ( 0.3 – 1.5 m/s ) A : opening area; m2
hi : enthalpy of infiltration air; kJ/kg hr : enthalpy of refrigerated air; kJ/kg r : density of refrigerated air; kg/m3
Dt : doorway open-time factor, decimal fraction (< 1.0)
𝑞𝑡 = 𝑉. 𝐴. ℎ𝑖 − ℎ𝑟 . 𝜌𝑟 . 𝐷𝑡 18
Ref: Chapter 24 Refrigerated Facility Loads, 2014 ASHRAE Handbook - Refrigeration
When known the air velocity
1. Transmission load
2. Product load
3. Internal load & Wet floor load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
• Fan motor • Reheat for humidity control • Heat from defrosting
• Electric defrost • Hot gas defrost • Water defrost • Air defrost
1. Transmission load
2. Product load
3. Internal load & Wet floor load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
• ASHRAE = 10% • General = 20 – 25% This factor should be selected in consultation with the facility user and should be applied individually to the first four heat load segments
1. Transmission load
2. Product load
3. Internal load & Wet floor load
4. Infiltration air load
5. Equipment related load
6. Safety factor
7. Refrigeration system load
Pull down time = 24 – (defrosting time + resting time)
𝑄𝐿 = 𝑄. 24ℎ𝑟
𝑃𝑢𝑙𝑙 𝑑𝑜𝑤𝑛 𝑡𝑖𝑚𝑒
Ref : KRACK “Engineering Manual Refrigeration Load Estimating”
Application Recommended Factors
24 hour (divide by)
Hourly (multiply by)
Coil temp. above 32OF, No frost accumulation
24 1.0
Light frost with positive defrost systems 22 1.1
Medium temp. with positive defrost systems
20 1.2
Low temp. with positive defrost systems 18 1.3
Off cycle defrost, 32OF or higher storage temp., with evap. temp. below 32OF
16 1.5
Table 8 Time Cycle Factors
Ref : KRACK “Engineering Manual Refrigeration Load Estimating”
Note: Factors noted are for average frosting. For heavier frost, or lower than normal evaporating temperature, use 1-2 hours less operating Time.
FREEZING TECHNOLOGY
Freezing Technology
• Air Blast Freezer • Contact Plate Freezer • Tunnel Freezer • Fluidized Bed Freezer • Spiral Freezer • Brine Freezer • Cryogenic Freezer • Cryodesiccation Freezer
Air Blast Freezer
Contact Plate Freezer
Tunnel Freezer
Fluidized Bed Freezer
Spiral Freezer
Brine Freezer
Brine Freezer
Cryogenic Freezer
Cryodesiccation Freezer (KD Freezer)
Cryodesiccation Freezer (KD Freezer)
Packaged Condensing Unit
M1
Freezer/Dryer Ice Condenser
Vacuum Pump
M2
M3
EV1
EV2
S3
Fast Freezing -- > Ice crystal very small
Slow Freezing -- > Ice crystal big
Water Phase Diagram
13.3 Pa
Primary Drying
Secondary Drying
Freeze Dried
Product 35OC
-18OC
+5
5OC
5OC
Vacuum
< 100 micron
Fresh / Cooked Product
Freeze
25OC
-18OC
1. ใส่ภาชนะ 2. เติมน า้รอ้น, หรือเตมิน ้าแล้วเวฟ 1 นาที 3. พร้อมอร่อย
ขั นตอนความอร่อยกับ
สารท้าความเยน็
วิธีการทา้ความเยน็
การท้าแห้ง
การท้าสญุญากาศ
การละลายน า้แขง็
ต้นทุนคา่ไฟ
ทั่วไป 2 ชนิด (Refrigerant + Heat Transfer Fluid) 1 ชนิด (Refrigerant)
Conduction + Convection
ต่้ากวา่ 100 ไมครอน
แก๊สร้อนทิ งจากชว่งฟรซีสนิคา้
35 บาทต่อชั่วโมง
Conduction
ต่้ากวา่ 1,000 ไมครอน
น ้า
100 บาทต่อชั่วโมง
Conduction + Radiation Conduction
Cryodesiccation Freezer (KD Freezer)
PRODUCT WEIGHT LOST
Product Weight Lost
• Weight lost in storage and freezing
• Chilling injury
• Freezing injury
• Ammonia injury
• C.A. injury
Percentage of Weight (Moisture) Loss from Fruits and Vegetable that Affects Produce Quality after Harvest
Product Weight Loss (%) Beans (broad, runner, snap) 6.0, 5.0, 41.0 Broccoli 4.0
Cabbage 8.0
Carrots (mature, young) 8.0, 4.0
Celery 10.0
Cucumbers 5
Lettuce 3.7
Onions 10.0
Potatoes 7.0
Spinach 3.0
Sweet Corn 7.0
Tomatoes 7.0
Weight lost during storage
Factors:- • Room temperature & temperature fluctuation • Humidity • Air flow over the product • Radiation effects of lighting • Shape and size of the product • Type of wrapper (packing)
Weight lost during freezing
Factors:- • Type of product • Type of packing • Type of freezer • Temperature different & Air velocity • Freezing time (Retention time) • Freezer operating conditions
Chilling Injury
Freezing Injury
Freezing Injury
Slow Freezing
Quick Freezing
Freezing
Freezing
Thawing
Thawing
Large ice crystals damage cell wall
Small ice crystals
Cell wall has been ruptured
Cell wall intact
Ammonia Injury
C.A. injury Table 3. Examples of C.A. injury (from Thompson A.K, 1998)
FRUITS &
VEGETABLES
Control Parameters
Fruits & Vegetables Commodity Max.
transit & Shelf life
(Days)
Opt. transit temp. (C)
Highest freezing
temp. (C)
Recomm. container
temp. setpoint
(C)
%RH Air Change
(cfm)
Ethylene
Produc-tion Rate
Sensi-tivity
Beans, Green
10-14 7.2 -0.7 5.0-7.2 90-95 45 (H) Low M
Broccoli 10-14 0 -0.6 0-1.1 90-95 20 (M) VL High
Cabbage (White)
90-180 0 -1.4 0-1.1 95-100 45 (H) VL High
Cantaloupes 10-14 3.3 -1.2 2.2-5.0 85-90 45 (H) High M
Carrot, Topped
28-180 0 -1.4 0-1.1 95-100 15 (L) VL Low
Celery 14-28 0 -0.5 0-1.1 90-95 45 (H) VL M
Cucumbers
10-14 10.0 -0.5 10.0-11.1 90-95 45 (H) Low High
Eggplant 10-14 10.0 -0.8 10.0-12.2 90-95 15 (L) Low Low
Fruits & Vegetables Commodity Max.
transit & Shelf life
(Days)
Opt. transit temp. (C)
Highest freezing
temp. (C)
Recomm. container
temp. setpoint
(C)
%RH Air Change
(cfm)
Ethylene
Produc-tion Rate
Sensi-tivity
Lettuce (butterhead)
8-12 0 - 0-1.1 90-95 45 (H) Low M
Onions, Green
7-10 0 -0.9 0-1.1 95-100 20 (M) VL Low
Onions, Dry
30-180 0 -0.8 0-1.1 65-75 20 (M) M M
Spinach 10-14 0 -0.3 0-1.1 95-100 45 (H) VL High
Strawberries 5-10 -0.5 -0.8 0-1.1 90-95 20 (M) Low Low
Sweet Corn 4-6 0 -0.6 0-1.1 90-95 15 (L) VL Low
Tomatoes, breaker to light pink
7-14 10.0 -0.5 10.0-11.1 90-95 45 (H) M High
PRE-COOLING METHODS
For Fruits & Vegetables
Pre-cooling Methods for Fresh Produce
• Top Icing • Hydro Cooling • Hydrair Cooling (air + cold water spray),
Wet Air Cooling • Air Cooling
Room Cooling Force Air Cooling
• Vacuum cooling
Top Icing
Hydro Cooling
Hydro Cooling
Water Distribution Pan Cooled Product Out
Water Reservoir
Evaporator
Continuous Flow Shower Type Hydrocooler
Hydro Cooling
Batch Hydrocooler
Evaporator
Water Pump
Refrigeration System
Water Reservoir
Bins
Water Distribution Pan
Hydro Cooling
Continuous Flow Immersion Type Hydrocooler
Immersion Tank
Cooled Product Out
Evaporator
Flighted Conveyor
Hydro Cooling
Thermal Storage Immersion Hydrocooler
Refrigerant Refrigeration
System
Hydrocooler
Ice/cold Water Storage Tank
Chilled Water 1 ~ 4C
Circulate Pump
Hydrair Cooling System, Wet Air Cooling System
Evaporative Condenser
Wet Air Cooler
Ice Chiller & Water Tank
Compressor
Cold, Humid Air
Produce
Cold Room
Ice
Wat
er
Hydrair Cooling System, Wet Air Cooling System
Hydro-Force Cooler (HAC)
Hydro-Force Cooler (HAC)
Evaporator
Circulate Pump
Drift Eliminator
Air In
Water Spray
High Humidity Air Supply
Air Cooling -- Room Cooling
Recommended Temperature (TD) for Four Classes of Foods (Forced Air Unit Coolers)
Class TD RH Suitable for 1 7-9F
(~5C) 90% Fruits, vegetables, flowers,
unpacked ice, chill room
2 10-12F (~7C)
80 - 85% General cool room, packed products
3 12-16F (~9C)
65 - 80% Beer, wine, pharmaceuticals, short term packaged products, tomatoes, onions, and tough skin fruits e.g. melons
4 17-22F (~12C)
50 - 65% Processing rooms, cutting rooms, candies, loading docks
Air Cooling -- Forced Air Cooling
Tunnel type FAC using cold-wall system
Fan
Evaporator
Cold Room Air In
Produce Produce
Cold-wall
Cold-wall
Fans
vent open when pallet is pushed against bumper
Air Cooling -- Force Air Cooling
Air Cooling -- Force Air Cooling
Canvas System Canvas System
Air Cooling -- Force Air Cooling
Canvas Free System
Air Cooling -- Force Air Cooling
Air Bag (Vertical Air Circulation)
Vacuum Cooling
Condenser
Compressor
Evaporator
Produce
Vacuum Chamber Vacuum Pump
Condensate
Typical schematic of a vacuum cooler
Vacuum Cooling
Compare Cooling Methods for Fruits and Vegetables Room
Cooling Vacuum Cooling
FAC Hydro Cooling
Top/Liquid icing
Typical cooling time (hr)
20 to 100 0.3 to 2.0 1 to 10 0.1 to 1.0 0.1 to 0.3
Product moisture loss (%)
0.1 to 2.0 2.0 to 4.0 0.1 to 2.0 0 to 0.5 No data
Water contact with product
No No No Yes Yes, unless bagged
Potential for decay contamination
Low none Low High Low
Capital cost Low Medium Low Low High
Energy efficiency Low High Low High Low
Water-resistant packing needed
No No No Yes Yes
Portable No Common Sometimes Rarely done Common
Feasibility of in-line cooling
No No Rarely done Yes Rarely done
Example:
Mango
Mango Max.
transit & Shelf life
(Days)
Opt. transit
temp. (C)
Highest freezing
temp. (C)
Recommended container temp.
setpoint (C)
%RH Air Change
(cfm)
Ethylene Production
Rate
Mango 14-25 13.3 -0.9 12.2-13.3 85-90 20 Medium
Export Fresh Mangos Process Flow Hand harvest into baskets,
nets or buckets
Remove latex
Transfer to field lug boxes
(shaded)
Transfer to packinghouse
Dump into chlorinated
water
Portable water brush & rinse
Pre-size for hot water treatment presort defect
Hot water quarantine treatment
Hydro cooling
Rest 12-24 hrs at ambient
temp.
Transfer to packing line &
wax application
Grade according to buyer
requirements
Pack fruit into cartons by size
Palletizing & strapping
Forced Air
cooling
Move pallets to cold storage room prior
to shipping
Ripen Mangos Process Flow Ripen Mangos
Clean & Rinse
Peel
Cut
Freeze (Air Blast, Tunnel)
Vacuum Pack
Cold Storage
Vacuum Dry
Pack
KD Freeze
Pack
CONTROL ATMOSPHERE (CA) For Fruits & Vegetables
Control Parameters
• Oxygen (O2)
• Carbon Dioxide (CO2)
• Ethylene Gas (C2H4)
• Temperature
• % RH
Effect of C.A. Parameters C.A. Storage Cold storage atmosphere is way out from
21% of O2 and 300 PPM of CO2
O2 Burn & Broken down the Nutrients. Reduce of O2 will reduce metabolism of the produce.
CO2 It generate from respiration. Too much will damage the product; Soft Scale, Cortex and Core heart Browning.
Ethylene Ripening agent, Stimulate aging process i.e. Kiwi Fruit allow only 200 ppm.
% RH Cause Dehydration, Shrinkage, Lost quality and weight. Rod & Mold will form during high RH.
Temperature Chilling, Freezing Injury, Low temperature breakdown. Vascular tissue becomes browning, often no external symptoms.
Average Optimum C.A. levels of Tropical Fruit Storage
Variety O2 (%)
CO2 (%)
Temp. (C)
%RH Storage (Month)
Banana 2-5 2-5 12-16 90-95 Commercial Use in '1997.
Durian 3-5 5-15 12-20 85-90 Information from 7th International CA
Research Conference July 13-18, 1997.
Many of them is using during Marine Transport. Further Specific evidence
levels need to be proved by more
researchers.
Grapefruit 3-10 5-10 10-15 85-90
Lemon/Lime 5-10 0-10 10-15 85-90
Lychee 3-5 3-5 5-12 85-90
Mango 3-7 5-8 10-15 85-90
Orange 5-10 0-5 5-10 85-90
Papaya 2-5 5-8 10-15 85-90
Pineapple 2-5 5-10 8-13 85-90
Rambutan 3-5 7-12 8-15 85-90
Average Optimum C.A. levels of Vegetable Storage
Variety O2 (%) CO2 (%)
Temp. (C)
%RH Storage (Month)
Asparagus 10-16 10-14 1-4 90-95 10-15 Days Artichokes 2-4 2-3 0-1 90-95 20-25 Days Broccoli, Florets
2-3 6-7 0 95 10 Days
Cabbage, Shredded
2-3 4-5 0 95+ 3-4 Months
Cauliflower 3-4 5-7 0 90-95 40-50 Days Garlic 3 5 -1 65-70 6-7 Months Leeks 2-4 5-10 0 90-95 4-5 Months Onion 2-5 10-15 0 70-75 8-9 Months Tomato 3-4 2-3 2 85-90 30-40Days
TYPE OF C.A. SYSTEM
Type of C.A. System
• Flow Through/Purge System
• Recirculation
• N2 Pressure Swing Adsorption (PSA)
• N2 Vacuum Pressure Swing Adsorption (VPSA)
Flow Through Test
รูปหน้า 46
Jars For Flow Through Test
Cabinet System
Control atmosphere (CA)
Membrane type Nitrogen Generator
PSA type Nitrogen Generator
Type of Material
• Hollow Membrane
• Carbon Molecular Sieve (CMS)
Type of Material -- Hollow Membrane
Type of Material -- Carbon Molecular Sieve (CMS)
VPSA Type O2 Scrubbers
C.A. Equipment & Accessories -- CO2 Scrubbers
C.A. Equipment & Accessories -- Ethylene Scrubber
C.A. Equipment & Accessories -- Gas Analyzer
Analyzer
C.A. Equipment & Accessories -- C.A. Door
C.A. Equipment & Accessories -- Gas Tight Doors for CA/ULO-Storage
Wall & Equipment Viewing Window
C.A. Equipment & Accessories
Air bags to equilibrate pressure in controlled atmosphere rooms
C.A. Accessories
Any question?
For more information please email to
[email protected] Tel: +66-2184-0055
Freezing and Refrigeration in Food Industry
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