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

apichit.lpana@itc-group.co.th Tel: +66-2184-0055

Freezing and Refrigeration in Food Industry

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