Good Loading Practices

Carrier Transicold and PLM Trailer Leasing

Transport Refrigeration what is its purpose

To maintain the Temperature of the Product

It is not designed to reduce or increase the temperature of the product

Summary of good practices

A well maintained working unit Reefer and Trailer

A Pre-Cooled box

Good loading conditions and practice

Consequences Chilled pork Optimum 29 Degrees F Rule of thumb : 2 Degree Increase =

10% decrease in shelf life

29F - 100% Life Attainable 32F - 70% 34 F-60% 36 F - 50% 41 F - 30%

Heat Sources

1. Through the body2. Through the rear door3. Warm Products4. Door Seal

Modern Longitudinal Divide

KemliteSmall door opening to retain cold

Flat floor

“E” Track

Three years old ?

Three years old ?

Bulkheads

Bulkheads

Pallet stop to protect bottom of bulkhead

Bulkheads should be sealed around the sides to make sure the air does not short cycle

Minimum 4” from the front of the trailer to allow adequate air return

Side Doors

Side doors should be kept as small as possible

Curtains and door seals should be well maintained

Flat Floor and “T “ Floor

Unless palletized multi temp

“T” Floor is recommended

Flat Duct Board

Inspect Equipment - Debris

Swing Doors V Roll up Door

Roll up is 25% less efficient Swing doors

can open oneside and retainthe cool

Curtains

Curtains are recommended for both rear and side doors

These should overlap by 2”

Rear Door Side Door

Types of Bulkheads

Mattress type bulkhead

Rigid type bulkhead with door

Air ChutesRecommended by Refrigerated Transportation Foundation

Proper InstallationRequired

Unit Positioning

Unit should not bepositioned any lower than normal

Air will hit the top of the load and short cycle

Summary of good practices

A well maintained working unit Reefer and Trailer

A Pre-Cooled box

Pre Cool the body

Removes the heat that has entered the body from the sun

When not in use try to park in the shade

Typical Heat Gain from Infiltration through the body

UA Factor -20F 0F 35F

110 UA 13,200 11,000 7,150 120 UA 14,400 12,200 7,800 130 UA 15,600 13,000 8,450 140 UA 16,800 14,000 9,100

Summary of good practices

A well maintained working unit Reefer and Trailer

A Pre-Cooled box

Good loading conditions and practice

Loading PracticesAirflow - Return

Air Flow down the side of the load

Minimum 1”airflow around the sides of load preferably 2”

Properly loaded pallet giving good airflow

Minimum 4” from the rear door

Short Cycling

Loading to the ceiling will cause short cycling

Loading Procedure

Poor air distribution is one of the primary causes of product deterioration even when unit capacity is more than adequate

Obstruction anywhere around the load can result in hot spots

Product should be loaded at correct temperature

Product should alwaysbe loaded at the correct temperature transport refrigeration is designed to maintain temperature only

Product should be loaded from a refrigerated loading bay

Different Containers

Do not use plastic wrap on fresh produce as it prevents air circulation reaching the load

Fresh FrozenProducts Products

Correct Pallets should be used

Pallets should allow airflow through and under the load

Orientation should allow airflow to the rear of the body

Load Properly

Do not mix refrigerated and dry goods in the same compartment

Separate items

Cold air is heavier than hot air

Opening doors with no curtains loses all the cold

Something has to replace the heavier air and the warm ambient does this instantly

Door switch is recommended

Typical heat gain (Btu/hr) from 15 min door openings in a 10 hour period

Trailer setpoint Average number of door openings per day

2 4 8 12

35f Btu / hr 560 1,125 2,250 3,375

0f Btu / hr 750 1,500 3,000 4,500

-20f Btu / hr 935 1,875 3,750 5,625

Loading Procedure

Pre-cool the box preferably until setpoint Initiate Manual Defrost during pre-cool Switch off the unit Load product at the correct temperature and in the

correct mannerClose doors Start up unitCheck thermostat settings

Do not load the product in front of the evaporator air outlet as this will block the airflow

Blockage above the load will result in short cycling

Leave a minimum of 9” between the top of the load and the ceiling

Inside of the truck should be clean and the floor free of shrink wrap and debris

Loading Procedure

Good Loading Procedure

Do not block the evaporator inlets (return air ) Make sure that the return air bulkhead is in a

good condition Keep the trailer door seals in good conditionUse air curtains wherever possible Keep door openings to a minimum Turn off unit while doors are open