Truck Cooling
Truck refrigeration requires special trailers bodies and refrigeration plants. Such bodies are 9' 18' (3 m (6 m) in length. They use 1 1/2 HP 2 HP (1120 VV 1490 J.V.) cooling system. Bodies should be light and well insulated. Vibration and rough handling can cause loss of insulating walls, if the body is not built soundlv.
Fig. 18-1 illustrates the cooling system is used on the trailer system. Hie main components of which are the compressor, air-cooled condenser, expansion valve, and direct expansion evaporator. These systems normally use R-134a as the refrigerant. Figures 18-2 and 18-3 illustrate cooling and heat-defrosting of diesel engines.
Various insulating materials. Most of the trailers, all-metal bodies with different insulation thickness, depending on the application. Foamed in the designated isolation is most often used. Fig. 18-4 shows this insulation was installed on the sidelines of the trailer body
There are many applications for the trailer cooling, Each application must be studied to the temperature can be recommended.
Truck using dry ice, for cooling must be isolated for 109CF (78C). Ice cream truck should be isolated-15T (-263C). Fresh products that require insulation for 32F 35aF (0CC 2C) temperatures. Fresh vegetables and fruits, flowers and fruits need precise control of temperature, humidity and ventilation. These materials tend to lose fluid to the surrounding air.
There are four main truck refrigeration systems:
- Mechanical:
- Blower system
- Hold the eutectic plates
- Expendable refrigerant, liquid nitrogen and liquid carbon dioxide)
- Ice
- Dry ice
Mechanical cooling system, it seems that in most cases, typical for refrigeration plants. The main difference is the drive of compressor. Two conventional disks.
- The engine of electric generator and motor.
- Individual gasoline or diesel engines.
Electrical generators and motors use the standard voltage, cycles and phases. These permissions of the device must be connected to the outlet in the garage, and useful in case if the trailer must be kept cold for off-road. Units with petrol engines are controlled automatically start and stop as the system requires. Some vans and short trucks use a cube-style, or a thin line wall of the evaporator. The roof or body-mounted capacitor and the motor of the compressor are used. There is also a remote control in Cockpit control module. Remote in the cockpit module includes solid state temperature controller, temperature selector and manual defrost operations.
Fig. 18-6 shows within the expectations of the motor-compressor compartment. In addition, compressor mounted above (and, driven by the engine can be used. Cm. Fig. 18-7. Most of these systems use a hot gas defrost. Some of the major commercial entities use diesel fuel. In some systems, generator provides power for the evaporator fans. Fig. 18-8 illustrates a typical finished installation mounted in the cab of the truck.
The eutectic plates operate without the use of mechanical assistance during normal operation. Cm. Fig. 18-9. A small electric condensing unit connects usually at night. It freezes eutectic solution store enough energy for positive cooling during the day. Plates act basically like a battery with stored energy. The eutectic plates made of small-diameter pipes for the refrigerant. Fins attached to a tube and conduct heat from the refrigerant in the EU-tectic solution. The Assembly is inserted between two steel pans. Condenser vacuum filled eutectic solution, freezes at a certain temperature. Available in various sizes.
Ice, dry ice rarely used today. Ice is not used due to its weight and load requirements. Dry ice is light and does not require drainage. However, this is rarely used because of the complexity of managing and maintaining certain temperatures. Another form of truck cooling involves the use of liquid nitrogen and liquid carbon dioxide. In this system, which provides excellent low-temperature cooling, condensing unit is not required.
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