The choice of the rerfigeration unit is made according to the following criteria:

Type of refrigeration unit

There are two main categories of refrigeration units:

  1. Refrigeration units with an air-to-air heat exchanger that operate autonomously or from the vehicle's engine and produce cooling when the vehicle is out on delivery.
  2. Cells with glycol plates, that produce cooling before the vehicle is out on delivery, by storing it in the glycol plates. The plates remain in very low temperatures (-20°C) and absorb heat from the environment. The cells are suitable fro transporting frozen puff pastry, ice cream etc. for frequent door opening, but only for daily use since they must remain permanently at very low temperatures.

 

Cooling capacity

The nominal cooling capacity of the unit must cover the losses of the chamber. These depend upon:

  1. The dimensions of the chamber.
  2. The number of doors.
  3. The thickness of the insulation.
  4. The type of delivery (the number of times the door opens per hour or the timelapse between the door openings, the amount of transported products).
  5. The type of doors and how they are sealed (single rubber, double rubber).
  6. The type of chamber (Isolated box, van internaly insulated).

 

Type of refrigerant

The type of refrigerant depends on the desired temperature in the chamber (15°C, 0°C, -10°C, -20°C)

  • For temperatures above 0°C the appropirate refrigerant is R134a which is a more economical refrigerant, it is recyclable and operates at low pressures creating less damage to the compressor.
  • For temperatures below -5°C it is necessary to use the refrigerant R452a which is a gas mixture and performs better at temperatures below 0°C.

 

Stand By and power supply (220V ή 380V)

The need for a Stand By system by an external supply 220 V or 380 V

  • When the vehicle is used as a temporary warehouse.
  • When the vehicle is loades at night tn order to start early the delivery.
  • When the vehicle remains loaded with goods.
  • When the vehicle delivers in islands.

 

The choice of 220 V or 380 V is made according to the following criteria

  • When the vehicle enters a boat then 380 V is necessary
  • When the vehicle is connected to household power supply then 220V is necessary

 

Common errors when choosing a unit.

Purchasing a freezer refrigeration unit for transporting maintenace temperature products.

Thinking that since it is suitable for freezing it will operate better for maintenace, is not correct. Freezer refrigeration units operate better below 0°C while at temperatures above 0°C they underwork. Just like in our home, we buy a fridge for vegetables and not a freezer that we set up at maintenace temperatures.

 

Purchasing a refrigeration unit with Stand By for daily deliveries.

If we don't need a Stand By system, then it is better to not buy it. That is because:

  • We will loose about 20kg of payload.
  • We will pay a respectable amount in order to purchase it.
  • The compressor of the Stand By system that will not be used, the seals will not be lubricated and as a result they will dry out and the refrigerant will be leaking.