Unitec Refrigeration Services - Post-Harvest cooling technologies - forced air

By: Unitec Refrigeration Services  11-11-2011
Keywords: cold rooms, Cooling, Cooling System

Benefits of Forced Air Cooling

  • Increase shelf life by removing field heat fast
  • Rapid cooling system with quick product turnaround
  • Efficient and quiet operation
  • Modular construction allows for relocation
  • Simple installation compared to plenum type systems
  • No special ducting required
  • No water resistant cartons required
  • Fans can operate at relatively high static pressures
  • More energy efficient than room cooling
  • Can be located in existing cold rooms

Suitable for:

Artichokes, Avocados, Green Beans, Brussels Sprouts, Cabbage, Cantaloupes, Cauliflower, Cherries, Cucumbers, Grapes, Honeydews, Kiwi, Nectarines, Onions (dry), Peaches, Plums, Strawberries, Tomatoes and more.

Real Energy savings!

The multispeed capability is a real energy saver over other single speed systems and can, in some cases, result in utility company rebates. Advanced temperature controls and PLC's on multiple systems are used to control the unit's functions, which are capable of interfacing with PC based plant management systems.

Refrigerated Cooling

The refrigerant gas in vapour form is compressed then cooled via the condenser to return it to a liquid state. It is then injected into one circuit of an evaporating vessel via a thermostatic expansion valve. Warm water from the process is circulating in the other circuit of the evaporator and the heat from the water transfers from one circuit to the other to evaporate the liquid refrigerant. The thermostatic expansion valve controls the flow of refrigerant into the evaporator according to the prevailing process heat load. Now as a vapour, the refrigerant gas returns to the compressor and the cycle continues. In this way water temperatures well below existing ambient air temperatures can  be achieved, typically 5ºC to 15ºC.

Forced Air Cooling

This functions very much like a car radiator. The warm process water is pumped through a radiator matrix. Air at ambient temperature is forced over the fins of the radiator matrix effecting a transfer of heat into the air. The now cooled water is pumped back through the cooling system and back to the plastics process equipment. This method of process cooling is entirely dependant on the ambient air temperature for its cooling efficiency and the water temperature achieved would normally be within 3º to 5ºC of the prevailing air temperature. Lower water temperatures can be achieved by using an “adiabatic cooler” which in principle is the same but with the addition of a water spray system which at high ambient temperatures coats the fins with a water mist.


  • High surface area cooling coil
  • High air flow fan capacity
  • Galvanized steel housing for long term protection against corrosion
  • Optimum temperature differential to achieve desired relative humidity
  • Digital controls
  • Multispeed control for room cooling conditions
  • Ammonia and “Freon” models available
  • Various defrosting options

Keywords: Air Cooling, cold rooms, Cooling, Cooling System, Forced Air, Forced Air Cooling, Increase Shelf Life, Modular Construction, Plant Management, Rapid Cooling, Room Cooling, Temperature Controls,

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