Refrigerated trucks: how do they work?
Have you ever seen a refrigerated truck on the road and wondered exactly how it manages to keep everything cold while still being mobile? The answer is so deceptively simple that it might just surprise you.The first thing you need to understand is the fundamental principle behind modern refrigeration equipment. We’re going to get into some physics here, but don’t worry, you don’t need to be Stephen Hawking to understand it.
Most people think that refrigeration equipment works by creating cold. The thing is, cold can’t be created. Cold is just the absence of heat energy. So in order to promote cold conditions, you need to remove the heat energy in the atmosphere. So in order to build a refrigeration system, you need to create a self-contained atmosphere, and then remove as much heat as possible from it.
Here’s how the cooling system works:
In a refrigerated truck, insulating a compartment and then sealing it create the self-contained atmosphere. The insulation is made from high-density polymer foam, which is quite similar to polystyrene, although it’s constructed from a higher density and more durable polymer than you’d find in typical polystyrene insulation. The insulation, combined with a seal around the door, creates an atmosphere that is fairly heat-tight. Then all you have to do is remove any heat that remains inside, and any heat that comes in when the door is opened. This is accomplished using a refrigeration system with a reasonably simple mode of operation. It has three different mechanisms all working together: a condenser, a compressor, and an evaporator.
The condenser consists of a metal piece of pipe work that is twisted into a convoluted shape. This pipe work is filled with an incredibly high tech type of liquid, known as coolant fluid. This type of fluid has been around for a long time, but the latest kind has been developed in a laboratory to be exceptionally efficient at absorbing heat. This fluid is circulated around the pipe work, sucking up all the heat that it’s inside the freezer van chamber. As the coolant fluid sucks up the heat and becomes hot, it turns into a gas.
Once the fluid has transferred into a gaseous state, it is taken into the condenser. This is a mechanism that tightly compresses the gas down, placing it under extreme pressure and forcing all of the molecules together. In this condition, the gas is in a similar state to gas that you’d find in a household aerosol. Once the gas has been condensed and is being held at high pressure, it’s placed into the evaporator. This machine then takes air from the exterior atmosphere and pushes it through the high-pressure coolant gas. This process cools down the coolant fluid, simultaneously converting it back into a gas and expelling the heat energy out into the atmosphere. The gas is then reintroduced into the condenser for the process to begin again. As this process is continually repeated, the atmosphere inside the refrigerated truck becomes gradually colder and colder.
As you can see, the principle behind the operation of a refrigerated truck is fairly simple. Of course this is a simplified explanation, and there are a few different subtleties beyond the scope of this FAQ, such as the temperature regulation mechanism and the intricacies of the condenser and evaporator systems, but it should have removed some of the mystery behind refrigerated trucks and their operation.
As always, Glacier Vehicles is always happy to answer any questions you have about refrigerated vehicles, so get in touch with us today!