19.01.2014 13:43

R134a used in refrigeration units

R134a Compressor

The R134A compressor is commonly used in refrigeration units - R134A (Freon 134A) being the coolant used in the system. Basically a tetrafluoroethane compound, R134A belongs to a group of chemicals that normally get classified as hydrogenated fluorocarbons (HFC). Non-toxic HFC coolants have today replaced chlorofluorocarbon (CFC) equivalents, such as the R12, that have proved detrimental to the environment by depleting the ozone content in the atmosphere.

The Workings

Coolant gases have been able to achieve the intended effects due to their innate thermal properties. Liquid coolants, when put through vapourisation, expand by absorbing energy from the surrounding environment and, hence, lower the temperatures. Not all gases have the ability to cause the same cooling effect. Freon, known to evaporate at about -15 degrees, is widely used as an efficient coolant in most industries. The R134A is first compressed to its liquid form in a condensing unit, so that it is able to force out excess heat into the atmosphere. The vapourised liquid is then allowed to expand, thereby triggering a drop in pressure, and resulting in lower temperatures than within the refrigeration unit. The R134A now draws heat from the chamber as it returns to its gaseous state, and is circulated back to the compressor for the next cooling cycle.

Types of R134a Compressors

R134A compressors can either sport an open structure, a partially open structure (semi-hermetic), or be fully sealed to prevent coolants from being rendered defunct or non-functional. Compressors, however, must be mechanically durable and should be capable of harnessing the thermal properties of the R134A compressor.

Open compressors expose internal components to the heat generated by the refrigeration unit, but are easy to repair and maintain. Semi-hermetic compressors allow access for repairs, while also protecting the refrigerant properties of the coolant from external heat.

All components of a hermetically sealed compressor are encased within its shell. This prevents any coolant leaks and exposure to heat, making these units more effective. It is, however, not possible to repair hermetically sealed R134A compressors, in case of any mechanical faults. Replacing the entire unit is mandatory to restore the normal functions.

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