Air Conditioning System

Refrigeration Cycle

Refrigeration Cycle:

The Compressor draws low pressure, low temperature, refrigerant from the evaporator and, by compression, raises the refrigerant temperature and pressure. High pressure, hot, vaporized refrigerant enters the condenser, where it is cooled by the flow of ambient air. A change of state occurs as the refrigerant cools in the condenser and it becomes a reduced temperature, high pressure, liquid.

From the condenser, the liquid passes into the receiver drier which has three functions:

Storage vessel for varying system refrigerant demand.
Filter to remove system contaminants.
Moisture removal via the desiccant.

With the passage through the receiver drier completed, the liquid refrigerant, still at high pressure, enters the expansion valve where it is metered through a controlled orifice, which has the effect of reducing the pressure and temperature. The refrigerant, now in a cold atomized state, flows into the evaporator and cools the air passing through the matrix.

As heat is absorbed by the refrigerant, it once again changes state, into a vapor, and returns to the compressor for the cycle to be repeated.

An automatic safety valve is incorporated in the compressor, which will operate if the system pressure rises above 41 bar. The valve will reseat when the pressure drops below 27, 6 bar.

The terms 'high' and 'low' pressure (or side) refer to the pressure differential between the compressor and expansion valve ports. This differential is critical to system fault diagnosis and efficiency checks.