Which component of a vaporcompression refrigeration machine

Which component of a vapor-compression refrigeration machine rejects the heat from the refrigerant circuit to outdoors? How does it accomplish this effect?

Solution

The cooler (also known as the condenser) rejects heat to the surroundings. Initially, the compressed gas (at S1) enters the condenser where it loses heat to the surroundings. During this constant-pressure process, the coolant goes from a gas to a saturated liquid-vapor mix, then continues condensing until it is a saturated liquid at state 2. Potentially, we could cool it even further as a subcooled liquid, but there is little gain in doing so because we have already removed so much energy during the phase transition from vapor to liquid.

f the cycle be?

We choose P_high so that we can reject heat to the environment. P_high is the same as P₂, and P₂ determines the temperature at state S2, T₂. (T₂ is just the saturation temperature at P_high). This temperature must at least be higher than that of the cooling source, otherwise no cooling can occur.

However, if T₂ is too high (that is, higher than the critical temperature T_C for the working fluid), then we will be beyond the top of the saturation dome and we will loose the benefits of the large energy the fluid can reject while it is being cooled. Furthermore, it is often impractical and unsafe to have very high pressure fluids in our system and the higher P₂ we choose, the higher T₁ must be, leading to additional safety concerns. To find an applicable pressure, use the saturation tables to find a pressure which is somewhere between the saturation pressure of the warm air yet still in the saturation region.