What is a condenser?
In the cooling system of ice machines, the heat taken from the evaporator and the additional heat during the compression process in the compressor is done in the condenser. Thus, the refrigerant is pressurized by becoming a liquid and it is expanded again and transformed into a state to take heat from the evaporator.
How does the condenser work?
The condensation of vapors and gases on a surface occurs in “Drop or film formation” styles, depending on the characteristics of the surface. In the case of dropwise condensation, much higher (4-8 times more than film formation) coefficients of heat permeability can be achieved with the drop formation. Although this is preferred, in practice, film-style condensation and to a lesser extent, droplet formation and condensate coexist due to their refrigerant properties and the condenser manufacturing being limited by economic factors.
It can be thought that the heat exchange in the condenser occurs in 3 stages. These;
Condensation of the refrigerant,
It is excessive cooling.
Depending on the condenser design, overcooling will use 0-10% of the condenser area. In order for the high temperature to drop, it is necessary to allocate 5% of the condenser area to this process.
Depending on these three different types of heat transfer, the heat transfer coefficients in the condenser and the temperature intervals will be different. However, a lower heat transfer coefficient will be present against the excess of the average temperature range in the phase of lowering the high temperature, but otherwise, the temperature range will be less and the heat transfer coefficient will be higher during overcooling. During condensation, both values will be between the upper and lower levels. In the experiments conducted, the decrease in the temperature difference (or vice versa) in comparison to the increase of the heat transfer coefficient results in approximately the same product, and it is possible to use the average of these values. Considering the simplicity it provides in the calculation, a single heat transfer coefficient and a single average temperature range values are applied in the calculation of the condensers.