Keep in mind that heat moves from a hotter to a colder substance. As a result, the temperature of the types of evaporators must be lower than the ambient temperature. With refrigerant-22, a residential air conditioner’s evaporator coil, at 68.5 PSIG, maintains a 40°F temperature, absorbing room heat. Alaqua is an evaporators supplier that also supplies other processing equipment like crystallizers, solvent recovery systems, distillation, and heat exchangers.
Various refrigeration applications use types of evaporators, leading to diverse designs. Classifying evaporators involves considering factors such as the evaporator’s architecture, refrigerant feeding technique, air circulation direction, and other relevant elements. Categorizing evaporators is based on their construction.
Evaporators Classification Based On Their Construction
Evaporators for refrigeration and air conditioning utilize various construction styles depending on the application. The different types of evaporators are classified according to their construction:
Bare Tube Evaporators-
Copper tubing or steel pipes comprise the bare tube evaporators. Small evaporators use copper tubing with non-ammonia refrigerants, while large ammonia-based ones employ steel pipes; bare tube evaporators feature multiple tubing rounds, commonly flat, zigzag, or oval trombone shapes. Bare tube evaporators commonly perform liquid cooling. During blast cooling and freezing processes, ambient air passes over the bare tube evaporator, and the chilled air leaves it for cooling purposes. Bare tube evaporators services are employed in a limited number of applications, while finned evaporators, which are bare tube evaporators with fins, are widely utilized.
Plate Type Evaporators-
Insert the coil, typically made of copper or aluminum, into the plate to create a smooth appearance on the surface of plate evaporators. The plate evaporator seems to be a single plate from the outside, but inside it has multiple turns of metal tubing through which the refrigerant flows. Plate evaporators have the benefit of being more robust due to the exterior plate providing a lot of safety. Additionally, the exterior plate aids in boosting heat transmission from the metal tube to the chilled material. In addition, plate evaporators are simple to clean and can be produced inexpensively.
Plate-type heat exchangers can easily take on various forms to suit the application’s requirements. In domestic refrigerators, manufacturers can shape plates into a box for a closed enclosure or weld them for larger evaporators.
Plate evaporators excel in freezer shelves, dividers, frozen food display cases, ice cream cabinets, and soda fountains, offering versatility and benefits.
Finned Evaporators-
Fins coat bare tube evaporators, turning them into finned evaporators. In a bare tube types of evaporators the chilled fluid loses much of the refrigerant’s chilling action due to reduced surface area. Because the fluid tends to travel through the tubing’s open gaps and does not come into contact with the coil’s surface, bare tube evaporators are less effective. Fins on bare tube evaporators boost heat transfer by increasing contact surface, making them more effective than bare tube counterparts.
Fins are protrusions from the coil’s surface that extend into space. They extract heat from fluid untouched by the coil, facilitating its removal.
Optimal coil and fin contact is crucial for effective performance. Fins are either soldered directly or slid over, expanding for tight thermal connection.Though fins aid in heat transmission, adding them in excess of a specific number will provide no extra benefits; thus, only a certain number of fins should be placed to the tube’s exterior surface.
Various air conditioning systems, like window, split, packaged, and central, use finned evaporators or cooling coils for cooling air. The front grill of the wall-mounted split system hides it below the indoor unit.
To enhance the efficiency of heat transmission from the evaporators, manufacturers add internal fins to the tubing during production. They create these fins by forming various internal cross-sections within the tube.
Tube or Shell Type Evaporators-
Large refrigeration and central air conditioning systems use shell and tube type evaporators. Evaporators, or chillers, have tube configurations in drums or shells and fall into dry expansion or flooded categories. The float valve, which also serves as an expansion valve in these chillers, keeps the refrigerant level constant.
Alaqua supplies processing equipment such as crystallizers, distillation equipment, solvent recovery systems, spray dryers, heat exchangers, and evaporators made in USA for food and beverages, pharmaceutical, and other industries along with equipment fabrication, installing and commissioning, personnel training, retrofitting, field and troubleshooting services. Contact them today to know more!
