Definiton of Evaporator and function

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What is an Evaporator? Here is the definition, process and function of the complete evaporator Examples of AC evaporators for cars, houses and refrigerators

When the air conditioner you use is damaged, there is a possibility of a problem in the evaporator. The evaporator is an important component, without which the air conditioner cannot run properly.

What is Evaporator?


Definition of evaporator is a device to convert liquid into gas through heat transfer to produce cold steam in the refrigeration system (cooling). The evaporator is tasked with changing the liquid form of a chemical substance, such as water, into a gaseous or vapor form so as to change the state of the substance (phase transition).

The working principle of the evaporator has a mechanism to separate liquid and steam through heat transfer. The raw material is put into the evaporator and passed through a heated tube, so that the heat will evaporate the water in the raw material.

Evaporator is one of the important components in the use of air conditioning in the car. This component is used to blow cold air into the interior of the cabin. Later the cabin with a higher temperature can decrease due to cold air coming out of the evaporator.

The shape of the evaporator is a box, with a room inside that is not straight. The shape of this twist and turn sometimes makes a lot of dirt clog the channel. Therefore, you are advised to clean it if it looks dirty and the cold air blowing from it is not as good as before.

Evaporators are widely used in the processing industry working with liquids and chemicals. They work best in low-temperature applications in the food and pharmaceutical industries as well as in sewage treatment.

The evaporator is an important component together with other major components in the refrigeration system such as compressors, condensers and expansion devices. The reason for using an evaporator in a cooling system is to remove heat from air, water or other substances.

Evaporator Function


The main function of the evaporator is to absorb heat from air, water and other substances in a certain area into the refrigeration system to produce cold gas / steam.

In addition to the main functions above, there are several other functions of the evaporator that you should know, including:

  • Ensuring Good AC Performance

The evaporator has a function to ensure the performance of the car air conditioner runs correctly. if there is a problem in the evaporator, it is likely that there is also a problem in the air conditioner used.

  • Changing Freon

Another function is to change the previously accommodated Freon, resulting in cooler air. Freon will be pumped so that the air conditioner can cool the air in the car faster.

  • Channeling Circulation

Next is the evaporator function to flow cold air. If you use an evaporator today, you can already get an evaporator that can filter cleaner air.

Evaporator Example


There are two types of evaporators that are most commonly used in refrigeration systems today. The first are flooded evaporators and dry evaporators or direct expansion (DX). Well, here are some examples of evaporators that we often encounter in everyday life:

  • Evaporator AC

AC is one of the electronic items that uses an evaporator. Its task is the same as other evaporators, which is to remove cool air in the AC component. Later if it takes place continuously, the room becomes cooler. The location of the evaporator is between the expansion valve and the compressor.

If the AC evaporator has a problem, the cold air released by the air conditioner is not as fresh as usual. This is because the evaporator has a lot of dirt, decreased performance or other causes. If this problem occurs, do not hesitate to ask for help from experienced parties.

  • Refrigerator Evaporator

Next is the evaporator in the refrigerator, this type of evaporator has the same function, which is to drain cooler air to the inner refrigerator. The shape is larger than the evaporator in the car air conditioner.

1-door or 2-door refrigerators already have an evaporator, so their use can be maximized. As a user, you still have to make sure that the evaporator used is running properly, if there is a problem immediately make repairs.

  • Car AC Evaporator

The evaporator is also located in the car air conditioner, this type of evaporator has a function to remove cold air into the car cabin. This air has been processed in such a way by other car AC components, so that it can produce temperatures that are cooler than those in the car.

The evaporator in the car air conditioner must be cleaned periodically, otherwise the cold air that comes out will not be optimal. You can clean it every 2-3 months if the condition is too dirty.

Types of Evaporator Types


Evaporators are differentiated into different types based on the way they achieve heat transfer. Among the types of evaporators are as follows:

  • Rotary Evaporator

A rotary evaporator (also referred to as a “rotavap” or “rotovap”) is a device used in laboratories to efficiently and gently remove solvents from samples through evaporation.

Rotary evaporators extract solvents at low temperatures with high repeatability rates and efficiency. The action method lowers the pressure inside the spherical base flask and increases the surface area through gentle rotation that increases the process time.

  • Rising Film Evaporator

Rising film evaporator or often known as rising film evaporator is basically a shell and tube type heat exchanger. The liquid to be evaporated is fed to the evaporator from the bottom of the tube.

There is steam condensation on the outer surface of the vertical tube, and the liquid inside the evaporator boils into steam. As the liquid moves up the tube, the volume of steam produced increases leading to a higher central core velocity.

This speed in turn forces the liquid onto the walls of the remaining tube, creating a thin, fast-moving liquid film. The rapid movement of the film leads to a high heat transfer coefficient and a reduction in the residence time of the material.

This type of evaporator is best suited for processing materials that have a tendency to light scaling, but cannot handle heavy scaling and heat-sensitive materials.

  • Forced Circulation Evaporators (Sirkulasi Paksa)

Forced circulation evaporators consist of tubular heat exchangers to concentrate the feed. This evaporator is used in cases where there is a high probability of feeders or slating or scaling liquid products.

In addition, the use of this evaporator is also required when the feed has high viscosity and the thermal and flow properties of the process fluid are poor, so forced circulation is required.

In the mechanism of forced circulation evaporators, the feed is pumped at high speed through the tube to ensure a high heat transfer coefficient. The working of this evaporator is best suited for crystallization of slurry and other solutions.

  • Agitated Thin Film Evaporator (ATFD)

This type of evaporator has a special characteristic, which consists of a jacketed shell and a high-speed rotor. The steam generated in the ATFD evaporator after the heating flow is simultaneously cleaned using an entrainment separator.

Turbulence aids thorough heat transfer and mechanically ensures that the entire mass undergoes a process to produce high yields of 30% to 80% possible concentration in a single pass.

The intensive mixing process inside the ATFD evaporator also serves to protect temperature-sensitive products from overheating.

  • Self Cleaning Evaporator

The principle of operation of the self-cleaning evaporator is based on the circulation of solid cleaning particles through shell tubes and vertical heat exchanger tubes.

The fouling fluid flows upward through bundles of heat exchanger tubes that combine specially designed inlets and outlets. Solid particles are fed to the fluid through the inlet.

A proprietary distribution system is used to ensure uniform division of particles across all tubes.

The particles are fluidized by the upward flow of the liquid, where they create a light scouring effect on the walls of the heat exchanger tube, thereby removing any deposits at the initial stage of fouling formation.

After the tube bundle the particles break away from the liquid in the separator and are returned to the inlet and the cycle is repeated.

  • Multi Effect Evaporator

Multi-effect evaporator operation is a process in which multiple evaporators are used, and the moisture removed from one effect is used as a heating medium for the next effect that has a lower boiling point.

Multi-effect evaporators are widely used to concentrate aqueous liquids, and allow businesses to obtain products at the lowest temperature. One or more objects operating at the same boiling temperature are defined as one ‘effect’ of a multi-effect evaporator.

Working Principle of Evaporator Process

The working principle of the evaporator is basically the opposite of the working principle of the condenser. In an evaporator, the refrigerant liquid is converted into a gas, absorbing heat from the air inside the compartment.

When liquid refrigerant reaches the evaporator, the pressure has decreased, removing its heat content and making it much cooler than the fan air flowing around it.

For example, the evaporator is located in the refrigerator, which is the part that makes the items in the refrigerator cold. As refrigerant changes from liquid to gas through evaporation, it cools the area around it, resulting in the right environment to store food.

Another example of how the evaporator works can be seen in Car AC. Freon that carries hot steam will be lowered in pressure at the condenser.

If it is cold, this air will be released, resulting in cool and comfortable air to feel in the car. This cold air also passes through the blower, where the gust is much stronger.

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There are 3 main factors that you need to pay attention to when designing a design for the working principle of the evaporator process, including the following:

  • Evaporation pressure drop. must have sufficient space for refrigerant circulation without too much pressure drop between outlet and inlet.
  • Evaporation Temperature. must have sufficient surface to absorb the necessary heat load to ensure the temperature difference between the cooled substance and the refrigerant is not excessive.
  • Liquid and Refrigerant Evaporation Vapors. It must have enough space for coolant and steam to separate from the liquid.

How to Clean the Evaporator

A dirty evaporator will certainly make the air conditioner unable to run optimally. To make it easier in the cleaning process, you can use the following methods, including:

  • Use Cleaning Fluid

You can clean the evaporator with cleaning liquid. However, make sure that the liquid does not damage other components present in it. In addition to making the evaporator cleaner, you can also use it longer.

  • Find a New AC Filter

If the evaporator is dirty and it is not possible to clean, you can replace the filter inside. After replacement, do not forget to install the blower and evaporator according to their place.

  • Clean Other Parts

In addition to cleaning the evaporator, you should clean the rest of the air conditioner entirely. If there is one part that is dirty, the clean part will later make the other AC components dirty. This will also make the air coming out of the air conditioner fresher.

After cleaning is complete, don’t forget to install each part of the AC or evaporator components in good condition. If it is not installed properly, it is likely that the air conditioner will have difficulty performing its performance.

The explanation above hopefully can help you how the evaporator works in a cooling machine. If you experience problems in maintaining and cleaning the evaporator, do not hesitate to use professional services. This will reduce errors in cleaning that cause damage.


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