Is there ice on the evaporator of your cold room?

Do you feel that your industrial freezer is not working as it used to? If the answer is yes, there is probably ice on the evaporator of your cold room. This happens often; these are minor maintenance issues that must be addressed regularly.

It may sound a little strange, but defrosting is a practice that will be very helpful if you are facing this problem. Ice on the evaporator of a cold room is one of the main maintenance issues in refrigerated warehouses.

At Inditer, we invite you to read this article, in which we will take an in-depth look at refrigeration systems and their proper maintenance. If you have any questions about this practice, keep reading.

Why is there ice on the evaporator of your cold room?

Defrosting is a very common practice that consists of the regular removal of frost or ice that forms on the evaporator of commercial or industrial refrigeration equipment.

The build-up of frost becomes a problem when it reaches the evaporator tubes, where it turns into ice as a result of the condensation and subsequent freezing of the water vapour contained in the air inside the room.

This condensation accumulates on the tubes and forms a layer of ice—frost—which acts as a true insulator that hinders normal heat exchange between the system to be cooled, the evaporator, and the refrigerant fluid.

In addition, this frost freezes the air in the room, causing humidity to decrease and leading to the loss of stored products. It could end up ruining all your frozen products!

Therefore, a key process in industrial refrigeration installations is good room ventilation and the regular removal of that ice or frost.

How to remove ice from the evaporator of your cold room

As is only logical, we will remove this frost using heat. Next, we will look at the stages of this defrosting process, which can be divided into 4 phases.

• Stage 1. This begins when we stop producing cold. Once this is done, we only need to wait for all the refrigerant liquid inside the evaporator to evaporate.

• Stage 2. We begin to apply heat. Heat is applied to the evaporator until the temperature rises to 0°C, the temperature at which the ice melts. Once melted, we then raise the temperature so that defrosting can be completed. It is recommended that the temperature reaches 8°C during the process.

• Stage 3. The frost begins to melt due to this heat input. As a result, the evacuation of the water generated by the melting of the ice from the evaporator begins. This water is collected in trays built into the evaporator itself.

• Stage 4. Once the water has been drained, we proceed to inject the refrigerant liquid into the evaporator. This will be responsible for lowering the temperatures again.

Important! We must not forget to delay switching on the fans before starting to introduce the refrigerant liquid. In this way, we will prevent the water from reaching the room directly.

Types of defrosting

There are several methods or techniques to remove ice from the evaporator of your cold room. We can even unplug the unit directly and wait for it to defrost on its own. This is the so-called “natural technique”. But there are many more options. If you are interested, keep reading.

Water defrosting

This technique is based on the spraying of water onto the ice on the evaporator of the cold room. This is done through a perforated pipe that is placed above the evaporator, from where atomised water will fall onto the ice, causing it to melt.

If the room operates at very low temperatures, it is recommended to use glycol water. This is a mixture of water and ethylene glycol that prevents ice formation in the heat exchangers of chillers located in hydraulic circuits.

Remember that before putting it back into operation, you must wait for the process to finish and for the unit to stop dripping.

Air defrosting

We can implement two different techniques based on the application of hot air.

• The first method is based on the use of bursts of hot air coming from the room itself, provided that the room temperature is above zero; specifically, it must be above 3°C.
• The second method is based on air circulating in a closed loop; in this case, air circulation takes place during defrosting and is heated with resistance heater banks.

For this method to be effective, it is necessary that there is no air outlet to the room. For example, a hatch. This hot-air circuit must be closed.

Defrosting with electric heaters

It consists of using several stainless-steel tubes that pass through the evaporator and act as conductors connected to the power supply. Once connected to the mains, these heaters convert energy into heat and melt the ice.

This method is one of the most widely used today and has several pros and cons. Its advantage is that it removes ice from the evaporator of the cold room very quickly and is very practical. However, it increases the installation cost and is more efficient in small refrigeration systems than in large industrial rooms.

Hot-gas defrosting

This technique is based on the operation of systems that divert the refrigerant at high temperatures, as gas or liquid, from the receiver to the evaporators. The gas is introduced into the evaporator, causing it to cool down.

This technique stands out for its energy savings and is more commonly used in centralised installations, where it delivers better results.

At Inditer we hope this short guide on how to remove ice from the evaporator of your cold room has been helpful. Visit our website if you would like to buy a new evaporator of excellent quality.

If you would like to choose an eco-responsible option, buy a CO2 evaporator and commit to a sustainable future.