Home » Posts tagged 'industrial freezer'

Tag Archives: industrial freezer

The Four Key Components of Refrigeration

Refrigeration is a process that cools enclosed spaces and substances. It operates by circulating refrigerant through the cooling system, which changes state to absorb and release heat. This cycle involves two different pressure areas: the evaporating low-pressure zone and the condensing high-pressure zone.

A refrigeration cycle is only effective if the food is cold when it goes into the fridge. This is why a fridge has special compartments to store items at the optimal temperature. Learn More About Us Here!

Refrigeration systems perform the seemingly magical task of transferring heat against its natural direction, keeping foods, spaces, and even industrial processes at the desired temperature. Behind the scenes, these cooling systems employ four key components: a compressor, condenser, expansion device, and evaporator. Each plays a unique role in the refrigeration cycle, but they all work together to transfer thermal energy. Let’s examine each of these parts to gain a better understanding of how refrigeration cycles function and how they can help with our daily lives and professional endeavors.

On call for refrigeration, the compressor (read more) sucks in superheated refrigerant vapor through its suction pipe and starts to compress it. As the compressor squeezes the vapor, its pressure and temperature increase while its specific volume decreases. This is what’s known as a phase change, as the vapor transitions from a liquid to a gas. After reaching its maximum pressure and temperature, the vapor moves into the condenser.

The condenser is a coil of tubing, typically copper, with metal fins and fans that remove the heat by dispersing it into the surrounding air. As the vapor from the evaporator moves through this coil, it absorbs the surrounding heat and changes back into a low-pressure liquid. The evaporator also serves to cool down the vapor.

Once the vapor from the condenser is in its low-pressure state, it is fed into an expansion valve, which reduces its pressure. This quick reduction induces the vapor to transform back into a low-pressure liquid-vapor mixture. The refrigerant then moves to the evaporator to repeat the cycle.

In the evaporator, the low-pressure liquid reverts into its vapor form once again and absorbs more heat from the surrounding environment. The evaporator is designed to amplify this process, by blowing hot air over the coil to speed up the rate of absorption and create more visible cooling effects. Once the evaporator is done absorbing heat, the liquid returns to the compressor for another round of compression.

Evaporator

The evaporator, or cooling coil, is where your refrigerator really gets cool. It takes the refrigerant that runs through copper tubing that’s connected to the outdoor unit and brings it into your home. The refrigerant passes through the evaporator’s coil and absorbs heat from the air that blows over it. The resulting condensation then flows into your drain pan and the cooling cycle begins again.

Immediately after the condenser, the refrigerant is sub-cooled and moves to its next step, the metering device. The metering device may be adaptive, such as a thermal expansion valve, or fixed like a capillary tube or an orifice. Its job is to “meter” the sub-cooled liquid into the evaporator. As it does, it creates a flash gas due to the drop in pressure as it enters the evaporator.

Once in the evaporator, it begins to evaporate or change state from liquid to vapor. This is accomplished by a combination of the heating medium (typically steam) and the refrigeration system’s low temperature. The evaporator comes in different types, including falling film, capillary, and flooded, each designed for a specific application.

In some systems, the evaporator is followed by a receiver. This is used to control the amount of refrigerant needed for the load. It also provides a storage tank for excess heat removal during normal operation.

Depending on the type of evaporator, it will have a large opening or multiple small ones. The larger opening allows the refrigerant to move into the cooler air as it vaporizes. This provides a very efficient method of heat transfer, as it’s like a heat pump in a sense.

It’s important to note that your evaporator coil must be kept clean. Even a fine layer of dust on the coil can prevent it from absorbing heat as effectively. This causes your refrigerator to use more energy and produce less cold, so it’s a good idea to keep the coil clear of dust and debris. In addition, be sure to maintain the proper airflow through your home’s vents and check the defrost timer and thermostat for problems.

Condenser

The cooling process starts in the evaporator, where cool air is blown across coils of low-pressure refrigerant gas. The vapor absorbs heat and rises, but because the air blowing over the coils is cooler than the vapor, it rejects that heat and cools down. This is why the evaporator is in your house, where you want the best cooling possible.

That cooled vapor then goes to the compressor. The compressor increases the pressure of the working gas, which causes the vapor to give up its heat in a different way by boiling into a hot liquid. The hot liquid then changes state again and is discharged into the condenser.

There are different types of condensers, with a few key differences in how they work. First, a condenser is usually made from metal, which helps to keep the vapor from losing its heat in the cold air blowing over it. Secondly, the condenser is typically designed with a fan in the top to pull cooling air into the unit and help the heat to release. A third important step is a metering device which controls how much vapor is released into the evaporator and helps the system maintain the desired temperature.

When the vapor enters the condenser, it will be at a higher temperature than either the air (in an air-cooled condenser) or water (in a water-cooled one). The difference in temperatures causes the vapor to give up its latent heat by changing back into a liquid, and because of the lowering of temperature, it will also experience a decrease in pressure.

Once the vapor changes state, it will pass through a heat exchanger, which may be either an unjacketed condenser tube or, more commonly, a flow-cooled condenser. The cooling system is a series of tubing that connects the various basic major components in the refrigeration cycle, with a suction line connecting the evaporator to the compressor, a hot gas or discharge line connecting the compressor to the condenser, and a liquid line from the condenser to the metering device (Thermal Expansion Valve).

The metering device ensures that only a certain amount of high-pressure liquid refrigerant is released into the evaporator. This is important to limit the loss of heat energy, which can cause other components in the cooling cycle to have to work harder.

Compressor

A compressor is the heart of any refrigeration system. It is considered to be the most important machine that can be used on any production site because it enables manufacturing to continue even when air pressure is lost. It is the compressor that makes or breaks the vapor compression refrigeration cycle. Without it, the cycle is not able to run and all of the work at that production site is suspended until the compressor is restored.

The compressor starts the refrigeration process by taking cold liquid refrigerant and absorbing it with heat from the evaporator at low temperature. This refrigerant is then pumped into the compressor where it is compressed and pressurised. It then goes into the condenser where it is cooled down to very low temperatures. As it cools down in the condenser it turns into a gas and absorbs heat from the cooling medium (usually air or water).

Once it is a hot gas, the refrigerant is pushed back into the compressor. It continues to be compressed in the compressor until it is at a high level of pressure and temperature. The compression of the refrigerant in the compressor is ideally isothermal which means that internal energy of the system is removed at the same rate as it is added by the mechanical energy of the compressor. However, due to mechanical limitations of the compressor it is not possible to achieve perfect isothermal compression.

There are five types of compressors commonly used in refrigeration systems. They include reciprocating, rotary, screw, centrifugal and scroll compressors.

Reciprocating compressors use pistons that move in a cylinder to pump up and compress the liquid. They are used in domestic and small commercial fridges.

Rotary compressors use a rotating blade inside a cage to trap and compress pockets of refrigerant. They are commonly found in industrial refrigerators.

Axial compressors are the largest and most powerful compressors. They have a cylindrical body with a hub and rim that contains impellers or disks. The rotating impellers spin to generate thrust and to increase velocity of the refrigerant. A diffuser section converts this velocity energy into pressure energy.