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Variable refrigerant flow (VRF) systems – definition

Just a few years ago air conditioning units were a symbol of luxury, installed exclusively in selected buildings. Today, both modernized and new buildings are fitted with air conditioning. Moreover, VRF air conditioning systems are now becoming a standard. Let’s take a closer look at what’s so special about this solution and why it may be worth considering.

What are VRF systems?

VRF systems are highly complex cooling installations that use the latest technological solutions. In the most basic variants they can function only as cooling systems, but the more advanced ones can serve both for cooling and heating rooms. This results mostly from the capability of inverting the flow of refrigerant circulation and use the heat pump with inverter, which allows all internal units of a given system to operate in cooling or heating mode, depending on the need of the user. What is more – it is possible to cool certain rooms while heating others, transporting system heat from the rooms being cooled to the ones that need heating. By doing this, we are able to recover free heat, transferring it with a VRF system between the individual rooms.

VRF System – description and principles of operation

Just the name, or rather the acronym, tells as lot about VRF systems. VRF stands for Variable Refrigerant Flow. You can also come across the VRV variant – which stands for Variable Refrigerant Volume. In both cases we are seeing changes in the refrigerant stream going through the evaporator.

That change can take place in various ways. One of the methods is using variable engine speed – which is controlled by means of a device called an inverter. That’s why such compressors or heat pumps are called inverter compressors or inverter heat pumps. Other possible solution are “scroll” compressors, where the stream of refrigerant travelling through a compressor is adjusted by temporarily raising one of the compressor coils. The device then goes into idle
and the refrigerant stream pumped into the installation is reduced.

What does the installation of a VRF system look like?

VRF systems need to be fitted
with complex electronics to function properly. First of all, we have systems that operate each individual device, i.e. a unit of a system. Group control is also installed, which allows for the management of all devices – heat pumps, air conditioning units, convectors etc. – all in one place, remotely. Often additional safeguards are used to help identify emergencies, as well as measure current levels of electric energy consumption. Additionally, every internal unit is provided with an EEV automatic expansion valve, which allow accurate management of internal conditions of the system, and, by so doing, conditions in the individual rooms of the building, where the VRF system is installed.

Surprisingly enough, VRF systems are still waiting for their peak popularity to come.  For a long time they were considered not viable due to high investment costs, especially in comparison to the purchase of a fan coil system. Currently, however inverter compressors are becoming a solution used more and more often in external units, which makes the installation of a VRF system a more economically justifiable solution, that can let you save a lot in the long run.


Variable refrigerant flow (VRF) systems – definition

Variable refrigerant flow (VRF) systems – definition

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