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| What is VRF air conditioning? |
VRFs employ refrigerant as the cooling and heating medium, just like ductless mini splits. One or more condensing units (which may be outdoor or indoor, water- or air-cooled) condition this refrigerant, which is then pumped throughout the building to various indoor units. Unlike traditional chiller-based systems, VRF systems may provide hot water in a heat recovery configuration without degrading efficiency and switch to heating mode (heat pump) during the winter without additional equipment, all of which may allow for less energy consumption. Additionally, VRF systems may supply hot water in a heat recovery configuration without degrading efficiency. Also, as VRF employs smaller penetrations for refrigerant pipes instead of ducts, air handlers, and huge ducts are not necessary, which can lower the height above a dropped ceiling as well as the structural impact.
Daikin has consistently developed new features since the introduction of the initial VRV system in order to satisfy shifting market expectations. To attain the best in comfort, efficiency, and dependability, they continue to enhance our VRV system by raising the capacity load and adding more recovery technologies.
Basics of VRF
So we have four main parts in a basic refrigeration system.
1) Compressor
2) Condenser
3) Expansion valve
4) Evaporator
The Working Principle of VRF/How Does VRF Work?
So, to understand VRF in detail, you need to understand the whole mechanism behind it. There is no need to panic; I'll try to make you understand in an easier way, so let's begin.
All of these are connected by a pipe, and inside the pipe, there is a refrigerant, which is a specific fluid that can easily convert between liquid and gas. The compressor squeezes the refrigerant into a small volume and pushes it around the entire system.
Both the condenser and the evaporator function as heat exchangers, allowing thermal energy to move between the air and the refrigerant without coming into contact with either of them directly. The refrigerant exits the compressor as a hot gas line, which is a high-pressure, high-temperature superheated vapour.
The refrigerant then passes through the tube of the condenser. The refrigerant inside the tube is at a much higher temperature than the ambient air surrounding it. That's done on purpose because heat flows from hot to cold, and we need to remove the heat from the system, so the system needs to be at a higher temperature.
The heat will flow from the refrigerant into the air through the tube wall. A fan blows the ambient air over the tube to help speed up that process and remove more heat. As the thermal energy is removed from the refrigerant, the refrigerant will condense into a liquid.
But by the time the refrigerant leaves the condenser, it will be a high-pressure, medium-temperature, saturated liquid. We call this the liquid line. This then flows to the expansion valve.
A thermostatic expansion valve or an electronic expansion valve is generally used in this system. These valves use a sensor and controller to measure something called the "superheat" at the exit of the evaporator. The valve will then open or close to restrict the flow of refrigerant into the evaporator in order to try and maintain a constant superheat value.
Superheating simply refers to heating the refrigerant to the point where it turns into pure gas. Since there is no liquid there, a high-pressure, medium-temperature, saturated liquid enters the expansion valve, followed by a low-pressure, low-temperature liquid-vapour combination.
The refrigerant drops in pressure and temperature because it is expanding in volume, much like when you spray a pressurized liquid through a nozzle. This will then flow through the evaporator. The refrigerant has a very low boiling point, so the room's heat is enough to boil the refrigerant, and as it boils it turns into a gas that carries the unwanted heat away.
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