Actually, VRV and VRF are two different terms for the same HVAC technology. Based on Inverter technology compressors, the first VRV HVAC systems were invented by Daikin during the early 1980’s.
What are the basics of AHU, FCU, and VRF?
AHU is abbreviated as Air Handling unit. As the name suggests it cools(using evaporator coil) the air from the air conditioned space & forces it to the conditioned space with the help of a Squirrel cage fan(in general).
FCU is abbreviated as Fan coil unit. As the name suggests its a set of Cooling coils & a Squirrel cage fan(in general). And the working principle is same as that of an AHU, but you can consider this as a compact form of AHU.
VRF abbreviated as Variable refrigerant flow. Its basically the other side(Outdoor Unit) of the AHU/FCU(Indoor units) which comprises of Condenser coil & a compressor. This is a type of Outdoor unit which operates multiple Indoor units unlike DX units which operates single Indoor unit.
What is the main difference between TFA and AHU in HVAC?
An Air Handling Unit (AHU) is a catch-all term for something with a supply blower that typically is involved & heating & cooling. Depending on the context, it be referred to by a number of other terms, Rooftop unit (RTU) when placed on a roof, Fan-coil unit (FCU) for smaller indoor units, and so on. It usually refers to a multi-purpose indoor supply air system that uses a mixture of return (recirculated) and outdoor (fresh) air.
Treated Fresh Air (TFA) is a term for a category of airflow, like supply, exhaust, return air, etc. Fresh air is outside air blown into a space from ventilation purposes without return air mixed in. It can be blown in just as is, treated fresh air handling units use filters and condition it some degree using an energy recovery system (passing through a heat exchanger) with air being exhaust and/or heating & cooling coils.
The term doesn’t appear to be common in the US. My understanding is “TFA” duty is usually handled by unit called an an energy recovery ventilator (ERV) or designated outside air unit (DAHU, or other terms) that uses heating & cooling coils.
