When setting up a fan coil controller the most common piping arrangements in hydronic systems for heating and cooling are two-pipe and four-pipe systems. The two or four-pipe designation refers to the water distribution system serving the climate control equipment in a building. Trosten is one of the few fan coil unit manufacturers in the GCC region to deliver ECM fan coil units with a SFP value of 0.2 – 0.3 w/lps as per Green Building Regulations.
So, what is the difference between two-pipe and four-pipe fan coil units in HVAC systems?
Two-pipe systems:
These systems have a total of two hydronic pipes for both heating and cooling. The 2-pipe fan coil serves as either a chill water coil or hot water coil which incorporates a single water coil connected to two pipes. There’s one supply pipe and one return pipe, which means that this type of fan coil can not heat and cool at the same time as there is one supply pipe and one return pipe.
You can manually choose whether you want to heat or cool the entire commercial or residential building. With a strap-on temperature sensor installed on the water supply, you can determine the mode of the 2-pipe fan coil unit system. The limitations of the system can be recompensed by equipping it with an auxiliary electric heater.
The 2-pipe HVAC system is reasonable and easy to install as it does not require several components to be fitted into the system. These systems suit areas where the weather stays constant. They are less flexible than a four-pipe system as they can either heat or cool and need to be manually operated to switch the temperature.
Four-pipe system:
Each fan coil in a four-pipe system has two supply pipes and two return pipes. They have separate hydronic piping for heating and cooling. This helps you to simultaneously heat and cool a single space. These systems work well in multi-climate regions which are exposed to both hot and cold outside temperatures. As it can cool the space and dehumidify it too, it has become a popular option for buildings that need heating and cooling throughout the year.
Its efficiency is higher than a two-pipe system, but it is also more expensive as it has several components that need to be installed.
Trosten offers aesthetically designed fan coil units in two-pipe and four-pipe systems and can help you make an informed decision for your residential and commercial spaces.
